This session invites contributions that advance understanding of mountain glaciations through various methodological approaches, including the integration of geomorphological mapping, geochronology, numerical modelling, and palaeoclimate analysis. Studies addressing cross-regional comparisons, hemispheric linkages, and interdisciplinary frameworks are particularly encouraged, as are those that connect Quaternary glaciations with contemporary glacier change, hazards, and water resource management. By bringing together researchers from a range of disciplines and regions, this session aims to provide a platform for both consolidating established knowledge and introducing innovative perspectives, fostering collaboration across temporal, spatial, and disciplinary boundaries.
Orals: Mon, 4 May, 08:30–10:15 | Room G1
Despite several studies (Coutterand, 2010 and references theirin) over the past decades, the chronology of glaciers advance and expansion at the Last Glacial Maximum (LGM) and subsequent retreat during the Lateglacial period in the northern French Alps remains poorly constraint, as data are still too scarce and sometimes contradictory. In this area, the interactions between major glaciers, such as the Rhône and Arve glaciers in the north and Isère glacier in the south, represent major challenges for reconstructing post-LGM glacial dynamics. Here, we present a new framework for understanding Lateglacial glacial dynamics in the Arve Valley, integrating 18 new 10Be exposure ages from glacially-transported boulders, with revised geomorphological mapping based on LiDAR-derived DEMs.
Our results indicate that the deglaciation of the Arve Valley initiated with a phase of glacial thinning around 17.6 ka BP. The Arve glacier subsequently thinned progressively but persisted in the downstream sector of the valley until the end of a readvance phase at 15.9 ka BP. Then, the glacier retreated by over 30 km within 300 years, before withdrawing toward the Mont-Blanc massif ahead of the Younger Dryas readvance.
These findings are integrated with previous studies (Wirsig et al., 2016; Roattino et al., 2022; Serra et al., 2022) conducted in the Northwestern Alps, including the Lyon piedmont lobe and the Mont-Blanc massif area, to propose a regionally consistent deglaciation scenario. To further refine our understanding, we confront 10Be exposure ages with numerical simulations using the Instructed Glacier Model (IGM, Leger et al., 2025). A dual approach enables a critically assessment of both methods: calibration of exposure ages corrections (e.g., erosion rates, snow shielding) using a model run, and inversely, using calculated exposure ages to constrain the resulting model. This will enable us to analyse possible deglaciation rates and spatial patterns in the Northwestern Alps, as well as the influence of key parameters such as geography, topography, and climate.
Coutterand, S. 2010: Etude géomorphologique des flux glaciaires dans les Alpes nord-occidentales au Pléistocène récent : du maximum de la dernière glaciation aux premières étapes de la déglaciation. PhD thesis. Université Savoie Mont-Blanc.
Leger, T. P. M., Jouvet, G., Kamleitner, S., Mey, J., Herman, F., Finley, B. D., Ivy-Ochs, S., Vieli, A., Henz, A. & Nussbaumer, S. U. 2025: A data-consistent model of the last glaciation in the Alps achieved with physics-driven AI. Nature Communications 16, 848. https://doi.org/10.1038/s41467-025-56168-3.
Roattino, T., Crouzet, C., Vassallo, R., Buoncristiani, J.-F., Carcaillet, J., Gribenski, N. & Valla, P. G. 2022: Paleogeographical reconstruction of the western French Alps foreland during the last glacial maximum using cosmogenic exposure dating. Quaternary Research 111, 68–83. https://doi.org/10.1017/qua.2022.25.
Serra, E., Valla, P. G., Gribenski, N., Carcaillet, J. & Deline, P. 2022: Post-LGM glacial and geomorphic evolution of the Dora Baltea valley (western Italian Alps). Quaternary Science Reviews 282, 107446. https://doi.org/10.1016/j.quascirev.2022.107446.
Wirsig, C., Zasadni, J., Christl, M., Akçar, N. & Ivy-Ochs, S. 2016: Dating the onset of LGM ice surface lowering in the High Alps. Quaternary Science Reviews 143, 37–50. https://doi.org/10.1016/j.quascirev.2016.05.001.
How to cite: Portal, Q., Crouzet, C., Buoncristiani, J.-F., Leger, T., Jouvet, G., and Carcaillet, J.: Lateglacial glaciers dynamics in the Mont Blanc foreland (Northern French Alps): new chronological and geomorphological constraints, with model-data coupling in the Arve Valley, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5367, https://doi.org/10.5194/egusphere-egu26-5367, 2026.
Mountain glaciers represent sensitive recorders of climate variability across a wide range of temporal and spatial scales. While their Lateglacial and Holocene dynamics are comparatively well constrained, glacier extent and behaviour prior to the Last Glacial Maximum (LGM) remain poorly documented in many mountain regions. In the Eastern Alps, the timing and magnitude of glacier advances during Marine Isotope Stage (MIS) 4 and MIS 3 are still debated, despite numerical glacier models predicting repeated pre-LGM advances into the Alpine foreland. This knowledge gap largely reflects (i) the scarcity of suitable terrestrial archives capable of recording such advances, (ii) the fact that organic material for radiocarbon dating is generally rare or absent in glacial settings and (iii) geomorphological evidence such as moraines is commonly eroded, reworked, or overprinted by subsequent glacier advances.
This study examines successions of ice-dammed glaciolacustrine sediments preserved in Alpine tributary valleys as alternative terrestrial archives for reconstructing pre-LGM glacier dynamics in the Eastern Alps. Ice-dammed lakes form when advancing trunk glaciers block the outlet of smaller tributary glaciers, creating temporary sediment traps that enable glaciolacustrine deposition. These ice-contact sediments record glacier advances and can survive multiple glacial cycles.
We focus on glaciolacustrine successions as ice-margin indicators and present a research approach that combines detailed sedimentological investigations with luminescence geochronology. The sedimentary architecture and stratigraphic relationships of ice-dammed sediments and associated delta complexes provide spatial constraints on an interconnected system of valley glaciers, including minimum ice-surface elevations and relative glacier extent. Chronological control is obtained using optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL) dating of fine-grained quartz and feldspar (4–11 μm), respectively. Methodological challenges related to partial signal resetting are addressed using adapted bleaching-plateau tests [1], increasing confidence in the luminescence-based age constraints.
Our initial results from inneralpine sites indicate glacier advances which potentially reached into the Eastern Alpine foreland during MIS 4 and eventually MIS 3c, implying that glacier extent prior to the LGM was potentially more dynamic and spatially extensive than previously assumed. These results are consistent with numerical glacier model predictions [2].
From a methodological point of view, we conclude that (i) precise dating of ice-dammed lacustrine sediments enables reconstruction of the spatiotemporal dynamics of the associated ice-stream network, and (ii) luminescence-based lacustrine dating might complement geomorphological and cosmogenic-nuclide methods focused on lateral and frontal moraines used to delineate former ice margins.
References
1. Reimann, Tony; Notenboom, Paul D.; De Schipper, Matthieu A.; Wallinga, Jakob (2015): Testing for sufficient signal resetting during sediment transport using a polymineral multiple-signal luminescence approach. In: Quaternary Geochronology 25, S. 26–36. DOI: 10.1016/j.quageo.2014.09.002.
2. Jouvet, Guillaume; Cohen, Denis; Russo, Emmanuele; Buzan, Jonathan; Raible, Christoph C.; Haeberli, Wilfried et al. (2023): Coupled climate-glacier modelling of the last glaciation in the Alps. In: J. Glaciol. 69 (278), S. 1956–1970. DOI: 10.1017/jog.2023.74.
How to cite: Spitaler, B., Gruber, A., Reitner, J. M., and Meyer, M. C.: Are ice-contact lacustrine sediments in the Eastern Alps capable of constraining pre-LGM ice-stream network dynamics? , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20278, https://doi.org/10.5194/egusphere-egu26-20278, 2026.
Reconstructions of glacier Equilibrium Line Altitudes (ELAs) from geomorphological evidence are often the only source of quantitative palaeoclimatic information in mountainous regions. The ELA is the average altitude of zero net mass balance and divides a glacier into an accumulation and an ablation area. While primarily controlled by summer temperature and winter precipitation, the position of the ELA is also frequently modulated by local topoclimatic factors, such as shading, supraglacial debris cover, avalanching or wind-driven snow redistribution. As a result, there can be substantial differences of several 100 meters between ELAs of neighbouring glaciers within the same climatic region. If such topoclimatic controls are not accounted for, this can introduce notable biases into ELA-based palaeoclimate reconstructions.
To better constrain the effect of topoclimatic control on glacier ELAs at the regional to global scale, we present the results of a comprehensive data analysis based on the Randolph Glacier Inventory (RGI), version 7.0. We compare glacier-specific ELAs calculated through the Accumulation Area Ratio and Area-Altitude Balance Ratio methods to a variety of topographic parameters, such as the amount of received solar radiation, the curvature of the ice surface and the topographic openness of the terrain. We show that there is a strong correlation between local ELA differences and some of these parameters and use a machine-learning tool to predict this ELA offset using only a digital elevation model and a glacier outline as input. This tool can be used to assess the topographic bias related to any calculated ELA and has the potential to lead to more reliable palaeoclimate reconstructions in a variety of settings.
How to cite: Rettig, L., Huss, M., and Kneib, M.: Quantifying topoclimatic control on glacier Equilibrium Line Altitudes at the regional and global scale, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12599, https://doi.org/10.5194/egusphere-egu26-12599, 2026.
Numerical palaeoglacier modelling is being applied to mountain glacier systems worldwide to investigate past ice dynamics, climatic controls, and glacier–climate interactions. At present, there is no overview or consensus framework for evaluating the performance of these models, nor agreed standards for determining whether simulated glacier distribution and geometry are plausibly reconstructed through time.
To assess how palaeoglacier models in mountains are being validated and evaluated, we conducted a systematic review of 94 coupled mass-balance–ice-dynamics palaeoglacier models worldwide. For each study, we recorded validation approaches (visual, quantitative, and/or statistical), the glaciological attributes evaluated (extent, area, ice thickness, mass balance, ice flow, glacier distribution), the validation datasets used (direct geomorphological evidence versus previous model outputs), and the spatial structure of validation (point-, line-, polygon-, or grid-based). We also synthesised validation workflows to document the datasets, metrics, and decision criteria employed.
Our results show that the methodological design used to validate model outputs vary considerably between studies. We found that 80% of reviewed studies incorporate visual evaluation of model outputs to some extent, and 43% rely exclusively on subjective visual interpretation. A further 4% of studies do not perform any form of model validation or evaluation. Most studies validate glacier length (89%), whereas 48% of cases validate only one individual model output. Geomorphic reconstructions are used as validation datasets in only 27% of studies, indicating that most validation workflows rely on mapped glacial landforms. Because glacier length and glacial landforms dominate validation strategies, point- and line-based features constitute the majority of spatial validation data, with polygon- or grid-based approaches remaining comparatively rare.
We observe that the interpretation of model performance often remains subjective and reliant on the judgement of a limited number of research authors, which hinders reproducibility and intercomparison across studies. This reliance on subjective visual interpretation reflects persistent challenges in palaeoglacier model validation that are not being solved by existing tools and workflows designed to measure model-data fit. Our review indicates that uneven geomorphic evidence coverage, positional uncertainty between mapped landforms and simulated ice margins, resolution mismatches between geomorphic data and model outputs, chronological dating uncertainties, parameter uncertainty, and ‘equifinality’ (i.e., where multiple parameter combinations can yield similarly plausible glacier geometries) within glacier models collectively hinder robust quantitative validation.
Therefore, we propose a probabilistic, equifinality-aware validation framework that integrates geomorphically based reconstructions, multiple model outputs (e.g., ice extent, ice thickness), temporal steps (e.g., LGM and present-day), and performance metrics (e.g., overestimation, underestimation). Our approach evaluates ice cover as a probability field derived from an ensemble of acceptable simulations, explicitly acknowledging parameter non-uniqueness of equifinal modelling outputs. This approach identifies spatial patterns of robust agreement and persistent uncertainty, avoids subjective selection of a best-fit simulation, and enables domain-wide validation that captures spatial and temporal heterogeneity in glacier behaviour, thereby providing a more transparent and reproducible basis for evaluating palaeoglacier model–data fit.
How to cite: Lima, A. C., Barndon, S., Chandler, D. M., Yingkui, L., and Flantua, S. G. A.: Validation Practices in Mountain Palaeoglacier Modelling, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19769, https://doi.org/10.5194/egusphere-egu26-19769, 2026.
The sensitivity of alpine glaciation to climatic warming is underscored by global reductions in ice mass over the last century and accelerated losses observed in recent decades. Given the dependence of local populations, infrastructure, and ecosystems on reliable snowpack and meltwater supply, the forecasted demise of many mountain glaciers critically motivates investigations into the dynamics underlying glacial retreat and advance under past boundary conditions. However, the timing and extent of glacial limits are progressively less well constrained through geologic time, particularly in mountain regions, due to the inevitable loss of geomorphic indicators through subsequent glacial advance and erosion. Secondary mineral deposits in some alpine caves offer a unique solution to glacial reconstructions, because warm-based ice cover allows the cave system to remain unfrozen with active speleothem growth. Importantly, the loss of soil cover and presence of glacial ice induces an abrupt switch from a carbonic-acid to a sulfuric-acid dominated system in caves hosted by impure carbonate rocks, which can be detected through geochemical analysis of radiometrically dated speleothems. While this category of ‘subglacial speleothems’ has long been described, only recently has a thorough multiproxy approach been developed and tested, which can robustly identify the timing and dynamics of glaciation over alpine cave sites. In addition to key changes in the stable-isotope composition of carbon (δ13C) and oxygen (δ18O), the dominance of sulfuric-acid dissolution leads to an increase in speleothem sulfate, often by more than an order of magnitude, which may be accompanied by a decrease in the δ34S of sulfate due to enhanced sulfide oxidation. Glacial weathering processes are captured by certain trace elements in speleothem calcite, whereas the redox evolution of infiltrating waters (reflecting the hydrological balance of surface and subglacial meltwaters) is reflected in the oxygen-isotope composition of speleothem sulfate. Finally, U-series dating (U-Th and U-Pb) allows for accurate geochronological constraints, sometimes with per mil precision, throughout the Quaternary and beyond. Herein, we present case studies from the European Alps and Western Caucasus that successfully document the advance and retreat of warm-based glaciers without reference to surficial deposits and landforms. We further discuss uncertainties associated with the site-specific behavior of geochemical proxies that may limit their application to some glacial reconstructions.
How to cite: Baker, J., Honiat, A., Wynn, P., Moseley, G., Mertz, R., and Spötl, C.: A multiproxy speleothem-based approach to reconstructing alpine glaciation beyond the limits of geomorphological evidence, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14454, https://doi.org/10.5194/egusphere-egu26-14454, 2026.
New 10Be exposure ages from the Arenig mountains, North Wales have been obtained to complement 36Cl ages and help constrain the timing of deglaciation in NE Wales. The last phase of cirque glaciation is dated to the Younger Dryas and this is consistent with previous assumptions of deglaciation in Wales. In South Wales, in the Brecon Beacons, the last cirque glaciers were higher than those in the north, which is consistent with increasing cirque altitude with lower latitude. Radiocarbon dating from bogs inside of moraines in these cirques also supports a Younger Dryas age for the last phase of glaciation. However, further south in the South Wales Valleys, the last former cirque glaciers were at some of the lowest altitudes in Wales. The glaciers occupied cirques that are lower than in the nearby Brecon Beacons and these cirques represent an anomalous population of low-lying cirques compared with the rest of Wales. Reasons for this are either because 1) wetter conditions existed the South Wales Valleys than the rest of Wales leading to lower cirque glaciation during the Younger or 2) the last cirque glaciers were present and formed moraines prior to the Younger Dryas, possibly when the Welsh Ice cap covered Wales north of the Brecon Beacon watershed divide. Ongoing work will apply 10Be exposure dating from moraine boulders and 14C dating from bogs inside of moraines in the cirques of the Brecon Beacons and South Wales Valleys to test these hypotheses further.
How to cite: Hughes, P., Thomas, O., Darvill, C., Ryan, P., and Fink, D.: Examining the nature and timing of deglaciation in Britain: new evidence from the Arenigs, Brecon Beacons and South Wales Valleys, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13791, https://doi.org/10.5194/egusphere-egu26-13791, 2026.
Numerical models simulating potential future climate schemes are tested against different proxy-based reconstruction of paleoclimate and must be finely tuned. In the north Atlantic region, records indicate that the Last Glacial Termination was interrupted by rapid, high-amplitude reversals (Heinrich Stadial 1, Younger Dryas) during which temperatures got back to nearly ice-age cold conditions.
These events are thought to be year-round cooling periods and could be close analogues for future climate change in the north Atlantic region. Terrestrial glacial deposits give a high resolution vantage on abrupt shifts but remain poorly investigated. Previous studies based on surface exposure dating on glacial landforms show that glaciers retreats occurred within HS1 and YD, contradicting the prevailing models. Thus mapping palaeo-mountain glaciers former extend, dating their retreat and reconstructing their successive palaeo-equilibrium lines altitude allow to determine whether this pattern is a consensus for the northern hemisphere palaeo-glaciers. This approach also provides information on the timing and magnitude of past climate change. This study is based on the west coast of Ireland directly impacted by westerlies, located downwind of the North Atlantic Ocean and which contains key sites where palaeo-mountain glaciers let the footprints of their passage. Here, we present the first results from the Geologic Perspectives on Abrupt Climate Change (GeoPAC2) project: Strengthening Ireland’s capacity for projecting future change. The new beryllium-10-dated glacier records reveals phase of ice retreat occurring within HS1. It questions the rising seasonality hypothesis which suggests an increase of summer temperatures during melting season. The results of this work will provide useful quantitative data for investigate North Atlantic climate variability and improve both climate and glaciological models.
How to cite: Roignot, A. and Bromley, G.: Palaeo-glaciers archives in western Ireland as a vantage on abrupt shifts of the Last Glacial Termination , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18404, https://doi.org/10.5194/egusphere-egu26-18404, 2026.
The Ural Mountains form a major physiographic boundary between the East European Plain and West Siberia, both repeatedly glaciated during the Pleistocene by the Barents–Kara ice sheet. Although the present-day topography reflects significant glacial modification, the extent, chronology, and interaction of mountain glaciers with the Barents–Kara ice sheet remain poorly constrained. Correlation of glacial and interglacial deposits across the range is hindered by incomplete sedimentary records, contrasting palaeoclimatic conditions, and limited chronological control, which collectively obscure regional glacial reconstructions. This study presents an extensive mapping exercise of hundreds of moraines in the northern Urals. These landforms are then used to reconstruct palaeoglacier equilibrium line altitudes (ELAs) to assess glacier distribution and synchroneity of moraine formation. ELA trends along the Urals are analysed to evaluate whether, and where, montane ice caps developed during the last major glaciation. Furthermore, palaeo-ELA data are used to link former ice margins to dated moraines in the Polar Urals, providing new insights into the spatial and temporal dynamics of montane glaciations south of the Arctic Circle. The findings indicate that the E-W asymmetry in the hypsometry of the Urals exerted the primary control on the development of the piedmont glaciers on the lowlands. Furthermore, Glacier reconstructions combined with geomorphological evidence favour the existence of extensive montane ice caps over the Urals with moisture sourced from extensive ice dammed lakes locates on both sides of the mountain range.
How to cite: Kurjanski, B., Spagnolo, M., Bushueva, I., Barr, I., Rea, B., Solomina, O., and Kutuzov, S.: Palaeoglaciations in the Polar and Subpolar Ural Mountains., EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21654, https://doi.org/10.5194/egusphere-egu26-21654, 2026.
Andean landscapes contain key paleoclimate records of the Southern Hemisphere. However, many mountain regions in the Andes remain scarcely investigated in detail. In this study, we present an analysis of the Nevados de Chillán Volcanic Complex (NCVC), in Southern Chile (37ºS), aiming at unveiling the potential of this landscape to register past climatic conditions. This site is within a region of Temperate-Mediterranean climate transition (TMT; 35.5°–39.5°S), which comprises most of the Southern Volcanic zone (SVZ) of the Andes, that host the most active volcanoes of the cordillera, almost all of them are ice-capped. These volcanoes witnessed the multiple expansions and retreats of the Patagonian Ice Sheet (PIS) during Pleistocene glaciations and of smaller mountain glaciers during the Holocene, reflecting local climatic variations. Our findings show the NCVC preserves a recent and diverse glacial record, as identified with a detailed geomorphological mapping (1:20.000). The elevation and preservation of glacial deposits and scoured bedrock point to multiple glacial advances after the Last Glacial Maximum. Current analysis of ages obtained with 36Cl dating of andesitic boulders atop moraines support field observations and geomorphological interpretations, with different episodes from Early-Middle Holocene until the last centuries. The oldest measurements in could represent late glacial advances, which also occurred in central Andes and Patagonia. Ages from frontal moraines are coeval with the Little Ice Age, consistent with results of recent studies in adjacent volcanic areas. From lateral moraines dispersed age results suggest persistent glacial activity since the last millennia until 200 years ago. The younger ages are supported by historical accounts from 19th century that document glacial extent comparable with the location of sampled boulders. Overall, these results should be interpreted in light of uncertainties related to geomorphological mapping and especially with chronological constraints. Despite these limitations, the integrated approach adopted here provides a useful framework to identify regional-scale patterns of glacier fluctuations and to assess their sensitivity to climatic variability during the Late Pleistocene–Holocene.
How to cite: Navas, S., Fernández, A., Jaque, E., Owen, L., Figueiredo, P., and Stansell, N.: Glacial record and 36Cl cosmogenic dating in the Nevados de Chillán Volcanic Complex, Northern Patagonia, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16061, https://doi.org/10.5194/egusphere-egu26-16061, 2026.
A detailed morphometric and modelling-based analysis was conducted on 197 palaeocirques across the western Putorana Plateau, Central Siberia, to refine reconstructions of mountain glacier extent and associated palaeoclimatic conditions during the last major phase of glaciation. Previous work in the region quantified cirque geometry and inferred palaeo-equilibrium line altitudes from cirque floor elevations. Here, these geomorphological constraints are integrated with physically based glacier reconstructions using the PalaeoIce 2.0 model to simulate ice thickness, surface geometry, and glacier extent for individual cirques.
The cirques display mean widths of approximately 1000 m and mean lengths of 936 m, forming near-circular, amphitheatre-like landforms indicative of sustained glacial erosion. Cirque heights range from 111 to 591 m, reflecting both variability in erosional intensity and topographic controls. Strong positive correlations between length, width, and height (L×W: 0.758; L×H: 0.610) indicate proportional scaling of cirque dimensions. Mean cirque slopes are 23.5°, with steep headwalls reaching up to 80°, while more than half of cirque areas are characterised by gentler slopes associated with overdeepened floors, where tarns are frequently present.
Cirque floor altitudes range from 447 to 1568 m, providing first-order constraints on former glacier geometry. PalaeoIce 2.0 reconstructions indicate a mean palaeo-equilibrium line altitude of approximately 658 m, corresponding to a depression of ~1042 m relative to present conditions. Modelled glacier geometries are consistent with extensive, topographically confined mountain glaciers developed within individual cirques during the Last Glacial Maximum. Associated palaeoclimate estimates suggest mean summer air temperatures of approximately −1.5 °C and annual precipitation of ~634 mm to sustain such glaciation.
These results demonstrate the value of combining cirque morphometrics with numerical ice-flow modelling to refine palaeoglacier reconstructions in high-latitude mountain regions. The PalaeoIce 2.0 simulations provide an independent, physically based framework for evaluating cirque-derived palaeoclimate inferences and for improving understanding of mountain glacier behaviour along the margins of larger ice-sheet systems.
How to cite: Oien, R. and Lee, E.: Integrating cirque morphometrics and numerical modelling reconstructions in Putorana, Central Siberia, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10021, https://doi.org/10.5194/egusphere-egu26-10021, 2026.
The Southern Alps of New Zealand are regarded as an important key site for studying Holocene glacier chronologies in the mid-latitudinal southern hemisphere. Consequently, most global reviews of the topic include respective records and utilise them for (intra-)hemispheric correlations and palaeoclimatic analyses. These particular approaches are, however, closely connected to three common paradigms: (i) There is a representative and reliable compilation of glacier records for the entire Southern Alps, (ii) the European Alps are a well-suited and appropriate northern hemispheric glacier region for any comparative purpose, and (iii) air temperatures are the sole relevant driver of glacier variability in New Zealand.
In a recent study 10Be cosmogenic radionuclide dating (CRN) and Schmidt-hammer exposure-age dating (SHD) were applied to extent the regional database and obtain surface-exposure ages from moraines on Holocene glacier forelands in eastern Aoraki/Mt.Cook National Park, Arrowsmith Range, and Liebig Range. Re-calculated published 10Be CRN age data were, alongside previously obtained results from both central Aoraki/Mt.Cook and Westland/Tai Poutini National Parks, utilised for a comparative chronological analysis. Unlike previous approaches glacier records were differentiated by sub-regions of the Southern Alps and interpreted accordingly. Neither amalgamation of individual glacier records nor non-differentiated compilation took place. This multi-proxy approach was combined with detailed geomorphological mapping and assessment to tackle the regionally specific 'geomorphological uncertainty' potentially interfering with all subsequent interpretation of chronological data.
Chronological analysis and subsequent palaeoclimatic interpretation worked well if they were restricted to sub-regional levels. In the Arrowsmith Range strong glacial activity and multiple advances during the Early Holocene could be confirmed, with a similar pattern likely for the Liebig Range. A correspondence to frequent Early Holocene cold periods indicated by rock glacier activity in the Ben Ohau Range is obvious. But in contrast to these drier eastern sub-regions no evidence for Early Holocene advances exists for central and western sub-regions. At Classen Glacier in eastern Aoraki/Mt.Cook National Park, geomorphologically reliable morainic evidence shows a significant Mid-Holocene advance at c. 5.4 ka. It is possibly corresponding to evidence from Mueller and Tasman Glaciers. This advance coincides with an intensification of westerly airflow established around that time. Together with a 'Little Ice Age'-maximum during the mid-/late 18th century CE in Aoraki/Mt.Cook National Park and recent advances at the end of the 20th century it also indicates that (seasonal) atmospheric circulation patterns, in particular the intensity of westerly airflow, and precipitation should not be ignored as climatic factors influencing glacier variability. Finally, with its pronounced West-East precipitation gradient potentially responsible for different sub-regional glacier records, the Southern Alps share several glaciologically relevant climatic conditions with the maritime Scandinavian Mountains, but hardly with the generally drier European Alps.
Further refinement of the Holocene glacier history for the Southern Alps constitutes a significant challenge. It requires a more detailed understanding of both the variability of individual glacier records and the need for spatial differentiation before attempting to compile a representative Holocene glacier chronology for the entire Southern Alps. Furthermore, certain common paradigms need to be critically reviewed and re-considered.
How to cite: Winkler, S.: Re-visiting New Zealand's Holocene glacier chronology - Time to overcome certain paradigms and consider spatial differentiation?, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1403, https://doi.org/10.5194/egusphere-egu26-1403, 2026.
During the Pleistocene ice ages, Central Europe formed a mostly unglaciated corridor between the Fennoscandian Ice Sheet and the Alpine ice complex. The mountains of this region hosted small ice masses at the time. However, the extent, timing and climate conditions under which glaciers existed, as well as their erosional imprint on the landscape remain poorly understood. Solving these challenges is important for understanding the impact glaciation may have had on the distribution of biota and permafrost, which, in turn, can be used to reconstruct former human migration routes in Central Europe. This project aims to reconstruct the past glaciation of the Central European uplands and its palaeoclimate implications, focusing on the mid-elevation mountains in the region, such as the Bohemian/Bavarian Forest, the Fichtel Mountains, the Ore Mountains, and the Sudetes.
Firstly, we aim to identify and date former ice extents and determine the style of glaciation through geomorphological mapping of glacial depositional and erosional landforms and their radiometric dating with terrestrial cosmogenic nuclides and optically stimulated luminescence. Secondly, we will conduct morphometric analyses and geophysical surveys to determine the degree of glacial erosion of cirques and valleys and assess the influence of plateau surfaces as potential snow or ice accumulation areas. Finally, we will apply a numerical glacier model (Parallel Ice Sheet Model) to identify the degree of temperature cooling and precipitation increase or decrease from present-day to grow glaciers that match the mapped and dated extents. Thus, an understanding of past glaciation and climate over Central Europe during the Pleistocene will be produced, with a wide relevance for the palaeoclimatology, ecology, and archaeology research communities. This poster will introduce the project and present initial results.
How to cite: Balaban, C. I., Nieslony, M., Krause, D., Engel, Z., Křížek, M., Seguinot, J., Zekollari, H., and Margold, M.: Reconstructing the Quaternary glaciation of the central European uplands and its palaeoclimate implications, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11933, https://doi.org/10.5194/egusphere-egu26-11933, 2026.
During the Last Glacial Maximum (LGM), many glaciers in the Eastern Alps terminated in narrow inneralpine valleys resulting in a limited amount of datable landforms. At the former Enns and Mur Glaciers, boulders, at or close to laterofrontal moraine ridges were dated with cosmogenic 10Be. Boulders at the Mur Glacier are composed of weathering-resistant pegmatite gneiss, whereas quartzbreccia/greywacke was the only suitable boulder lithology in the Enns Glacier region. This lithology consists of large quartz components within a fine matrix and is more easily affected by weathering. Ages inferred from 10Be concentrations in pegmatite gneisses (Mur Glacier) are around 20 ka, in accordance with other ages around the Alps. In contrast, Enns Glacier boulders yielded surprisingly young ages between 14-17 ka. In order to obtain plausible LGM ages via erosion corrections from the 10Be concentrations, a 30 cm thick surface layer would need to be removed (if the boulder was at the surface since deposition). In order to understand, if such a large amount of material can be removed from the quartzbreccia, we applied freeze-thaw cycle experiments to both lithologies. For the experiment, we produced four cubes, roughly 2x2x4 cm in size, three of quartzbreccia and one of pegmatite gneiss. Each of the quartzbreccia cubes has a different thickness of weathering crust (0-4 cm) with abundant holes and cracks. Their mineralogical composition is quartz, carbonate, and phyllosilicates with a preferential orientation. All cubes were dried, weighted and their volume determined and afterwards they were subjected to over 100 freeze-thaw cycles. To simulate moisture and rain, the cubes were thawed in a water bath at a constant temperature of 20 °C. All cubes were photodocumented before the test, roughly every three weeks over a 4 months period, and after the test. CT scans were made of one quartzbreccia cube before and after the test to better visualise structural changes within the cube. The freeze-thaw cycles show that the quartzbreccia cubes weather much more intense than the pegmatite gneiss. No visual changes were detected in the latter, whereas quartzbreccia cubes constantly changed. Water seems to enter the cubes following pathways along the aligned sheet silicates. These delicate minerals are then destroyed and once enough matrix is removed, larger quartz crystals fall out, which is nicely seen on the photos. Overall, this process seems to result in a rather continuous loss of material, but varies in different cubes and even on different planes of the cubes. As a result, cosmogenic 10Be is removed constantly. Additionally, the nature of discontinuous weathering results in an inhomogeneous 10Be production due to edge effects resulting in loss of 10Be at the rim of a raised quartz pebble. In summary, the freeze-thaw cycles show that the quartzbreccia weathers much faster than the pegmatite gneiss and therefore the age difference could at least partly be explained. Therefore, caution is required when dating conglomerates, breccias or similar lithologies with cosmogenic 10Be.
How to cite: Griesmeier, G. E. U., Hausenberger, A., Nacu, C., Reitner, J. M., Braumann, S., Neuhuber, S., and Le Heron, D. P.: Freeze-thaw cycles investigate weathering properties of different lithologies used in 10Be exposure age dating in the Eastern Alps, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5511, https://doi.org/10.5194/egusphere-egu26-5511, 2026.
During the last Pleistocene glacial cycle, Taiwan's high mountain ranges were glaciated in the uppermost altitudinal zone with a calculated lowering of the equilibrium line altitude (ELA) of ca. 1500 m down to 2800 m (Hebenstreit et al. 2025). Glacial erosion of the upper valley reaches formed trough-valleys. Lateral and terminal moraines as well as outwash deposits were deposited at or near the ice margins, respectively, at different stages of the glaciation. Subsequently, slope processes and fluvial activity have been reworking those sediments and reshaping those landforms during and after the glaciation to adjust the relief gradually to its present shape. These processes are called paraglacial processes (Ballantyne 2002).
In the Hsueh Shan range, we mapped a sequence of terraces composed of cobbles and boulders at the confluence of the Taoshan river and the Chijiawan river at an altitude of ca. 1900 m, which corresponds with the assumed lowest altitude of the last-glacial glacier termini. Surface exposure dating with paired in-situ produced terrestrial cosmogenic nuclides (TCN) of meter-sized boulders on the terrace surfaces gives evidence of enhanced glacio-fluvial activity, presumably reworking glacial deposits during the last phase of the glaciation at the Pleistocene-Holocene transition.
Lowering of the altitudinal zones and consequently of surface processes during glacial times entails periglacial processes on slopes not affected by glacial or fluvial processes (Böse 2006). This includes frost weathering and solifluction. The periglacial zone is presently restricted to altitudes above 3500 m in Taiwan.
A sediment profile at ca. 2050 m on the slope above the glacio-fluvial terraces shows a stratification typical for cover beds in mountainous periglacial environments (Kleber & Terhorst 2024): Above debris of local underlying bedrock follow layers enriched by aeolian dust. The sediment has been partly reworked and mixed by solifluction. Optically stimulated luminescence (OSL) ages of the silty matrix confirm its formation during the last glacial cycle; and a lowering of the periglacial altitudinal zone of 1500 m can be inferred.
References
Ballantyne, C. K., 2002: Paraglacial geomorphology. Quaternary Science Reviews
21 (18–19), 1935-2017.
Böse, M., 2006: Geomorphic altitudinal zonation of the high mountains of Taiwan. Quaternary International 147 (1), 55-61.
Hebenstreit, R., Hardt, J., Böse, M., 2025: The lowermost last‐glacial equilibrium line altitude in the Taiwanese Central Mountain Range and its implications for the palaeoclimate and the tropospheric moisture transport in East Asia. Journal of Quaternary Science 40 (5), 831-846.
Kleber, A., Terhorst, B. (eds.) 2024: Mid-Latitude Slope Deposits (Cover Beds)
2nd Edition. Elsevier Science
How to cite: Böse, M. and Hebenstreit, R.: Late Quaternary paraglacial and periglacial deposits in the high mountains of Taiwan, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2778, https://doi.org/10.5194/egusphere-egu26-2778, 2026.
Paleoclimatic evidence suggests that during the Holocene Climatic Optimum , glacier extent in many regions was substantially reduced or absent despite temperature conditions comparable to those observed today. This apparent discrepancy raises questions about the controls on glacier persistence over centennial to millennial timescales and the role of climate history, variability, and transient adjustment processes.
In this work, we take first steps into investigating the evolution of glacier ice masses across the Holocene using a thermo-mechanical ice flow modelling framework. By exploring glacier response across key Holocene climate intervals, including periods of warming and cooling, we aim to examine how prior climate states, rates of change, and long-term disequilibrium may influence glacier extent under similar mean conditions. This approach provides a long-term context for present-day glacier evolution and offers insight into why modern glaciers may differ from their earlier Holocene counterparts under comparable climatic forcing.
How to cite: Van Cappellen, M. and Zekollari, H.: Towards Reconstructing Ice-Dynamical Holocene Glacier Fluctuations , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18100, https://doi.org/10.5194/egusphere-egu26-18100, 2026.
Yukon Territory has been repeatedly affected by the northern Cordilleran Ice Sheet (NCIS). Although termed an ice sheet, it is better described as an ice complex, with quasi-independent lobes originating from mountainous areas around the border of the Yukon. This ice complex produced irregular, digitate glacial limits largely on the plateau area of central Yukon, at the eastern edge of unglaciated Beringia. These limits have broadly followed a pattern of progressively diminished extent. It is likely that variable precipitation across the source areas of these lobes affected their extent and timing during various glacial cycles. The growth model of the NCIS is contingent on ice from numerous cirques and ice fields in the source areas eventually amalgamating into these large, coalescent, ice lobes. What is unclear is the contribution of cirque and valley glaciers from the distal mountainous areas near the limits of glaciation. This research describes the contribution of cirque and valley glaciers in two areas at or near the limit of glaciation from MIS 6-2.
Ruby Range in southwest Yukon was affected by the Saint Elias lobe. It encompasses the limits of MIS 2, 4 and 6 glaciations. Stratigraphic analysis paired with 10Be surface exposure dating indicates extensive local ice production from cirques and plateau surfaces during MIS 2. During early MIS 2, local valley glaciers advance to the edge of the range but had retreated up valley during inundation by the St. Elias lobe, likely due to local precipitation reduction. These alpine ice centres were responsive to deglacial climatic fluctuations and hosted significant re-advances during the Older Dryas during rapid retreat of the St. Elias Lobe despite their location in the rain shadow of the St. Elias Mountains. The MIS 4 limit is slightly more extensive than the MIS 6 limit, likely because local ice growth contributed significantly to this portion of the St. Elias Lobe. The record and limit of the MIS 6 glaciation is poorly constrained here but 150 km to the NW, MIS 6 is 4 km more extensive than 4.
Granite Creek is in Gustavus Range in central Yukon at the MIS 2 limit of the Selwyn lobe. It was completely overrun during MIS 6, but cirque glaciers were extensive early enough that the Selwyn lobe did not inundate local cirque valleys. Stratigraphic studies indicate extensive MIS 4 cirque glaciation but provide no evidence of a proximal Selwyn lobe. During MIS 2, cirque glaciers near the margin were partially overrun by the Selwyn lobe. A tongue of the Selwyn lobe blocked Granite Creek forming a lake, and cirque glaciers terminating in the lake advanced due to floating ice margins. These limits are not reflected in the geomorphic record; well-defined MIS 2 moraines are recessional from this maximum.
This research indicates peripheral ice accumulation could contribute to the NCIS. However, stratigraphic studies indicate that peripheral ice sources in many cases were asynchronous with advances from primary source areas, likely due to variations in precipitation caused by the expansion of the CIS.
How to cite: Ward, B., Cronmiller, D., Steinke, J., Bond, J., and Lamothe, M.: Distal Cirque Contribution to the Northern Cordilleran Ice Sheet, Yukon Territory , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14826, https://doi.org/10.5194/egusphere-egu26-14826, 2026.
During the Last Glacial Maximum (LGM), the European Alps were occupied by an extensive glacial network in which major trunk glaciers interacted with smaller tributary glaciers. In several areas, local glaciers flowed in directions opposite to those of trunk glaciers, particularly in distal sectors characterized by complex topography and high precipitation. Despite their likely widespread occurrence, the dynamics, the peculiar morphologies and specific related depositional facies of these glacier–glacier interactions remain poorly constrained.
In the southeastern Alps (Italy), the glacial system was dominated by the Adige trunk glacier. Regional-scale reconstructions have defined glacier geometry, flow paths, and Equilibrium-Line Altitudes across the Adige and Astico valleys, including an ELA of ~1580 m for the Fiorentini glacier (Monegato et al., 2024). However, these reconstructions primarily address trunk glacier behavior, leaving the interactions with local valley glaciers largely unexplored.
This study focuses on valleys where the Adige trunk glacier interacted with local glaciers descending from adjacent massifs, with the two ice bodies flowing in opposite directionsunder conditions of high orographic precipitation. The Terragnolo Valley represents a key example, where the presence of the distal Adige glacier, is documented by moraines at elevations of ~1400 m a.s.l., and were it interacted with local glaciers descending from the Monte Pasubio massif (~2200 m a.s.l.). Similar geomorphological configurations are found also in the Vallarsa and Ossaria valleys, enabling a comparative, valley-scale analysis within the same glacial system.
In the Terragnolo Valley, the interaction zone is marked by a thick glacigenic succession extending for ~10 km upstream, dominated by locally derived carbonate clasts, with only minor contributions from lithologies typical of the trunk glacier. This sedimentary pattern indicates a complex interaction between the two ice bodies and raises key questions regarding ice-flow coupling, relative timing of glacier advances, and the degree of dynamic independence of local glaciers during the maximum extent of the trunk glacier.
Overall, the studied valleys highlight how interactions between trunk and local glaciers in distal sectors can generate complex dynamics and sedimentary architectures, providing new constraints for reconstructing Alpine glacier dynamics and the distribution of glacigenic deposits in the tributary valleys.
How to cite: Fontana, A., Vidi, C., Monegato, G., and Rossato, S.: Interactions between trunk and local glaciers in distal Alpine valleys (southeastern Alps, Italy), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19840, https://doi.org/10.5194/egusphere-egu26-19840, 2026.
Cosmogenic nuclide surface-exposure dating has emerged as a key tool in glacial geomorphology. Accurate application of the technique relies first on establishing local nuclide production rates using independently dated calibration sites. Certain regions of the world, such as the low latitudes, host few existing calibration sites. Developing local production rate calibrations in the low-latitudes is therefore a crucial first step for robust application of surface-exposure dating in these regions, particularly as cosmogenic nuclide production is theoretically more sensitive to changes in Earth’s magnetic field in the low-latitudes. Here we present a new local cosmogenic beryllium-10 production rate from the equatorial Rwenzori Mountains of Uganda based on radiocarbon dating of basal sediments from the moraine-dammed Lake Mahoma (~21.3 kyr BP; ~2,900 m asl). We also present the results of a systematic investigation of the performance of different parameters used to scale production rates spatially and temporally (e.g., scaling frameworks, geomagnetic field reconstructions, atmospheric models) using two public online calculators and limiting radiocarbon age data from nearby Lake Kopello (~4,000 m asl) in the Rwenzori. Our results highlight the sensitivity of low-latitude, high-elevation cosmogenic nuclide production to discrete parameters and underline the need for additional low-latitude production rate calibration sites.
How to cite: Jackson, M., Anderson, N., Kelly, M., Russell, J., Mason, A., Garelick, S., Doughty, A., Nakileza, B., Hutchinson, L., Geier, G., and Hidy, A.: A new low-latitude, high-elevation cosmogenic beryllium-10 production rate from the Rwenzori Mountains, Uganda, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13373, https://doi.org/10.5194/egusphere-egu26-13373, 2026.
Information on past glacier states is fundamental for improving projections of future glacier evolution under ongoing climate change. In this study, we present a 170-years reconstruction of glacier area and volume changes of five glaciers providing comprehensive regional representation of the Austrian Alps, covering the period from the Little Ice Age (LIA) maximum (~1850) to the present. LIA glacier extents are derived from the national moraine-based LIA glacier inventory and complemented by historical topographic maps, terrestrial oblique photographs, historical orthophotos, and modern digital elevation models (DEMs) as references.
We evaluate glacier geometry and its temporal changes at specific, data-constrained time points between the LIA maximum and the first comprehensive Austrian glacier inventory in 1969 by using monoplotting and DEM differencing techniques. Monoplotting intersects terrestrial photographs with DEMs to extract georeferenced glacier outlines from oblique photographs, for example. This approach allows us to derive glacier front variations or even approximate glacier areas at times where observational records are lacking. Historical DEMs were generated from scanned topographic maps, co-registered with modern elevation data, and used to compute volumetric changes. These multi-source datasets enable the reconstruction of glacier extents and ice-surface topography for several dates between the LIA and the first Austrian glacier inventory in 1969.
Results show that, across all glaciers studied, area decline rates increased around the 1940s relative to the period between end of LIA (~1850) to the 1940s, coinciding with periods of positive summer air-temperature anomalies, particularly during the 1940s. Between approximately 1975 and 1990, decline rates decreased for most glaciers, reflecting the cooler period of the 1970s and 1980s. Whereas most glaciers stabilized or even temporary advanced around that period, Niederjochferner exhibited strong glacier area loss, consistent with front position measurements of the Austrian Alpine Club (Österreichischer Alpenverein, ÖAV). Relative area decline rates are generally larger for smaller glaciers. While the area of Gepatschferner, one of Austria’s largest glaciers, has decreased by around 30% since 1850, the medium-sized glaciers (< 6 km2 at LIA) have lost at least 45% of their LIA area. Despite its northward orientation, the Niederjochferner shows the strongest area reduction with over 70% since LIA. In contrast, the Mullwitzkees shows the lowest relative area retreat (≈45%) since LIA, even though it is the only southward facing glacier in this study.
Ongoing work uses aerial imagery of high quality for its time, acquired by the US Army in 1945 covering the entire Austrian Alpine region, to reconstruct glacier extents and volumes. By generating orthophotos and DEMs, we aim to create a new national glacier inventory that can be used in various research fields. The extended time series of glacier volume and area change can provide valuable calibration and validation data for glacier models, such as the Integrated Glacier Model (IGM), enabling three-dimensional surface reconstruction and forward simulations under various climate scenarios.
How to cite: von Römer, L., Zandler, H., Hartl, L., Lauria, M. V., Schöner, W., and Abermann, J.: Refining the history of changes in glacier geometry since the LIA at selected sites across the Austrian Alps , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18543, https://doi.org/10.5194/egusphere-egu26-18543, 2026.
