Quartz is one of the most common minerals in the Earth’s crust and can be found in a large diversity of geological environments. Due to its ubiquity and resilience towards weathering, it is a major mineralogical component in terrestrial sediments. A good understanding of quartz properties can thus be very useful to understand quartz dynamics and thereby Earth surface dynamic processes such as erosion, transport and deposition.

Electron spin resonance (ESR) spectroscopy is a method which allows to characterize paramagnetic centres (unpaired electrons related to geochemical impurities) in quartz. Two paramagnetic centres generally present in quartz (Al and Ti-Li centres) are sensitive to ionizing radiation on the one hand and light exposure on the other hand and can be used to date the transport and deposition of quartz in the timescale of ca. 50 ka to 3 Ma making ESR dating of quartz an excellent tool to constrain quaternary geological processes.

While this method has continuously been developed and improved over the last decades, some key aspects of the method, notably the sample dependency of dose response and sensitivity, remain poorly understood, leading to difficulties or even impossibility to date some samples.

In this contribution, we aim to identify the influence of source-specific signature and sediment cycling on ESR dose response and sensitivity. Our research focuses on the well characterized Strengbach catchment in the Vosges mountains (NE France) which drains a large variety of quartz bearing rocks (granites, gneiss, sandstones). Quartz extracted from different bedrocks was analyzed geochemically by Laser ablation coupled to mass spectrometry (LA-ICPMS) and by ESR. Subsequently, the quartz was artificially irradiated and bleached in order to reproduce natural sediment cycling and reinvestigated by ESR. We discuss the observed ESR differences in relation with their geochemical signature and examine possible reasons for the observed results.

How to cite: Heller, B., Voinchet, P., Chourio Camacho, D. N., Aupart, C., Rixhon, G., Lach, P., Valla, P., Boulay, M., Rizza, M., and Tissoux, H.: ESR dating of quartz revisited: towards a better understanding of ESR sensibilities through investigation of different quartz types and experimental reproduction of sediment cycling, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10339, https://doi.org/10.5194/egusphere-egu25-10339, 2025.

The Variscan basement units of the Bohemian Massif and other Variscan domains in Central Europe are thought to be less affected by Cenozoic tectonics. However, analyses using geomorphic indices and river profiles reveal spatial variations in the evolved topography in the Bavarian Forest, the southwestern segment of the Bohemian Massif. The geomorphic analyses suggest disequilibrium along drainage divides and in river profiles. It has been suggested that the topography in the southern parts of the Bohemian Massif has rejuvenated (Zebari et al., 2024). However, interpretations aimed at extracting tectonic signals from geomorphic analysis are inherently relative, and it is sometimes challenging to separate tectonic signals from climate signals or differential erodibility. To further quantify landscape dynamics in the Bavarian Forest, we estimated long-term watershed-averaged denudation rates from in-situ produced ¹⁰Be cosmogenic nuclide analysis of sand samples collected from outlets of 15 representative watersheds in the Bavarian Forest.

Our initial results indicate that watershed-averaged denudation rates in the Bavarian Forest range from 21.1 ± 2.4 to 40.5 ± 4.8 mm/kyr. These denudation rates represent a time period equivalent to the removal of approximately 60 cm of rocks, corresponding to about 15 kyr for the fastest-eroding watershed and about 28.5 kyr for the slowest one. There are spatial variations in the denudation rates, with the watersheds clustering into several distinct subregions. Overall, watersheds in the southeast, within or around the Ilz catchment, and those in the high-elevation areas of the Hinterer Bayerischer Wald, have relatively higher denudation rates than those in the central segment of the Vorderer Bayerischer Wald. Furthermore, notable differences are also found across the drainage divide between the Regen and Danube rivers in the adjacent watersheds, and these differences are consistent with the analysis of drainage divide dynamics using the χ (Chi) integral. Additionally, the calculated denudation rates also correlate with the topographic metrics of watershed and river profiles.

The same climatic conditions and minimal contrast in rock erodibility are expected for the adjacent watersheds in the Bavarian Forest; therefore, these denudation rates may represent a brief time window within a longer span of tectonic processes that shaped the relief there. Broad surface uplift of the Northern Alpine Foreland Basin and beyond, since prior to 6 Ma, and associated drainage network reorganization may have also affected the southern regions of the Bohemian Massif, resulting in the rejuvenation of topography in the Bavarian Forest, notably within its southeastern part. Thus, it is expected that the driving forces for the broad-scale recent surface uplift event(s), which affected the Bavarian Forest, also reactivated the major bounding faults.

References:

Zebari, M., Friedrich, A. M., Ludat, A. L., Kahle, B., Rieger, S. M., & Kübler, S. (2024). The role of late Cenozoic intraplate tectonic in shaping the topography of the Bavarian Forest, southwestern Bohemian Massif, Germany. Geologica Bavarica, 130: 35–55.

How to cite: Zebari, M., Wittmann, H., and Friedrich, A.: Late Pleistocene-Holocene denudation rates in the Bavarian Forest from in-situ produced 10Be cosmogenic nuclides , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5647, https://doi.org/10.5194/egusphere-egu25-5647, 2025.

Quantifying the magnitude of rapid changes in our past climate system is paramount to our awareness of the scale and impact of current and future climate change. While a number of proxies enable surface air temperature reconstructions, methodological limitations and preservation issues limit the spatial coverage and timeframe for which most of these can be sucessfully applied. As a result, for major changes in our climate system like the Pleistocene-Holocene transition including the rapid warming and environmenal adaptions following the Last Glacial Maximum (LGM), the lack of  terrestrial records leads to increased uncertainty in reconstructions of continental temperature.

Recently, low-temperature thermoluminescence (TL) signals of feldspar (i.e., 200–280 °C) have been shown to be sensitive to terrestrial temperature fluctuations over geological timescales and can thus inform on past surface temperature in terrestrial settings (Biswas et al., 2020). Using physical principles best known from trapped charge dating, the trapped charge population can be used to infer paleotemperatures in the form of temperature histories through inverse modelling. For this, other time resolved relative temperature records such as the Greenland ice sheet 𝛿¹⁸O-, speleothem-, or pollen records can be used as additional constraints.

Applying the TL paleothermometry approach, we present first reconstructions of LGM surface air temperatures at central European study sites. Additionally, we benchmark improvements of the method against samples from stable temperature crustal environments, namely the KTB and MIZ-1 boreholes located in Germany and Japan, respectively. Our ultimate objective is to combine these data with other northern hemisphere samples to improve our understanding of the Euro-African LGM continental surface air temperature.

References

Biswas, R.H., Herman, F., King, G.E., Lehmann, B., Singhvi, A.K., 2020. Surface paleothermometry using low-temperature thermoluminescence of feldspar. Clim. Past 16, 2075-2093.

How to cite: Oehler, S., Schmidt, C., Niyonzima, P., King, G. E., Biswas, R. H., and Herman, F.: Thermoluminescence paleothermometry enables LGM surface temperature reconstruction at central European study sites, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6215, https://doi.org/10.5194/egusphere-egu25-6215, 2025.

Latest with the onset of the Neolithic period, humans have modified the landscape by farming, extracting natural resources, and reducing forest cover. Many studies have demonstrated that these human activities can increase the vulnerability of soils to erosion. However, the magnitude and duration to which such activities have reduced forest cover and accelerated soil erosion have been mainly based on proxy data derived from sediment and pollen records. In this study, we test a new methodological approach by coupling leaf wax isotope analyses with erosion rate measurements based on ¹⁰Be and ¹⁴C to investigate the impact of human activities during the Holocene on vegetation and erosion rates on the island of Elba, Italy. We hypothesize that meeting the substantial fuel demands for iron smelting on Elba Island, initiated by the Etruscans and subsequently continued by the Romans from the 4^th century BCE onwards, exerted significant pressure on the island's forest ecosystems. This reduction of forest cover likely accelerated soil erosion processes, driven by the removal of vegetative cover essential for soil stability. To test our hypothesis, we measured cosmogenic ¹⁰Be and ¹⁴C in quartz from stream sediment samples to reconstruct changes in erosion rates during the Holocene. We complemented this with leaf wax isotope analysis (δ²H, δ¹³C) from floodplain sediment cores to explore vegetation and hydrological changes. Due to the shorter half-life of ¹⁴C compared to ¹⁰Be (~5.7 kyr and ~1.4 Myr, respectively), ¹⁴C records erosion on shorter time scales than ¹⁰Be. Apparent erosion rates obtained from the two nuclides show a marked offset: ¹⁴C apparent erosion rates of 129 to 1080 mm kyr ^-1 are up to two orders of magnitude faster than the corresponding ¹⁰Be erosion rates of 20 to 50 mm kyr ^-1. This discrepancy can be explained by a substantial increase in erosion toward modern times. To identify the timing of erosion change and thickness of soil loss, we apply a Markov chain Monte Carlo inversion with several simple erosion histories. These data allow us to compare the history of land use with vegetation change and the erosion response on a landscape scale.

How to cite: Cerón Espejo, N., Scherler, D., Bernhardt, A., Rohrmann, A., Bebermeier, W., Becker, F., Wittmann, H., Dunai, T., Fulop, R., and Ott, R.: Erosion rate response to the reduction of forest cover following metallurgical activities on Elba Island (Italy), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10549, https://doi.org/10.5194/egusphere-egu25-10549, 2025.

Neotectonics of Eastern Türkiye is mainly characterized by immensely complex deformation patterns driven by the convergence between the Arabian Plate and the Eastern Anatolian Plateau. This apparent convergence accommodates a primary intraplate strike-slip fault system, encompassing the North Anatolian Fault Zone (NAFZ) and the East Anatolian Fault System (EAFS). Recent seismic events, such as the 24 January 2020 (Mw6.8) earthquake and the 6 February 2023 doublet earthquake (Mw7.7 and Mw7.6), dramatically highlight the structural intricacy of the region and signify that the conundrum is much broader than initially thought. The ruptures occurred after the two earthquake sets abruptly terminated the onset of the Pütürge segment residing in the EAFS. The segment splits the Şiro Valley in two and is hypothesized to accumulate strain, potentially driven by aseismic creep.

Our multidisciplinary investigations focus on the deformation and seismic potential of the Pütürge segment, emphasizing critical questions regarding its long-term slip rate, uplift rate, and past earthquake cycle. Geochronological methods, including Optically Stimulated Luminescence (OSL) and Radiocarbon (¹⁴C) dating methods, have been applied to Quaternary River terrace deposits along the Şiro Valley. Three distinct terrace levels (T0, T1, and T2) were identified by measuring stratigraphic sections, with thickness of approximately ~1 m, ~11 m, and ~12 m, respectively. These terraces, shaped by predominantly sinistral strike-slip movement with somewhat oblique components, stand out as geologic archives of tectonic and fluvial activity.  The terrace deposits primarily consist of clays, silts, sands with organic material, gravels, and boulder stemming from the Maden Complex and Pütürge Metamorphics, rich in quartz and feldspar. Preliminary OSL dating employing the single-aliquot regenerative dose (SAR) technique on quartz grains from the T1 terrace yielded ages ranging from 11.42 ± 1.97 ka to 28.18 ± 3.00 ka at the Gölkan site and 12.82 ± 0.95 ka to 30.92 ± 4.85 ka at the Yazıca site, located on the northern and southern margins of the Şiro Valley, respectively. Further analyses of samples from additional terrace levels are still ongoing.

These preliminary yet clear findings suggest that the Pütürge segment has experienced significant post-Quaternary tectonic activity. Furthermore, the seismogenesis of the Pütürge segment, in conjunction with known geological information, raises another issue to consider. The fault's seismicity patterns and parameters will be examined in that sense. Spatial and temporal Gutenberg-Richter recurrence parameters are valuable knowledge that helps us to calculate the return periods of apparent and possible scenario earthquakes. The deformation pattern will be tested to see if it is used as a key indicator of how the Valley is heading through and evolving. As the fieldwork, lab tests, and computational modeling have been underway and are close to finalization, this study aims to present preliminary geochronological dating results inferred from Quaternary fluvial terrace formations. Also, it explores their implications for the seismic hazard and tectonic evolution of the East Anatolian Fault System. This study is fully supported by the Scientific and Technological Research Council of Turkey (TÜBİTAK; Project No:122Y266).

How to cite: Akgün, E., Softa, M., Nas, M., Yüksel, M., Spencer, J. Q. G., Sözbilir, H., Aksoy, E., Gürgöze, S., and Topal, S.: Evidence for Long-term Quaternary Tectonic Activity of the Pütürge Segment in the East Anatolian Fault System (EAFS) by Using Luminescence and Radiocarbon Dating Methods, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12012, https://doi.org/10.5194/egusphere-egu25-12012, 2025.

Cosmogenic nuclides measured in depth-profiles are a valuable tool for reconstructing the depositional and erosional history of sedimentary sequences. The burial ages of these sequences can be determined by measuring cosmogenic nuclide pairs such as ²⁶Al and ¹⁰Be. However, some conventional approaches neglect post-burial nuclide production, a major source of error.

A new model, CosmoChron (Sørensen et al., 2024, Quat. Geochron. 85, 101618), enables a more versatile and comprehensive analysis by integrating nuclide data with independent age constraints, such as OSL dating or magnetostratigraphy. CosmoChron employs probabilistic inverse modeling, incorporating prior information about accumulation processes and sample origins. The forward model accounts for ²⁶Al/¹⁰Be ratios, pre-burial conditions, radioactive decay, post-burial production, and unconformities, allowing for more precise reconstructions, including hiatuses at unconformities.

We demonstrate CosmoChron via two case studies: (1) a drill-core at Wapenveld (the Netherlands) penetrates the Early Pleistocene “Hattem” beds—thought to be among the earliest glacigenic deposits in Europe. The samples are from three distinct layers with several unconformities and a stratigraphic age constraint at the base. And (2) Fisher Valley (Utah, USA) contains samples from Early Pleistocene alluvial sediments with depth-profile burial ages published by Balco and Stone (2005, ESPL 30, 1051-1067). We recalculate the age-depth relationship, compare the methods, and explore the differences in the results.

We discuss the advantages and limitations of depth-profiles and CosmoChron, emphasizing its ability to provide detailed temporal reconstructions while requiring robust site-specific information.

How to cite: Ylä-Mella, L., Wagner, K., Sørensen, A. L., Knudsen, M. F., Busschers, F., Bakker, M., Eriksen, B. L., Andersen, J. L., Olsen, J., Margold, M., and Jansen, J. D.: Unraveling burial histories with CosmoChron, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12361, https://doi.org/10.5194/egusphere-egu25-12361, 2025.

Exposure dating has become a critical tool in addressing specific geoscientific challenges, including glaciology, active fault studies, and environmental reconstructions. Cosmogenic exposure dating (e.g., ³⁶Cl) and luminescence surface exposure dating are widely used techniques, often complementing each other. In active tectonic studies across Türkiye, cosmogenic ³⁶Cl dating has been applied extensively to active faults to elucidate paleoseismic histories and slip rates. Although luminescence surface exposure dating is relatively new in this context, its initial applications along the Manisa Fault in Western Türkiye have shown promising results. In this study, we focus on the Kalafat and Yavansu faults within the Kuşadası Fault Zone, which is considered the eastern continuation of the Samos Fault that ruptured during the 30 October 2020 earthquake. This region, characterized by N-S extensional tectonics with horst-graben structures and normal faulting, offers well-preserved fault scarps that serve as natural laboratories for exposure dating.

Preliminary luminescence depth profiling of scarp samples and optically stimulated luminescence (OSL) dating of associated colluvial wedges provide valuable insights into the paleoseismic history of these faults: (i) Luminescence profiling revealed stable signal limits at ~6 mm, with intensity increasing with depth; (ii) Calibration against prior cosmogenic dating yielded uppermost ages of ~15 ka for KF and ~8 ka for YF; (iii) OSL dating of colluvial wedge bases produced ages of 16.56 ± 1.77 ka for KF and 14.45 ± 0.74 ka for YF. These results indicate significant seismic activity along both faults during the Late Pleistocene, consistent with regional tectonic processes. This research underscores the utility of integrating luminescence surface exposure techniques with cosmogenic methods for refining paleoseismic chronologies. This study is fully supported by the Dokuz Eylül University Scientific Research Project (Project No. FBA-2023-3042).

How to cite: Softa, M., Şahiner, E., Spencer, J. Q. G., Sözbilir, H., Yüksel, M., Utku, M., Akçar, N., Kırallı, S., Yerli, B., Çakır, R., Büyüktopçu, F. M., and Deniz, F.: Luminescence Surface Exposure Dating and Paleoseismic Insights from the Kuşadası Fault Zone, Western Türkiye, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14332, https://doi.org/10.5194/egusphere-egu25-14332, 2025.

Cosmogenic nuclide concentrations are typically inverted for erosion and soil production rates under the assumption that these rates are temporally invariant, and that soil thickness is in steady state. Yet, transience in process rates and soil thickness is expected to occur in landscapes that are experiencing changes in land use, tectonic uplift, and climate. Pairing cosmogenic nuclides with different half-lives provides a means for resolving transience if process rates are sufficiently slow that radioactive decay is significant. Here, we examine ¹⁰Be and ²⁶Al concentrations in quartz collected from saprolite at 6 positions along a hillslope transect in the Belgian Ardennes. This transect runs from a low relief paleosurface to the bottom of a catchment incised ca. 30 meters into the paleosurface. We find that all measured ²⁶Al/¹⁰Be ratios are below the production ratio and that the ratio on the paleosurface is near secular equilibrium. Furthermore, all samples plot below the steady-state erosion line on an ²⁶Al/¹⁰Be two-isotope plot. Given the geomorphic position of the site on a regional topographic high, it is unlikely that the ²⁶Al and ¹⁰Be concentrations can be explained by burial by sediment to a depth sufficient to shut-off cosmogenic nuclide production. Rather, we model the isotope concentrations as resulting from transience in the soil production rate and soil thickness. The model indicates that the mean soil thickness over the integration timescale of the cosmogenic nuclide signal exceeds the modern measured soil thickness.

How to cite: Moore, A., Li, Y., Henrion, M., Christl, M., Gautschi, P., Jonard, F., Lambot, S., Van Oost, K., Opfergelt, S., and Vanacker, V.: Using paired cosmogenic 26Al and 10Be to study landscape transience in the Belgian Ardennes , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15019, https://doi.org/10.5194/egusphere-egu25-15019, 2025.

Understanding the temporal pace and spatial pattern of alluvial fan-river system evolution in front of active orogens would help us properly extract information of active tectonics and increase our resilience to landscape evolution of this habitable area. The northern piedmont of Chinese Tianshan, where the landscape is shaped by the interactions among fan building and abandonment, river aggradation and degradation and fault related fold growth. Comprehensive studies have been performed to delineate fan distribution, river incision and fold growth history. However, it is lack of investigation on the detailed spatial and temporal pattern of river channel evolution in a full aggradation and degradation cycle, which hinders formulating the law for alluvial system evolution. In this study, we address this question by using luminescence dating technique to constrain the chronological sequences of sandy samples collected from the terrace deposits. The architecture of the terrace deposits is characterized by upper very coarse gravels and cobbles (VCGC) unit and lower medium and coarse gravels (MCG) unit. The VCGC unit is attributed to the deposition during the incisional phase while the MCG unit is related to the aggradation phase of Jingou River. The coupled luminescence ages from VCGC and MCG units suggested a gradual and slow aggradation of 25 m sediments from 16 ka to 8 ka ago, which was followed by an almost instant incision around 5.5 ka ago by 25 m at least. These observations echo to the patterns unveiled by previous numerical studies. Further, the abandonment ages determined by employing the samples from the MCG unit of the most extensively distributed terrace surface T5 along the middle reach of Jingou river decrease in downstream direction from 16 ka to 5.5 ka, which poses an evidence of diachronous terrace formation. The implication of asymmetric degradation-aggradation phases and diachronous terrace formation will be discussed, with respect to the mass redistribution processes and active tectonics characterization of the alluvial fan and river system.

How to cite: Qin, J., Li, K., Chen, J., Liu, J., and Yao, Y.: Unconventional spatial and temporal pattern of alluvial river aggradation and degradation, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16613, https://doi.org/10.5194/egusphere-egu25-16613, 2025.

Quantifying erosion and linking its topographic imprint to underlying controls is critical for understanding landscape evolution and sediment dynamics across time and space. Over the past decades, catchment-wide denudation rates from cosmogenic ¹⁰Be concentrations in river sediment emerged as a standard method for quantifying erosion. As such, ¹⁰Be-based erosion data have been instrumental in proposing different controlling mechanisms and processes for distinct mountain ranges. These include tectonic uplift, often modulated by periglacial processes, precipitation gradients, bedrock erodibility, landslide frequency, and most prominently, hillslope morphology, i.e., the slope angle. However, disentangling the individual effects of these processes has proven challenging, and often, the correlation between erosion rates and topography is observed only up to threshold values, e.g., slope angles <30° in the European Alps. One potential reason for this is that most data on the erosion rate are obtained for catchments on a regional scale (>10¹ to 10³ km²), where sediment mixing and storage, as well as the (dis)connectivity and stochastic nature of sediment sources, obscure the influence of individual processes on local erosion dynamics.

Here we present 16 new detrital ¹⁰Be erosion rates from two nested river catchments in Switzerland: the Luetschine in the Alps and the Schwarzwasser in the Pre-Alps. Despite being close (<50 km between outlets), these catchments display significant differences in topography within and between them. While the Schwarzwasser catchments are characterized by gentle slopes (mean values <21°) and mean altitudes of <1500 m a.s.l., the Luetschine catchments drain the northern rim of the highly elevated Aar Massif, resulting in steeper (up to 37° for mean slopes) and higher (mean altitudes of >2000 m a.s.l.) landscapes. To investigate how these topographic variations influence erosion rates, we sampled sub-catchments with progressively smaller drainage areas ranging from over 340 km² to less than 3 km² in the smallest upstream tributaries.

Overall, our resulting detrital ¹⁰Be erosion rates for the entire catchments are, 3-4 times higher for the Luetschine catchment than for the Schwarzwasser. They align with the general regional trend and the first-order control by the topographic uplift rate inferred by previous studies. In more detail, even in the topographically homogeneous Schwarzwasser basin, where erosion rates generally correlate with the average slope angle, the erosion rates internally vary by up to a factor of two, with the delivery of landslide material to the stream being the primary control. In the Luetschine basin, which comprises highly heterogeneous landscapes, the erosion rates differ by a factor of up to five among sub-catchments. Here, the highest and lowest values are obtained from the smallest catchments, and they do not correlate with slope angles in these steeper catchments (> 30 ° mean slope). Instead, locally different mechanisms, such as peri-glacial and glacial erosion, effectively modulate erosion rates. These findings reconcile contrasting control mechanisms for mountain range scale erosion on a local scale within the close geographical vicinity of our study area. These results underscore the need to sample smaller catchments and to consider topographic heterogeneity to link erosion and topography in steep environments.

How to cite: Mair, D., von Allmen, J., Ruffiner, P., Binaghi, M., Schmidt, C., Garipova, S., Akçar, N., Christl, M., and Schlunegger, F.: Linking highly variable Detrital 10Be Erosion Rates to heterogeneous Topography in Small and Alpine Catchments, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18560, https://doi.org/10.5194/egusphere-egu25-18560, 2025.