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(a) Reconstructed palaeogeographic situation during the deposition of the first sedimentary evidence of ice decay at the southern slope of Wilder Kaiser. The extent of lateral moraines (dark) of the independent and advancing local glaciers as well as delta sediments (dotted area) and ice-dammed lakes are associated with different stages of down wasting of the stagnant Inn glacier. The thick dotted line marks the limit of the Inn glacier domain during the LGM. (b) Glacier extent during the Lateglacial Maximum Position (LMP) of the Wilder Kaiser glaciers.
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Results of a geological re-investigation of the type localities of the Bühl stadial, the supposed first halt during ice decay of the Inn glacier in the basin of Hopfgarten and at the southern flank of the mountain range Wilder Kaiser (Northern Tyrol, Austria) are presented. It is shown that in this region no stationary or advancing Inn glacier tong...
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Citations
... In the context of a major deglaciation phase, at the onset of the Würmian Lateglacial just after the LGM (Reitner, 2007), a small proglacial lake was formed and infilled by delta deposits, which led to the formation of Unit B during EP III (Fig. 2c). During this ice decay, a short oscillation of the remnants of the still-active Achen glacier resulted in a spatially limited overriding of the previously deposited glaciolacustrine Unit B (Fig. 1b, c). ...
... 4. The glaciolacustrine deposits (Unit B) are the result of the EP III event (Fig. 2c), which occurred in the early Lateglacial phase of ice decay (Reitner, 2007) after the more than 1.2 km thick glacier collapsed and melted in this sector of the Jochberger Ache Valley. Slump folds at the macroscale, not discussed here but occurring in other neighbouring locations, indicate a highly dynamic infill in a short-lived ice marginal to proglacial lake. ...
Knowledge of subglacial conditions is of great relevance in understanding glacier dynamics. A combination of micro- and macrosedimentological analysis of diamictons and deformation structures can form the basis for the reconstruction of past subglacial conditions. We present the results of such a study on subglacial tills, within an Alpine environment, at Einödgraben in the Kitzbühel Alps (Tyrol, Austria). The Late Pleistocene succession there (MIS 5d–MIS 2) shows great diversity in facies from alluvial and glaciolacustrine deposits to subglacial deposits. Two glaciogenic diamictons (tills) within the sequence were analysed at the microscale and are correlated to the Last Glacial Maximum (LGM; Würmian Pleniglacial) and the early Lateglacial phase of ice decay. The first deformation phase of pre-LGM deposits most likely occurred in a subglacial setting close to the advancing glacier margin and resulted in diapir-like glaciotectonic macrostructures, which are unique to an inner-alpine area. Subglacial erosion over these structures occurred, and later pre-LGM-emplaced deposits underwent deformation and partial homogenisation immediately beneath the glacier base, leading to diamictons, indicative of subglacial deformable bed conditions. The tills of the LGM and the Würmian Lateglacial show a range of microfacies and deformation structures that are evidence of close and rapid changes in till rheology and the stress field dynamic in the subglacial environment. Our study demonstrates the need for a reinvestigation of deposits occurring in the proximity of past active ice interfaces. The paleoglaciological evidence assembled from the detailed and spatially close research on the microsedimentology of tills at Einödgraben reflects our increasing comprehension and understanding of till microsedimentology in Alpine environments. An awareness is also shown of the need for much further research on the glacial depositional mechanics in mountainous terrains that are different from those in the immense lowland plains of the extensive paleo-ice sheets of North America and northern Europe.
... Other Iberian mountains where the recession of ice masses at the end of the LGM has been documented are Cuerpo de Hombre River (Sierra de Gredos; Carrasco et al., 2015) and the Cantabrian mountains (Rodríguez-Rodríguez et al., 2018). European mountainglacier and ice-sheet recession at the end or immediately after the global LGM has also been reported elsewhere, such as in the Kavron valley (Turkey; Akçar et al., 2007), the Tatra mountains (Poland; Makos et al., 2013), the Greenland, Scandinavian and British-Irish ice sheets (Clark et al., 2009;Vasskog et al., 2015) and especially in the Alps, where most of the ice disappeared in a short time (~1-2 kyrs) such as the Rhine valley (80% of ice mass was lost at 18 ka) (Ivy-Ochs et al., 2004, Ivy-Ochs, 2015Reitner, 2007;Dielforder & Hetzel, 2014;Reber et al., 2014;Wirsig et al., 2016). ...
... Thus, the 5 km long glacial valley of La Vega gorge was most likely completely icefree by~18 ka. In addition, one 10 Be CRE and three of the four OSL ages (BARCO 1a, 1b and BARCO 2b) obtained from the A rapid deglaciation of the La Vega gorge at the end of the global LGM is consistent with the data reported from other glacial valleys of Sierra de Gredos (Palacios, de Marcos, Vázquez-Selem 2011), other Iberian mountains such as the Pyrenees (Calvet et al., 2011;Palacios et al., 2015;Delmas, 2015) and Sierra Nevada (Palacios et al., 2016) and especially the European Alps (Reitner, 2007;Dielforder & Hetzel, 2014;Reber et al., 2014;Ivy-Ochs, 2015;Wirsig et al., 2016) where a similar rate of deglaciation was obtained, implying a homogeneous climate warming in the Mediterranean and central Europe at the end of the global LGM. ...
Previous studies from the Iberian Central System and other mountains of the Iberian Peninsula and Europe suggest that deglaciation in this area occurred at the end or immediately after the global Last Glacial Maximum (LGM, 26.5–19 ka). In this research, we investigate the timing and speed of deglaciation of the palaeoglacier in La Vega gorge (Iberian Central system) since the global LGM, dating the outer moraines, glacially polished bedrock and glaciofluvial deposits by means of in situ cosmogenic ¹⁰ Be and optically stimulated luminescence. The results show that one intermediate arc located at the outer frontal moraine system has an age of ~21 ka, being consistent with the global LGM. Deglaciation began at ~21–19 ka, speeding up at ~19 ka. We estimate that around 4–5 km of the palaeoglacier receded in ~1–2 kyrs since ~19 ka, leaving La Vega gorge probably ice‐free at ~18 ka. Therefore, our data confirm that deglaciation in Sierra de Gredos began at the end of the global LGM, characterised by a rapid and massive retreat of glaciers.
... Samples of a pale reddish-brown till (Munsell 4.5YR) (blue dot) were taken from this site 100 m southeast of the Wegscheid-Niederalm hut, some 2 km north-northeast of the community of Scheffau in the Wegscheid Creek valley (Fig. 10). Reitner (2007) established that the tills are derived from the IGIS in contact with the ice-dammed lakes filled with glaciolacustrine sediments. Wegscheidalm till was deposited by a local glacier (Menzies and Reitner 2016). ...
Subglacial sediments are subject to erosion, transport, and deposition in active, ephemeral, and spatially localized glacial environments. It is critical to determine how these mobilized sediments become immobilized in a time-transgressive process and can be frequently remobilized and reimmobilized. Microscopic sedimentary structural signatures provide invaluable information on subglacial processes and contribute to understanding till formation. Data were obtained from a series of field sites in Canada and Austria investigating the microsedimentological aspects of both alpine and continental glaciation tills to construct a conceptual model of subglacial deformation. Microstructures in these tills indicate rheological behaviors that can be summarized into a potential model for soft deforming subglacial sediments. Most microstructures noted in these subglacial till examples highlight the development of subglacial interface kinematics providing clues to till deposition mechanics, subglacial bedform development, and the processes involved in till provenance distributions. A conceptual process model of subglacial interface conditions in soft mobile sediments is developed that uses microsedimentological evidence and highlights how an active ice mass integrates with ongoing substrate deformation. In the model, interaction occurs between the ice and its sediment bed with internal sediment microstructures evolving where multiple transient shear deformation processes cause localized deformation linked to pervasive and nonpervasive sediment deformation.
... In the European Alps, intensive work has been undertaken over the past two decades on the timing and character of deglaciation from the Late Glacial Maximum (LGM) (van Husen, 2000;Reitner, 2007;Ivy-Ochs et al., 2008, 2023, but not on the processes involved in icesheet growth to the LGM position. Glacially shaped lake basins often preserve an excellent record of deglaciation from the LGM (Daxer et al., 2018), but the record of ice buildup from lakes is far less clear. ...
... 27-19 ka; Supplemental Material 1 : glaciological maps). After a rapid phase of ice decay (Reitner, 2007), large valleys became ice free around 18.5 ka, according to calibrated 14 C data from peat base layers in the Enns river catchment and other sites in the eastern European Alps (van Husen, 1997;Reitner, 2007). Previous research regarded the gravels and sand as (glacio-)fluvial remnants of a pre-penultimate glaciation resting on a preglacial valley floor (van Husen, 1968). ...
... 27-19 ka; Supplemental Material 1 : glaciological maps). After a rapid phase of ice decay (Reitner, 2007), large valleys became ice free around 18.5 ka, according to calibrated 14 C data from peat base layers in the Enns river catchment and other sites in the eastern European Alps (van Husen, 1997;Reitner, 2007). Previous research regarded the gravels and sand as (glacio-)fluvial remnants of a pre-penultimate glaciation resting on a preglacial valley floor (van Husen, 1968). ...
Although the retreat process of glaciers from the Late Glacial Maximum (LGM) is well documented, high-resolution insight into conditions prior to the maximum is lacking in the eastern European Alps, resulting in a gap in our understanding about the processes associated with this important climatic tipping point. We describe an outstanding sand and gravel outcrop at Gröbming in the Enns Valley (Ennstal), Austria, that represents the development of a delta complex that debouched into a large body of water that we name paleo-Lake Gröbming, fed by a major valley glacier. The succession consists of sands bearing climbing ripples, parallel laminations, and supercritical bed forms (bottomsets) overlain by meter-scale gravelly foresets. Topsets comprise gravels. We argue that sustained accumulation of supercritical bed forms required a jet efflux feeder mechanism best explained by a direct glacial meltwater source. Complex vertical and lateral repetition of this tripartite succession is observed, with sequence stratigraphic analysis permitting us to argue that stratal complexity is attributable to base-level changes in paleo-Lake Gröbming resulting from dam breaches of the lake. Thus, application of well-established sequence stratigraphic approaches to Quaternary ice-marginal successions in the Alps has significant potential to yield unprecedented insights into conditions prior to the LGM.
... Les stades de réavancée glaciaire du Bühl et du Steinach ont été mis en évidence en Autriche, et sont marqués par des terrasses de kame recouvertes de till et des moraines du glacier de l'Inn (Penck & Brückner, 1909;Mayrs & Heuberger, 1968). Plus tard, une analyse sédimentologique et géomorphologique a montré que les morphologies associées à ces deux stades ne sont pas issues de réavancées glaciaires contrôlées par des variations climatiques (van Husen, 2000;Reitner, 2007), mais sont plutôt liées à la fonte de masses de glaces datée par luminescence à 17 ka (Klasen, et al., 2007). Ceci implique que le terme de « stade » est difficile à utiliser pour cette période tardiglaciaire (Reitner, 2007). ...
... Plus tard, une analyse sédimentologique et géomorphologique a montré que les morphologies associées à ces deux stades ne sont pas issues de réavancées glaciaires contrôlées par des variations climatiques (van Husen, 2000;Reitner, 2007), mais sont plutôt liées à la fonte de masses de glaces datée par luminescence à 17 ka (Klasen, et al., 2007). Ceci implique que le terme de « stade » est difficile à utiliser pour cette période tardiglaciaire (Reitner, 2007). Néanmoins, des réavancées glaciaires au début du Tardiglaciaires ont été identifiées sur de petits bassins versants. ...
... Parallel to this ice surface lowering in the alpine accumulation zones deglaciation of the Po plain foreland take place between 18 and 17 ka (Gianotti et al., 2008;Gianotti et al., 2015;Ravazzi et al., 2012a;Ravazzi et al., 2014;Lauterbach et al., 2012, Serra et al., 2022. In the north-eastern part of the Alps, the withdrawal seems to be slightly older between 20-18 ka (Lister, 1988;van Husen, 1997;Reitner, 2007;Schmidt et al., 2012;Fontana et al., 2014). Finally, our results will improve the modelling of alpine glacier dynamics during the last glacial cycle. ...
Dans les Alpes occidentales françaises, de nombreuses morphologies et dépôts issus d’environnements glaciaires et proglaciaires sont hérités des glaciations du Quaternaire. Depuis plus d’un siècle, deux complexes morainiques ont été reconnus dans la zone de piémont et attribués aux dernières glaciations du Quaternaire. A partir d’analyses géomorphologiques et géologiques sur le piémont et dans les vallées internes, différentes avancées glaciaires ont été identifiées. Ces avancées glaciaires ont été définies par une approche morphostratigraphique, mais le cadre chronologique absolu basé principalement sur des datations 14C reste très fragmentaire. Ainsi, l’âge absolu du complexe des moraines internes (CMI) se trouvant sur le piémont et mis en place par le lobe glaciaire lyonnais reste encore débattu. De même, la dynamique et la chronologie du retrait glaciaire, depuis le dernier maximum glaciaire jusque dans les vallées alpines restent très parcellaires. Le but de cette thèse est donc de définir un meilleur cadre chronologique du dernier maximum glaciaire et des différents stades de retrait dans les Alpes occidentales françaises. Ce travail de thèse se focalise sur le piémont des Alpes occidentales françaises et plus précisément sur le CMI et sur les dépôts fluvioglaciaires associés. Ce travail se concentre également sur la dynamique de retrait depuis le piémont jusqu’en amont de la vallée de la Maurienne. Pour la première fois sur ce secteur, les méthodes de datation absolue par radionucléides cosmogéniques 10Be et par luminescence (OSL) ont été utilisées. Cette étude est basée sur une nouvelle caractérisation géomorphologique et sédimentologique des dépôts glaciaires et proglaciaires, afin de mettre en évidence et de dater les fluctuations (avancées et retraits) des glaciers des Alpes occidentales françaises depuis le front montagneux jusqu’en amont de la vallée de la Maurienne. Dans le piémont, les analyses géomorphologiques et sédimentologiques des systèmes fluvioglaciaires localisés au front du CMI ont mis en évidence une corrélation topographique entre les terrasses fluvioglaciaires et les différents ensembles de moraines. Ces systèmes fluvioglaciaires ont été ensuite datés par luminescence. Les résultats indiquent une activité fluvioglaciaire à 75-60 ka au cours du MIS 4 à l’origine du dépôt des terrasses corrélées aux moraines du maximum d’extension du lobe lyonnais. Une seconde activité fluvioglaciaire à 30-40 ka au MIS 3 est à l’origine des terrasses fluvioglaciaires corrélées aux moraines laissées par une extension du lobe lyonnais géométriquement proche de celle du MIS 4. Pour compléter cette chronologie OSL, nous avons réalisé des datations par âges d’exposition 10Be sur 9 blocs glaciaires localisés sur le complexe morainique et sur 12 blocs erratiques situés sur le reste du piémont. Les résultats montrent un retour du lobe glaciaire sur le piémont au LGM à 24-21 ka. Cette extension LGM est légèrement moins étendue que les extensions du MIS 4 et du MIS 3. En arrière de ces moraines, une réavancée / stabilisation a été mise en évidence à 19 ka. Enfin, les âges d’exposition indiquent que le piémont est déglacé à 16,5 ka. En amont du piémont, des âges d’exposition 10Be ont permis de reconstituer la dynamique de déglaciation dans les Alpes occidentales françaises au Tardiglaciaire. Ces âges d’exposition sont issus de datations inédites sur blocs erratiques ainsi que de datations sur blocs erratiques et glaciaires publiées. Ces résultats ont permis de retrouver des positions glaciaires de l’entrée du piémont (Culoz) jusqu’en amont de la Maurienne (Bessans) entre ~16,5 et ~12,5 ka. Entre l’entrée du piémont et la partie aval de la Maurienne (Pas du Roc), des âges d’exposition proches les uns des autres suggèrent un retrait rapide à environ 16,5 ka sur ~120 km, probablement favorisé par un vêlage dans de grands lacs proglaciaires. En Maurienne, des analyses sédimentologiques de deux affleurements (Verney et Lanslebourg) ont permis de mettre en évidence deux avancées glaciaires n’ayant pas laissé de moraines. La première avancée glaciaire est marquée par des déformations retrouvées dans un dépôt deltaïque au Verney. ALanslebourg, des faciès de plus en plus proximaux vers le haut de la succession sédimentaire et des déformations de cônes proglaciaires sous-aquatiques attestent de la seconde avancée glaciaire. Les analyses sédimentologiques, les datations par exposition et les âges par luminescence, permettent de reconstituer six fluctuations du glacier de l’Arc. Trois étapes de retrait glaciaire ont été mises en évidence à 16,7-14,6 ka ; 15,3 et 14,5 ka respectivement. Puis, deux stades de réavancée du glacier de l’Arc mis en évidence par les analyses sédimentologiques dont l’âge est estimé entre 14,5 et 13,6 ka. Enfin le dernier stade est marqué par des moraines frontales issues d’une réavancée à 12,5 ka au Dryas récent. Pour les six fluctuations glaciaires identifiées en Maurienne, une modélisation géométrique glaciaire a été réalisée et a permis d’estimer les variations de la ligne d’équilibre glaciaire (ELA) entre 16,7 et 12,5 ka. Ces modèles ont également permis de quantifier les variations de volume de glace et le bilan de masse moyen entre 16,7 et 14,5 ka, pendant la période de réchauffement climatique au début du Bølling-Allerød. Les variations de l’altitude de la ELA suggèrent des conditions de plus en plus sèches en Maurienne. Le bilan de masse moyen a été comparé aux bilans de masse des glaciers actuels soumis au réchauffement climatique anthropique. Ces comparaisons montrent que les bilans de masse moyens des glaciers actuels sont 10 à 100 fois supérieurs aux valeurs calculées pour le glacier de l’Arc pendant le Bølling-Allerød.
... decay (Reitner, 2007;Reitner et al., 2016). Field evidence does not support the previously accepted view of a successive retreat of still nourished valley glacier tongues back into the Alps. ...
... Only small tributary glaciers showed advances over delta deposits into ice-dammed lakes. In many cases, the most likely cause of such small advances was not related to climate forcing, but conversely was largely mechanical due to downwasting of the blocking trunk glaciers at the valley mouths (Reitner, 2007). The glaciers did not reach steady-state conditions as no end moraines from this time period have been found that would testify to stabilisation. ...
... The most prominent landforms of this early Lateglacial phase are staircases of kame terraces partly with kettle holes (Fig. 20.5) depicting post-LGM ice decay. These are known from all the major valleys of the Eastern Alps, like the Inn Valley and surrounding valleys (Bobek, 1935;Reitner, 2007), the Rhine Valley and its catchment (Keller, 1988;de Graaff et al., 2007), the Drau Valley (Bobek, 1959;Schuster et al., 2006) and the Resia Valley in the Julian Prealps (Colucci et al., 2014). In rare cases, eskers indicating the last subglacial drainage of already stagnant valley glaciers are preserved, as in the Inn Valley catchment (Fig. 20.5). ...
The deglaciation period in the Alps was characterised by the collapse of the huge system of interconnected glaciers. Active valley glaciers almost disappeared from most of the catchments, stagnant and downwasting ice remnants filled the main valleys during the earliest part of the Alpine Lateglacial, which is defined as the phase of ice decay (19–18 ka, in some sectors until 17 ka). In the lower valley reaches of the south-eastern sector tree vegetation had already started to recover. A short readvance and glacier front stabilisation took place at 17–16 ka (Gschnitz stadial) with the formation of prominent moraines, with most of the evidence coming from the Eastern Alps. This can be related to the ‘Ragogna oscillation’ cooling recognised in the south-eastern sector, which is highlighted by a period of reduced forest cover. At the end of GS2, before the onset of the Bølling interstadial, Alpine glaciers had already withdrawn and forest environments were spreading rapidly.
... Geiger, 1943;Weidenbach, 1975;Schmidt, 1976;Keller and Krayss, 2000). Final downwasting of the Rhine glacier likely occurred in concert with other major Alpine valleys ( van Husen, 1997;Klasen et al., 2007;Schlüchter et al., 2021) in the early Lateglacial phase of ice decay (Reitner, 2007). Stagnant, climatically decoupled, ice bodies may have persisted in the Alpenrhein Valley, but no clear ice marginal landforms were left behind neither at Eschnerberg nor along Fläscher Berg (Fig. 7). ...
... Moraine ridges of the described readvance stadials reflect the last morphologically well-constrained foreland positions of Rhine and Reuss glaciers (Fig. 15). The rapid collapse of both foreland glaciers likely occurred without significant glacier halts as upstream moraines are lacking (Schlüchter, 1988;Reitner, 2007). Several 14 C dates indicate an ice-free Swiss foreland no later than 18 ka (Rey et al., 2020 and references therein). ...
Fresh glacial landforms of the Alpine forelands evidence the presence and extent of large piedmont glaciers during the Last Glacial Maximum (LGM) and yield valuable insights into LGM glacier dynamics. This study assesses widespread ice marginal landforms preserved within the limit of the former LGM Rhine glacier and the eastern lobes of the LGM Reuss glacier system by means of geomorphological mapping. Timing of formation of the studied ice margins in Rhine and Reuss systems are chronologically framed by new ¹⁰Be and ³⁶Cl surface exposure ages, as well as new radiocarbon dates. This includes redating of radiocarbon samples first determined in the 1980s. Results of this and an earlier study focussing on outwash deposits downstream of the outer LGM ice margin, suggest that the Rhine glacier advanced to and reached its LGM maximum between ca. 26–22 ka, thereby forming a broad >100 km wide foreland piedmont lobe and constructing prominent and largely continuous chains of frontal moraines (outer Schaffhausen moraines). The eastern lobes of the Reuss glacier likely advanced to their LGM maximum position by 25/24 ± 2 ka as indicated by published luminescence dates. Stabilization of the corresponding Untertannwald ice margin and the slightly internal yet more prominent Mellingen moraines (Reuss glacier system) occurred no later than 22 ± 1 ka and 21 ± 1 ka, respectively. Glacier oscillations following the LGM maximum position are evidenced in both Rhine and Reuss systems but show varying degrees of preservation. Largely contemporaneous, late LGM readvances of Rhine (Stein am Rhein stadial) and Reuss (Bremgarten stadial) glaciers occurred after 20.6 ± 1.7 ka and 20.8 ± 1.3 ka, respectively. Absence of upstream moraines suggests rapid ice decay without marked stabilization, thereafter. Despite clear differences in the size and nature of their foreland lobes, with Rhein glacier as a broad piedmont lobe and narrow valley glacier like lobes characterising the eastern Reuss system, a remarkable similarity in timing is shown between the two.
... During the post-LGM deglaciation, a series of glacial readvances across the Alps characterized the Lateglacial period (19.0e11.7 ka) (i.e., the Termination I Reitner, 2007) preceding the onset of the Holocene. Numerous cosmogenic nuclide surface exposure ages of frontal moraines demonstrate a consistent timing of these glacial readvances across the Alps, strengthening the Alpine Stadial chronology and elucidating the link between climatic events and Alpine glacier readvances 2015;Federici et al., 2017;Rea at al. 2020). ...
We combined data from geomorphologic surveys, glacial modelling, and ¹⁰Be exposure ages of boulders on moraines, to investigate the Last Glacial Maximum (LGM) and the early retreat glacial phases in the Stura Valley of the Maritime Alps. We used the exposure ages to reconstruct the timing of standstills or readvances which interrupted the post-LGM withdrawal, initiated ∼24 ka. We mapped and dated the frontal moraines of a first glacial standstill/readvance at a short distance (∼7 km) from the maximum external limit of the LGM, which occurred at ∼22 ka, and a second one at ∼19 ka (Bühl stadial). This morpho-chronologic succession is congruent with that obtained in the adjacent Gesso Valley and, combined with the similarity of Equilibrium Line Altitude values, demonstrates a consistent glacial response in the Maritime Alps to climatic forcing.
Our data are chronologically consistent with those of the southern flank of the European Alps, stressing not only a general synchroneity of the LGM across the various sectors, but also that of a LGM recessional standstill or readvance at ∼22 ka. The short distance between the LGM moraines and the recessionary phase moraines, and minimal difference in ELA indicate a modest variation in the mass balance of the Maritime Alps glaciers during this time interval. A similar modest variation between LGM and the first recessional phase glacier mass balance is also found throughout the western sector of the Southern Alps but is considerably more pronounced for the glaciers of the central-eastern sectors. This behaviour can be explained by the interplay between the moisture supplied by southern currents sourced in the Western Mediterranean and that advected by the westerlies sourced in the North Atlantic, which affected the various sectors of the Southern Alps differently.
... Parallel to this ice surface lowering in the alpine accumulation zones, deglaciation of the Po plain foreland occurs between 18-17 ka (Gianotti et al., 2008;Lauterbach et al., 2012;Ravazzi et al., 2012Ravazzi et al., , 2014Gianotti et al., 2015;Serra et al., 2022). In the north-eastern part of the Alps, the withdrawal seems to be slightly older (20-18 ka ;Lister, 1988;van Husen, 1997;Reitner, 2007;Schmidt et al., 2012;Fontana et al., 2014). Finally, our results will improve the modeling of alpine glacier dynamics during the last glacial cycle. ...
The extent of glaciers in the western French Alps foreland during the last glacial maximum (LGM, 26.5–19 ka) has not yet been determined, so understanding glacial paleogeography during the LGM remains an open question. This study focuses on the glacial chronology in the western French Alps piedmont using ¹⁰ Be surface exposure ages on nine glacial boulders and 12 erratic boulders. Results indicate an LGM glacier advance between ca. 24 and 21 ka. During the late LGM, a smaller glacier readvance or stabilization phase occurred at ca. 19 ka, which was followed by a withdrawal phase between ca. 19 and 16.5 ka. Our outcomes show that the LGM extent in the western French Alps was similar or slightly less extensive than the pre-LGM ice extents during the last glacial. Such paleogeography has also been suggested in the western Italian Alps, which share the same accumulation zone with the western French Alps glaciers. The LGM dynamic of the western French Alps foreland glaciers highlighted by our exposure ages is consistent with the timing of the LGM glacier advances and deglaciation with the western Italian ice lobes.
... The most impressive geomorphic records of rapid deglaciation during this early Lateglacial phase of ice-decay (Reitner 2007) are staircases of kame terraces (Fig. 3.14c). They document the infill of ephemeral lakes formed on the rim of the first stagnant and eventually collapsing transection glacier complex. ...
... Hummocky terrains with a series of kettle holes due to decaying dead ice bodies and eskers are further characteristic elements of rapid ice decay. Impressive successions of kame terraces are present in areas of the Rhine Glacier on the flanks of the Rhätikon (Keller 1988) and in the Bregenzer Wald (de Jong et al. 1995), of the Inn Glacier in the Inn Valley (Bobek 1935) and in the Kitzbühel Alps (Reitner 2007), and of the Drau Glacier around Spittal/Drau (Reitner 2005b). Some smaller glaciers were still active and showed brief advances as documented by the presence of till on top of kame terraces (Mayr and Heuberger 1968;van Husen 1977;Reitner 2007;Reitner et al. 2016;Reitner and Menzies 2020). ...
... Impressive successions of kame terraces are present in areas of the Rhine Glacier on the flanks of the Rhätikon (Keller 1988) and in the Bregenzer Wald (de Jong et al. 1995), of the Inn Glacier in the Inn Valley (Bobek 1935) and in the Kitzbühel Alps (Reitner 2007), and of the Drau Glacier around Spittal/Drau (Reitner 2005b). Some smaller glaciers were still active and showed brief advances as documented by the presence of till on top of kame terraces (Mayr and Heuberger 1968;van Husen 1977;Reitner 2007;Reitner et al. 2016;Reitner and Menzies 2020). ...
Abstract
Austria has a diverse landscape as a result of the interplay of processes linked to tectonics and climate change. The final shaping occurred during the Quaternary (the last 2.58 Ma). This period is characterized by strong climatic variations on the global scale between glacial and interglacial conditions, which had different effects on the heterogeneous landscape, and its archives depending on the magnitude and duration of the climatic signal. The tectonic influence during the Quaternary is evident in instances of uplift as indicated by the Pleistocene terrace staircases of the Alpine foreland. In contrast, parts of the Vienna basin are characterized by subsidence linked to strike-slip faults. The oldest deposits are loess–palaeosol sequences (LPSs) which document the onset of loess accumulation with the occurrence of the Gauss/Matuyama alaeomagnetic reversal at the beginning of the Quaternary.
The Early Pleistocene record consists of LPSs and gravel deposits with no indication of a glacier advance.
Four major glaciations, namely Günz, Mindel, Riss and Würm (from oldest to youngest)—are known. These Ice Ages were characterized by a large complex of transection glaciers, i.e. an interconnected system of valley glaciers covering large sections of the Eastern Alps with glacier
tongues terminating in the Alpine foreland. The three older glaciations are of Middle Pleistocene age, whereas the youngest happened during the Late Pleistocene. All four glaciations are recorded by Glacial Sequences
genetically linking tongue basins with (subglacial) till, terminal moraine deposits and terraces consisting of proglacial outwash. Sediments of these glaciations differ in the degree of weathering and the characteristics of cover beds (e.g. LPSs). Based on geochronological data and the
relation between type and magnitude of the global climate signal, the amount of reconstructed sediment production following correlation with major phases of global glaciation is used: Günz (MIS 16; 676–621 ka), Mindel (MIS 12; 478–424 ka), Riss (MIS 6; 191–130 ka) and (Late)
Würm (MIS 2; 29–12 ka). Detailed knowledge of the Last Interglacial-Glacial cycle (130–12 ka) allows establishing models for climatically controlled sedimentary processes and for glacier expansion in the longitudinal valleys of the Eastern Alps. Overdeepened valleys and increased relief leading to different types of mass movements are also a legacy of glaciations. Evidence of Pleistocene permafrost (e.g. relict rock glaciers) as well as Holocene fluvial activity are further indications of the dynamic landscape development of the Austrian landscape during the Quaternary.
