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Luminescence rock surface burial and exposure dating approaches hold enormous potential to contribute to the archaeological sciences. These methods enable the dating of previously undatable archaeological site types and can be used to determine how and when lithic artefacts have been sequentially buried and transported. Studies have already used these approaches to overcome limitations of classical dating methods to constrain the ages of lithic artefact discard and post-depositional movement at surface scatter sites, to chronologically constrain rock art production by dating rockfall and exposure events, as well as dating a variety of rock-based archaeological features such as pavements, petroforms, megalithic structures, and walls. Here, we present a review of these developing methods, including an introduction to the underlying principles and applications, a series of case studies, and a discussion of the obstacles and complexities to be considered when applying these methods. We conclude with a discussion of future applications and developments, including direct dating of rock engravings, buried artefacts, megalithic stone structures, and chert artefacts. With ongoing work and applications, luminescence rock-surface dating has the potential to become widely applicable, shining new light on a diverse range of previously intractable archaeological contexts. [ABSTRACT FROM AUTHOR]

During marine oxygen isotope stage (MIS) 2, the Swiss Plateau temporarily hosted large piedmont lobe glaciers that retreated after their maximum advance back to the fringe of the Alps. The presence of moraines in this region indicates that overall glacier recession was punctuated by repeated phases of ice-marginal stability and re-advances. The timing of these events in the region formerly covered by the eastern lobe of the Rhône (or Valais) glacier has been controversial and remains poorly constrained due to the lack of chronological data. To fill this gap, 10Be cosmic-ray exposure (CRE) dating was applied to erratic boulders inside the assumed MIS 2 maximum extent of this piedmont lobe. An erratic boulder at an ice-marginal position upstream from the suspected MIS 2 maximum extent gave an age of about 19 ka. Erratic boulders at a presumably younger ice-marginal position (Brästenberg position) yielded an average age of ca. 20 ka. However, several erratic boulders beyond the Brästenberg position gave internally consistent, but stratigraphically too young ages of ca. 17 ka. We cannot rule out that glacier recession from the Brästenberg position began no later than 17 ka. CRE dating of a moraine of a presumably younger ice-marginal position (Solothurn position) gave unrealistically old ages and an incredibly young age (86 ka, 40 ka, and 4 ka). Carbon-14 CRE dating should be applied to provide additional information on the last deglaciation of the Swiss Plateau. Nevertheless, despite outlying ages, the presented chronological data contribute to an overall consistent and increasingly refined chronology of the last deglaciation of the Swiss Plateau when compared with 59 previously published CRE ages.

The Hengduan Mountains is in the transitional zone between the Qinghai-Tibet Plateau (QTP) and the Yunnan-Guizhou Plateau in China, and a key area for elucidating the Quaternary environmental changes in Asia. The paleo-Daocheng ice cap was located on the Shaluli Hilly Plateau in the northeastern Hengduan Mountains, the oldest moraines in the Hengduan Mountains region were found in the ice cap area. Such glacial landforms provide key evidence to study the timing when this area entered the cryosphere with the uplift of the QTP. However, it is difficult to collect suitable glacial boulders from these moraines for traditional terrestrial in-situ cosmogenic nuclide (TCN) exposure dating because of long-term severe moraine degradation. Here, we collected clast samples from the moraine surface and depth profile to constrain the age of the oldest moraine in Kuzhaori (moraine E) using TCN 10Be dating technique. The minimum 10Be ages of five clast samples from the moraine surface range from 187.4±1.5 to 576.8±4.3 ka, implying that the moraine has been seriously degraded since deposition. Based on the TCN 10Be concentrations of the samples from a depth profile and simulations, the exposure-erosion-inheritance history of the profile was obtained. By fitting to the profile 10Be concentrations using the chi-square test, the simulations yielded a reliable age of 626.0±52.5 ka for the moraine. Therefore, the oldest moraine (moraine E) in Kuzhaori was most likely formed at about 0.63 Ma ago, corresponding to the marine isotope stage (MIS) 16. This glaciation represents the maximum Quaternary glaciation after the QTP was elevated into the cryosphere by the Kunlun-Yellow River Tectonic Movement. [ABSTRACT FROM AUTHOR]

Ongoing speculation regarding the existence of large Late Pleistocene ice masses in Northeast Eurasia reflects the dearth of age constraints on glaciations across this vast region. Here, we report the first dates from the central part of Northeast Siberia, consisting of 22 cosmogenic 10Be exposure ages from boulders deriving from a sequence of three moraines in the Chersky Range. The dated moraine sequence indicates progressive contraction of maximum glacier extent from Marine Isotope Stage 6 to the Last Glacial Maximum, while the remotely‐sensed mapping indicates an older, more expansive glaciation in the region yet undated. Our results show that Late Pleistocene glaciations were limited to the highlands, and Northeast Siberia did not host a large, coalescent ice sheet during the Last Glacial Maximum or Marine Isotope Stage 6. Plain Language Summary: Very little is known about the glacial history of Northeast Siberia, which has led to speculations concerning the size and timing of past ice masses in this vast region. Some have previously suggested the area was covered by a large ice sheet during the Last Glacial Maximum 20 Kyr ago, but the consensus today maintains that the ice cover was limited due to restricted moisture sources. It is clear, however, that Northeast Siberia at one point in time hosted large ice masses, as the region is home to extensive glacial landforms of unknown age. We use cosmogenic 10Be exposure dating to study a glacial moraine complex with three well‐defined moraine ridges in the Chersky Range located in central Northeast Siberia. Our results show that the youngest and innermost moraine was emplaced toward the end of the Last Glacial Maximum, whereas the oldest and outermost moraine was emplaced during the penultimate glaciation ∼130 Kyr ago. This suggests that Northeast Siberia did not host a large ice sheet during the Late Pleistocene, and that the ice cover was limited to mountain glaciers. Satellite‐based mapping of glacial landforms confirms the existence of at least one older, more expansive glaciation that remains undated. Key Points: Be‐10 exposure ages from moraines in the Chersky Range show that glaciers in central NE Siberia contracted over the last two glacial cyclesNortheast Siberia hosted mountain‐centered icefields during the Late Pleistocene, but no large‐scale continental ice massesLargest ice extent in the Chersky Range predates the penultimate glacial cycle and likely occurred during the Mid‐Pleistocene super‐glacials [ABSTRACT FROM AUTHOR]

Abstract Ongoing speculation regarding the existence of large Late Pleistocene ice masses in Northeast Eurasia reflects the dearth of age constraints on glaciations across this vast region. Here, we report the first dates from the central part of Northeast Siberia, consisting of 22 cosmogenic 10Be exposure ages from boulders deriving from a sequence of three moraines in the Chersky Range. The dated moraine sequence indicates progressive contraction of maximum glacier extent from Marine Isotope Stage 6 to the Last Glacial Maximum, while the remotely‐sensed mapping indicates an older, more expansive glaciation in the region yet undated. Our results show that Late Pleistocene glaciations were limited to the highlands, and Northeast Siberia did not host a large, coalescent ice sheet during the Last Glacial Maximum or Marine Isotope Stage 6.

Glaciation during the late Middle Pleistocene is widely recognized across continental northwest Europe, but its extent and palaeoenvironmental significance in the British Isles are disputed. Although glaciogenic sediments at Wolston, Warwickshire, in the English West Midlands, have been used to define the stratotype of the Wolstonian Stage, their age has been variably assigned between marine isotope stages (MIS) 12 and 6. Here we present sedimentological and stratigraphical observations from five sites across the English West Midlands whose chronology is constrained by new luminescence ages from glaciofluvial sediments, supplemented by cosmogenic 36Cl exposure dating of erratic boulders. The ages suggest that between 199 ± 5 and 147 ± 2.5 ka the British Ice Sheet advanced into the English West Midlands as far south as Moreton-in-Marsh, Gloucestershire. This advance is assigned to the Moreton Stadial of the Late Wolstonian Substage. Dating of the glaciation to this substage allows correlation of the Moreton Stadial glacial deposits in the English West Midlands with those of the Drenthe Stadial during the Late Saalian Substage across continental northwest Europe.

Palaeoglacier modelling is a crucial approach for reconstructing palaeoclimate. Although the timing of glaciations during the Little Ice Age (LIA) and Neoglacial in the central Gangdise Mountains has been partially determined, there are still undated fresh-looking moraines. This study utilized coupled mass balance and ice flow models to simulate the palaeoclimate during the five LIA glacial events (LIA-1 to LIA-5) and two Neoglacial glacial events (Neo-1 and Neo-2). The results revealed that the glacial volumes in the Gangdise Mountains during the LIA and Neoglacial periods ranged from ∼1.10 to 1.57 km3. Comparing the reconstructed climate with other proxies, it was found that Neo-2 and Neo-1 exhibited temperatures 0.54 to 0.82 °C and 0.7 to 1.0 °C lower than the present, respectively, with precipitation levels at 110–140% of the present. The temperatures during the LIA periods were 0.36 to 1 °C lower than the present, with precipitation levels at 80–120% of the present. The interannual variability of climate at decadal or centennial scales may have played a significant role in the formation of the LIA moraines. • Palaeoglaciers during the Little Ice Age (LIA) and Neoglacial were reconstructed. • Palaeo- temperatures and precipitations were inferred. • The presence of five fresh-looking moraines may reflect the interannual climate variability during the LIA. [ABSTRACT FROM AUTHOR]

Concentrations of cosmogenic nuclides in rocks at the Earth's surface are routinely measured by AMS (accelerator mass spectrometry) to obtain exposure ages. One particular application of this technique has been to derive ages for the formation of marine terraces, thus allowing constraints to be placed on rates of tectonic uplift. However, multiple rock samples from the same terrace surface have typically shown an amount of scatter in cosmogenic nuclide concentrations in excess of analytical uncertainties, potentially undermining the confidence in the resulting uplift rates. In addition, earlier works have considered the application of bedrock samples for exposure age dating marine terraces, but little attention has been directed towards the validity of sampling clasts exposed on terrace surfaces. Here, we use 10Be and 26Al measurements from a flight of marine terraces in northern Chile to compare the results from pebbles with those from bedrock samples and to investigate assumptions that sample pre-exposure and burial are negligible. We examine the influence that processes of surface deflation and pebble erosion will have on cosmogenic nuclide concentrations using a Monte Carlo model, the results of which are compared to our 10Be measurements. We find good agreement of 10Be concentrations between bedrock and pebble samples. At the sampled location, sample burial is rare and 10Be inheritance in pebble samples is low relative to the age of the terraces. Our modelling suggests that in arid environments, such as northern Chile, pebble erosion will be a secondary effect compared to surface deflation and that multiple periods of deflation will result in multimodal distributions of 10Be concentrations. More broadly, our findings show that measuring multiple surface clasts from a single marine terrace reveals the geomorphological processes influencing exposure ages, and may also be used to help identify the operation of past surface processes such as episodic deflation. [ABSTRACT FROM AUTHOR]

Future changes in sea level will largely be dictated by changes in the world's ice sheets. Yet the magnitude and rate at which these ice sheets will respond to climate change remain uncertain, necessitating a deeper investigation into past ice sheet‐climate interactions. Numerous studies have documented the timing and pattern of Laurentide Ice Sheet margin retreat since the Last Glacial Maximum, but few studies have provided vertical constraints necessary for accurate sea level contribution estimates. Here we present 21 36Cl ages from boulder and bedrock samples along vertical transects spanning ~1,000 m of relief from multiple peaks in the Adirondack Mountains of northeastern New York, USA. Our exposure ages span the Last Glacial Maximum through the last deglaciation, with the highest‐elevation sites (~1,500 m) ranging between 25 and 19 ka, and the lower elevation sites (≤1,300 m) between 16 and 13 ka. These data suggest gradual ice sheet thinning of 200 m initiated at ~20 ka followed by more rapid surface lowering of 1,000 m approximately coincident with Bølling‐Allerød warming. Key Points: The 36Cl exposure ages from the Adirondacks show regional ice sheet thinning historiesThe Laurentide Ice Sheet experienced two‐phase thinning in this region ~21–14 kaGradual thinning was followed by rapid retreat coincident with the Bølling‐Allerød [ABSTRACT FROM AUTHOR]

Abstract Gour de Tazenat is a maar volcano on the crystalline Plateau des Domes, the uplifted margin of the Limagne Rift of the Massif Central of France, and forms one of the northernmost volcanic centers of the Chaîne des Puys volcanic field. Although long recognized as a relatively young volcanic center in the area, age determinations have been elusive, with the only one quantitative estimate based upon radiocarbon ages of bulk sediments in the crater lake and extrapolation of sedimentation rates to account for the full thickness of the sediments; that age is ∼35 cal ka. Here we test application of cosmogenic 10Be exposure dating to quartz-bearing subvolcanic rocks exposed in the wall of the maar crater. Considering erosion rates (∼5 m/Myr) that we determined from 10Be data on a nearby tor (located outside the crater), and corroborated by inverted relief of older, dated lavas in the region, the 10Be data yield an age of 29–34 ka for the maar-forming eruption of Gour de Tazenat. This is consistent with the one previous quantitative estimate, and provides confidence in the age range of the maar. This age corresponds to a pulse of volcanic activity around 30 ka in other parts of the Chaîne des Puys. [ABSTRACT FROM AUTHOR]

Landslides affecting the north-western coast of the Island of Malta have been investigated and monitored for 10 years. As a result of a bathymetric survey, it was discovered the deposits continued out onto the seafloor, thus raising questions as to the timing of their development. Furthermore it was uncertain as to which environment they developed in and which factors controlled their movements. The aim of this paper is to investigate representative detachments to chronologically constrain these mass movement events and outline their spatial and temporal evolution. Samples for exposure dating using the cosmogenic nuclide 36Cl were collected from head scarps and blocks located within two long-term monitored landslides characterised by extensive block slides. The results indicate the oldest dated block detachment occurring in a subaerial environment at ca. 21 ka, when the sea level was about 130 m lower than at present. Mass movement possibly accelerated when sea level reached the landslide toe during the post-glacial marine transgression. Considering the timing of block movement, the landslide deposits observed today appear to be related to a first-time failure involving a large part of the slope, though and alternative hypothesis is also taken here into account. This main event is likely to have been followed by secondary movements influenced by toe undercutting and clay saturation due to rising sea level. However, further research on mass movement kinematics is required in order to model their evolution and explore whether this interpretation is widely applicable along the Maltese coast. [ABSTRACT FROM AUTHOR]

Moraines preserved around Mount Xuebaoding (5588 m above sea level) on the eastern margin of the Tibetan Plateau, represent past glacial activity in this area. The chronology of these moraines was established using 10Be exposure dating. The dating results revealed multiple glacial events prior to the late glacial (> 14.1±2.2 ka), the late glacial (15.6±1.6 to 11.2±3.0 ka), the early-middle Holocene (9.1±0.9 to 6.7±0.7 ka), and the Neoglacial periods (2.5±0.5 to 1.5±0.1 ka). These glacial stages are consistent with the recalculated ages from surrounding areas throughout the Indian and East Asian monsoon-influenced region on the eastern Tibetan Plateau. Comparing with other paleoclimate indexes, we suggest that the late glacial event was mainly driven by low temperature, the early–middle Holocene event by high precipitation, and the late Holocene/Neoglacial event by low temperature. [ABSTRACT FROM AUTHOR]

The measurement of erosion and weathering rates in different geomorphic settings and over diverse temporal and spatial scales is fundamental to the quantification of rates and patterns of earth surface processes. A knowledge of the rates of these surface processes helps one to decipher their relative contribution to landscape evolution – information that is crucial to understanding the interaction between climate, tectonics and landscape. Consequently, a wide range of techniques has been developed to determine short- ( < 10 2 a ) and long-term ( > 10 4 a ) erosion rates. However, no method is available to quantify hard rock erosion rates at centennial to millennial timescales. Here we propose a novel technique, based on the solar bleaching of luminescence signals with depth into rock surfaces, to bridge this analytical gap. We apply our technique to glacial and landslide boulders in the Eastern Pamirs, China. The calculated erosion rates from the smooth varnished surfaces of 7 out of the 8 boulders sampled in this study vary between < 0.038 ± 0.002 and 1.72 ± 0.04 mm ka − 1 (the eighth boulder gave an anomalously high erosion rate, possibly due to a recent chipping/cracking loss of surface). Given this preferential sampling of smooth surfaces, assumed to arise from grain-by-grain surface loss, we consider these rates as minimum estimates of rock surface denudation rates in the Eastern Pamirs, China. [ABSTRACT FROM AUTHOR]

ABSTRACT: Our new dataset from the Rivoli‐Avigliana end‐moraine system, the westernmost amphitheatre of the Italian Alps, provides an important step towards understanding foreland‐reaching glaciations before and during the Last Glacial Maximum (LGM) in the Western Alps. 10Be data from six boulders in pre‐LGM deposits gave ages between 26.8 ± 2.1 and 41.2 ± 1.9 ka. Based on morphological and pedological data, we interpret the oldest age as a minimum age for the glacier advance(s). 10Be results suggest that the LGM occurred in two major steps. During the first at 24.0 ± 1.5 ka, several ridges were constructed demonstrating oscillation of the Dora Riparia glacier snout at the maximum position. Our data demonstrate a significantly larger LGM extent in the Rivoli‐Avigliana amphitheatre than shown on previous maps. The maximum advance was followed by a short re‐advance of the glacier at 19.6 ± 0.9 ka, as recorded by 10Be ages from boulders in lateral positions along the lower Susa Valley. The maximum ice surface during the LGM was at 1000–920 m a.s.l. in the final reach of the valley (560–620 m of elevation above the alluvial plain) and at 620–340 m a.s.l. at the continuous moraines in the amphitheatre. [ABSTRACT FROM AUTHOR]

The combined Rhone and Aare Glaciers presumably reached their last glacial maximum (LGM) extent on the Swiss Plateau prior to 24 ka. Two well-preserved, less extensive moraine stades, the Gurten and Bern Stade, document the last deglaciation of the Aare Valley, yet age constraints are very scarce. In order to establish a more robust chronology for the glacial/deglacial history of the Aare Valley, we applied 10Be surface exposure dating on eleven boulders from the Gurten and Bern Stade. Several exposure ages are of Holocene age and likely document post-depositional processes, including boulder toppling and quarrying. The remaining exposure ages, however yield oldest ages of 20.7 ± 2.2 ka for the Gurten Stade and 19.0 ± 2.0 ka for the Bern Stade. Our results are in good agreement with published chronologies from other sites in the Alps. [ABSTRACT FROM AUTHOR]

Optically Stimulated Luminescence (OSL) depth profiles can be used to extrapolate rock surface exposure ages by understanding a sample's light attenuation and OSL bleaching behaviors. However, the current measuring procedure for producing depth profiles, by measuring the luminescence of millimeter slices from surface core samples, offers limited resolution data, limiting parameter extrapolative precision. The use of OSL laser scanning measuring protocols on transverse core slices has potential for improving the data resolution of OSL depth profiles from core samples. An 11-year exposed rock surface was parameterized for light attenuation and luminescence bleaching rates using depth profile data from four surface cores collected via wafer and scan measuring techniques, to show the potential of OSL laser scanning to improve depth profile dataset resolutions and parameter extrapolative precision. Additionally, non-quartz OSL anomalies were filtered from scan datasets to determine if non-quartz mineral filtering can further improve the resolution and parameterization of depth profile datasets. OSL scanning measures improved the resolution of depth profiles over wafer derived depth profiles for the measured samples, and in comparing absolute uncertainties of parameters, broadly improved parameter precision using maximum likelihood estimate fitting protocols. Non-test dose corrected spatially resolved data error bounds were generally larger than from wafer derived data. When compared to unfiltered spatially resolved depth profile data, OSL anomaly filtered scanned depth profiles improved error bounds of anomaly affected data, and improved parameter extrapolative precision with roughly a similar effect as using non-filtered scan data. The absolute uncertainty in parameterization was impacted by scatter prevalent from scan datasets, which is caused by low OSL sensitivity from samples, the potential recording of remnant OSL, the lack of regenerative dose normalization applied to the scan dataset, as well as other scanning instrument measuring limitations. Still, these influences can be mitigated with optimized instrumentation and scanning protocols. • OSL depth profile measures from rock samples obtained using both wafer slices and OSL laser scanning. • OSL laser scanning produces sub-millimeter resolution datasets. • Non-quartz OSL filtered from depth profiles using SEM-EDS assessments. • Application on 11-year exposed quartzite. [ABSTRACT FROM AUTHOR]

Detailed mapping of dolerite slope deposits overlying sedimentary Triassic rocks on the northern slopes of the Nicholas Range in northeastern Tasmania has revealed an extensive mass movement complex. Landforms north of the summit plateau of the Nicholas Range include the following: (1) a cliff of dolerite columns with associated scree slopes at its base; (2) a topple landscape consisting of several topples that have fallen in a north-easterly direction; (3) a 'ripple' landscape consisting of a series of long boulder ridges aligned approximately east-west. Exposure dates were obtained for three large boulders (collapsed dolerite columns) from a ridge within the ripple landscape. The two youngest dates gave a mean age of 52.1 ± 1.9 ka using Cl. This is the estimated age for collapse of the dated columns from the cliff face c. 750 m to the south. Boulder ages and landscape morphology indicate that the ripple landscape developed by physical and chemical degradation and concurrent northern displacement of topples over a slip plane formed at the contact between dolerite colluvium and underlying Triassic sedimentary rocks. There is no evidence of movement today, other than localised debris flows associated with knickpoints in streams, and it is deduced that movement on the slip plane occurred under a cooler climate than that prevailing today, possibly under the influence of melting of winter snow during the last glacial cycle. As there is no evidence of significant recent mass movement and forests in the area are likely to have experienced many stand-destroying forest fires in the Holocene, forest harvest is not considered to pose a risk to landscape stability. [ABSTRACT FROM AUTHOR]

A two-phased moraine system in the high Alpine valley of Lisenser Längental in the Stubai Alps of western Austria is located in an intermediate morphostratigraphic position constrained by 'Egesen Stadial' (Younger Dryas) moraines down valley and 'Little Ice Age' ('LIA') positions (modern times) up valley. The equilibrium line altitude (ELA) was about 50 m lower than during the 'LIA' when applying an accumulation area ratio of 0.67. Exposure dating of boulders with 10Be yields a mean age of 3750 ± 330 years for the more extensive outer moraine system and a single age of 3140 ± 280 years for the inner one. The ages correspond well to the 'Loebben oscillation', a sequence of multi-decadal to multi-centennial cooling phases at the onset of the late-Holocene, also recognized in other Alpine records. The climatic downturn was severe enough to cause small to medium-sized Alpine glaciers in the central Alps to advance significantly beyond their 'LIA' extent, but too short to trigger a similar reaction with large glaciers. [ABSTRACT FROM AUTHOR]

Deglaciation of the Ross Sea following the last ice age provides an important opportunity to examine the stability of marine ice sheets and their susceptibility to changing environmental conditions. Insufficient chronology for Ross Sea deglaciation has helped sustain (i) the theory that this region contributed significantly to Meltwater Pulse 1A (MWP-1A) and (ii) the idea that Ross Sea grounding-line retreat occurred in a 'swinging gate' pattern hinged north of Roosevelt Island. We present deglaciation records from southern Transantarctic Mountain glaciers, which delivered ice to the central Ross Sea. Abrupt thinning of these glaciers 9-8 kyr B.P. coincided with deglaciation of the Scott Coast, ∼800 km to the north, and ended with the Ross Sea grounding line near Shackleton Glacier. This deglaciation removed grounded ice from most of the central and western Ross Sea in less than 2 kyr. The Ross Sea Sector neither contributed nor responded significantly to MWP-1A. [ABSTRACT FROM AUTHOR]

Understanding how marine-based ice streams operated during episodes of deglaciation requires geochronological data that constrain both timing of deglaciation and changes in their flow behaviour, such as that from unconstrained ice streaming to topographically restricted flow. We present seventeen new 10 Be exposure ages from glacial boulders and bedrock at sites in western Scotland within the area drained by the Hebrides Ice Stream, a marine-based ice stream that drained a large proportion of the former British-Irish Ice Sheet. Exposure ages from Tiree constrain deglaciation of a topographic high within the central zone of the ice stream, from which convergent flowsets were produced during ice streaming. These ages thus constrain thinning of the Hebrides Ice Stream, which, on the basis of supporting information, we infer to represent cessation of ice streaming at 20.6 ± 1.2 ka, 3–4 ka earlier than previously inferred. A period of more topographically restricted flow produced flow indicators superimposed on those relating to full ice stream conditions, and exposure ages from up-stream of these constrain deglaciation to 17.5 ± 1.0 ka. Complete deglaciation of the marine sector of the Hebrides Ice Stream occurred by 17–16 ka at which time the ice margin was located near the present coastline. Exposure ages from the southernmost Outer Hebrides (Mingulay and Barra) indicate deglaciation at 18.9 ± 1.0 and 17.1 ± 1.0 ka respectively, demonstrating that an independent ice cap persisted on the southern Outer Hebrides for 3–4 ka after initial ice stream deglaciation. This suggests that deglaciation of the Hebrides Ice Stream was focused along major submarine troughs. Collectively, our data constrain initial deglaciation and changes in flow regime of the Hebrides Ice Stream, final deglaciation of its marine sector, and deglaciation of the southern portion of the independent Outer Hebrides Ice Cap, providing chronological constraints on future numerical reconstructions of this key sector of the former British-Irish Ice Sheet. [ABSTRACT FROM AUTHOR]

Few data are available to infer the thinning rate of the Laurentide Ice Sheet (LIS) through the last deglaciation, despite its importance for constraining past ice sheet response to climate warming. We measured 31 cosmogenic 10 Be exposure ages in samples collected on coastal mountainsides in Acadia National Park and from the slightly inland Pineo Ridge moraine complex, a ∼100-km-long glaciomarine delta, to constrain the timing and rate of LIS thinning and subsequent retreat in coastal Maine. Samples collected along vertical transects in Acadia National Park have indistinguishable exposure ages over a 300 m range of elevation, suggesting that rapid, century-scale thinning occurred at 15.2 ± 0.7 ka, similar to the timing of abrupt thinning inferred from cosmogenic exposure ages at Mt. Katahdin in central Maine (Davis et al., 2015). This rapid ice sheet surface lowering, which likely occurred during the latter part of the cold Heinrich Stadial 1 event (19–14.6 ka), may have been due to enhanced ice-shelf melt and calving in the Gulf of Maine, perhaps related to regional oceanic warming associated with a weakened Atlantic Meridional Overturning Circulation at this time. The ice margin subsequently stabilized at the Pineo Ridge moraine complex until 14.5 ± 0.7 ka, near the onset of Bølling Interstadial warming. Our 10 Be ages are substantially younger than marine radiocarbon constraints on LIS retreat in the coastal lowlands, suggesting that the deglacial marine reservoir effect in this area was ∼1,200 14 C years, perhaps also related to the sluggish Atlantic Meridional Overturning Circulation during Heinrich Stadial 1. [ABSTRACT FROM AUTHOR]

Retreat of the Antarctic ice sheets since the Last Glacial Maximum (LGM) contributed to sea-level rise, but the location, amount, and timing of ice mass loss has been controversial. This paper presents new 10 Be exposure ages from glacially transported erratics which record post LGM retreat of grounded ice in the western Ross Sea. Ice elevation in southern McMurdo Sound was ≥520 m above present day sea level on the eastern side of Mount Discovery during the LGM, and the onset of major deglaciation in the region was after 14 ka. The ice surface lowered from ∼520 to 234 m above present day sea level between 14.0 ka and 10.3 ka and from 234 m to ∼30 m between 10.3 ka and 7.4 ka. This late-glacial and Holocene deglaciation chronology from southern McMurdo Sound is consistent with other records on the margins of the Ross Embayment, and implies that the western margins of the Ross Sea Ice Sheet (RSIS) experienced most mass loss during the early to middle Holocene. These 10 Be exposure ages coupled with sediment provenance define a two-stage ice flow scenario for McMurdo Sound subdividing differing reconstructions into an early and late phase. Prior to Termination I, an expanded Koettlitz Glacier flowed north and northeast between Brown Peninsula and Mount Discovery and coalesced with northward flowing ice fed from the Skelton and Mulock Glaciers. Thinning and retreat of the Koettlitz Glacier and perhaps other outlet glaciers flowing through the Royal Society Range allowed ice grounded in the Ross Sea to flow westward and northward, north of Brown Peninsula. Grounding-line recession in the Ross Sea during the late-glacial and Holocene was likely driven by Southern Ocean warming and sea-level rise from the retreat of the Northern Hemisphere ice sheets and the outer margins of the Antarctic ice sheets. [ABSTRACT FROM AUTHOR]

With the aim of improving the accuracy and applicability of OSL surface exposure dating, modified sampling and measuring procedures incorporating controlled exposure experiments (CEE) and OSL scanning methods were performed in a trial study on 11-year exposed quartzite rocks in Washington, USA, as well as millennial to decamillennial exposed quartzite surfaces a part of the Foothills Erratics Train in Alberta, Canada. CEE sampling approaches attempt to reliably determine exposure dating model parameters directly from the rock surface of interest using OSL saturated core samples subjected to controlled light exposures. OSL laser scanning measures are used in tandem to record sub-millimeter resolution OSL depth profiles from transverse slices of core surface samples. Scanning electron microscopy with energy dispersive spectroscopy analyses (SEM-EDS) is used additionally to identify and filter non-quartz OSL anomalies in scans to generate less scattered depth profile data which more closely follows depth profile forms of the first-order kinetic exposure dating model. The 11-year exposure study showcases that such measuring and sampling techniques can assist in acquiring precise depth profiles and accurate exposure ages, yet may face resolution issues in OSL data collection depending on rock sample composition. The trial exposure dating study on the Foothills Erratics Train, a site hosting millennial to decamillennial exposed quartzite erratic surfaces, aims to provide an enhanced timeline of glacial retreat for the Erratics Train, offering an interpretable timeline to when humans could have accessed an ice-free corridor to migrate into North America. [ABSTRACT FROM AUTHOR]

Limited information on the East Antarctic Ice Sheet (EAIS) geometry during Marine Isotope Stage 3 (MIS 3; 60-25 ka) restricts our understanding of its behaviour during periods of climate and sea level change. Ice sheet models forced by global parameters suggest an expanded EAIS compared to the Holocene during MIS 3, but field evidence from East Antarctic coastal areas contradicts such modelling, and suggests that the ice sheet margins were no more advanced than at present. Here we present a new lake sediment record, and cosmogenic exposure results from bedrock, which confirm that Rauer Group (eastern Prydz Bay) was ice-free for much of MIS 3. We also refine the likely duration of the Last Glacial Maximum (LGM) glaciation in the region. Lacustrine and marine sediments from Rauer Group indicate the penultimate period of ice retreat predates 50 ka. The lacustrine record indicates a change from warmer/wetter conditions to cooler/drier conditions after ca. 35 ka. Substantive ice sheet re-advance, however, may not have occurred until much closer to 20 ka. Contemporary coastal areas were still connected to the sea during MIS 3, restricting the possible extent of grounded ice in Prydz Bay on the continental shelf. In contrast, relative sea levels (RSL) deduced from field evidence indicate an extra ice load averaging several hundred metres thicker ice across the Bay between 45 and 32 ka. Thus, ice must either have been thicker immediately inland (with a steeper ice profile), or there were additional ice domes on the shallow banks of the outer continental shelf. Further work is required to reconcile the differences between empirical evidence of past ice sheet histories, and the history predicted by ice sheet models from far-field temperature and sea level records. [ABSTRACT FROM AUTHOR]

We describe glacial-geological observations and cosmogenic-nuclide exposure ages from the Schmidt, Williams, and Thomas Hills in the Pensacola Mountains of Antarctica adjacent to the Foundation Ice Stream (FIS). Our aim is to learn about changes in the thickness and grounding line position o f the Antarctic Ice Sheet in the Weddell Sea embayment between the Last Glacial Maximum (LGM) and the present. Glacial-geological observations from all three regions indicate that currendyice- free areas were covered by ice during one or more past ice sheet expansions, and that this ice was typically frozen to its bed and thus non-erosive, permitting the accumulation of multiple generations of glacial drift. Cosmogenic-nuclide exposureage data from glacially transported erratics are consistent with this interpretation in that we observe both (i) samples with Holocene exposure ages that display a systematic age-elevation relationship recording LGM-to-present deglaciation, and (ii) samples with older and highly scattered apparent exposure ages that were deposited in previous glacial-interglacial cycles and have experienced multiple periods of surface exposure and ice cover. Holocene exposure ages at the Thomas and Williams Hills, upstream o f the present grounding line o f the FIS, show that the FIS was at least 500 m thicker prior to 11 ka, and that 500 m of thinning took place between 11 and 4 ka. However, exposure-age data from the Schmidt Hills, downstream of the present grounding line of the FIS, show no evidence for LGM thickening of the FIS and, in fact, provide some evidence that the FIS could have been no more than 200 m thicker than present at the LGM. If all these observations are correct, they imply that the LGM and early Holocene ice surface slope in the vicinity of the present grounding line was steeper than present, which is inconsistent with glaciological model predictions o f possible LGM ice sheet configurations. Specifically, scenarios in which the LGM grounding line of the FIS advanced to the outer continental shelf appear inconsistent with exposureage data from the Schmidt Hills, whereas scenarios in which the FIS grounding line did not advance at the LGM appear inconsistent with exposure-age data from the Williams and Thomas Hills. [ABSTRACT FROM AUTHOR]

We develop a modeling framework to describe the accumulation of terrestrial cosmogenic 3 He in Antarctic debris-covered glaciers. The framework helps quantify the expected range in cosmogenic-nuclide inventories for measured clasts at the surface of supraglacial debris. We first delineate the physical factors that impact clast movement within, and on top of, debris-covered glaciers, including the effects of (1) ice ablation, (2) erosion at the debris surface, and (3) stochastic geomorphic processes that impact clast movement within and on top of supraglacial debris; we then explicitly calculate the impact of each process in altering the total inventory of cosmogenic nuclides in surface clasts. Assuming basic elements of ice-dynamics and debris entrainment are known, the model results provide an estimate for the total accumulation of cosmogenic nuclides, as well as the expected range in nuclide inventories, for any clast at the surface of debris-covered glaciers. Because the values are quantified, the approach can be applied to help evaluate the robustness of existing and future cosmogenic datasets applied to these systems. As a test, we applied our model framework towards Mullins Glacier, a cold-based debris-covered alpine glacier in the Dry Valleys of Antarctica. Our simulated values for cosmogenic-nuclide inventories compare well with those previously measured from fifteen surface cobbles along Mullins Glacier ( 3 He), both in terms of expected ranges and absolute values, and suggest that our model framework adequately incorporates most of the complicating factors that impact cosmogenic datasets for cold-based, debris-covered glaciers. Relating these cosmogenic-nuclide inventories to ice ages, the results show that ice within Mullins Glacier increases non-linearly, ranging from 12 ka to ∼220 ka in areas of active flow, to ≫1.6 Ma in areas of slow-moving-to-stagnant ice. [ABSTRACT FROM AUTHOR]

Among the many well-preserved moraine systems that are found throughout the Austrian Silvretta Mountains, a set of prominent moraines in the upper Kromer Valley located in front of the ‘Little Ice Age’ positions are of particular interest as they have been allocated to contrasting time periods in the past. Initial assumptions associated them with the transition period from the Younger Dryas to the early Holocene, but first exposure dating results published in 2006 suggested a relation to the ‘8200-year event’. However, since then, the lack of comparable evidence elsewhere in the Alps prompted a re-evaluation of the moraines at this site based on the recalculation of the original ages with the recently available lower 10Be production rate (‘Northeast North America’) and by dating additional boulders in the Kromer Valley and in the neighbouring Kloster Valley. The newly sampled boulders (n = 9) show, depending on interpretation, moraine stabilization around 10,000 years. These ages implicate that glacier termination occurred considerably earlier than during the previously suggested 8200-year cooling event, but also clearly after the climatic cold period of the Younger Dryas (>11,700 years) and the Preboreal Oscillation (~11,400 years). Consequently, our results suggest that the Kromer Valley moraines represent a marked glacier advance during the Boreal period before the final recession to mid- and late Holocene glacier size. [ABSTRACT FROM AUTHOR]

ABSTRACT We combine 10Be surface exposure ages from boulders and bedrock, field observations and measurement of bedrock ice-flow direction indicators with numerical ice surface models to develop a model of the evolution of the Oberhasli area in the central Swiss Alps from the Last Glacial Maximum (LGM) to the early Holocene. Surface exposure ages from bedrock and boulder samples imply that the highest ice surface at the glacial trimline in Haslital was attained at 23.0 ± 0.8 ka. Significant retreat followed no later than 17.7 ± 0.8 ka. Several boulders were let down on the Gelmerhörner ridge during lowering of the ice surface of the Aare LGM glacier. Their exposure ages of 16-14 ka suggest that patches of remnant ice persisted on the trough shoulder until the Bølling-Allerød interstadial. Lateglacial glacier systems in the High Alps were of a dendritic character, confined to the trunk valleys and cirques. Based on combined evidence from glacial erosional marks, surface exposure ages and numerical modelling we have been able to constrain the likely terminal position and ice surface of the Egesen stadial glacier (Younger Dryas equivalent) in Haslital. Exposure ages from the trough floor imply that deglaciation was completed at the end of the Younger Dryas at 12.2-10.8 ka. [ABSTRACT FROM AUTHOR]

The Tangra Yum Co graben is one of the active structures that accommodate the east-west extension of the southern Tibetan Plateau and hosts one of the largest Tibetan lakes, which experienced lake-level changes of ~200 m during the Holocene. In this study, cosmogenic 10Be is employed to: (1) quantify catchment-wide denudation rates in fault-bounded mountain ranges adjacent to the Tangra Yum Co graben; (2) date palaeo-shorelines related to the Holocene lake-level decline; and (3) determine the age of glacial advances in this region. The fault-bounded, non-glaciated mountain range north of Tangra Yum Co - and presumably most other areas around the lake - erode at low rates of 10-70 mm/ka. Owing to the slow erosion of the landscape, the sediments delivered to Tangra Yum Co have high 10Be concentrations. As a consequence, accurate exposure dating of sediment-covered terraces and beach ridges is difficult, because the pre-depositional 10Be concentration may exceed the post-depositional 10Be concentration from which exposure ages are calculated. This difficulty is illustrated by a rather inaccurate 10Be exposure age of 2.3 ± 1.4 ka (i.e. an error of 60%) for a terrace that is located 67 m above the lake. Nevertheless, the age is consistent with luminescence ages for a series of beach ridges and provides further evidence for the decline of the lake level in the late Holocene. At Tangra Yum Co exposure dating of beach ridges via 10Be depth profiles is not feasible, because the pre-depositional 10Be component in these landforms varies with depth, which violates a basic assumption of this approach. 10Be ages for boulders from two moraines are much older than the early Holocene lake-level highstand, indicating that melting of glaciers in the mountain ranges adjacent to Tangra Yum Co has not contributed significantly to the lake-level highstand in the early Holocene. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Accuracy and precision in the measurement of natural aluminium abundances in quartz can affect the reliability of 26 Al exposure dating and 26 Al/ 10 Be burial dating. At ANSTO, aliquots extracted from the HF solutions of dissolved quartz are treated in our laboratory, whereas ICP-OES analysis is performed at a commercial laboratory. The long-term inter-run reproducibility of our in-house standards show a limiting precision in Al measurements of 3–4% (1 σ ), which is lower than the claimed precision of Al analysis by ICP-OES. This indicates that unaccounted random errors are incorporated during our aliquot preparation. In this study, we performed several controlled tests to investigate effects of possible inconsistencies and variances during our aliquot preparation procedure. The results indicate that our procedure is robust against any subtle change in the preparation procedure, e.g., fuming temperatures, fuming reagents, and drying conditions. We found that the density of the solutions dispatched for ICP analysis is occasionally variable due to the presence of residual fuming reagents in the solution. A comparison of the results between the calibration curve and standard addition methods show that the former results are consistently lower than the latter by up to ∼14%. Similar offsets have been reported by previous studies. The reason for these discrepancies is mostly likely matrix effect, which is not accounted for by the calibration curve method. Further tests by varying matrix with impurities such as HF, HClO 4 , H 2 SO 4 and Si identified that Si could cause lower offset in Al measurements; however, our ICP solutions are confirmed to be free from Si and the cause of matrix effect remains to be investigated. Hence, care must be taken for the measurement of Al concentrations in quartz by ICP-OES, either by ensuring that matrix effect is fully accounted for or by routinely employing standard additions when required. [ABSTRACT FROM AUTHOR]

Katahdin, the highest peak in Maine and part of the second highest mountain range in New England, provides an opportunity to assess the timing and style of continental ice sheet surface lowering during deglaciation. We collected 14 samples from boulders on the adjacent Basin Ponds moraine, from bedrock and boulders on the upper part of the mountain, and from boulders in the surrounding area to estimate the age at which they were exposed by deglaciation of the Laurentide Ice Sheet. Measurements of in situ produced 10 Be, which are consistent with measurements of 26 Al, indicate that the Katahdin edifice became exposed from under ice by 15.3 ± 2.1 ka (n = 6), an age indistinguishable from the adjacent Basin Ponds moraine (16.1 ± 1.2 ka, n = 5). A boulder in the lowlands several km south of the moraine dates to 14.5 ± 0.8 ka, and a boulder deposited at Pineo Ridge, about 170 km SE of Katahdin, dates to 17.5 ± 1.1 ka. These data show that samples collected over an elevation range of 1.6 km and a distance of >170 km all have exposure ages that are indistinguishable within uncertainties. Together these data suggest that the Laurentide Ice Sheet surface dropped rapidly and the ice sheet margin retreated quickly across Maine between about 16 and 15 ka, perhaps influenced by calving of the marine-based ice sheet in the St. Lawrence Lowlands to the north and the Penobscot basin to the south. [ABSTRACT FROM AUTHOR]

Optically stimulated luminescence (OSL) depth profiling utilizes an OSL-at-depth signal to extrapolate an exposure age from rock surfaces. Exposure ages are commonly obtained by fitting the forms of luminescence depth profiles, which depend on parameter estimates of light attenuation and defined rates of luminescence bleaching. Current procedures for obtaining these parameters for a rock surface require matching luminescence depth profiles from compositionally and morphologically matched rock surfaces with known exposure ages, which limits the accuracy and applicability of the technique. A modified procedure is presented to improve the accuracy and applicability of luminescence surface exposure dating, that aims to reliably determine light attenuation and luminescence bleaching parameters directly from the rock surface of interest using luminescence saturated samples subjected to controlled light exposures. Both this proposed 'controlled exposure experiment' technique and the proximal rock matching technique were tested on decade surface exposed quartzite quarry samples from eastern Washington, USA. Parameters derived from the controlled exposure technique, using natural sunlight equivalent to the sampling site, produced the most accurate ages. Data scatter in the luminescence depth profiles substantially limit age accuracies of all techniques. However, the trials of the controlled exposure experiment techniques show procedural insight and potential in offering comparable depth profiling applications to current extrapolative techniques at sites where either no proximal rock surfaces exist, or proximal samples are deemed problematic. A combination of incorporating equivalent solar paths and average solar radiations of the site may provide the most accurate parameter extrapolations for controlled exposure experiments, and the technique should be investigated with more refined datasets. • OSL depth profiles produced from two sample sources on the same quarry site are compared. • Controlled exposures using natural site-equivalent sunlight show promise for extrapolating parameters for exposure dating. • Insight into how simulated and natural sunlight exposures uniquely influence luminescence depth profiles. [ABSTRACT FROM AUTHOR]

Highlights: [•] We document a flight of 13 marine bedrock terraces on eastern Crete. [•] The terraces indicate rock uplift at a rate of ∼0.5m/ka since at least ∼600ka. [•] Long-term uplift is governed by underplating of subducted sediment beneath Crete. [ABSTRACT FROM AUTHOR]

Abstract: Over 30 samples from bedrock and boulders from the Veliki vrh rock avalanche have been collected for surface exposure dating. The limestone rocks have been radiochemically treated to isolate and determine long-lived 36Cl by accelerator mass spectrometry. It could be shown that the Veliki vrh rock avalanche from the Košuta Mountain (Slovenia) event can be very likely linked to one of the major historical earthquakes in Europe happening on the 25th of January 1348. Taken into account independently determined denudation rates, inherited 36Cl originating from pre-exposure at shallow depths (20–55 m) could be calculated. The high amount of inherited 36Cl, i.e. 17–46% of the total 36Cl, makes this site not suitable for a precise determination of the 36Cl production rate as it was originally anticipated. Veliki vrh is a “classic” rock avalanche of high velocity. The slope failed in the upper part with a translational slide predominantly along the bedding planes, whereas dynamic fragmentation is the cause for further crushing of the material and the long runout. [Copyright &y& Elsevier]

ABSTRACT The abundant production of in situ cosmogenic 36Cl from potassium renders 36Cl measurements in K-rich rocks or minerals, such as K-feldspars, potentially useful for precisely dating rock surfaces, either in single-nuclide or in multi-nuclide studies, for example combined with 10Be measurements in quartz. However, significant discrepancies in experimentally calibrated 36Cl production rates from spallation of potassium (36PK-sp), referenced to sea-level/high-latitude (SLHL), limit the accuracy of 36Cl dating from K-rich lithologies. We present a new 36Cl calibration using K-feldspars, in which K-spallation is the most dominant 36Cl production pathway (>92% of total 36Cl), thus minimizing uncertainties from the complex multi-pathway 36Cl production systematics. The samples are derived from boulders of an ∼13.4 ka-old landslide in the Swiss Alps (∼820 m, 46.43°N, 8.85°E). We obtain a local 36PK-sp of 306 ± 16 atoms 36Cl (g K)−1 a−1 and an SLHL 36PK-sp of 145.5 ± 7.7 atoms 36Cl (g K)−1 a−1, when scaled with a standard scaling protocol ('Lm'). Applying this SLHL 36PK-sp to determine 36Cl exposure ages of K-feldspars from 10Be-dated moraine boulders yields excellent agreement, confirming the validity of the new SLHL 36PK-sp for surface exposure studies, involving 36Cl in K-feldspars, in the Alps. [ABSTRACT FROM AUTHOR]

Geologic mapping in Yukon Territory, Canada, over the past 100 years has revealed a consistent pattern of diminishing Cordilleran Ice Sheet (CIS) extent during successively younger glaciations. Although this pattern is generally accepted, there is still much uncertainty about the number of glaciations, their ages, and the dynamics of the different lobes that constituted the digitate ice sheet margin, their subglacial thermal regimes, and ice thicknesses. We address uncertainties in the timing of glaciation using cosmogenic nuclide exposure dating at key localities that straddle several major lobes of the CIS in west-central Yukon Territory. Differences in exposure duration within what are thought to be the same map units are perhaps due to inheritance (older than expected), but more likely result from postglacial shielding (younger than expected) or surface erosion. Despite a significant spread in exposure durations on moraines and within map units, and tending to rely on longest exposure durations on moraines due to postglacial degradation and shielding, our results indicate that the McConnell glacial advance occurred during Marine Oxygen Isotope Stage (MIS) 2, judging from oldest minimum apparent exposure ages of 15.7 ± 1.5 and 17.7 ± 1.6 ka, a Gladstone glacial advance occurred before 51.8 ± 4.7 ka (MIS 4) and Reid glacial advances before 79.8 ± 7.3 and 82.8 ± 7.5 ka (consistent with MIS 6). Traces of even older glacial advances predate 100 ka (107.5 ± 9.9–154.3 ± 14.2 ka). [ABSTRACT FROM AUTHOR]

The Tibetan Plateau holds an ample record of past glaciations, and there is an extensive set of glacial deposits dated by exposure dating. Here a compilation is presented of 10Be exposure ages from 485 glacial deposits with 1855 individual samples on the Tibetan Plateau, and ELA depression estimates for the glacial deposits based on a simple toe to headwall ratio approach. To recalculate the Tibetan Plateau exposure ages, 10Be production rates from 24 calibration sites across the world are compiled and recalibrated yielding an updated global reference 10Be production rate. The recalculated exposure ages from the Tibetan Plateau glacial deposits are then divided into three groups based on exposure age clustering, to discriminate good (well-clustered) from poor (scattered) deglaciation ages. A major part of the glacial deposits have exposure ages affected by prior or incomplete exposure, complicating exposure age interpretations. The well-clustered deglaciation ages are primarily from mountain ranges along the margins of the Tibetan Plateau with a main peak between 10 and 30 ka, indicating glacial advances during the global LGM. A large number of deglaciation ages older than 30 ka indicates maximum glaciation predating the LGM, but the exposure age scatter generally prohibits accurate definition of the glacial chronology. The ELA depression estimates scatter significantly, but the main part is remarkably low. Average ELA depressions of 337 ± 197 m for the LGM and 494 ± 280 m for the pre-LGM indicate restricted glacier expansion. [ABSTRACT FROM AUTHOR]

Abstract: The Garonne River drains an important part of the northern Pyrenees and its northern foreland. We investigated the middle reaches of the Garonne River establishing a detailed morphogenetic profile of its foreland terrace staircase and the preserved palaeoglacier margins. We particularly focussed on the glaciofluvial interface, linking (also genetically) the fluvial sediment archives in the foreland with the terminal glacial basin upstream of the Pyrenees mountain front. Using cosmogenic nuclide 10Be analyses, two terrace exposures have been dated, including a prominent fluvioglacial outwash fan at the foreland transition. We identified three terminal margins of late Pleistocene glacier advances. The prominent Garonne staircase consists of three major terrace complexes, comprising eight individual terrace levels. Results indicate a young age of the lower terrace complex of the Garonne staircase (MIS 4–2). The morphogenetic relationships and the new 10Be exposure age constraints suggest that during the last glaciation (Würmian) the Garonne glacier reached its maximum extent at the north Pyrenean mountain front, apparently already during MIS 4. Two different ice margins were associated with MIS 2, indicating close to maximum ice-extent during early MIS 2 (LGM) and relatively stationary ice-recession in the late MIS 2. The extensive Garonne terrace complexes formed under cold-climate conditions and were abandoned by incision during major glacial–interglacial transitions. During warm–cold climate transitions lateral erosion caused the reworking of previously abandoned palaeofloodplains. The long-term (Quaternary) incision of the Garonne and other north Pyrenean rivers indicates that the proximal Aquitaine foreland basin experienced uplift. However, non-uniform lateral course migrations and valley asymmetries of the north Pyrenean piedmont rivers indicate that uplift magnitude is variable, with maximum amounts in the centre of the molasse-fan of Lannemezan: Rivers on the western part of the fan were tilted toward the west, whereas rivers in the eastern part, like the Garonne, were tilted to the east. [Copyright &y& Elsevier]

The Lavini di Marco rock avalanche deposit (“Marocca di Marco”) is located along the left side of the middle Adige Valley, south of the town of Rovereto (NE Italy). The deposit is estimated to have a volume of ∼2 × 108 m3 and cover an area of ∼6.8 km2. It comprises Jurassic Calcari Grigi limestones that detached from the western slope of Mt. Zugna Torta. The Lavini di Marco is composed of at least two different rock avalanche bodies, the main deposit known as Lavini di Marco (the principal) and the much smaller Costa Stenda deposit. Costa Stenda deposits overlie Lavini di Marco deposits. Samples for 36Cl exposure dating were collected from boulders within the deposits, from sliding plane bedrock and from the bedrock wall at the head scarp. Exposure ages range from 800 ± 210 to 21310 ± 1000 years. The latter age stands as a notable outlier suggesting that that Costa Stenda boulder was exposed for a considerable amount of time in the pre-slide bedrock. Lavini di Marco and Costa Stenda boulder ages are 2600 ± 200, 2700 ± 200, 3100 ± 300, 3300 ± 300, 3400 ± 300, 4400 ± 290, 5300 ± 300, and 5400 ± 300 years. The latter three are Costa Stenda boulders which we also interpret to contain inherited nuclide concentrations. The five remaining boulder ages cluster around 3000 years. We calculate a mean age for the Lavini di Marco and Costa Stenda rockslides of 3000 ± 400 years. Within the uncertainties of our data the two slides were simultaneous. For the bedrock sliding plane we obtained significantly younger ages, 1600 ± 100 and 1400 ± 100 years, and for the head scarp 800 ± 200 years. The sliding plane ages record small-scale reactivation which seems to overlap in time with a catastrophic flood event of the Adige River in Verona, as reported in the Fulda Annales, in 883 AD. Only the single age of 800 ± 210 years suggests activity at Lavini di Marco coincident with the well-known Verona earthquake (1117 AD). [ABSTRACT FROM AUTHOR]

We reconstruct the timing of ice flow reconfiguration and deglaciation of the Central Alpine Gotthard Pass, Switzerland, using cosmogenic 10Be and in situ 14C surface exposure dating. Combined with mapping of glacial erosional markers, exposure ages of bedrock surfaces reveal progressive glacier downwasting from the maximum LGM ice volume and a gradual reorganization of the paleoflow pattern with a southward migration of the ice divide. Exposure ages of ∼16–14 ka (snow corrected) give evidence for continuous early Lateglacial ice cover and indicate that the first deglaciation was contemporaneous with the decay of the large Gschnitz glacier system. In agreement with published ages from other Alpine passes, these data support the concept of large transection glaciers that persisted in the high Alps after the breakdown of the LGM ice masses in the foreland and possibly decayed as late as the onset of the Bølling warming. A younger group of ages around ∼12–13 ka records the timing of deglaciation following local glacier readvance during the Egesen stadial. Glacial erosional features and the distribution of exposure ages consistently imply that Egesen glaciers were of comparatively small volume and were following a topographically controlled paleoflow pattern. Dating of a boulder close to the pass elevation gives a minimum age of 11.1 ± 0.4 ka for final deglaciation by the end of the Younger Dryas. In situ 14C data are overall in good agreement with the 10Be ages and confirm continuous exposure throughout the Holocene. However, in situ 14C demonstrates that partial surface shielding, e.g. by snow, has to be incorporated in the exposure age calculations and the model of deglaciation. [ABSTRACT FROM AUTHOR]