SSS3.5

EDI
Soils as records of past environmental conditions, climate change and anthropogenic impact

Soils develop under the influence of various environmental factors that produce specific soil features, and thus keep a memory of nowadays and past environments. They also are valuable archives of past human activity, which has increasingly shaped environments and affected soil formation over the Holocene period.
Palaeosols, developed under the influence of past environmental conditions, are considerably valuable archives of past environments.They can be studied to reconstruct the environmental factors that were present during the time of their formation, and to disentangle the relative influences of different, local to regional, environmental background conditions on soil formation. Also peatlands have become increasingly recognized as a useful archive of palaeoenvironmental and palaeoclimatic archives. They offer a wide range of proxies (physical, geochemical and biological). Their global occurrence and high accumulation rates allow developing the past environmental change history of sub-decadal to millennial scales.
Human land occupation and cultivation often result in characteristic modifications of the surface, sediments and soils. Anthropogenically-affected soils keep a record of past human settlement cycles and land use and have enormous potential for geoarchaeological studies. Furthermore, their properties often clearly differ from those of the surrounding soils and thus also affect current ecosystems.
This session gathers contributions from all aspects of research dealing with soils as records of past environmental conditions, climate change and anthropogenic impacts; and with the geoarchaeological and ecological significance of anthropogenically-affected soils. A specific focus is on studies trying to provide more evidence for better understanding of the global definition of the Anthropocene and to distinguish the natural and human induced changes.

Co-organized by GM12
Convener: Oren Ackermann | Co-conveners: Anna Schneider, Kunshan Bao, Maria Bronnikova, Gaël Le Roux, Tobias SprafkeECSECS, Barbara Fiałkiewicz-Kozieł, Claudio Zaccone
vPICO presentations
| Tue, 27 Apr, 09:00–12:30 (CEST)

vPICO presentations: Tue, 27 Apr

Chairpersons: Kunshan Bao, Barbara Fiałkiewicz-Kozieł, Claudio Zaccone
09:00–09:05
Peatland records of climate change and anthropogenic impact
09:05–09:15
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EGU21-1241
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solicited
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Highlight
William Shotyk, Fiorella Barraza, Rene Belland, Sundas Butt, Na Chen, Kevin Devito, Chad Cuss, Jacqueline Dennett, Lukas Frost, Iain Grant-Weaver, Muhammad Javed, Scott Nielsen, Tommy Noernberg, and Andrii Oleksandrenko

Sphagnum moss and age-dated peat cores from bogs have long been used to study contemporary and past atmospheric deposition of trace elements (TEs). However, other components of bog ecosystems represent additional scientific opportunities. Snowpack sampling, for example, represents a chance to study winter deposition while providing the perfect matrix for ICP-MS analyses of TEs. The berries that grow in bogs, including blueberry (Vaccinium myrtilloides), cloudberry (Rubus chaemomorus), cranberry (Vaccinium oxycoccus) and lingonberry (Vaccinium vitisidaea), provide insight into the bioavailability of micronutrients (and contaminants) at the surface of the bog, as well as an index of dust deposition onto the fruits themselves. Labrador Tea (Rhododendron groenlandicum) provides similar information, but with greater relevance for Indigenous Peoples, as this is an important medicinal plant for them, along with the Pitcher Plant (Sarracenia purpurea). The acidic, organic-rich waters which represent > 90 % of the mass of these ecosystems, presents an even greater opportunity: the chance to quantify the extent to which aerosols and dusts dissolve, subsequent to deposition from the air. In this study, we present data for TEs in all of these media, with a view to exploring the broader potential of ombrotrophic peatlands as natural, holistic, integrated, long-term monitoring systems. The approach presented here not only addresses our need for information regarding  atmospheric deposition of environmental contaminants to terrestrial ecoystems, but also insight into their release, or potential release, to downstream aquatic ecosystems.

How to cite: Shotyk, W., Barraza, F., Belland, R., Butt, S., Chen, N., Devito, K., Cuss, C., Dennett, J., Frost, L., Grant-Weaver, I., Javed, M., Nielsen, S., Noernberg, T., and Oleksandrenko, A.: Ombrotrophic peatlands: natural, holistic, integrated, long-term monitoring systems for atmospheric deposition of environmental contaminants to terrestrial and aquatic ecosystems, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1241, https://doi.org/10.5194/egusphere-egu21-1241, 2021.

09:15–09:20
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EGU21-7993
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solicited
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Highlight
Julie Loisel and Kristen Sarna

Here we present a 4200-year-old high-resolution peat core reconstruction from southern Patagonia. Our detailed carbon isotope (δ13C) record and testate amoeba-inferred water table depth reconstruction point to a progressive wetting of the peatland surface from 4200 to 1500 cal. yr BP, followed by a dry event at 1200-800 cal. yr BP and drier conditions since then. Superimposed on this trend are centennial-scale dips in δ13C values and water table depths that we associate with warm/dry spells. We interpret these shifts, which are akin to positive phases of the Southern Annual Mode (SAM), as reflecting century-scale changes in the Southern Westerly Wind belt during the late Holocene. Other records from southern South America and Tasmania have revealed synchronous changes in local vegetation and fire activity, strengthening our hypothesis. We know that millennial-scale shifts in the Westerly winds influence ocean upwelling in the Southern Ocean, with effects on global atmospheric carbon dioxide (CO2) concentrations. Our study, along with a few others, may help elucidate whether centennial-scale SAM-like shifts could also modulate the global carbon cycle via CO2 degassing from the deep ocean. This is important because instrumental and reanalysis records indicate strengthening and poleward contraction indicate a positive phase of the SAM since the late twentieth century.

How to cite: Loisel, J. and Sarna, K.: Peat-based record from southern Patagonia shows centennial-scale variability since 4.2 ka, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7993, https://doi.org/10.5194/egusphere-egu21-7993, 2021.

09:20–09:22
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EGU21-1381
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ECS
Fiorella Barraza, James Zheng, Michael Krachler, Chad W. Cuss, Andrii Oleksandrenko, Iain Grant-Weaver, and William Shotyk

Cadmium (Cd) is a potentially toxic chalcophile element with profound health consequences when organisms are exposed to elevated concentrations. Cadmium is emitted to the atmosphere through various industrial processes (metallurgical smelting, coal combustion), but it is also derived from natural sources (volcanic emissions, wind-borne soil particles). In contemporary air samples collected within urban areas across the globe, Cd enrichment factors (EF) relative to the Upper Continental Crust (UCC) are often up to 100, and are typically interpreted as reflecting inputs exclusively from anthropogenic activities.

This presentation reports on the range of Cd EF values in aerosol archives from various locations representing up to 15,500 years of atmospheric Cd deposition, including: (i) Polar ice collected at Devon Island (Nunavut, Canada), and; (ii) Peat from ombrotrophic bogs collected at Etang de la Gruère (Jura Mountains, Switzerland), Birch Mountain (BMW) and Caribou Mountain Wildlands (CMW) (Alberta, Canada), and Drizzle Bog (DB) (British Columbia, Canada). The ice samples were melted and acidified, and the peat samples digested, with double sub-boiled concentrated nitric acid, analyzed using SF-ICP-MS and ICP-QMS, respectively. All analyses were undertaken in metal-free, ultraclean laboratories. Age-dating of ice was obtained using electrical conductivity and oxygen isotopes, and the peat samples with conventional 14C AMS and 210Pb. Cadmium concentrations were normalized to the conservative lithophile reference elements (Sc, Ti, and Th) to calculate the EF.

Regardless of the reference element and the compilation selected for the UCC, the EF in old and ancient samples was often very high: up to 4000 in ice and up to 400 in peat bogs. These profound enrichments of Cd and dramatic variation pre-dating anthropogenic activities suggest that either natural emissions of Cd were not constant, or that non-crustal sources of Cd have been underestimated. 

In the ice cores, the period with the lowest and most constant Cd concentrations was found between 2,500 and 4,500 years BP (0.92 ± 0.13 pg g-1), with an average EFSc of 107. Samples from the early and middle Holocene (4,500 to 12,000 years BP) contained higher concentrations of Cd (2.43±0.50 pg g-1), with an average EFSc of 255. In the Swiss bog, the Cd EFTh ranged from 9 to 800, and was more stable in the period between 9,000 to 11,000 years BP (14±5). In the pre-industrial layers of peat bogs from remote locations in Canada, the EFTh values averaged 30 (DB), 54 (BMW) and 167 (CMW).

These variations in Cd enrichment levels likely reflect differences in contributions from natural sources: volcanic activity, deposition of fine airborne soil particles, and natural forest fires. The biological uptake and recycling of Cd observed in some terrestrial plants and corresponding enrichment in humus may also play a role, but these potential contributions have received limited attention. The very high EF found in contemporary aerosols, recent peat layers and modern snow samples should be interpreted with caution pending improved understanding of the sources of natural aerosol Cd enrichments, and associated processes.

How to cite: Barraza, F., Zheng, J., Krachler, M., Cuss, C. W., Oleksandrenko, A., Grant-Weaver, I., and Shotyk, W.: Geochemical perspectives from the past: understanding the natural enrichment of Cd in pre-industrial and pre-anthropogenic aerosols using polar ice and peat cores from remote locations, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1381, https://doi.org/10.5194/egusphere-egu21-1381, 2021.

09:22–09:24
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EGU21-1430
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ECS
Sundas Butt, William Shotyk, Fiorella Barraza, Na Chen, Chad Cuss, Lukas Frost, Iain Grant-Weaver, Muhammad Javed, Tommy Noernberg, Andrii Oleksandrenko, and Lei Pei

Open-pit mining for bitumen extraction generates considerable volumes of dust in northern Alberta. This area contains abundant peatlands, some of which are ombrotrophic bogs that are exclusively fed by atmospheric inputs. The most reactive mineral phases of dust deposited on these bogs can potentially dissolve in their surface waters because of the low pH and abundance of organic acids. Thus, peat bog surface waters could be used as unique monitors, to determine the chemical reactivity and dissolution characteristics of atmospheric dusts in industrial areas. The main goal of this study is to determine whether the elevated rates of dust deposition to peat bogs near bitumen mines have led to greater concentrations of trace elements (TEs) in the surface waters. To achieve this goal, it is essential to ensure that the TEs being measured in surface waters represent dust dissolution only and are not influenced by other element sources such as groundwaters or surface runoff.
Peat bog surface waters were collected in the autumn of 2019 from four peatlands near industry and a control site located more than 260 km upwind. Concentrations of TEs were determined in the dissolved fraction (i.e. filtered through a 0.45 μm membrane) using an ICP-MS. Surface waters near industry have elevated concentrations of Li, Fe, Mn, Ni, Y, selected REE (Tm, Dy, Yb, Sm) and Pb at 3 out of 4 sites, relative to the control location (UTK). Most of the elements are enriched 2x when compared to control site (UTK), but only Li, Mn, and Rb show enrichments >1Ox. At JPH4, the site closest to industry (12 km from the mid-point between the two central bitumen upgraders), a vegetation survey indicates that this peatland includes both ombrotrophic and minerotrophic zones, and this was confirmed by the pH and concentrations of major ions in the surface waters. At McK, the site next closest to industry (25 km), electrical conductivity as well as concentrations of chloride, Na, and K, all increase with distance toward the highway which is evidence of road salt runoff. Thus, at these two sites nearest industry, the TE concentrations in surface waters are supplied not only from airborne dusts, but contributions from groundwaters and road salt must also be considered. In contrast, the surface waters from the McM (49 km) and ANZ (69 km) sites are ombrotrophic, and elevated concentration of TEs in these samples can be attributed exclusively to dust dissolution.
The elevated concentrations of lithophile TEs in the dissolved fraction includes those which are
mobile in surficial environments (e.g. Li and Sr), but also those which are immobile (e.g. Y and the lanthanides). Elevated concentrations of the former are not surprising, but elevated concentrations of the latter are puzzling, given that they tend to be hosted within stable mineral phases that are resistant to chemical weathering. Size-resolved TE analyses of the dissolved fraction using AF4-ICP-MS will be used to distinguish between colloidal forms and ionic species, to differentiate inputs of nano-dusts from mineral dissolution in bog waters.

 

 

How to cite: Butt, S., Shotyk, W., Barraza, F., Chen, N., Cuss, C., Frost, L., Grant-Weaver, I., Javed, M., Noernberg, T., Oleksandrenko, A., and Pei, L.: Trace elements in peat bog surface waters as indicators of the dissolution of atmospheric dusts from open-pit bitumen mines, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1430, https://doi.org/10.5194/egusphere-egu21-1430, 2021.

09:24–09:26
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EGU21-1515
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ECS
Nana Luo, Kunshan Bao, Rui Yu, Xingtu Liu, Yelebolat Tuoliuhan, and Bolong Wen

Black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs) are potentially proxies of changes in natural and human activities during the past century. It is important to identify historical BC sources and differentiate human activities contribution to BC in the environment. In this study, a 30 cm peat profile from the Jiadengyu (JDY) peatland in Altay Mountain was dated by the 137Cs and 210Pb methods. BC, total PAHs content and δ13CBC in JDY peat were tested. The results showed that the TOC, BC and PAHS contents in JDY peat core were 17.09 ~ 47.16%, 1.14 ~ 67.138 mg/g and 260.58 ~ 950.98 ng/g, respectively. The value of δ13CBC ranged -31.5‰ ~ -27.43‰, with an average of -30.52‰. The range of total PAHs concentrations in JDY peat core were between 260.59 ng/g and 950.98 ng/g. The BC was significantly correlated with PAHs and regional population. The BC fluxes have slightly increased since 1900s with the increasing population and cultivate area, and more significantly in 1980s. The burning of biomass and yak dung, fossil fuels, and human activities (mining, coking coal) may have important effects on the BC emission of soil in the Altay region. The change of BC and δ13CBC reflected the change of local energy structure. With the regional reclamation increasing and environment- friendly industry developing, the BC source of JDY peatland is mainly the result of the interaction between biomass combustion and fossil fuel combustion.

How to cite: Luo, N., Bao, K., Yu, R., Liu, X., Tuoliuhan, Y., and Wen, B.: Centennial records of PAHs and black carbon in Altay mountain peatlands, Xinjiang, China, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1515, https://doi.org/10.5194/egusphere-egu21-1515, 2021.

09:26–09:28
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EGU21-3795
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ECS
Na Chen, William Shotyk, Fiorella Barraza, René Belland, Muhammad Babar Javed, Chad W. Cuss, and Iain Grant-Weaver

The Athabasca Bituminous Sands (ABS) industry has dramatic benefits for the economy of Alberta, Canada. However, with increasing industrial operations, environmental concerns have grown regarding the contamination of air and water with trace elements (TEs). The ABS are composed of both minerals (ca. 85%) and bitumen (ca. 15%). While V, Ni, Mo, and Re are found primarily in bitumen, other potentially toxic TEs such as As, Cd, and Pb occur mostly in minerals. The mechanical processing of ABS by industry generates considerable volumes of dust particles from processes and sources such as open-pit mining, quarrying, road construction, petroleum coke transport and storage, and dry tailings. These dusts are dominated by coarse aerosols with short atmospheric residence times, consisting primarily of recalcitrant and sparingly reactive silicate minerals enriched in lithophile elements such as Al, Fe, and Mn. In contrast, high-temperature industrial processes such as the smelting and refining of metallic ores and coal combustion yield fine aerosols (< 2 µm) that can be transported for thousands of kilometers. These fine aerosols are respirable and mostly in the forms of oxides and hydroxides rich in TEs such as As, Cd, and Pb, posing a risk to all living organisms. Hence, it is important to differentiate between TEs in the two aerosol fractions.

Here, Sphagnum mosses collected from ombrotrophic (rain-fed) bogs within the ABS region are used as biomonitors of atmospheric deposition, and compared with mosses from a reference site 264 km to the southwest. The aim is to estimate the percentage of TEs in the fine versus coarse aerosol fractions by determining the abundance of TEs in the acid soluble ash (ASA) and acid insoluble ash (AIA) in Sphagnum. Trace element concentrations (total, in ASA and in AIA) were obtained using ICP-MS.

Concentrations of AIA and total concentrations of TEs increased towards industry, reflecting increasing dust deposition. Comparing the site nearest industry (JPH4) to the control site (UTK), the greatest differences in total concentrations were measured for lithophile elements such as Li, Be, and the lanthanides; V, Ni, and Mo were all 10x more abundant; the differences in chalcophile elements were much less apparent: Pb and Tl 6x, Ag 3x and Cu, Cd, and Zn < 2x. In AIA, Cs, Li, La, and Al were all more abundant at JPH4; Tl was slightly more abundant (3x); Ag, Cu, and Pb were all more abundant at UTK. In ASA, Th, Al, and the lanthanides were more abundant at JPH4; however, concentrations of Cd, Cu, Ag, Zn, Sb, and Tl were higher at UTK. In general, therefore, lithophile elements were more abundant in samples collected near industry, in total concentration as well as in the AIA and ASA fractions. However, chalcophile elements exhibited either insignificant differences, or were more abundant at the control site. Clearly, measuring only the total concentrations of TEs in moss from a dusty industrial region provides limited information about their associated health risks.

How to cite: Chen, N., Shotyk, W., Barraza, F., Belland, R., Javed, M. B., Cuss, C. W., and Grant-Weaver, I.: Distinguishing trace elements in acid soluble ash (ASA) and acid insoluble ash (AIA) of Sphagnum mosses within the Athabasca Bituminous Sands Region, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-3795, https://doi.org/10.5194/egusphere-egu21-3795, 2021.

09:28–09:30
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EGU21-5395
Prokushkin Anatoly, Novenko Elena, Kupryanov Dmitry, and Serikov Sergey

Palsa peatlands are a significant carbon pool in Northern hemisphere which is subjected to change due to accelerated permafrost thaw and peat decomposition with progressing global warming. On the other hand, peat deposits of palsas serve as an important conduit of information about variability of environment conditions in the past millennia and respective vegetation changes. In our study we applied the multi-proxy record to distinguish variation in hydrothermal regimes of palsa peatland in Northern Siberia and to trace the likely diagenetic alteration of accumulated peat.

The study site is located 10 km North-East of Igarka settlement (67o31’ N, 86o38’E) within the area underlain discontinuous permafrost. The peat core was obtained in the central intact part of elevated (ca. > 3.5 m above surrounding hollows) dry hummock. The active layer, thawed seasonally layer, at the coring site was about 0.6 m. The entire depth of peat deposit was 8.6 m, but interrupted with several relatively thin (0.1-0.2 m) ice-rich lenses. Thawed and frozen peat samples of 0.5-5.0 cm thickness (mean = 2.8 cm) were collected at 2.5-12.0 cm step (mean =5.4 cm) depending on the amount of peat material. Collected samples (n = 160) after drying at 60oC for 48 h were subjected to the analysis for C and N content, stable isotopic composition of C and N. These measurements will further accompany radiocarbon dating, loss on ignition, plant macrofossil and macro charcoal analyses.

The analyzed 8.6 m deep peat core demonstrated the large variation of C (17.3-54.7%) and N (0.37-3.26 %) contents as well as C:N ratios (14-134). The isotopic depth profile was in the range from -24.51 to -34.31 ‰ for d13C and from -1.77 to 6.96 ‰ for d15N. The highest enrichment in 15N (2.69±1.60 ‰ d15N) was found in seasonally thawed layer (≤0.6 m). A layer close to the bottom (6.9-8.3 m) contained peat the most depleted by 13C (<-30 ‰ d13C). Meanwhile, along the peat profile depth we detected significant fluctuations in these parameters suggesting the different periods with specific environmental conditions.

Further combined with radiocarbon dating and plant macrofossil analyses we will attempt to capture the changes occurred during the past epochs in an input matter (vegetation changes and/or its productivity), decomposition rates as well as hydrothermal regimes and permafrost processes like aggradation (e.g. hummock uplift and cryoturbation) and degradation (e.g. hummock collapse, shifts from minerotrophic to ombrotrohic conditions and vice versa).

This work was supported by the Russian Science Foundation, project № 20-17-00043.

How to cite: Anatoly, P., Elena, N., Dmitry, K., and Sergey, S.: Peat isotopic composition of a deep deposit of palsa mire for the reconstruction of environmental changes in permafrost domain of Northern Siberia, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-5395, https://doi.org/10.5194/egusphere-egu21-5395, 2021.

09:30–09:32
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EGU21-7531
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ECS
Prabhakaran Ramya Bala, Gaël Le Roux, Francois De Vleeschouwer, Raman Sukumar, and Sajeev Krishnan

Mineral dust, especially from the Middle-East, has been known to affect monsoon circulation in India, a country whose economy is heavily contingent on the timely arrival of the monsoon. Reconstruction of dust circulation in the past and its relationship to the monsoon has never been attempted in India although inorganic geochemical proxies from peat have been used in various parts of the world. Finding suitable peat archives to use inorganic geochemical proxies in the largely tropical and sub-tropical Indian environments is a challenge. Montane peat in the Sandynallah valley in the southern Western Ghats, peninsular India, is one of the oldest in the world (>50 ka) and has been shown to record continuous climatic and vegetation changes of at least 30,000 yrs of the past. We explored the usefulness of inorganic geochemical proxies for the first time here to reconstruct dust circulation. Inorganic geochemical analysis was carried out on acid digested peat samples analyzed using Inductively Coupled Plasma-Mass Spectrometry and Optical Emission Spectroscopy at EcoLab, Toulouse. We see that the major (e.g., Al, Fe, Mn, K, Na, Mg, Ca) and commonly used trace (Cu, Zn, Pb) elements do not show many significant trends for paleoenvironmental interpretation. Preliminary analyses indicate that lithogenic elements Ti and Zr have high correlation through time. In this study, we used scaled Rare Earth Element (REE) concentrations and Zr as a reference to calculate enrichment factors (REE EFs) and found that the Lanthanide series showed promise for identifying potential sources of atmospheric dust. We find strong enrichments in some sections of the last glacial (the strongest enrichment is observed at ~30 ka), indicative of environmental conditions that supported increased dust input, possibly related to the higher dust circulations in the glacial periods as evidenced by ice core studies. We report for the first time inorganic geochemical proxies from peat in India and propose that the lanthanide group could be established as a useful proxy for atmospheric dust sources in tropical montane peat.

How to cite: Ramya Bala, P., Le Roux, G., De Vleeschouwer, F., Sukumar, R., and Krishnan, S.: Rare Earth Elements as geochemical tracers of paleoenvironments in tropical montane peat, Western Ghats, India, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7531, https://doi.org/10.5194/egusphere-egu21-7531, 2021.

09:32–09:34
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EGU21-15329
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ECS
Tingwan Yang, Hongyan Zhao, Zhengyu Xia, Zicheng Yu, Hongkai Li, Zhaojun Bu, and Shengzhong Wang

Montane bogs—peat-forming ecosystems located in high elevation and receiving their water supply mostly from meteoric waters—are unique archives of past environmental changes. Studying these ecosystems and their responses to recent climate warming will help improve our understanding of the sensitivity of high-elevation peatlands to regional climate dynamics. Here, we report a post-bomb radiocarbon-dated, high-resolution, and multi-proxy record in Laobaishan bog (LBS), a mountaintop bog from the Changbai Mountains Range in Northeast China. We analyzed plant macrofossils and testate amoebae of a 41-cm peat core dated between 1970 and 2009 to document the ecohydrological response of peatland to the anthropogenic warming in recent decades. We quantitatively reconstruct the surface wetness changes of LBS bog using the first axis of the detrended correspondence analysis (DCA) of plant macrofossil assemblages and depth to water table (DWT) inferred by transfer function of testate amoebae assemblages. We distinguished two hydroclimate stages: the moist stage before the 1990s and the rapidly drying stage since the 1990s. During the moist stage, plant macrofossils were characterized by the low abundance of Sphagnum capitifolium and Polytrichum strichum that prefer dry habitats, and testate amoebae assemblages were dominated by low abundance of dry-adapted Assulina muscorum and Corythion dubium. High score of first axis and low DWT also suggested a moist habitat at LBS. After the transition into the drying stage, the abundance of S. capitifolium and P. strichum increased and that of A. muscorum and C. dubium showed similar trend. Score of first axis and DWT reconstructions show that LBS have experienced rapid surface desiccation since the 1990s. Based on the high-resolution gridded reanalysis data, these ecohydrological changes occurred with a rapid increase in temperature (~1°C) but without notable change in total precipitation during the growing season (May–September) since the 1990s. Besides, backward trajectory analysis showed no apparent changes in atmospheric circulation pattern since the 1990s, supporting our interpretation that the ecohydrological changes in LBS bog were induced by climate warming. These results demonstrate that the plant communities, microbial assemblages, and peatland hydrology of montane peatland show a sensitive response to climate warming that might be in larger amplitude than the low-elevation areas.

How to cite: Yang, T., Zhao, H., Xia, Z., Yu, Z., Li, H., Bu, Z., and Wang, S.: Rapid Ecohydrological Response of a Mountaintop Peatland to Recent Climate Warming in Northeast China, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15329, https://doi.org/10.5194/egusphere-egu21-15329, 2021.

09:34–09:36
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EGU21-13836
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ECS
Lukas Frost, Rene Belland, Iain Grant-Weaver, and William Shotyk

Sphagnum mosses have been used in some of the earliest works in biomonitoring of atmospheric deposition of trace elements (TEs). Since their adoption into the field the Sphagnaceae have become one of the foremost biomonitors. When taken as contemporary samples, these mosses have allowed us to identify spatial variations as well as trends and major changes in atmospheric deposition due to changing policy, technology, industry, and land use. While long term monitoring programs, such as the European Moss Survey, allow us to track these changes through time, these ongoing studies only reach as far back as their start dates. In the case of the European Moss Survey this was 1990. The use of materials already collected and archived in herbaria provides a low-cost method for retrospective analysis of atmospheric deposition of TEs. The critical advantage of herbarium specimens over other historical monitoring method is their high temporal resolution, as their exact collection date is known. Once collected, stored, and protected from atmospheric dust, the concentrations of non-volatile TEs present remain effectively unchanged. The oldest herbarium records can predate industrialisation, but most have records from the beginning of industrialisation, with the frequency of collection increasing in the modern era. Using only the top 2 cm of herbarium specimens of Sphagnum mosses (S. fuscum, S. angustifolium, S. capillifolium, S. magellanicum) found in Canadian ombrotrophic bogs, we will be creating historical reconstructions of atmospheric deposition in northern Alberta since the 1940s and southern Ontario since 1860’s. The first objective is to determine how best to balance preservation of the limited herbarium material available while also using sufficient material to achieve suitable levels of analytical accuracy. As TE analyses using ICP-MS are destructive and some specimens have immeasurable value from a natural history perspective, as little material as possible should be taken for analysis. Grinding of the sample was avoided, to minimize sample loss and the risk of contamination. We compared the measured concentrations obtained with ICP-MS as a function of the mass of Sphagnum digested, using selected herbarium samples as well as two certified, Standard Reference Materials (NIST 1515 and HB36-M2). These analyses allow us to determine the optimal amount of material necessary to balance the analytical accuracy and preservation of material of 4 species of Sphagnum mosses from Alberta over the last 80 years. The results will be compared with the data already available for TE concentrations in age-dated peat cores from the same region.

How to cite: Frost, L., Belland, R., Grant-Weaver, I., and Shotyk, W.: Balancing preservation of material and the need for analytical accuracy: Mass requirements of Sphagnum moss from herbarium collections for trace element analysis, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-13836, https://doi.org/10.5194/egusphere-egu21-13836, 2021.

09:36–09:38
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EGU21-11669
Simon Hutchinson, Andrei Diaconu, Sergey Kirpotin, and Angelica Feurdean

Although interest in peatland environments, especially in terms of their carbon storage, has gained momentum in response to a heightened awareness of the climate emergency; significant gaps remain in the geographical coverage of our knowledge of mires, including some major wetland systems. This paucity has implications, not only for our understanding of their development and functioning, but also for adequately predicting future changes and thus providing effective mire environmental management. Our INTERACT-supported study provides radiometrically dated, well-characterised millennial scale peat records from two contrasting undisturbed and impacted (ditched) ombrotrophic sites in the Great Vasyugan Mire (GVM) near Tomsk, Siberia and two additional mesotrophic sites to the east of the Ob river. In addition, the geochemical record was complemented by multiproxy palaeoecological characterisation (pollen, charcoal, stable isotopes, testate amoeba). We identified both natural (lithogenic) and anthropogenic geochemical signals recording human impacts with site specific variations. Elevated trace element concentrations in the peat profiles align with the region’s wider agricultural and economic development following the colonisation of Siberia by Russia (from ca. 1600 AD) when pollen assemblages indicate the decline of forest cover and an increase in human disturbance, including the use for fire. Trace element concentrations peak with the subsequent, post WWII industrialisation of regional centres in southern Siberia (after 1950 AD). On a global scale, our sites, together with evidence from the few other comparable studies in the region, suggest that the region’s peatlands are relatively uncontaminated by human activities with a mean lead (Pb) level of < 5 mg/kg. However, via lithogenic elements including Rb, Ti and Zr, we detected both a geochemical signal as a result of historical land cover changes enhancing mineral dust deposition following disturbance, as well as fossil fuel derived pollutants as relatively elevated, subsurface As and Pb concentrations of ca. 10 and 25 mg/kg respectively with the development of industry in the region. Nevertheless, the potential significance of local factors on the sites’ geochemical profile is also highlighted. For example, we identify the effects of past peat drainage for afforestation (ca. 1960s) and the scheme’s subsequent abandonment. Although the region’s mire systems are remote and vast, they appear to hold a legacy of human activity that can be detected as a geochemical signal supporting the inferences of other palaeoenvironmental proxies. Such geochemical peat core records, from Eurasia in particular, remain relatively scarce in the international scientific literature and therefore, as yet, inadequately characterised and quantified compared to other regions.

How to cite: Hutchinson, S., Diaconu, A., Kirpotin, S., and Feurdean, A.: Geochemical peat records from the Great Vasyugan Mire and Tomsk region, Siberia. Regional temporal trend of human impact over the last 500 years and local perturbations., EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-11669, https://doi.org/10.5194/egusphere-egu21-11669, 2021.

09:38–09:40
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EGU21-10942
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ECS
Zuo Wang and Zicheng Yu

Northeast China—located near the northern limit of the influence by the East Asian summer monsoon—receives most moisture through the westerly airflow, but variations in moisture contributions from the Yellow Sea in the western Pacific Ocean determine its hydroclimate during summer monsoon season. The proportion of moisture from the Yellow Sea is strongly modulated by the location and intensity of the Western Pacific Subtropical High (WPSH). However, it is still unclear how sensitive regional hydroclimate to WPSH-modulated change in moisture sources and its impact on peatland carbon accumulation. Here, we used macrofossil data and paired δ13C and δ18O isotope analysis of Sphagnum moss cellulose from a well-dated bog from a steep mountain slope in the Greater Khingan Mountains (~47˚N) to reconstruct peatland moisture changes and elucidate past shifts in moisture sources. δ13C values reflect peatland surface moisture, as dry conditions with less water film effects would increase isotopic discrimination against 13C and result in lower δ13C values. Our results from a 250-year peat record show a decrease of ~3‰ in δ13C from -25 to -28‰—with corresponding increase in dry-adapted moss Polytrichum—suggesting a drying trend since about 1980 AD. Also, the down-core δ18O and δ13C data show a positive correlation (r = 0.65, p < 0.001), in contrast with evaporative enrichment of δ18O being the dominant effect. We argue that δ18O values reflect the input of moisture derived from the Yellow Sea—that has higher δ18O values than that from the westerlies—as modulated by the WPSH. When the WPSH extends westward, it blocks moisture transport from the Yellow Sea to North China, causing low δ18O values in summer precipitation, dry conditions, and negative shifts in δ13C, and vice versa. Furthermore, carbon accumulation rates show a major decrease after the 1980s—despite that more recent peat tends to have higher apparent accumulation rates—suggesting a sensitive response of this steep-slope mountain peatland to shift in regional hydroclimate in monsoon-margin region of Northeast China.

How to cite: Wang, Z. and Yu, Z.: Atmospheric circulation, hydroclimate change, and peat accumulation over the last 250 years inferred from a Sphagnum peatland in the southern Greater Khingan Mountains of Northeast China , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10942, https://doi.org/10.5194/egusphere-egu21-10942, 2021.

09:40–09:42
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EGU21-9018
Kunshan Bao, Mingrui Qiang, Kewei Zhao, Ying Yan, Ulgiichimeg Ganzorig, and Ochirbat Batkhishig

Peat records of trace metals pollution history over thousands of years are not widely reported in northeastern Asia, although the mining/metallurgy have already started in the past 5000 years. Peat core was collected in September 2015, from the Nur Sphagnum bog, in Selenge province, in the NW part of the Kenthii Mountains, Mongolia. The Nur Sphagnum bog (49°39’N; 107°48’E; 1250 m.a.s.l.) is the largest wetland located in the mountain taiga forest of Mongolia in the northern part of the Hentei highlands. The mean January and July temperatures are -27.1°C and 18.3°C respectively, while mean annual precipitations are 288 mm. The peatland is composed of than 10 species of Sphagnum, while herb layer is dominated by Carex rostrata, and several species of Sphagnum. The dominant tree species are composed of Betulaplatyphylla, Pinussylvestris, Piceaobovata and Abiessibirica. As for the Nur bog, no research on elemental or isotopic geochemistry was undertaken currently. Our preliminary geochemical study established a baseline for typical heavy metal, Pb, 1.1 mg kg-1, which is reasonable to represent a pre-industrial background value in Mongolia, even in northeastern Asia. The average Pb content through the cores was 2.2 mg kg-1, which was significantly lower than the level in northeastern China and showed that the it was still typical area of pristine ecosystem in northern Mongolia. However, the elevation of Pb and Tl contents in the near surface layers was also observed, with an enrichment factor of 6, which suggested that the anthropogenic impact was approaching in this region and more attention should be paid to safeguard its nature heritage.

How to cite: Bao, K., Qiang, M., Zhao, K., Yan, Y., Ganzorig, U., and Batkhishig, O.: Mongolian peatland documents 5000-year pollution history and a baseline of Pb and Tl in northeastern Asia, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9018, https://doi.org/10.5194/egusphere-egu21-9018, 2021.

09:42–09:44
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EGU21-6959
Chunmei Ma and Zhenhui Huang

We identified four climatic stages between 6.2 and 1.3 cal kyr before present (BP) based on pollen and charcoal concentrations by high‐resolution Accelerated mass spectrometer (AMS) 14 C‐dated sediment profile from Taiwan's Toushe Basin. From 6.2 to 4.6 cal kyr BP, the region was warm‐wet with infrequent wildfires and dominant subtropical evergreen broad‐leaved forests. The climate was cooler‐drier from 4.6 to 3.0 cal kyr BP, with a decline in forest and increased fire frequency. From 3.0 to 2.1 cal kyr BP,climate further cooled and dried, with the development of alpine meadows and higher fire frequency. The region became warmer and wetter from 2.1 to 1.3 cal kyr BP, accompanied by forest recovery. Climatic changes were linked to changes in East Asia Summer Monsoon intensity,which is mainly controlled by solar radiation. Wildfires were likely controlled by precipitation variability that is influenced by East Asia Summer Monsoon and El Niño–Southern Oscillation. Toushe Basin experienced drought conditions and frequent wildfires during the El Niño years.

How to cite: Ma, C. and Huang, Z.: Paleofire, Vegetation, and Climate Reconstructions of the Middle to Late Holocene From Lacustrine Sediments of the Toushe Basin, Taiwan, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-6959, https://doi.org/10.5194/egusphere-egu21-6959, 2021.

09:44–09:46
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EGU21-7430
Marco Cantonati, Daniel Spitale, Emma Donini, Giorgio Galluzzi, Nicola Angeli, and Claudio Zaccone

Peatland is a major carbon (C) sink, sequestering more atmospheric carbon dioxide (CO2) than any other terrestrial ecosystem. Peatlands, and especially bogs, are typically nutrient-poor environments, extremely sensitive to increases in nitrogen (N) deposition. In fact, increasing N content often causes a shift from a moss- to a vascular-plant-dominated vegetation resulting in lower C sequestration rates and/or mobilization of N and C stored in peat by promoting microbial activity. Peatlands are also very selective environments (sub-oxic to anoxic conditions, acidic pH, low N), and thus important habitats for nature conservation because of the occurrence of specifically adapted organisms. Peatlands cover ca. 3% of the world’s land surface but Europe lost >60% of this habitat type in the last decades. Moreover, in Italy they are in a marginal position from the phytogeographical standpoint.

Cattle grazing and trampling is a cause of peatland degradation resulting in peat compaction, shift in plant and microbial community composition, and N inputs in form of excreta. In Alpine peatlands overgrazing has been identified as a main problem for habitat integrity and biodiversity.

In the present work, 50-cm deep Belarus cores were collected from the Canton di Ritorto peatland (Adamello-Brenta Nature Park, Trentino, Italy) along a grazing-induced disturbance gradient. The study site has a bog-like vegetation; common species are Pinus mugo, Carex pauciflora, C. echinata, Eriophorum vaginatum, Vaccinium uliginosum, and many Sphagnum species including S. capillifolium, S. medium, S. subfulvum, S. subnites. Peat thickness ranges between 40-160 cm, while electrical conductivity and pH at the surface range between 10-31 µS/cm and 4.0-5.2, respectively.

Cores were cut frozen into 3-cm sections, and analysed for bulk density, water and ash content, and elemental composition (C, N and S). Moreover, diatom taphocoenoses were studied in two peat cores (i.e., the most affected by grazing and the control), investigating alternate slices (i.e., at 6-cm resolution). Diatoms were prepared using hot hydrogen peroxide and/or muffling, and finally embedded in the Naphrax© resin to produce permanent mounts for identifications and counts. The whole procedure was kept quantitative to allow not only the assessment of the per cent composition of taphocoenoses, but also the calculation of absolute abundances (N-valves/g-peat-dw).

Preliminary data show that small-scale grazing significantly lowered water content (by 5-10%) and gravimetric water content (by 30-50%), and increased bulk density (1.5-2.2x) compared to the control. Moreover, N concentration was 2-to-3 times higher in grazing-affected sites. Differences between cores affected by grazing and the control were evident in the top 20 cm, whereas no significant differences were observed below 30 cm of depth. More than 80 diatom species were identified throughout the two cores. Several of these are included in threat categories of the Red List for central Europe, and we could also identify a putative species new to science, which is being characterized and described. Some species that tolerate moderate nutrient enrichment were found in the core at the "grazed" extreme of the gradient, whilst several species sensitive to organic pollution were detected only (or were clearly more frequent) in the control.

How to cite: Cantonati, M., Spitale, D., Donini, E., Galluzzi, G., Angeli, N., and Zaccone, C.: Using diatoms and physical and chemical parameters to unveil cow-pasture impact in peat cores from a mountain mire in the south-eastern Alps, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7430, https://doi.org/10.5194/egusphere-egu21-7430, 2021.

Palaeosols as records of past environmental conditions
09:46–09:48
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EGU21-650
Svetlana Sycheva, Manfred Frechen, Birgit Terhorst, Sergey Sedov, and Olga Khokhlova

A detailed pedocryostratigraphic scheme of the Late Pleistocene periglacial region of the East European Plain has been developed on the basis of study of the paleorelief, sediments, paleosols, and cryogenic horizons. OSL and 14C-dating of paleosols and sediments in Aleksandrov quarry and in other sections made it possible to substantiate this scheme and correlate it with analogous ones for different regions of Europe. The loess-paleosol sequence in Aleksandrov quarry (51º05'N, 36º08'E) does not have an analogous with respect to the completeness in the whole East European Plain. In the filling of paleobalka the Ryshkovo paleosol of the Mikulino interglacial (MIS 5e) is observed. Over this paleosol, the Valdai soil-sediment series (MIS 5d – MIS 2) is located. It includes four interstadial soils, two of them of the Early Valdai (Kukuevo and Streletsk ones), and two, sometimes three, of the Middle Valdai (Aleksandrov, Hydrouzel и Bryansk ones). The OSL date, 127 ± 8 ka BP, (beginning of MIS 5e) was obtained for a sample taken from the bottom of the Ryshkovo soil. The interglacial soil is overlain by the Seym layer formed mainly from destroyed and redeposited horizons of this soil. For the upper part of the Seym layer, OSL dates of 115 ± 7 ka BP and 112 ± 20 ka BP were obtained (MIS 5d). But the process of burial of Ryshkovo soil in the bottom of the paleobalka began at the end of the interglacial after a catastrophic forest fire. Large post-permafrost deformations - pseudomorphosis is confined to Selikhovodvor loess - MIS 4 (65 ± 8 ka BP). Two soils occurring between Seym and Selikhovodvor loesses: Kukuevo and Streletsk - Early Valdai (MIS 5c and MIS 5a). For Mlodat loess which separates those two soils (MIS 5b), OSL dates of 91 ± 1 and 89 ± 7 ka BP were obtained. For paleosols of Middle Valdai (MIS 3), 14C-dates were obtained: Aleksandrov (53.742 - 2.124 ka cal BP) and Bryansk soils (37.618 ± 0.668 ka cal BP). For Tuskar loess, which separates Alexandrov and Bryansk soils, OSL dates of 50 ± 3 and 51 ± 3 ka BP were obtained. The new stratigraphic scheme of Late Pleistocene agrees with the ideas of researchers from Eastern, Central, and Western Europe , which allows the following correlations. The identified paleosols correspond to the following intervals: Ryshkovo – Eemian interglacial (127-117 ka BP); Kukuevo to Amersfoort + Brørup – Saint-Germain 1 (105-95 ka BP); Streletsk – Odderade to Saint-Germain 2 (about 85-75 ka BP); Aleksandrov to Oerel (56-53 ka BP); Hydrouzel to Moershoofd – Poperinge (44-45 ka BP) and Hengelo (40-38 ka BP); and Bryansk (33-27 ka BP) to Stillfried B, Denekamp or Grand Bois interstadials. The reconstructed Late Pleistocene loess-paleosol sequence has the most similar structure with loess-paleosol sequences of Ukraine, with sequence Dolní Věstonice in Moravia (Czech Republik), Stillfried in Austria and Mainz-Weisenau in the Rhenish area (Germany), and other archives. This work was supported by RFBR, grant N19-29-05024 mk.

How to cite: Sycheva, S., Frechen, M., Terhorst, B., Sedov, S., and Khokhlova, O.: Stratigraphy and chronology of Late Pleistocene loess-paleosol sequence of the East European Plain and correlation with Late Pleistocene archives of Europe, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-650, https://doi.org/10.5194/egusphere-egu21-650, 2021.

09:48–09:50
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EGU21-9728
Daniel Šimíček, Ondřej Bábek, Karel Hron, and Ivana Pavlů

The loess-paleosol sequences (LPS) are an important source of proxy data documenting climatic fluctuations in the Quaternary. Understanding the relationship between the grain size distribution and the geochemistry is crucial for the reliable palaeoclimatological and palaeoenvironmental interpretation of the LPS. For this purpose, the large granulometric (389 samples) and geochemical datasets (542 samples measured using EDXRF spectrometer) were acquired at four LPS in Moravia (eastern part of Czech Rep.). Czech loess represent an important part of the European loess belt, because they characterize region with alternating influence of the oceanic and continental macroclimate, modified by close contact to the front of both continental and alpine glaciation during glacial periods. Moreover, a very diverse geology is characteristic for the source area (the Bohemian Massif) of Czech loess. Therefore, distinguishing of provenance and transporting and post-deposition processes effects on the formation of the Czech LPS requires finding new approaches of statistical evaluation of datasets. Centered log-ratio (clr) transformation and scalar-on-function regression allow finding a relationship between the geochemical composition and the grain-size distribution of loess and soils. Centered log-ratio (clr) transformation was applied to the key elemental proxies of grain size, provenance and weathering and their spatial and stratigraphic distribution. Nearly all LPS samples are characteristic by bimodal grain-size distribution with the main modes corresponding to medium/coarse silt and clay fractions. The scalar-on-function regression shows that the grain-size control of the distribution of Al, Si, K, Ca, Fe, Rb, Sr and Zr is highly site-specific. The provenance signal is recorded especially in coarser-grained fractions transported for short distance. The content of the authigenic phyllosilicates in clay fraction, the alteration of feldspars and micas, low contents of K, and high values of Rb/Sr and Sr/Ca ratios reflect the intensity of weathering, which is highest in the weakly developed brown paleosols. The precipitation rates are suggested the most important microclimatic factor, which affect the intensity of loessification and pedogenic processes forming the Czech LPS.

This research was supported by the Czech Science Foundation (GAČR) research project 19-017685.

How to cite: Šimíček, D., Bábek, O., Hron, K., and Pavlů, I.: Palaeoclimatological interpretation of loess-paleosol sequences using log-ratio transformation of granulometric and geochemical data; Czech Republic, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9728, https://doi.org/10.5194/egusphere-egu21-9728, 2021.

09:50–09:52
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EGU21-3207
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ECS
Jie Chen

Loess-palaeosol sequences are the most intensively studied terrestrial archives used for the reconstruction of late Pleistocene environmental and climatic changes in the Sea of Azov region, southwest Russia. Here we present a revised luminescence-based chronostratigraphy and a multi-proxy record of late Pleistocene environmental dynamics of the most complete and representative loess-palaeosol sequences (Beglitsa and Chumbur-Kosa sections) from the Azov Sea region. We propose a new chronostratigraphy following the Chinese and Danubean loess stratigraphy models that refines the subdivision of the last interglacial palaeosol (S1) in two Azov Sea sites, resolves the uncertainty of the stratigraphic position of the weakly developed paleosol (L1SSm) in Beglitsa section, and allows direct correlation of the Azov Sea sections with those in the Danube Basin and the Chinese Loess Plateau. More importantly, it adds important data to better constrain local and regional chronostratigraphic correlations, and facilitates the interpretation of climatic connections and possible forcing mechanisms responsible for the climatic trend among these regions. In addition, a general succession of environmental dynamics is reconstructed from these two vital sections, which is broadly consistent with other loess records in the Dnieper Lowland and Lower Danube Basin, demonstrating similar climatic trends in these regions at glacial-interglacial time scales. However, differences in details were also identified, especially for palaeosols developed during the last interglacial period, and the cause of these dissimilarities between loess records appears complex.

Furthermore, our results have important implications for the chronostratigraphic representativeness of Beglitsa as a key loess section and the reconstruction of the temporal and spatial evolution of late Pleistocene palaeoclimate in the Sea of Azov region.

 

How to cite: Chen, J.: Revised chronostratigraphy and palaeoenvironmental record of loess-palaeosol sequences in the Azov Sea region of Russia since the late Pleistocene, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-3207, https://doi.org/10.5194/egusphere-egu21-3207, 2021.

09:52–09:54
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EGU21-2394
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ECS
Daniela Constantin, Joseph Mason, Ulrich Hambach, Daniel Veres, Cristian Panaiotu, Christian Zeeden, Liping Zhou, Slobodan Marković, Natalia Gerasimenko, Anca Avram, Viorica Tecsa, Stefana Madalina Sacaciu-Groza, Laura del Valle Villalonga, Robert Begy, and Alida Timar-Gabor

Here we investigate the timing of Pleistocene-Holocene climatic transition as reflected in nine luminescence dated loess-palaeosol sequences across the northern hemisphere, from the Chinese Loess Plateau, the southeastern European loess belt and the central Great Plains, Nebraska, USA.
First, logs of high-resolution magnetic susceptibility and its frequency dependence were used as palaeoclimatic proxies to define the environmental transition from the last glacial loess to the current interglacial soil. Second, the onset of increase in their values above typical loess values was used to assess the onset of, and developments during, the Pleistocene-Holocene climatic transition. The variability seen in the magnetic susceptibility records are interpreted based on high-resolution luminescence dating applied on multiple grain-sizes (4-11 µm, 63-90 µm, 90-125 µm) of quartz extracts from the same sample. In order to increase the overall precision of the luminescence based chronology we rely on weighted average ages. Based on these, Bayesian modeling allowed the determination of age-depth models and mean sedimentation rates for each investigated site.
The magnetic susceptibility signal shows a smooth and gradual increase for the majority of the sites from the typical low loess values to the interglacial ones. At all but one site, this increase, associated to the onset of the Pleistocene-Holocene boundary (ie., 11.7 ka) was dated to 14 ka or even earlier. Our results highlight the need of combining palaeoclimatic proxies (magnetic susceptibility) with absolute dating when placing the Pleistocene-Holocene climatic transition as reflected by the evolution of this proxy in order to avoid misinterpretations in loess-paleosol records caused by simple pattern correlation. These results indicate diverse environmental dynamics recorded in the different North Hemisphere loess regions during the major global climatic shift from the last glacial to the Holocene.
The detailed luminescence chronology coupled with magnetic susceptibility records indicate the formation of accretional Holocene soils in the sites investigated. Modeled accumulation rates for the Holocene soil are similar for European, Chinese and American loess sites investigated and vary from 0.02 m/ka to 0.09 m/ka.

How to cite: Constantin, D., Mason, J., Hambach, U., Veres, D., Panaiotu, C., Zeeden, C., Zhou, L., Marković, S., Gerasimenko, N., Avram, A., Tecsa, V., Sacaciu-Groza, S. M., del Valle Villalonga, L., Begy, R., and Timar-Gabor, A.: Accretional soil formation in northern hemisphere loess regions - evidence from OSL-dating of the P/H climatic transition from China, Europe and North America, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2394, https://doi.org/10.5194/egusphere-egu21-2394, 2021.

09:54–10:30
Break
Chairpersons: Anna Schneider, Oren Ackermann, Maria Bronnikova
11:00–11:02
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EGU21-9158
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ECS
Keerthika Nirmani Ranathunga, Peter Finke, Qiuzhen Yin, and Yanyan Yu

To better understand interglacial paleosol formation by quantifying the paleosol formation processes on the Chinese Loess Plateau (CLP), we need a soil genesis model calibrated for long timescales.  Here, we calibrate a process-based soil genesis model, SoilGen2, by confronting simulated and measured soil properties for interglacial soils formed in the CLP for various parameter settings. After the calibration of the intrinsic soil process parameters, the effect of uncertainty of external forcings (e.g. dust deposition) on calibration results was assessed.

This calibration comprises three major soil process formulations, represented by various process parameters. Sequentially : [1]. decalcification by tuning (i) the dissolution constant of calcite (ii) the interception evaporation fraction [2]. clay migration by tuning (iii) the volume of clay in-contact with macropores (iv) the filter coefficient (v) physical weathering (vi) the ectorganic layer thickness [3]. soil organic carbon by tuning the decay rates of (vii) humus and (viii) resistant plant material, and (ix) the ratio of ectorganic/endorganic litter (natural vegetations) (x) the ratio of carbon mineralized (CO2) over that still in the food web (biomass and humus) during decomposition. The order of the tuned parameters was based on sensitivity analyses on parameters for modelling (de-)calcification and clay migration done for West European leaching climates, and on C-cycling parameters done for both West European and Chinese circumstances. These parameters, [1 and 3] and [2] were successfully calibrated to the Holocene and the Marine Isotope Stage (MIS) 13 climate evolution of the CLP, respectively. After calibration, soil properties show a strong response to 10 reconstructed dust deposition scenarios reflecting the propagation of uncertainty in dust deposition.

Our results emphasize the equal importance of calibrating soil process parameters and defining correct external forcings in the future use of soil models. Nevertheless, this calibrated model permits interglacial soil simulation in the CLP over long timescales.

How to cite: Ranathunga, K. N., Finke, P., Yin, Q., and Yu, Y.: Calibrating SoilGen2 for interglacial soil evolution in the Chinese Loess Plateau considering soil parameters, and the effect of uncertain forcings’, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9158, https://doi.org/10.5194/egusphere-egu21-9158, 2021.

11:02–11:04
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EGU21-6170
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ECS
Alena Sverchkova and Olga Khokhlova

Geoarchaeological studies of soils buried under burial mounds (kurgans) and materials of kurgan structures make it possible to solve a wide range of scientific problems. In the steppe zone of Russia, such studies are carried out in order to determine and compare the composition of buried soils and materials of kurgan structures, as well as to study the structure of earth monuments and to obtain data on the technology used by ancient people for their building.

We carried out geoarchaeological studies in two key areas: in Krasnodar (kurgan Beisuzhek 9) and Stavropol (kurgan Essentuksky 1) regions. For each object, the particle-size distribution and physicochemical properties of the earthen materials of the kurgans and buried soils were investigated.

Kurgan Essentuksky 1 was built in the second quarter of the 4th millennium BC (Maykop culture) according to a single plan in a short time (several decades). The kurgan with a height of 5.5-6.0 m and a diameter of 60 m consisted of four earthen and three stone structures. The earthen structures consisted of alternating layers of dark, slightly compacted humified and light dense carbonate-rich material that were taken from buried soils, i.e. dark material from the Ahkb and AhBkb horizons, and light material from the B1kb horizon. This is confirmed by similar changes in the physicochemical properties of paleosols and overlying kurgan structures. A decrease in the organic carbon content and an increase in the content of calcium carbonate, values of pHH2O and magnetic susceptibility from the first to the fourth paleosols predetermined similar changes in the materials from the first to the fourth earthen structures (from the center to the periphery of the kurgan).

In the Beysuzhek 9 kurgan, three earthen structures of different ages were identified: the first and the second - the middle of the 2nd millennium BC (Novotitorovsk culture), the third construction - the beginning of the 2nd millennium BC (Catacomb culture). Each of the subsequent structures overlapped and went beyond the boundaries of the previous one: the second overlapped the first and also untouched soil next to the first; and the third overlapped the second completely and also overlapped previously uncovered soil next to the second structure. The height of the kurgan was more than 4 m, the diameter - about 100 m. The material of each structure was a soil mass from the middle horizons of the buried soils, most likely the Bkb horizon. Samples from the kurgan structures were taken from one column in the middle of the central baulk. Physicochemical analysis of paleosols and earthen structures overlying them showed a decrease in the content of organic carbon and magnetic susceptibility, an increase in the content of carbonate carbon and pHH2O from the center to the periphery of the kurgan.

According to the results of the physicochemical properties of paleosols and materials of both key areas in the second half of the 4th millennium BC there was a climate change in the study region - the average annual temperatures increased and the amount of precipitation decreased.

How to cite: Sverchkova, A. and Khokhlova, O.: Paleoclimatic reconstructions based on the study of structures of large kurgans of the Bronze Age and soils buried under different structures for the steppe zone of Russia, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-6170, https://doi.org/10.5194/egusphere-egu21-6170, 2021.

11:04–11:06
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EGU21-14619
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ECS
Anna Revunova and Olga Khokhlova

In this work, the samples of red-coloured pedosediments were analyzed. They were found in two sections of the Lori Basin, Armenia - Kurtan-IV and Yagdan. Micromorphological analysis, the measurement of magnetic susceptibility, particle size distribution, CHN, determination of bulk, and biomorphic composition was made. Based on the results of previous studies, the age of the deposits overlying these sections was known. The pedosediment from the Kurtan-IV section is overlain by a mixture of sand and volcanic ash, which is dated at about 1.4 Ma (Calabrian). The pedosediment from the Yagdan section is overlain by 2-2.5 Ma basaltic lava (Gelasian). As a result of our research, it was revealed that both pedosediments were formed in conditions differ from current ones and have differences between themselves also. The pedosediment from the Yagdan section was formed during the dominance of the subtropical climate. It was revealed the presence of manganese-ferruginous and clayey films, a low index of carbonization and salinity, and a relatively high index of weathering. Pedo-sediments from the Yagdan section can be classified as Cambisols with vitric, argic, chromic qualifiers. By the time the later section Kurtan-IV was formed, the climate became cooler, which was reconstructed by the appearance of phytoliths of coniferous plants. Pedosediment from the Kurtan-IV section can be classified as Stagnic Luvisols. The later factors influencing the preservation of pedosediments and changes in their composition and properties were identified. Thus, the upper horizon of the Yagdan section sharply differs from the underlying ones in increased weathering and oxidation, and these properties are retained up to the third layer. It has increased indicators of magnetic susceptibility and the content of copper elements, cobalt, nickel, vanadium, chromium, which were brought in by basalt lava. The pedosediment from the Kurtan-IV section was overlain by lacustrine deposits, which led to a decrease in the magnetic susceptibility and an increase in the SiO2 content and carbonation index. This work was supported by RFBR, grant N19-29-05024 mk.

How to cite: Revunova, A. and Khokhlova, O.: Red-coloured pedosediments of the Lori Basin, Armenia , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14619, https://doi.org/10.5194/egusphere-egu21-14619, 2021.

11:06–11:08
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EGU21-13681
Juan Luis García, Christopher Luethgens, Misael A. Cabello, Estefanía A. Quilamán, Claudio Latorre, Antonio Maldonado, and Marco Pfeiffer

We have started a program of detailed mapping and sampling buried paleosols and paleodunes sequences that occur along the semiarid coast of central Chile (32-34ºS). Previous work has postulated these stratigraphic records afford evidence for past climate change linked to the latitudinal oscillations/intensification of the southern westerly winds (SWW): Bt horizons resembling humid conditions associated with north shifted SWW, and paleodunes with arid conditions and south shifted SWW. Nonetheless, multiple factors can affect long-term (e.g., orbital to suborbital time-frames) eolian dune variability (stabilization-reactivation, expansion-contraction, pedogenesis-morphogenesis), including sea level, sediment supply, wind intensity, and tectonics. It is therefore a pending work to expand our research in these eolian archives and understand their causes and environmental implications. Here, we present preliminary research results from the Ritoque paleodune, Comuna de Quintero, Chile (32ºS). The study site is a 15 m deep gully incision that allowed us to built a very complete sediment stratigraphic sequence postdating the Miocene-Pliocene marine Horcón Formation. Previous luminescence geochronologic control in nearby paleodune deposits indicate eolian morphogenetic and pedogenetic activity during the last glacial period. We interpret the geomorphic context together with standard sediment field and laboratory data to discriminate between stratigraphic units and their origin. A total of 13 sediment units were mapped, which include mostly couplets of buried paleosols (Bt horizons) and underlying paleodunes. Other units resembling rather paleowetlands and possibly sea side sand beaches were also found. We discuss our results in light of available evidence to unravel the environmental meaning of this extraordinary well-preserved terrestrial record in the SE subtropical Pacific.

How to cite: García, J. L., Luethgens, C., Cabello, M. A., Quilamán, E. A., Latorre, C., Maldonado, A., and Pfeiffer, M.: Exploring the potential of buried paleosols and paleodunes sequences for unraveling Late-Pleistocene climate change in subtropical Coastal Chile, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-13681, https://doi.org/10.5194/egusphere-egu21-13681, 2021.

11:08–11:10
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EGU21-5354
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ECS
Emanuele Pintaldi, Michele Eugenio D'Amico, Nicola Colombo, Marco Giardino, and Michele Freppaz

In the framework of climate change research, alpine soils may provide excellent paleoenvironmental information, thus representing a powerful tool for paleoclimate reconstruction. However, since Pleistocene glaciations and erosion-related processes erased most of the pre-existing landforms and soils, reconstructing soil and landscape development in high-mountain areas can be a difficult task.

This study was performed in the periglacial environment of the Stolenberg Plateau (LTER site Istituto Mosso), located on the watershed between Valsesia and Lys Valley, at the foot of the southern slope of the Monte Rosa Massif (Western Italian Alps, elevation: ca. 3030 m a.s.l.). The plateau is covered by thick periglacial blockfields and blockstreams, with a plant cover that reaches no more than 3-5% of the surface.

These periglacial landforms unexpectedly revealed well-developed soils below the superficial coarse deposits. In particular, below the stone layer, thick (between 30 and 65 cm) umbric horizons were observed, under which discontinuous cambic Bw ones were developed. In contrast, the surrounding snowbed communities (Salicetum herbaceae) were characterized by Regosols or Cambisols with 10-15 cm thick A horizons and weak signs of cryoturbation.

Despite the sparce plant cover, the organic carbon (C) stocks were surprisingly high (above 5 kg*m-2), comparable to vegetated and even forest soils at lower elevation. In addition, geophysical investigations showed that these soils are widespread under the stony cover, with a thickness ranging between 20 and 90 cm.

Radiocarbon dating (14C) indicated that these soils are paleosols, probably originated during the main warming phases/interstadials occurred between the end of Last Glacial Maximum and the beginning of the Neoglacial. In particular, the ages of the oldest samples were 20.5-20 ka cal. BP (values obtained from two independent and blind datings performed in different moments), others were dated ca. 17.5, 13, 8.5, 6.5, 5.7 ka cal. BP, while the youngest ages were 4.4-4.1 ka cal. BP.

These dates, particularly the oldest ones, show that the Stolenberg Plateau was presumably free of ice at the beginning of the Early Lateglacial, and its summer temperatures were already compatible with some kind of vegetation development. The origin of these unexpected high-elevation soils, below blockstreams and blockfields, is of great relevance for unraveling the climatic history in the Western Alps. The results, including the soil characteristics, the geomorphological framework and the specific local landform setting, aspect, and position, suggest that the plateau may have been a Nunatak, which acted as a refugium for alpine vegetation during the last glacial pulses, serving as a hot-spot for the rapid reoccupation of deglaciated high-elevation landscapes.

How to cite: Pintaldi, E., D'Amico, M. E., Colombo, N., Giardino, M., and Freppaz, M.: Hidden paleosols at high elevation in the Alps (Stolenberg Plateau - NW Italy): evidence for a Lateglacial Nunatak?, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-5354, https://doi.org/10.5194/egusphere-egu21-5354, 2021.

11:10–11:12
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EGU21-2296
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ECS
Lior Siman-Tov, Onn Crouvi, Efrat Morin, Rivka Amit, Yehouda Enzel, Francesco Marra, Itay J. Reznik, and Ravid Rosenzweig

Hyperarid (< 80 mm yr-1) soils in hot deserts are characterized by accumulations of soluble salts (gypsum and halite) in diagnostic horizons as a result of limited moisture availability. In most desert terrains, the source for pedogenic gypsum and halite is atmospheric dust and rainwater. The interplay between climatic properties such as frequency and intensity of rain events, rainfall composition, dust flux, and evaporation rates, govern the depth and concentration of these salts. Better understanding of these relationships can improve our estimation of regional paleoenvironmental and paleoclimate conditions. Up to date, only empirical correlations between annual rainfall and pedogenic salt horizons are available.

The goals of this study are to: 1) quantify rates of pedogenic gypsum accumulation with time and the role of controlling climatic conditions that govern its accumulation, 2) estimate the most likely climatic scenarios that led to the formation of the diagnostic gypsic horizon developed in late Pleistocene (~ 60 ka) abandoned alluvial fan surfaces in the hyperarid Negev desert,  southern Israel. To achieve these goals, we constructed a compartment model that simulates gypsum accumulation in soil and tests its sensitivity to various changes in the long-term climate properties. The model predicts gypsum content and depth of accumulation in the soil profile over thousands of years and more. The input parameters are stochastically simulated rainstorms, evaporation, dust flux, and sulfate concentration in rainwater, at daily time steps. The model was tested and calibrated using data of Holocene (< 11 ka) soil profiles developed on stable alluvial fans in the hyperarid Negev. With the assumption that the climate during the Holocene was not much different than today (i.e., mean annual rainfall < 50 mm). Sensitivity analyses indicate that gypsum accumulation is highly sensitive to mean annual rainfall and sulfate concentration in rainwater. Synthetic gypsum profiles were calculated using different climate scenarios and compared to late Pleistocene soils. Our results suggest that: (a) gypsum accumulation in late Pleistocene soils cannot occur simply by extending current climate conditions for a much longer duration. (b) The plausible climate scenarios for the late Pleistocene must include additional rain input (1.5 – 2.0 times than mean annual rainfall today) and increased sulfate concentration in rainwater (2.0 – 2.5 times than today) to successfully reconstruct the observed accumulated gypsum in mature (60 – 12 Ka) soil profiles.

How to cite: Siman-Tov, L., Crouvi, O., Morin, E., Amit, R., Enzel, Y., Marra, F., J. Reznik, I., and Rosenzweig, R.: Evaluating climate effects over long-term salts accumulation in hyperarid soils using stochastic modeling, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2296, https://doi.org/10.5194/egusphere-egu21-2296, 2021.

11:12–11:14
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EGU21-5768
Yunsen Lai, Shaoda Li, Xiaolu Tang, Xinrui Luo, Liang Liu, Yuehong Shi, and Peng Yu

Soil carbon isotopes (δ13C) provide reliable insights at the long-term scale for the study of soil carbon turnover and topsoil δ13C could well reflect organic matter input from the current vegetation. Qinghai-Tibet Plateau (QTP) is called “the third pole of the earth” because of its high elevation, and it is one of the most sensitive and critical regions to global climate change worldwide. Previous studies focused on variability of soil δ13C at in-site scale. However, a knowledge gap still exists in the spatial pattern of topsoil δ13C in QTP. In this study, we first established a database of topsoil δ13C with 396 observations from published literature and applied a Random Forest (RF) algorithm (a machine learning approach) to predict the spatial pattern of topsoil δ13C using environmental variables. Results showed that topsoil δ13C significantly varied across different ecosystem types (p < 0.05).  Topsoil δ13C was -26.3 ± 1.60 ‰ for forest, 24.3 ± 2.00 ‰ for shrubland, -23.9 ± 1.84 ‰ for grassland, -18.9 ± 2.37 ‰ for desert, respectively. RF could well predict the spatial variability of topsoil δ13C with a model efficiency (pseudo R2) of 0.65 and root mean square error of 1.42. The gridded product of topsoil δ13C and topsoil β (indicating the decomposition rate of soil organic carbon, calculated by δ13C divided by logarithmically converted SOC) with a spatial resolution of 1000 m were developed. Strong spatial variability of topsoil δ13C was observed, which increased gradually from the southeast to the northwest in QTP. Furthermore, a large variation was found in β, ranging from -7.87 to -81.8, with a decreasing trend from southeast to northwest, indicating that carbon turnover rate was faster in northwest QTP compared to that of southeast. This study was the first attempt to develop a fine resolution product of topsoil δ13C for QTP using a machine learning approach, which could provide an independent benchmark for biogeochemical models to study soil carbon turnover and terrestrial carbon-climate feedbacks under ongoing climate change.

How to cite: Lai, Y., Li, S., Tang, X., Luo, X., Liu, L., Shi, Y., and Yu, P.: Spatial variability of topsoil δ13C across Qinghai-Tibet Plateau, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-5768, https://doi.org/10.5194/egusphere-egu21-5768, 2021.

Soils as archives of past human land-use and settlement
11:14–11:19
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EGU21-9082
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solicited
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Highlight
Polina Pushkina, Svetlana Sycheva, Nikolay Gribov, Olga Khokhlova, and Pavel Ukrainskiy

The landscapes of the Volga-Oka right bank are currently changed by human activity considerably. Most of the forests have been cleared and only preserved in the upper reaches of the ravines and on the valley slopes. The soils are largely eroded. The zone of deciduous forests has actually turned into a natural-agricultural area. A geoarchaeological study carried out jointly with archaeologists from Nizhny Novgorod in the area of the ancient Russian sites of Mordvina Gora and Podvyazye 1 made it possible to determine the beginning and maximum of anthropogenic impact on landscapes, which caused catastrophic changes in biota, soils, and landforms.

During the existence of the ancient Russian settlements of the 14th century in the study area, mixed and broad-leaved tree species grew on light gray forest and sod-podzolic soils (Retisols). The houses were built from oak and spruce. At first, the development of landscapes by the ancient Russian population proceeded along the banks of small and large rivers. Starting from the 14th century and especially sharply since the 18th century, accelerated anthropogenic soil erosion manifested itself. On the watersheds and slopes, the upper part of the soil profile (up to the Bt2 horizon) was destroyed by erosion. As a result, watersheds and slopes decreased by no less than 40-60 cm. Coastal ravines and microdepressions were almost completely filled with colluvium. Mordvin's gully has turned into a flat-bottomed ravine. The sediment thickness in the bottom of the ravine reaches 4.5 m. The depth of dismemberment has decreased by 4-5 m. The relics of the Ah and AE horizons of gray forest soils (Retisols) have been preserved only in a buried state on the slopes and in the bottoms of depressions.

The reasons for the described ecological catastrophe are associated with the imposition of anthropogenic impact (deforestation and plowing of land) on an unfavorable natural background - climate change towards humidification and cooling (wet phase preceding the Little Ice Age). Throughout the forest zone of the Russian Plain in the 14th century, the strategy of placing settlements has been changed. From the riverside settlements were relocated to watersheds since the former habitats - floodplains and low terraces became unsuitable for settlement due to frequent floods and high standing groundwater. Since that time, the widespread development of watersheds has been taking place for the first time. For life support, ponds were dug near the settlements or ravines, and gullies were blocked by dams, which were subsequently drained and completely covered by sediments.

Accelerated erosion increased significantly in the 18th century due to the further deterioration of the climate during the pessimum of the Little Ice Age, the growth of the agricultural population, and the introduction of the poll tax. It occurred repeatedly with a periodic deceleration of the pace, following low-amplitude climatic rhythms and local factors of agricultural development.

This work was supported by RFBR, grant N19-29-05024 mk.

How to cite: Pushkina, P., Sycheva, S., Gribov, N., Khokhlova, O., and Ukrainskiy, P.: Catastrophic changes in landscapes of the right bank of the Volga-Oka rivers in 14-18th centuries, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9082, https://doi.org/10.5194/egusphere-egu21-9082, 2021.

11:19–11:24
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EGU21-1772
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ECS
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solicited
Sara Cucchiaro, Guido Paliaga, Daniel J. Fallu, Ben R. Pears, Kevin Walsh, Pengzhi Zhao, Kristof Van Oost, Lisa Snape, Andreas Lang, Antony G. Brown, and Paolo Tarolli

Geomorphometric information can be exploited to study the most extensive and common landforms that humans have ever produced: agricultural terraces. An understanding of these historical ecosystems can only be determined through in-depth knowledge of their origin, evolution, and current state in the landscape. These factors can ultimately assist in the future preservation of such landforms in a world increasingly affected by anthropogenic activities. High-resolution topographic (HRT) techniques allow the mapping and characterization of geomorphological features with wide-ranging perspectives at multiple scales. From HRT surveys, it is possible to produce high-resolution Digital Terrain Models (DTMs) to extract important geomorphometric parameters such as topographic curvature, to identify terrace edges, even if abandoned or covered by uncontrolled vegetation. By using riser bases as well as terrace edges (riser tops) and through the computation of minimum curvature, it is possible to obtain environmentally useful information on these agricultural systems such as terrace soil thickness and volumes. The quantification of terrace volumes can provide new benchmarks for soil erosion models, new perspectives for land and stakeholders for terrace management in terms of natural hazard and offer a measure of the effect of these agricultural systems on soil organic carbon (SOC) sequestration. This work aims to realize and test an innovative and rapid methodological workflow to estimate the minimum anthropogenic reworked and moved soil of terrace systems in different landscapes. This aspect of new technology and its application to terrace soil-systems has not been fully explored in the literature. We start with remote terrace mapping at a large scale (using Airborne Laser Scanning) and then utilize more detailed HRT surveys (i.e., Structure from Motion and Terrestrial Laser Scanning) to extract geomorphological features, from which the original theoretical slope-surface of terrace systems were derived. These last elements were compared with in-field sedimentological recording obtained from the excavations across the study sites to assess the nature of sub-surface topographies. The results of this work have produced accurate DTMs of Difference (DoD) for three terrace sites in central Europe in Italy and Belgium. The utilization of ground-truthing through field excavation and sampling has confirmed the reliability of the methodology used across a range of sites with very specific terrace morphologies, and in each case has confirmed the nature of the reconstructed, theoretical original slope. Differences between actual and theoretical terraces from DTM and excavation evidence have been used to estimate the minimum soil volumes and masses used to remould slopes. Moreover, geomorphometric analysis through indices such as sediment connectivity permitted also to quantify the volume of sediment transported downstream, with the associated and mobilized C, after a collapsed terrace. The quantification of terrace soil volumes provides extremely useful standards for further multi-disciplinary analysis on the terrace sediments themselves, aiding physical geographers, geoarchaeologists, palaeo-environmentalists, and landscape historians in the understanding of terrace systems and the impact of agricultural processes on the landscape.

How to cite: Cucchiaro, S., Paliaga, G., Fallu, D. J., Pears, B. R., Walsh, K., Zhao, P., Van Oost, K., Snape, L., Lang, A., Brown, A. G., and Tarolli, P.: A geomorphometric approach to estimate soil volumes stored in agricultural terrace systems, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1772, https://doi.org/10.5194/egusphere-egu21-1772, 2021.

11:24–11:26
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EGU21-16454
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ECS
Alina Kurasova, Alexandr Konstantinov, Sergey Loiko, and Sergey Kulizhskiy

The activities of ancient population strongly affected the development of landscapes and soils in Western Siberia during the late Holocene. It should be noted that studies devoted to the processes of natural and anthropogenic evolution within this vast territory are extremely irregular. Thus, the significant proportion of the materials on the dynamic of Siberian landscapes in the Holocene, related to the studies of various natural archives and archeological monuments, falls on the southern part of region. On the one hand, this situation is due to the relatively recent development of Western Siberia in relation to the development of hydrocarbon deposits, on the other hand, on the peculiarities of the relief and landscapes prevailing in the central and northern parts of the West Siberian Plain. A significant part of the territory under consideration is characterized by low, poorly dissected relief, which largely contributes to its bogging and widespread distribution of organogenic peat soils. It is not surprising that the deposits of lakes and peat bogs are the main natural archives that provide information on the dynamics of the natural environment within the central parts of Western Siberia and, first of all, the taiga zone, while the potential of mineral soils and sediments from this point of view is insignificant, compared to other regions. At the same time the boreal zone of Western Siberia is very large and includes regions with more complex geomorphological conditions.

To assess the possibility of using buried soils and colluvial layers in the middle taiga of Western Siberia for reconstruction of the Holocene landscape’s dynamics, we carried out research on two key sites with rather contrast relief and high frequency of archeological sites: in the middle Yugan River Basin and in the North of the Kondinskaya Lowland. Buried soils and colluvial sediments in a number of sections characterizing foots of the steep slopes on the border with peat bogs were selected as objects for our study. Based on the obtained radiocarbon dates it is possible to preliminarily identify several stages of the activation of erosional processes. For the north of the Kondinskaya lowland three remarkable phases of erosional activity were identified, while for the Yugan River Basin the number of phases was larger - 6. It is interesting to note that the obtained results make it possible to correlate these two regions. The presence of a larger number of recorded erosion-pyrogenic events for the Yugan River basin reflects a longer permanent human presence in the area under consideration, which is also consistent with archaeological data.

The study was funded by the Ministry of Science and Higher Education of the Russian Federation and was performed as a part of project FEWZ-2020-0007 “Fundamentals of the natural environment history of the south of Western Siberia and Turgay in the Cenozoic: sequence sedimentology, abiotic geological events and the evolution of the Paleobiosphere“. The studies were carried out using the equipment of the Center for Collective Use "Bioinert Systems of the Cryosphere", Tyumen Scientific Center, SB RAS and RFBR, project number 20-04-00836.

How to cite: Kurasova, A., Konstantinov, A., Loiko, S., and Kulizhskiy, S.: Evaluating the potential of buried soils and colluvial layers for tracking natural and human-induced transformation of landscapes in the middle taiga of Western Siberia , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-16454, https://doi.org/10.5194/egusphere-egu21-16454, 2021.

11:26–11:28
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EGU21-9780
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ECS
Matteo Meli and Luigi Bruno

Changes in land use represent, after fossil-fuel combustion, the greatest cause of greenhouse-gases emission into the atmosphere. Coastal wetlands, also referred as coastal blue carbon ecosystems (e.g. salt marshes, mangrove forests, seagrass meadows, swamps), represent one of the most powerful C sinks among the Earth’s ecosystems, being capable to sequester organic carbon (OC) at rates ca. 30-50 times higher than terrestrial forests. Historically, land reclamation for agriculture, farming and urban expansion, severely impacted coastal wetlands, causing their loss and degradation. Wetlands drainage lead to the oxidation of organic matter previously stored under anaerobic conditions and the release of CO2 into the atmosphere. Only recently the critical role of blue carbon ecosystems in climate-change mitigation has been recognised, highlighting the importance of protecting and studying these precious environments.

In this work, changes in land use in the last two centuries are reconstructed through comparison with historical maps. At the beginning of the 19th century Napoleon Bonaparte requested the development of high-quality maps of occupied territories. Among these, the so-called ‘Carta del Ferrarese’ (CdF), completed between 1812 and 1814, is composed of 38 sheets and represents, to a scale of 1:15.000, 240.000 hectares of the Po lowlands, roughly corresponding to the present-day Ferrara district. The CdF, archived at the Kriegsarchiv in Vienna, is an extraordinary example among historical maps for its high quality and accuracy, which constitute a two-centuries-old reliable paleo-landscape picture.

Within the Historical Land Use Change research project, leaded by the Emilia-Romagna Statistical and GIS Service, the CdF was scanned, accurately georeferenced and orthorectified, showing a surprising generalized match with recent maps. More than 31.000 polygons were digitized in a GIS environment and interpreted on the basis of the European Corine Land Cover codes, properly modified for the land uses at the time.

Comparison with the recent land use analysis, carried out in 2014, highlights changes in land use, mainly related to land reclamation. Salt marshes and swamps, originally extended for 100.000 hectares, were reduced of about 85%, starting from 1861. Major phases of land reclamation occurred in 1870s and 1960s. Geochemical analyses on shallow samples (depth < 50 cm), depict OC content of artificially drained soils < 5% of the total volume. Soil texture testifies to the almost complete mineralization of OC after reclamation. Only recently drained soils show higher OC content, in the range of 10-15%.

How to cite: Meli, M. and Bruno, L.: Changes in land use in the last two centuries in the Po lowlands (northern Italy), EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9780, https://doi.org/10.5194/egusphere-egu21-9780, 2021.

11:28–11:30
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EGU21-9043
Olga Druzhinina, Kasper van den Berghe, and Alexandra Golyeva

In 2018, the Voorthuizen-Wikselaarseweg archaeological site was excavated. This settlement dates back to Roman and Medieval times and is located in the central part of the Netherlands: the so-called Gelderse Vallei, an area build-up of fluvioperiglacial and eolian sands. Questions related to the anthropogenic influence of settlers on the surrounding landscape, as well as the specification of the ancient agricultural activity, were among the main research tasks posed to this archaeological study. Despite the fact that modern geoarchaeology offers a variety of methods of researching archaeological sites, in practice, the vast majority of archaeological work in the Netherlands is limited to the use of palynological and macrobotanical analyzes and radiocarbon dating. The choice of research methods in relation to the sandy cultural layer is especially narrow as it is assumed to bear worse conditions of preservation of traces of anthropogenic activity.

For the investigation of the sandy cultural layer of Voorthuizen, a method of microbiomorphic (phytolith) analysis was proposed. The information that is given by this method is different from that provided by palynological study (though they strongly complement each other). While pollen provides a general insight into the plant growth in the region around the settlement, phytoliths (silica copies of plant cells)  present data on the plant species grown, eaten, and used on the settlement itself. This information is contained in the old living layer, as well as in the pits (working places and waste pits), postholes, ditches etc. The combination of phytoliths and other microbiomorphs (e.g. detritus, diatoms, etc.) essentially broadens the range of palaeoecological information.

In Voorthuizen 34 samples have been collected and processed according to standard sample treatment technique (Golyeva, 2008). All samples were found to be suitable for analysis, with a sufficient number of microbiomorphs.

The results of the study not only allow to clarify significantly the archaeological interpretation of the site but also provides new information on the anthropogenic impact on the landscape. Microbiomorphic analysis manifests the genesis of the cultural layer and the several phases and types of anthropogenic use of the territory. The research also demonstrates the applicability of the microbiomorhic (phytolith) analysis in the case of sandy archaeological layers.

References:

Golyeva А. А., Microbiomorphic complexes of natural and anthropogenic landscapes. Genesis, geography, informative capacity (LKI, Moscow, 2008) (in Russian).

How to cite: Druzhinina, O., van den Berghe, K., and Golyeva, A.: Application of the microbiomorphic (phytolith) analysis in the geoarchaeological study of the land-use at the Voorthuizen-Wikselaarseweg archaeological site (Netherlands) , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9043, https://doi.org/10.5194/egusphere-egu21-9043, 2021.

11:30–11:32
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EGU21-12753
Bernhard Lucke, Jago Birk, Michael Zech, Nora Voss, Günther Schörner, and Hussein al-Sababha

Patterns and intensities of past land use are mostly unknown. However, soils in the vicinity of archaeological sites usually carry significant amounts of material culture (mostly pottery sherds) which testify to past human activity. We surveyed surface transects of material culture and soil distribution, radiating from the city center of ancient Abila of the Decapolis. The city had been abandoned during the Medieval and was never resettled, which minimizes the presence of material culture from younger periods. In addition, earlier studies suggested that soil erosion of the rather level limestone plateau surrounding the site was rather limited, indicating that actual land surfaces largely represent those of antiquity. Our survey encountered strongly varying quantities of material culture, which correspond to some soil properties such as concentrations of faeces biomarkers of pork excrements. As the material culture mainly dates to Late Antiquity, and as pork consumption during the Islamic periods is rather unlikely, this indicates that the distribution of the archaeological material was to some degree connected with pig breeding during Antiquity. A possible practice leading to sherd deposition on fields could be manuring, such as from applying dung including pork excrements, but ratios of N-isotopes do not suggest that fields surrounding Abila were subject to application of larger amounts of manure. Therefore, it seems very likely that material culture deposition on the land surrounding Abila was partly connected with the herding of pigs, a land use practice that is attested in Biblical sources on the region.

How to cite: Lucke, B., Birk, J., Zech, M., Voss, N., Schörner, G., and al-Sababha, H.: Distribution of archaeological material scatters and soils at the site of Abila of the Decapolis, northern Jordan, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-12753, https://doi.org/10.5194/egusphere-egu21-12753, 2021.

11:32–11:34
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EGU21-14163
Oren Ackermann, Yaakov Anker, David Ben-Shlomo, Ralph Hawkins, and Naomi Porat

Dating of desert enclosure sites is challenging, as they have minimal diagnostic elements. Moreover, these sites are composed primarily of a single layer, which raises the question of whether they are of single or multi-period settlements. 

The current research aims to answer this question by assessing a group of enclosures in the Jordan Valley. The sites were previously surveyed and dated to the early Iron Age (ca. 1200–1000 BCE), and linked to tribes of Israelite settlement in the region. We present new excavations and OSL ages from Khirbet el Mastarah that indicate several periods of usage, and the possible construction and occupation of the enclosures during the following periods: 

Iron Age II (2570±220 yr), Late Hellenistic or Early Roman periods (2090±150 yr and 2120±160 yr), Late Byzantine (1410±200 yr, 1370±150 yr), Early Islamic and Islamic/Abassid periods (1000±90 yr and  1080±110 yr). Another indication that emerges from the results is that different enclosures were used at various locations during various periods, and are still used by local herders. Therefore, the site has horizontal chronology rather than vertical stratigraphy, and is characterized by a single-layer with multi periods of spatial usage.

How to cite: Ackermann, O., Anker, Y., Ben-Shlomo, D., Hawkins, R., and Porat, N.: Single-layer multi-periods? A Case Study of the Enclosure Site of Khirbet el Mastarah, Jordan Valley , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14163, https://doi.org/10.5194/egusphere-egu21-14163, 2021.

11:34–11:36
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EGU21-7615
Martin Janovský, Jan Horák, Oren Ackermann, Aharon Tavger, Deborah Cassuto, Ladislav Šmejda, Michal Hejcman, Yaakov Anker, and Itzhaq Shai

An ancient tell is a multi-period archaeological site, where anthropogenic, and natural sedimentation processes took place. Although a tell is primarily an anthropogenic type of geomorphological feature, it is affected by natural processes as well. This contribution discusses how these processes can be determined within the context of archaeological research and how it is possible to differentiate and interpret past-human activities and natural processes. Tel Burna, a site intensively occupied from the Early Bronze to Iron Ages (3rd millennium BCE – 6th century BCE) located in the southern Levant, was chosen for this study of the studying sedimentary processes and chemical compositions of sediments. The sedimentary processes were studied in the course of an archaeological excavation using POSL (portable optically stimulated luminescence), granulometry and PXRF (portable X-ray fluorescence). Focusing on the area along the fortification walls, data was collected from strata around the casemate fortifications dating from the Late Bronze Age to the Late Iron Age.

The gradual increase of OSL values obtained inside the casemate wall, indicate accumulation of sediment during a long period of time. Whereas similar values along the entire profile outside the casemate wall indicate sediment accumulation in one-time event. This might be related to defensive preparations, allegedly in response to advances made by Sennacherib’s army in 701 BCE. Results from the PXRF demonstrated a correlation between the Cu, P, K, Zn, Mn content and human activities. Ca content decreased as sampling descended from the tell's surface, suggesting its origin in post-abandonment aeolian processes.  The results demonstrate that the use of POSL and PXRF can be useful for determining sedimentary processes at ancient tells. The presented abstract is adapted from the article published in Quaternary International in 2020.

Acknowledgements:

The research is supported by project “Geochemical insight into non-destructive archaeological research” (LTC19016) of subprogram INTER‐COST (LTC19) of program INTEREXCELLENCE by Ministry of Education, Youth and Sport of the Czech Republic.

How to cite: Janovský, M., Horák, J., Ackermann, O., Tavger, A., Cassuto, D., Šmejda, L., Hejcman, M., Anker, Y., and Shai, I.: Biblical Tel Burna: contribution of POSL and PXRF to the discussion on sedimentary and site formation processes in archaeological contexts of the southern Levant, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7615, https://doi.org/10.5194/egusphere-egu21-7615, 2021.

11:36–11:38
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EGU21-13745
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ECS
Yoon Jung Choi and Byoungrok Yu

Reflectance spectroscopy is widely used to rapidly and quantitatively determine soil properties. This study introduces a method to identify archaeological soils, which are soils influenced by ancient anthropogenic activities, from the surrounding landscape using a portable VIS-NIR reflectance spectrometer. To identify spectral features of archaeological soils, the method statistically calculates the difference between an archaeological soil spectrum and a non-archaeological soil spectrum. Such difference is quantified by an R-value. Any soil spectra with R-values larger than 1 are more likely to be anthropogenically-affected soils.

Previously, the method was successfully applied to several archaeological sites in Italy and Hungary showing clear differences between the archaeological and non-archaeological soils. In this study, we will investigate the R-values for soils from prehistoric settlement sites in Sintanjin, Korea, and compare these to the results from Italy and Hungary. Both in-situ and topsoil spectral measurements were gathered using a portable ASD spectrometer. In this site, soils from kitchen areas showed R-values between 2.5 and 4.2, while soils from graves ranged from 1 to 1.4. The results indicate that the R-values vary a lot depending on the type of archaeological remains and a more detailed investigation of the method to various archaeological remains is essential to improve the method. One of our interesting results is that the method can be applied to soil spectra gathered with low-resolution spectrometers which leads to the possibility of applying continuous 2D spectral imaging applications.

How to cite: Choi, Y. J. and Yu, B.: Detection of archaeological soils through portable VIS-NIR spectrometer, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-13745, https://doi.org/10.5194/egusphere-egu21-13745, 2021.

11:38–11:40
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EGU21-9335
Joel Roskin, Oren Ackermann, and Yotam Asscher

Growing infrastructure development in Israel has increased the number of rescue excavations involving multi-layer archaeological sites and "megasites" in landscapes ranging from dunes to clay-rich soils and yielding prehistoric to early modern finds. The limited time and resources allocated for the excavations requires rapid on-site scientific data, which are used for research during and after excavation, prioritizing artefact treatment, sediment analysis, and absolute and relative dating.

Lateral and vertical pulsed-photon (portable) OSL (PPSL) profiling of sections of anthropogenically-altered sediments containing feldspar or quartz, provide rapid and partial answers for interpreting depositional processes. These answers allow researchers to discriminate between natural and human-intervened sedimentation, identify relative age and laterally synchronize between similar sediment units, which, in turn, often help to orient the excavation goals. The potential for inhomogeneity of archaeological sediments in some cases constrain the comparability of results and call for complementary analysis of the measured sediments in order to define their inter-compatibility. Independent mineralogical and chemical and textural properties of the sediments affect the inherent luminescence signals and should therefore be analyzed.

Here we present a PPSL profiling approach combining tailored sedimentological analyses to validate sample comparability in different sedimentological and archaeological settings. The analyses include gamma and FTIR spectroscopy, portable XRF geochemistry, carbon content, particle-size distribution and colorimetry. The complementary data are intended to improve PPSL protocols by characterizing the context inhomogeneity and helping to prioritize samples for OSL dating

How to cite: Roskin, J., Ackermann, O., and Asscher, Y.: Lateral and vertical pulsed-photon portable luminescence (PPSL) profiling of anthropogenically-altered sediments in rescue excavations of different landscapes , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9335, https://doi.org/10.5194/egusphere-egu21-9335, 2021.

11:40–11:42
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EGU21-15765
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ECS
Sofiya Demina, Ksenia Makhinya, and Viacheslav Vasenev

Soils and green spaces are involved in ensuring the sustainable development and functioning of cities, contributing to the reduction of volatile organic substances and fine dust in the air, the formation of a microclimate, optimization of water balance and the preservation of biodiversity, and provide cultural, aesthetic and educational functions and services. The interaction of soil and plant components has a more significant impact on the sustainable development of green infrastructure in the city. The study of these processes is relevant for new urbanized territories, where their properties are primarily influenced by the history of land use. The research is aimed at studying the soil and plant components of 10 parks located in New Moscow with a different history of land use. According to the data obtained from 4 parks (2 formed on the site of arable land and two formed on the site of a forest), the lightest particle size distribution can be noted in parks located at a distance of more than 15 km from Moscow Ring Road (sandy loam and light loam). The difference between soils in parks formed on the site of arable land from forest parks can be observed in color, the number of horizons in the profile, the abundance of anthropogenic inclusions, and a less pronounced structure. Chemical analysis data show the most significant pollution in parks located far from the Moscow Ring Road. For example, in the parks of the 3rd microdistrict of Moskovsky and Butovo, at none of the points is there an excess of the RPC of Ni, Cu, Cd, As, Pb, in contrast to the other two parks. Analysis of the state of tree plantations shows the impact of land-use history on species diversity in recreational areas. So in the parks formed on the site of arable land, decorative growing trees prevail, which do not grow in natural conditions, this territory. And in the forest-park zones, there is a similarity of the species composition because both parks are formed on the site of a mixed forest.

How to cite: Demina, S., Makhinya, K., and Vasenev, V.: Analysis of the interaction between soil and plant components of green infrastructure in urbanized areas: the case of New Moscow., EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15765, https://doi.org/10.5194/egusphere-egu21-15765, 2021.

11:42–11:44
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EGU21-16537
Maria Bronnikova, Lyudmila Shumilovskikh, Yulia Karpova, Andrey Panin, Irina Arzhantseva, and Heinrich Härke

Anthropogenic soils and soil-sedimentary systems (cultural layer, occupation deposit) in settlement archaeological settings are highly valuable and underappreciated archives of past environments, land-use activities, and life cycles within past residential areas. This study is aimed to reconstruct fire history for the early medieval town of Dzhankent located in Eastern Aral region, Kazakstan as based on the C14 dated stratigraphy, morphology and micromorphology, data on charcoal morphology, C:N and C13 isotope records.  

Several sections of cultural layers were studied within excavated areas. Stratigraphic units were thoroughly C14 dated (58 dates). Most 14C dates are between the 7th and 10th centuries, and most of the dates have overlapping intervals of calibrated age although clear up-section trends from older to younger ages may be seen. This demonstrates the slow, progressive accumulation of occupation deposits. The analysed excavation sections are very well stratified. Stratigraphic units based on char-enriched marker beds could sometimes be traced for long distances. Char enriched layers contain enormous quantities of both grass and wood charcoals. Thin, about 1 m long lenses of ash and charcoals of poor and unified taxonomic variety are thought to be fireplaces. Extended thick char-enriched layers (about 10 meters long and 0,1 m thick), well stratified at macro-, and micro-levels, with sub-parallel oriented charcoals of highly variable taxonomic compositions considered to be traces of big fires. Three fire events were detected based on the stratigraphy, morphology, charcoal amounts, C, N and C13 isotope depth variability.  

Filed studies and were funded by DFG project 389351859. The analytical part was supported by RFBR 19-29-05238, and DFG 389351859.

How to cite: Bronnikova, M., Shumilovskikh, L., Karpova, Y., Panin, A., Arzhantseva, I., and Härke, H.: Stratigraphy of habitation deposits and fire history of the early medieval town Dzhankent (Kazakhstan, Eastern Aral region)  , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-16537, https://doi.org/10.5194/egusphere-egu21-16537, 2021.

11:44–11:46
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EGU21-5161
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ECS
Anna Schneider, Alexander Bonhage, Florian Hirsch, Alexandra Raab, and Thomas Raab

Human land use and occupation often lead to a high heterogeneity of soil stratigraphy and properties in landscapes within small, clearly delimited areas. Legacy effects of past land use also are also abundant in recent forest areas. Although such land use legacies can occur on considerable fractions of the soil surface, they are hardly considered in soil mapping and inventories. The heterogenous spatial distribution of land use legacy soils challenges the quantification of their impacts on the landscape scale. Relict charcoal hearths (RCH) are a widespread example for the long-lasting effect of historical land use on soil landscapes in forests of many European countries and also northeastern USA. Soils on RCH clearly differ from surrounding forest soils in their stratigraphy and properties, and are most prominently characterized by a technogenic substrate layer with high contents of charcoal. The properties of RCH soils have recently been studied for several regions, but their relevance on the landscape scale has hardly been quantified.

We analyse and discuss the distribution and ecological relevance of land use legacy soils across scales for RCH in the state of Brandenburg, Germany, with a focus on soil organic matter (SOM) stocks. Our analysis is based on a large-scale mapping of RCH from digital elevation models (DEM), combined with modelled SOM stocks in RCH soils. The distribution of RCH soils in the study region shows heterogeneity at different scales. The large-scale variation is related to the concentration of charcoal production to specific forest areas and the small-scale accumulation pattern is related to the irregular distribution of single RCH within the charcoal production fields. Considerable fractions of the surface area are covered by RCH soils in the major charcoal production areas within the study region. The results also show that RCH can significantly contribute to the soil organic matter stocks of forests, even for areas where they cover only a small fraction of the soil surface. The study highlights that considering land use legacy effects can be relevant for the results of soil mapping and inventories; and that prospecting and mapping land use legacies from DEM can contribute to improving such approaches.

How to cite: Schneider, A., Bonhage, A., Hirsch, F., Raab, A., and Raab, T.: Accumulation patterns of soil organic matter in forests as a legacy of historical charcoal burning, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-5161, https://doi.org/10.5194/egusphere-egu21-5161, 2021.

11:46–11:48
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EGU21-5691
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ECS
Alexander Bonhage, Samuel Bayuzick, Patrick Drohan, Florian Hirsch, and Thomas Raab

Across much of the Mid-Atlantic United States and Europe, relict charcoal hearths (RCHs) are a common landscape feature once used as a primary fuel source for iron smelting and quick-lime production. We investigated a landscape surrounding the Monroe Furnace in central Pennsylvania, which was in operation for around 17 years until 1846. This preliminary investigation explores landscape patterns of hearth placement in relation to the furnace and landscape position and resulting potential effect on soil moisture. We mapped RCHs using LiDAR derived hillshade models of varying aspects, elevation, and slope. We classified the different shapes of RCHs in relation to their geomorphic positions and modeled both a topographic and soil wetness index for selected hearths and off-hearth locations nearby. Two hearths were sampled in the field and their morphology and soil properties investigated.

Hearths that were constructed on flatter slope gradients are seemingly more circular in shape and have more equal axes whereas steep slopes have a more oval shape elongated in one axis with the slope direction. More circular hearths are on or near flatter hillslope positions (such as on summits or shoulders) whereas eye-like shaped hearths are on steeper hillslope positions (like backslopes).  Based on initial topographic wetness index data, hearths are not acting as sinks for flow but instead often cause water to flow around them leading to drier conditions within RCHs.

Trenches alongside the slope orthogonal direction of the two sampled RCHs show a single layered stratigraphy, i.e. both sides had only one continuous technogenic, charcoal rich layer. The downslope half of both sites had generally higher contents of macroscopic charcoal pieces as well as buried colluvial- and buried fossilized A-horizons underlying the charcoal rich layer. Both sites are not perfectly levelled, but slightly sloped. Buried B- and colluvial horizons show signs of heat induced reddening of iron oxides on the top few centimeters. Preliminary results suggest significant differences in soil chemical and physical properties of the technogenic layer in comparison to the adjacent forest soils.

How to cite: Bonhage, A., Bayuzick, S., Drohan, P., Hirsch, F., and Raab, T.: Relict charcoal hearth landscape and soil profile characteristics surrounding a mid-19th century Appalachian iron furnace , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-5691, https://doi.org/10.5194/egusphere-egu21-5691, 2021.

11:48–11:50
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EGU21-13618
Patrick Drohan, Samuel Bayuzick, Duane Diefenbach, Marc McDill, Thomas Raab, Florian Hirsch, and Alexander Bonhage

Abrupt changes in a forest ecosystem, whether natural or anthropogenic, are changes that occur over short time periods; such disturbance has the potential to drive state changes and alter forest resilience. Understanding how present-day abrupt forest change may alter ecosystem services is becoming more important due to ever-growing anthropogenic stresses. Forest managers trying the adapt to anthropogenic stress can benefit from the study and quantification of past abrupt changes in forests, especially when the legacy of past disturbance is still evident. Across the United Kingdom, Europe, and recently the northeastern United States, the examination of historic forest change due to charcoal manufacturing for the firing of iron or lime furnaces is yielding new insights relative to landscape stability, anthropogenic vs natural soil genesis, and forest evolution. We present results of a study that strives to evaluate how historic land clearing for the charcoal industry (supporting iron furnaces) affected local soils and may drive surrounding present day forest composition. We incorporate field sampling of hearth soils and modeled hydrologic parameters (in hearth and non-hearth areas), to quantify the uniqueness of relict charcoal hearth (RCH) systems. We identified 1,239 hearths using a LiDAR terrain analysis; approximately 10% of these were visited to quantify hearth morphology and soil moisture differences on and off hearth. Nine hearths from this 10% were intensively sampled and were associated with a northern Appalachian, USA furnace that was in operation from 1867 to 1904. Three profiles were excavated across each hearth and compared to an adjacent soil profile on the same contour. Soil descriptions were made of hearths and soil samples analyzed for total, trace and rare earth element content (Aqua Regia digestion). Soil pH (water) and fertility (Mehlich III extraction) were also determined. Results indicate that hearths have a unique geochemistry with higher bases and some concentrated metals and higher organic carbon. Coupled with a higher hearth soil water content, hypothesized to be due to an observed restrictive subsurface morphology and higher organic carbon, hearths are potentially unique locations of refugia for forest flora and fauna. Future research should more closely investigate whether hearths support unique species assemblages and how they may play a role in enhancing today’s forest biodiversity.

How to cite: Drohan, P., Bayuzick, S., Diefenbach, D., McDill, M., Raab, T., Hirsch, F., and Bonhage, A.: Northern Appalachian, USA relic charcoal hearths and their unique Ecological Fingerprint , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-13618, https://doi.org/10.5194/egusphere-egu21-13618, 2021.

11:50–11:52
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EGU21-6243
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ECS
Samuel Bayuzick, Patrick Drohan, Thomas Raab, Florian Hirsch, Alexander Bonhage, Marc McDill, and Duane Diefenbach

Throughout the northeastern United States and Europe, relic charcoal hearths (RCHs) are more regularly being discovered in proximity to furnaces used for iron or quick-lime production; charcoal was used as a primary fuel source in the furnaces.  RCHs have been found across parts of Europe and Connecticut, USA in different hillslope positions, on vary degrees of slope and aspect, all of which can be a factor affecting the shape of the RCH.  Their usage for charcoal production varied with the time period, furnaces were in operation with some hearths being used once and older ones (such as in Europe) being used multiple times. RCHs across the northcentral Appalachians, USA have been minimally investigated, thus determining where they occur on the landscape, their shape, and their morphologic positions will be useful in discerning their effect on surface hydrology and soil development. Our study focuses on developing a repeatable process for: finding RCHs and quantifying how RCHs may alter surface hydrology.  

We used a combination of processed LiDAR data to create hillshades, and slope gradients to visualize RCHs.  A total of 6,758 hearths have been digitized across three study areas that reflect different historical time periods of construction and environments. We hypothesize that the construction of RCHs can alter the surface hydrology of their surrounding environments. To fully quantify the landscape-level effects of RCHs, a subset of the total was created to fully digitize the RCHs’ area.  The RCH was broken into their rim and platform components.  A topographic wetness index (TWI), and SAGA wetness index (SWI) was created for two study areas in order to quantify surface hydrology effects.  We found that RCH platforms have a significantly higher TWI and SWI than the rim counterparts indicating that the platform is wetter than the RCH outer rims.  Geomorphic position was found to not effect wetness.  Using field measured volumetric water content, we found that as distance from the center of the hearth increases, the drier the soil becomes. Using a combination of GIS flow path analysis, and RCH geometry, standardized ellipses using the axis of local RCHs and the mean area of the total RCHs were created to understand the upslope (control) and downslope (experiment) effects of hearths on the surface hydrology.  Preliminary analysis indicates that downslope positions from RCHs are drier than upslope positions and that there is a significant difference in the relationship between slope position and distance from an RCH and the corresponding TWI and SWI values. Future research will address the effect of slope position and distance to quantify the effect of RHCs on surface hydrology. Furthermore, the soil chemical changes from RCH creation and the increase moisture may increase the habitat for rare species of both plants and animals that otherwise would not be present.  Understanding the extent of the impact human activity can have on various ecosystems can help forest managers, conservationists, pedologists, and climatologists better adapt their management or research pursuits within a specific environment to prepare for future changes, natural or anthropogenic.

How to cite: Bayuzick, S., Drohan, P., Raab, T., Hirsch, F., Bonhage, A., McDill, M., and Diefenbach, D.: Relic charcoal hearths geomorphology and hydrology in mid-Appalachian region of Pennsylvania , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-6243, https://doi.org/10.5194/egusphere-egu21-6243, 2021.

11:52–12:30