The New Zealand Alps offers excellent opportunities to investigate the nature and timing of past climate variability during the Holocene. Some glacial geochronological studies have been published focussing on this key site for the mid-latitudinal southern hemisphere, but a considerable degree of uncertainty and differences in individual chronologies have emerged. Specific glacial characteristics of this climatically and geomorphologically dynamic mountain region coupled with different analytical dating methodologies need to be correctly quantified, combined, and evaluated to better understand the complexities of New Zealand’s more recent glacial history.

In this study we applied ¹⁰Be cosmogenic radionuclide dating (CRN; n = 54) and Schmidt-hammer exposure-age dating (SHD; n = 42,000) to obtain surface exposure-ages from moraine boulders on Holocene glacier forelands in the eastern Aoraki/Mt.Cook National Park (Classen Glacier, Godley Glacier, Murchison Glacier and its tributaries) and the Arrowsmith Range (Ashburton Glacier, Cameron Glacier). SHD was performed utilising both regional SHD age-calibration equations based on published independent CRN ages and locally-adjusted equations based on our new CRN data and additional chronological information. This multi-proxy approach was combined with detailed geomorphological mapping and analysis to tackle the regionally specific 'geomorphological uncertainty' potentially interfering with subsequent interpretation of chronological data. We directed considerable effort to carefully define the glacial geomorphological context to guide our sampling strategies to ensure robust and reliable results.

On the foreland of Classen Glacier we establish a new geomorphologically reliable moraine site for a significant Mid-Holocene advance at 5 - 6 ka. At Godley and Murchison Glaciers, new precise ¹⁰Be ages reveal the outermost Holocene moraines date from the 'Little Ice Age'.  Our new SHD and CRN data coupled with geomorphological mapping shows that Late Holocene moraines which pre-date the 'Little Ice Age', occur at two glaciers in this area. In contrast, SHD and CRN data from Ashburton Glacier constrain the outermost moraine ridge to strong glacial activity during the Early Holocene. The number of advances unambiguously represented by moraines is, however, smaller than previously reported from nearby Cameron Glacier. At both glaciers, moraines representing the maximum 'Little Ice Age' glacier advance give SHD-age estimates that predate respective moraines in Aoraki/Mt.Cook National Park by more than 150 years. With no confirmed evidence for multiple advances during the Early Holocene in Aoraki/Mt.Cook National Park, these significant differences indicate that amalgamation of Holocene glacier chronologies from both areas is not justified. The morphostratigraphic configuration and individual morphology of moraines on the glacier forelands is complex and in some cases may be explained by excessive supraglacial debris caused by large mass movement events. This situation seems prevalent across the forelands and probably typical for the entire Southern Alps.

Our new Holocene glacier chronology shows considerable discrepancy to previously published studies, in particular regarding the number and timing of Late Holocene glacier advances. Further refinement of the Holocene glacier history for the Southern Alps constitutes a significant challenge requiring a more detailed understanding in the spatial variability of individual glaciers of the region.

How to cite: Winkler, S., Fink, D., Baldwin, S., and Simon, K.: An Early Holocene to 'Little Ice Age' glacier chronology for New Zealand's Southern Alps - challenges, improvements, and implications, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1979, https://doi.org/10.5194/egusphere-egu25-1979, 2025.

The geochronological dating of glacial landforms, particularly terminal and lateral moraines, is invaluable for determining the extent and timing of past glaciation and for reconstructing the magnitude and rate of past climate changes. In the central Himalayas, well-dated glacial geomorphological records have constrained the last glacial cycle around much of the Mount Everest region. However, the eastern Ama Drime Range remains comparatively less constrained.

Here, we present a detailed chronology dataset from the Marine Oxygen Isotope Stage (MIS) 3 (~29–57 ka) and subsequent deglaciation, focusing on the Zongcuo Valley and Riwu Valley in Ama Drime Range, China (28°6′N, 87°4′E). This analysis is based on 19 beryllium-10 (¹⁰Be) surface-exposure ages from terminal moraine systems within these valleys. We reconstructed the extent and thickness of Last Glacial Maximum (LGM) glaciers through geomorphological mapping and a flowline-based glacial model, PalaeoIce. Additionally, we applied the accumulation area ratio (AAR) method to estimate the equilibrium-line altitude (ELA) for each stage identified.

Our results reveal that the Zongcuo Glacier and Riwu Glacier reached their maximum extents at 39.9 ± 3.3 ka, coinciding with MIS 3. By 25.2 ± 2.9 ka, the Zongcuo Glacier had retreated slightly up-valley. This retreat is evidenced by well-preserved moraine landforms from the LGM, which greatly facilitated our reconstruction of the ancient Zongcuo Glacier. At its maximum, the glacier covered an area of 26.3 km², had a maximum thickness of 343 m, and an ELA ~560 m lower than present (~5260 m a.s.l.), which we used as a baseline for comparison.

By 15.8 ± 1.5 ka, corresponding to the Late Glacial period, the glacier had retreated ~2 km up-valley, indicating at least a ~20% reduction in glacier length relative to its LGM extent. The glacier area decreased to 19.6 km² (a ~25% reduction), with a maximum thickness of 316 m (a ~25% reduction). The ELA was ~480 m lower than present (~5350 m a.s.l.).

By 860 ± 160 years ago, during the Little Ice Age (LIA), the glacier had retreated ~7 km up-valley from its LGM position, representing at least a ~50% reduction in glacier length. The glacier area had decreased to 6.8 km² (~65% reduction), and the maximum thickness was 140 m (~59% reduction) compared to the LGM. The ELA was ~390 m lower than present (~5440 m a.s.l.).

Using a temperature lapse rate estimate, these ELA anomalies suggest that the local mean annual temperature was ~2.1°C colder than the present (1981–2010) at 860 ± 160 years ago, ~2.6°C colder at 15.8 ± 1.5 ka, and ~3.0°C colder at 25.2 ± 2.9 ka, assuming no significant change in precipitation.This study provides critical insights into the response of glaciers to climate change over the past 40 ka in the southern Tibetan Plateau.

How to cite: Liu, F., Liu, G., Chen, M., and Hou, G.: Cosmogenic 10Be Constraints on Deglacial Snowline Rise Since MIS 3 in the Central Himalayas, China, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6753, https://doi.org/10.5194/egusphere-egu25-6753, 2025.

This study presents the glacial geomorphology and chronology of the Gongba Mountain area in Daocheng (28°58'N, 100°23'E), located in the southeastern sector of the Tibetan Plateau, an important region influenced by significant climatic oscillations during the Quaternary. Utilizing advanced remote sensing technologies, we generate a high-resolution Digital Elevation Model (DEM) with the aid of an Uncrewed Aerial Vehicle (UAV) to map the glacial geomorphology of this sector. We supplement our DEM mapping with satellite imagery (SPOT, ArcGIS Basemap), Google Earth Pro and field surveys to reveal a range of landforms reflecting the area's glacial history. Meanwhile, within this region, we also collected and statistically analysed the ¹⁰Be exposure ages of 13 boulders from 4 moraine ridges. These data are of great significance for understanding the timing of glacier advance and retreat in the Gongba Mountain area during the Quaternary.

This is the first map of such high resolution for the Daocheng area. Within a 32 square kilometer region, we have meticulously mapped 270 moraine ridges at the meter scale. Additionally, we precisely identified and delineated glaciolacustrine, glaciofluvial and post-glacial landforms (e.g., outwash plains, glaciofluvial deposits, shorelines, kettle holes and deltas) and bedrock features influenced by subglacial and periglacial processes (ice-scoured bedrock and weathered bedrock). We integrated the geomorphological characteristics of the moraine ridges in the study area with the ¹⁰Be results. The exposure-ages of the four sampled moraine ridges from south to north are 14.8 ± 1.0 ka, 19.3 ± 1.2 ka, 30.4 ± 1.9 ka, and 83.5 ± 5.1ka, respectively. These data reveal the existence of large-scale glacier advances during MIS 5 and MIS 3 in the study area, provide evidence of glacier advance during the global Last Glacial Maximum (LGM), and indicate small-scale glacial fluctuations with a lack of significant moraine deposits during the lateglacial period.

By establishing a foundational dataset for glacial geomorphology in this region and providing corresponding chronological data with good consistency, our work serves as a critical resource for future research on paleoclimate and environmental changes, providing a longer-term context for ongoing and future impacts of climate change on glacial dynamics in high-altitude environments.

How to cite: Luo, W., Cooper, E.-L., Yang, W., Tielidze, L., Zhang, X., Mackintosh, A., and Liu, G.: Glacial geomorphology and chronology of the Gongba Mountain area, Daocheng, southeast Tibetan Plateau, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14401, https://doi.org/10.5194/egusphere-egu25-14401, 2025.

Glacial forms, which are products of the cold periods of the Quaternary, are found in many parts of Türkiye. Being a mountainous country, the high parts of Türkiye, which are above the permanent snow line, were occupied by glaciers many times during the Quaternary and some glaciers have survived to the present day despite rapid melting in recent decades. In the parts where the glaciers have completely melted, the shapes of glacial geomorphology have preserved their freshness to a great extent. Although Türkiye's current glacier inventory is considered to be complete, there are still glaciated areas of different sizes that have not yet been identified in the literature. One such area is Mount Kısır, located just west of Lake Çıldır in the far northeast of Türkiye. Glaciated sites there have not been reported in the literature and there is a lack of geomorphological, climatological and chronological information about these sites. Mount Kısır (40°57′ N, 43°04′ E) is a mass of Pliocene andesites with a peak of 3197 m, 35 km southeast of Ardahan. We used topographic maps, UAVs and detailed field studies to map the glacial morphology on Mount Kısır. This established 20 cirques, 10 glacial valleys, prominent lateral moraines on their slopes and frontal moraines descending to 2200 m a.s.l. The main ridge runs north from Mount Kısır with more cirques and glacial valleys on the east slope than on the west. The former glaciers were up to 250 m thick and the longest were 11.8 km in Guvercin Valley and 12 km in Kose Valley, both on the east slope. The next goal of this study is to obtain cosmogenic dating of the glacial deposits of Mount Kısır and to contribute to the modelling of the Quaternary climatic conditions of Türkiye by establishing the relationship between these data and local climatic conditions.

This study was supported by TUBITAK project number 122Y360

How to cite: Bayrakdar, C., Keserci, F., Çılğın, Z., and Evans, I. S.: Geomorphological and morphometric characteristics of former glaciers on Mt. Kısır, Northeast Turkey, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1194, https://doi.org/10.5194/egusphere-egu25-1194, 2025.

Geomorphological evidence of cold environments in the Drakensberg, southern Africa, has long been debated. Previous work, based on geomorphological, micromorphology and modelling techniques has suggested glacial conditions above ca. 3200 m a.s.l. However, this has been challenged due to the unclear glacial genesis of geomorphological features. This work aims to provide new evidence of past glacial and periglacial conditions in the Drakensberg.

Our aim is addressed by mapping a geomorphological sketch (1:25000) near the Sani Pass, Drakensberg, based on a 0.5 m resolution Digital Surface Model and an orthomosaic derived from Pléiades satellite imagery, and validated by field reconnaissance work. Specifically, the areas of the Sehonghong plateau, the upper reaches of the KwaNtuba cutback, and the Mangaung catchment, were investigated with several uncrewed aerial vehicle surveys for a detailed geomorphological mapping (1:5000). Finally, we applied Schmidt-Hammer exposure-age dating (SHD) and collected sixteen samples for Cosmic-Ray Exposure (CRE) dating from well-preserved features suggesting glacial and periglacial dynamics, which are currently being processed.

The Sehonghong plateau is located adjacent to the Great Escarpment, between 3400 and 3290 m a.s.l., and has gentle NE-facing slopes. The highest terrain is characterised by the widespread occurrence of weathered surfaces. The bedrock surfaces are littered with highly weathered and eroded ‘shattered’ debris, which provides the source for block fields and which have been reworked by periglacial processes, as evidenced by large sorted stone circles. At the plateau floor, degraded earth hummocky terrain and turf exfoliation areas are examples of wetland degradation. The different landforms suggest wind and seasonal frost conditions are the major geomorphic agents.

The KwaNtuba cutback faces ESE from 3350 to 2870 m a.s.l and encompasses steep slopes along the SW-NE-oriented Great Escarpment. The cutback headwall is shaped by an amphitheatric feature with 220 m high (3340-3120 m a.s.l) steep rock-plucked surfaces. From the foot of this rock face to the valley bottom, a 400 m wide and 200 m long deposit covers the slope. Here, five SE-facing elongated ridges developed along the deposit from 3120 to 2870 m a.s.l. The deposit is composed of subangular to angular metric-sized boulders embedded in a sandy matrix. The geomorphological context and sedimentological features suggest traces of ice flux dynamics, typically observed in debris-covered glaciers.

In the Mangaung catchment, two S-facing cirque-shaped basins were analysed. The eastern one has two well-developed parallel ridges at ca. 3210-3110 m a.s.l with subangular-subrounded metric-size boulders embedded in the sandy matrix that are considered lateral moraines. The centre of the basin has polished surfaces with striations suggesting former temperate subglacial abrasion. At the bottom of the western basin, a 1 km long and 60 m wide block stream developed between 3160 and 2980 m a.s.l. It has elongated ridges and is composed of matrix-free boulders whose central axis preserves alignment patterns downvalley.

The climatic conditions under which these features developed will be revealed in future results from CRE dating, palaeoclimate simulations and palaeoglacier modelling.

How to cite: Fernandes, M., Biskop, S., Vivero, S., Grab, S., and Engelbrecht, F.: New evidence of past glacial and periglacial landforms in the Drakensberg, southern Africa, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3777, https://doi.org/10.5194/egusphere-egu25-3777, 2025.

The glaciology community aims to link climate with moraine positions; however, this is challenging because the glacial dynamics responsible for moraine deposition depend on both precipitation and temperature. These dynamics are further influenced by various physical parameters, such as valley hypsometry (Pratt-Sitaula et al., 2011). Consequently, many studies focus solely on dating morphologies to discuss relative chronologies, rather than attempting to reconstruct past climates from moraine extents. Thus, even though moraines are a key archive of continental paleoclimatology, they have not yet delivered their full potential in reconstructing past climates.

To overcome these issues, we propose a novel methodology for interpreting past climate conditions using sets of moraines from different glaciers that (i) have close or similar ages and (ii) lie close enough to each other to assume they experienced the same paleoclimate. We rely on simulations performed with the numerical glacier model Elmer/Ice, which combines a 3D full Stoke-type glacier flow model with a distributed surface mass balance model, accurately capturing glacier dynamics and geometry sensitivity to valley hypsometry. Within a steady state setup, we simulate the extent of two neighboring paleo glaciers under different precipitation (P) and temperature (T) conditions, finding a P-T solution curve for each that explains the glaciers position/volume constrained by their moraines. The intersection of both curves, therefore, reveals the climatic condition that dominated the valley during the age of the moraines.

We implemented our method in the altiplano valley of Zongo, Bolivia, taking advantage of the long-term glaciological monitoring of the Zongo glacier to calibrate our mass balance model. We studied late-glacial moraines from Telata and Charquini (5390 m asl), two neighboring paleo glaciers with almost the same geomorphological characteristics. We also considered the Zongo glacier itself (6088 m asl), but since it does not have moraines that match the ages of those from Telata and Charquini, we created a similar moraine formation for analysis purposes. Charquini and Telata showed close and almost parallel P-T solution curves, which were crossed by the steeper solution curve of Zongo, thus highlighting the dependence of our method on hypsometry contrasts between glacial valleys.

The fact that these P-T curves have a single intersection suggests that, with a good elevation contrast, our methodology allows us to reconstruct past climatic conditions and decipher the joint contribution of precipitation and temperature from moraine positions only, which has never been achieved in previous studies based on ELA reconstruction or energy balance models (e.g., Autin et al., 2022; Rabatel et al., 2006) where strong assumptions about P or T are needed. We are currently working with two other Altiplano paleoglaciers (Aricoma and Llampu) that have a good hypsometry contrast and will allow us to compare the P-T results with the paleoclimatic conditions presented in the literature (e.g., Martin et al., 2018; Jomelli et al., 2014), enhancing our understanding of the regional signature of global climate changes.

How to cite: Acuña Reyes, N., Martin, L., Gilbert, A., and Jomelli, V.: Reconstructing paleoclimates through 3D numerical modeling of tropical Andes paleoglacial flow., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10384, https://doi.org/10.5194/egusphere-egu25-10384, 2025.

The last glacial termination (LGT; ~19.6-11.7 ka) was a period of rapid climate change. Global temperatures increased by ~6ºC, causing extensive ice mass loss, large shifts in atmospheric and ocean circulation, and approximately 120 m of sea level rise. However, records indicate that warming during the LGT was not uniform, with several abrupt, high-amplitude changes in temperature recorded in North Atlantic proxy records. Because climate models currently struggle to replicate these rapid climate events, it is crucial to produce additional climate proxy data, particularly from the underrepresented terrestrial realm, to better understand these changes and their potential to inform future climate models.

Mountain glaciers respond rapidly to climate forcing, and thus are sensitive indicators of changes in climate. Mapping and dating past glacier fluctuations provides important information about changes in past glacial mass balance, which can be used to understand the timing and magnitude of associated climate change. In Ireland, immediately downwind of the North Atlantic, there is extensive evidence that mountain glaciers occupied mountain ranges across the island as the British-Irish Ice Sheet receded during the LGT. Therefore, investigating past Irish mountain glacier fluctuations provides the opportunity to examine a terrestrial signal of abrupt climate change in the North Atlantic region.

Here we present an overview of the Abrupt Climate Change in Terrestrial Ireland (ACCTIR) project, which aims to use past Irish mountain glaciation to investigate palaeo-climate in the terrestrial North Atlantic during the LGT. ACCTIR pairs geomorphic mapping and cosmogenic surface-exposure dating of mountain glacier moraines with glaciological modelling to establish the timing and magnitude of glacial – and thus climatic – change in terrestrial Ireland during the LGT. We present new glacial-geomorphic mapping of target field areas in southern Ireland, as well as unpublished surface-exposure ages from the Wicklow Mountains. Once the dating is complete, we will combine our results with previously published ages to model potential climate scenarios compatible with past glacial fluctuations.  This work will provide a range of quantitative data that will be useful for improving climate and glaciological models and will help us to better understand North Atlantic climate variability.

How to cite: Dulfer, H. E., Jackson, M. S., Kelley, S. E., Bromley, G. R. M., and Eaves, S.: Using past Irish mountain glaciation to improve our understanding of abrupt climate changes in the terrestrial North Atlantic during the last glacial termination, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10213, https://doi.org/10.5194/egusphere-egu25-10213, 2025.

Despite extensive research on Last Glacial Maximum (LGM) glaciers, the complexity of the record means that data are often fragmented and regionally focused, limiting the availability of cohesive global field-based reconstructions and models. Developing methods to work globally is necessary to uncover undocumented glaciations and gain a better understanding of the extent of past glacial systems. In this study we used a 30 arcsecond, degree-day based glacial inception threshold map, estimating the temperature reductions required for glaciation relative to the current climate. By integrating results from eleven PMIP4 (Paleoclimate Modelling Intercomparison Project Phase 4) simulations, we identified areas where temperatures dropped sufficiently during the LGM to support glaciation in each model, and aggregated them into a global map of the number of PMIP4 models predicting conditions for glacial inception. To validate these findings, we used a dataset of ¹⁰Be and ²⁶Al radionuclide dates from glacial landforms. Using these dated points as outlet locations, we delineated watershed basins approximating potential glacier extents. The resulting polygons were merged with a vector map of documented glacial extents and then spatially compared to the modelled inception areas. Initial results indicated that only 25.99% of the documented LGM glaciers align with the aggregated inception areas as modelled by the majority of PMIP4 models, while 74.01% remain unreproduced, likely due to paleoclimate modelling resolution and spatial mismatches between inception areas and outlet points. Conversely, 49.19% of the inception areas lacked corresponding documentation, suggesting the potential existence of previously unreported glaciers. When considering regions where at least one PMIP4 model predicts threshold temperatures, 67.01% do not correspond with known paleoglaciers. Areas where all models agree on suitable conditions for glaciation, coincide with only 6.06% of documented glaciers. Future research could refine these methods by incorporating higher-resolution palaeoclimate model outputs and using ice flow modelling to delineate glacier extents more accurately.

How to cite: Van Cappellen, M., Seguinot, J., Legrain, E., and Zekollari, H.: Global Glacial Inception Areas during the Last Glacial Maximum, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6672, https://doi.org/10.5194/egusphere-egu25-6672, 2025.

How to cite: Serra, E., Gianotti, F., Mueller, D., Monegato, G., and Preusser, F.: Late Pleistocene glacial history of the Ivrea Morainic Amphitheatre, western Italian Alps, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5484, https://doi.org/10.5194/egusphere-egu25-5484, 2025.

Running along the spine of the Italian Peninsula, the Apennine mountains contain numerous traces of Late Pleistocene glaciations. Most glacial sediments and landforms in the Apennines, such as frontal and lateral moraine ridges, have been tentatively ascribed to the Last Glacial Maximum (LGM). Numerical age control to confirm this hypothesis, however, is only available at very few sites, in particular in the Tosco-Emilian Apennines. Improving glacial chronologies in other sectors of the mountain range is necessary to understand how glaciers in the Italian Peninsula responded to variations in the position of the North Atlantic storm track and changes in Mediterranean circulation throughout the Late Pleistocene.

GLAMED is a new project funded by the University of Padova that aims at better constraining the Late Pleistocene glaciation history in different sectors of the Apennines by integrating geomorphological mapping with the analysis of soil profiles and various geochronological techniques. First field campaigns in the northernmost part of the mountain range (Ligurian Apennines - Aveto catchment) have revealed the existence of small, confined mountain glaciers, likely related to the LGM. However, there is also scattered evidence for a much more extensive and older glaciation, possibly during MIS 6, which has not been described in the northern Apennines previously. Samples for surface exposure dating have been collected to test this hypothesis and to compare the results with chronological data from the central and southern part of the mountain range.

How to cite: Rettig, L., Mozzi, P., Monegato, G., Ribolini, A., Spagnolo, M., Rellini, I., and Maerker, M.: GLAMED Project: Unravelling the Late Pleistocene glaciation history of the Apennine mountains (Italian Peninsula), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11805, https://doi.org/10.5194/egusphere-egu25-11805, 2025.

During the Pleistocene epoch the Alpine scenery with its surroundings was repeatedly reshaped by glacial activity. Subglacial erosion led to basin-shaped structures, so-called ‘overdeepenings’ (OD), embedded in bedrock. Their sedimentary fillings are important archives for understanding glacial history and the glacial impact on environmental transformation. Some of these infills are composed of multiple cycles representing separate glaciations.

Numerous well investigated cores in the Northern Alpine Foreland led to the recognition of typical fining-upward OD-fill sequences – characterized by glaciolacustrine deposits overlying glacially originated diamicts at the basal unconformity (e.g. Gegg & Preusser 2023, and references therein). These fining-upward sequences typically start with glacitectonites that regularly transition into coarse-grained, sand-dominated, and finally fine-grained basin fills, and can occur as several unconformably stacked units (Buechi et al. 2024).

In the ICDP-DOVE framework (Anselmetti et al. 2022), two new cored profiles were recovered north of Lake Constance (drill sites Gaisbeuren and Lichtenegg). These consist of OD-fills that are not typical for the Alpine Foreland, because they are almost entirely composed of diamictic deposits. While these deposits show some variations in concentration and size of clasts, well sorted lacustrine sediments are missing. Here we aim to start a discussion about potential reasons for the atypical character of these OD-fills.

Anselmetti, F.S., Bavec, M., Crouzet, C., Fiebig, M., Gabriel, G., Preusser, F., Ravazzi, C., DOVE scientific team, 2022. Drilling Overdeepened Alpine Valleys (ICDP-DOVE): quantifying the age, extent, and environmental impact of Alpine glaciations. Scientific Drilling, 31, 51–70. https://doi.org/10.5194/sd-31-51-2022.

Buechi, M.W., Landgraf, A., Madritsch, H., Mueller, D., Knipping, M., Nyffenegger, F., Preusser, F., Schaller, S., Schnellmann, M., Deplazes, G., 2024. Terminal glacial overdeepenings: Patterns of erosion, infilling and new constraints on the glaciation history of Northern Switzerland. Quaternary Science Reviews, 344, 108970. https://doi.org/10.1016/j.quascirev.2024.108970.

Gegg, L., Preusser, F., 2023. Comparison of overdeepened structures in formerly glaciated areas of the northern Alpine foreland and northern central Europe. E&G Quaternary Science Journal, 72, 23–36. https://doi.org/10.5194/egqsj-72-23-2023.

How to cite: Pomper, J., Zeeden, C., Preusser, F., Wielandt-Schuster, U., and Gegg, L.: Two atypical overdeepening-fills from the Lake Constance area (Southern Germany), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17419, https://doi.org/10.5194/egusphere-egu25-17419, 2025.

The erosive impact of glaciers during the Last Glacial Maximum (LGM) has largely obscured evidence of earlier, less extensive glacial advances within the Alps. While Alpine paleoclimate records show that the Marine Isotope Stage (MIS) 3 was characterized by pronounced changes between stadial and interstadial conditions, similar to the Dansgaard-Oeschger (D-O) cycles observed in ice-cores from Greenland, depositional evidence of glacial extent during this period remains scarce. Here, we present new data from a sedimentary archive in the inner-alpine Bad Aussee Basin in the Austrian Eastern Alps. Located close to the main accumulation areas of the former Traun Glacier, its topographic setting suggests that down-valley glacial damming is a major factor controlling the timing of depositional phases throughout glacial-interglacial cycles. Under present interglacial conditions, fluvial incision takes place.

Our investigations are focused on an 880-m-long Pleistocene sedimentary record, recovered by a drilling intended for salt exploration and later included in the ICDP (International Continental Scientific Drilling Program) project DOVE (Drilling Overdeepened Alpine Valleys). Three distinct depositional phases can be distinguished. The basal Unit A (880–580 m), dominated by glaciolacustrine deposits, can be correlated with the Penultimate Glaciation (MIS 6) based on luminescence dating and consists of locally sourced material from the Northern Calcareous Alps. In contrast, Unit B (580–67 m) records a succession of lacustrine and deltaic sediments largely derived from the Austroalpine crystalline basement to the south of the Enns Valley. Luminescence results indicate that deposition took place mainly during MIS 3. Unit B exhibits several abrupt increases in total organic carbon (TOC), which we interpret as organic productivity events, followed by a gradual decrease. This TOC pattern closely resembles the D-O cycles, allowing a tentative correlation between individual events. Unit C (67–0 m) consists of subglacial till which we attribute to the LGM, although no numerical dating results are available.

Based on the sedimentological, chronological and provenance data, this study presents a reconstruction of the pre-LGM landscape evolution of the Bad Aussee Basin with particular focus on the MIS 3 stadial-interstadial cycles. Placing our results in a broader regional context, we discuss the implications for glacial dynamics and drainage evolution in the Traun and Enns valleys.

How to cite: Schmalfuss, C., Firla, G., Neuhuber, S., Lüthgens, C., Diendorfer, P., Leitner, T., Anselmetti, F., and Fiebig, M.: Reconstructing pre-LGM landscape evolution in the Eastern Alps (Austria): New insights from the Bad Aussee Basin, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11353, https://doi.org/10.5194/egusphere-egu25-11353, 2025.

The Adige glacier during the Last Glacial Maximum (LGM) spread into different branches downstream of Trento. Here, reliefs exceeding 2000 m in elevation are present, which hosted local plateau glaciers, namely: Pasubio, Vigolana, Campoluzzo and Fiorentini. The present Adige valley was filled by one of the major Alpine glaciers with an ice-thickness exceeding 1500 m, as testified by well-expressed lateral moraines. On the southern Vigolana, the Adige lateral moraine cuts those belonging to the local glacier, suggesting an early advance of the plateau glacier before the maximum spreading of the Adige glacier. This branch flowed into the left tributary valleys, which were dammed and acted as local depocenter for glaciofluvial and slope deposition. Another minor branch of the Adige glacier overflowed the Carbonare saddle towards the Astico valley, which in his middle sector was filled by a 600-m-thick tongue, as documented by the lateral moraines of Tonezza. This glacier dammed the Posina valley, which was filled by glaciofluvial deposits related to Pasubio and Campoluzzo glaciers. Field observations and remote sensing analyses allowed for the modeling of the Equilibrium Line Altitudes for both valley and plateau glaciers.

How to cite: Monegato, G., Rettig, L., Rossato, S., Mozzi, P., and Picotti, V. and the CARG Rovereto scientific team: Tracking the LGM glaciers across the Adige and Astico valleys (European Alps, Northern Italy), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12174, https://doi.org/10.5194/egusphere-egu25-12174, 2025.