ORCID Profile
0000-0003-2859-3293
Current Organisation
Scottish Universities Environmental Research Centre
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Physical Geography and Environmental Geoscience | Geomorphology | Geochronology | Geodesy | Geomatic Engineering | Land Capability And Soil Degradation | Glaciology | Geophysics Not Elsewhere Classified | Climatology (Incl. Palaeoclimatology) | Instruments And Techniques
ANZSRC Socio-Economic Objective (SEO)
Climate change | Other | Land and water management | Other | Land and water management | Land and water management | Earth sciences |
Related Links
Publications
Cosmogenic surface exposure dating the last deglaciation in Denmark: Discrepancies with independent age constraints suggest delayed periglacial landform stabilisation
Publisher: Elsevier BV
Date: 12-2012
Growing topography due to contrasting rock types in a tectonically dead landscape
Publisher: Copernicus GmbH
Date: 25-08-2020
Abstract: Abstract. Many mountain ranges survive in a phase of erosional decay for millions of years (Myr) following the cessation of tectonic activity. Landscape dynamics in these post-orogenic settings have long puzzled geologists due to the expectation that topographic relief should decline with time. Our understanding of how denudation rates, crustal dynamics, bedrock erodibility, climate, and mantle-driven processes interact to dictate the persistence of relief in the absence of ongoing tectonics is incomplete. Here we explore how lateral variations in rock type, ranging from resistant quartzites to less-resistant schists and phyllites and up to the least-resistant gneisses and granitic rocks, have affected rates and patterns of denudation and topographic forms in a humid semitropical, high-relief, post-orogenic landscape in Brazil where active tectonics ended hundreds of Myr ago. We show that denudation rates are negatively correlated to topographic relief, channel steepness and modern precipitation rates. Denudation instead correlates with inferred bedrock strength, with resistant rocks denuding more slowly relative to more erodible rock units, and suggest that the efficiency of fluvial erosion varies primarily due to these bedrock differences. Variations in erodibility continue to drive contrasts in rates of denudation in a tectonically inactive landscape evolving for hundreds of Myr, suggesting that equilibrium is not a natural attractor state and that relief continues to grow through time. Over the long timescales of post-orogenic development, exposure at the surface of rock types with differential erodibility can become a dominant control on landscape dynamics by producing spatial variations in geomorphic processes and rates, promoting the survival of relief, and determining spatial differences in erosional response timescales long after cessation of mountain building.
Importance of sampling across an assemblage of glacial landforms for interpreting cosmogenic ages of deglaciation
Publisher: Cambridge University Press (CUP)
Date: 07-2011
DOI: 10.1016/J.YQRES.2011.04.004
Abstract: Deglaciation chronologies for some sectors of former ice sheets are relatively poorly constrained because of the paucity of features or materials traditionally used to constrain the timing of deglaciation. In areas without good deglaciation varve chronologies and/or without widespread occurrence of material that indicates the start of earliest organic radiocarbon accumulations suitable for radiocarbon dating, typically only general patterns and chronologies of deglaciation have been deduced. However, mid-latitude ice sheets that had warm-based conditions close to their margins often produced distinctive deglaciation landform assemblages, including eskers, deltas, meltwater channels and aligned lineation systems. Because these features were formed or significantly altered during the last glaciation, boulder or bedrock s les from them have the potential to yield reliable deglaciation ages using terrestrial cosmogenic nuclides (TCN) for exposure age dating. Here we present the results of a methodological study designed to examine the consistency of TCN-based deglaciation ages from a range of deglaciation landforms at a site in northern Norway. The strong coherence between exposure ages across several landforms indicates great potential for using TCN techniques on features such as eskers, deltas and meltwater channels to enhance the temporal resolution of ice-sheet deglaciation chronologies over a range of spatial scales.
Glacial Lake Pickering: stratigraphy and chronology of a proglacial lake dammed by the North Sea Lobe of the British–Irish Ice Sheet
Publisher: Wiley
Date: 15-01-2016
DOI: 10.1002/JQS.2833
Widespread erosion on high plateaus during recent glaciations in Scandinavia
Publisher: Springer Science and Business Media LLC
Date: 26-02-2018
DOI: 10.1038/S41467-018-03280-2
Abstract: Glaciers create some of Earth’s steepest topography yet, many areas that were repeatedly overridden by ice sheets in the last few million years include extensive plateaus. The distinct geomorphic contrast between plateaus and the glacial troughs that dissect them has sustained two long-held hypotheses: first, that ice sheets perform insignificant erosion beyond glacial troughs, and, second, that the plateaus represent ancient pre-glacial landforms bearing information of tectonic and geomorphic history prior to Pliocene–Pleistocene global cooling (~3.5 Myr ago). Here we show that the Fennoscandian ice sheets drove widespread erosion across plateaus far beyond glacial troughs. We apply inverse modelling to 118 new cosmogenic 10 Be and 26 Al measurements to quantify ice sheet erosion on the plateaus fringing the Sognefjorden glacial trough in western Norway. Our findings demonstrate substantial modification of the pre-glacial landscape during the Quaternary, and that glacial erosion of plateaus is important when estimating the global sediment flux to the oceans.
Topographic Relief Response to Fluvial Incision in the Central Tibetan Plateau: Evidence From Cosmogenic 10Be
Publisher: American Geophysical Union (AGU)
Date: 10-2021
DOI: 10.1029/2021JF006111
Abstract: Fluvial incision, regarded as one of the fundamental geomorphic processes, drives the evolution of mountainous landscapes. The transitional landscape from low‐relief to high‐relief in the central Tibetan Plateau is rapidly evolving as it is influenced by river dynamics, climate change and tectonic uplift. Combining cosmogenic 10 Be depth profile dating and topographic analysis, this study provides new constraints on the formation and destruction of low‐relief surfaces in the central Tibetan Plateau. We find that the high‐relief landscape in the Suoqu area (a major tributary of the upper Nu River) shows a rapid fluvial incision rate of 710 ± 70 mm kyr −1 since the late Pleistocene, while the low‐relief topography in the adjacent Xiaqiuqu area presents an order of magnitude lower incision rate of 70 ± 10 mm kyr −1 . These results are consistent with the long‐term (multi‐million‐year) exhumation rates derived from low‐temperature thermochronology, suggesting that this region has experienced an evolving incision history. We interpret that the higher relief was caused by enhanced fluvial incision, and the lower relief was slowly developed by sedimentation and relatively steady low exhumation rate. The presence of a knickzone appears to mark the boundary between these differentially incising landscapes, which may be caused by rapid headward retreat and higher river discharge in the Suoqu River. The coincidence of fluvial terraces ages with climate‐driven events, in addition to paleodenudation rates, indicates that the formation of fluvial terraces in the Xiaqiuqu and Suoqu areas might be associated with the quick sedimentation of weathered materials in early warming periods.
Growing topography due to contrasting rock types in a tectonically dead landscape
Publisher: Copernicus GmbH
Date: 09-03-2021
Abstract: Abstract. Many mountain ranges survive in a phase of erosional decay for millions of years following the cessation of tectonic activity. Landscape dynamics in these post-orogenic settings have long puzzled geologists due to the expectation that topographic relief should decline with time. Our understanding of how denudation rates, crustal dynamics, bedrock erodibility, climate, and mantle-driven processes interact to dictate the persistence of relief in the absence of ongoing tectonics is incomplete. Here we explore how lateral variations in rock type, ranging from resistant quartzites to less resistant schists and phyllites, and up to the least resistant gneisses and granitic rocks, have affected rates and patterns of denudation and topographic forms in a humid subtropical, high-relief post-orogenic landscape in Brazil where active tectonics ended hundreds of millions of years ago. We show that catchment-averaged denudation rates are negatively correlated with mean values of topographic relief, channel steepness and modern precipitation rates. Denudation instead correlates with inferred bedrock strength, with resistant rocks denuding more slowly relative to more erodible rock units, and the efficiency of fluvial erosion varies primarily due to these bedrock differences. Variations in erodibility continue to drive contrasts in rates of denudation in a tectonically inactive landscape evolving for hundreds of millions of years, suggesting that equilibrium is not a natural attractor state and that relief continues to grow through time. Over the long timescales of post-orogenic development, exposure at the surface of rock types with differential erodibility can become a dominant control on landscape dynamics by producing spatial variations in geomorphic processes and rates, promoting the survival of relief and determining spatial differences in erosional response timescales long after cessation of mountain building.
Production of21Ne in depth-profiled olivine from a 54 Ma basalt sequence, Eastern Highlands (37° S), Australia
Publisher: Elsevier BV
Date: 2018
Holocene Chronology of the Brattforsheden Delta and Inland Dune Field, Sw Sweden
Publisher: Walter de Gruyter GmbH
Date: 11-03-2015
Abstract: Brattforsheden is a large glacifluvial deposit in southwestern Sweden and associated with it is one of Sweden’s largest inland dune fields. Although the relative ages of the Brattforsheden depos-its are well known, absolute ages from the area are few. In this study we have used optically stimulat-ed luminescence (OSL), surface exposure ( 10 Be) and radiocarbon ( 14 C) dating to provide an absolute chronology for the deglaciation and for the Holocene development of the aeolian dunes. Our data show that the deglaciation took place just before 11 ka (11.5 ± 0.6 ka OSL, 11.3 ± 0.8 ka 10 Be), in line with the 14 C-based regional deglaciation age. Aeolian dunes started forming immediately after degla-ciation and were active for at least 2000 years, well after vegetation had established. Renewed aeolian activity occurred 270-180 years ago, resulting in the deposition of sand sheets. Comparison between dating methods and studies of OSL dose distributions show that glacial, glacifluvial and littoral sedi-ments suffer from incomplete bleaching and thus that mean OSL ages from such deposits overesti-mate the true depositional age. By using small aliquots and statistical age models, this effect can part-ly be countered. Also, some of the 10Be ages appear too old, which may be due to previous exposure.
Arctic–alpine blockfields in the northern Swedish Scandes: late Quaternary – not Neogene
Publisher: Copernicus GmbH
Date: 21-07-2014
Abstract: Abstract. Autochthonous blockfield mantles may indicate alpine surfaces that have not been glacially eroded. These surfaces may therefore serve as markers against which to determine Quaternary erosion volumes in adjacent glacially eroded sectors. To explore these potential utilities, chemical weathering features, erosion rates, and regolith residence durations of mountain blockfields are investigated in the northern Swedish Scandes. This is done, firstly, by assessing the intensity of regolith chemical weathering along altitudinal transects descending from three blockfield-mantled summits. Clay / silt ratios, secondary mineral assemblages, and imaging of chemical etching of primary mineral grains in fine matrix are each used for this purpose. Secondly, erosion rates and regolith residence durations of two of the summits are inferred from concentrations of in situ-produced cosmogenic 10Be and 26Al in quartz at the blockfield surfaces. An interpretative model is adopted that includes temporal variations in nuclide production rates through surface burial by glacial ice and glacial isostasy-induced elevation changes of the blockfield surfaces. Together, our data indicate that these blockfields are not derived from remnants of intensely weathered Neogene weathering profiles, as is commonly considered. Evidence for this interpretation includes minor chemical weathering in each of the three examined blockfields, despite consistent variability according to slope position. In addition, average erosion rates of ~16.2 and ~6.7 mm ka−1, calculated for the two blockfield-mantled summits, are low but of sufficient magnitude to remove present blockfield mantles, of up to a few metres in thickness, within a late Quaternary time frame. Hence, blockfield mantles appear to be replenished by regolith formation through, primarily physical, weathering processes that have operated during the Quaternary. The persistence of autochthonous blockfields over multiple glacial–interglacial cycles confirms their importance as key markers of surfaces that were not glacially eroded through, at least, the late Quaternary. However, presently blockfield-mantled surfaces may potentially be subjected to large spatial variations in erosion rates, and their Neogene regolith mantles may have been comprehensively eroded during the late Pliocene and early Pleistocene. Their role as markers by which to estimate glacial erosion volumes in surrounding landscape elements therefore remains uncertain.
Inner gorges cut by subglacial meltwater during Fennoscandian ice sheet decay
Publisher: Springer Science and Business Media LLC
Date: 09-05-2014
DOI: 10.1038/NCOMMS4815
Abstract: The century-long debate over the origins of inner gorges that were repeatedly covered by Quaternary glaciers hinges upon whether the gorges are fluvial forms eroded by subaerial rivers, or subglacial forms cut beneath ice. Here we apply cosmogenic nuclide exposure dating to seven inner gorges along ~500 km of the former Fennoscandian ice sheet margin in combination with a new deglaciation map. We show that the timing of exposure matches the advent of ice-free conditions, strongly suggesting that gorges were cut by channelized subglacial meltwater while simultaneously being shielded from cosmic rays by overlying ice. Given the exceptional hydraulic efficiency required for meltwater channels to erode bedrock and evacuate debris, we deduce that inner gorges are the product of ice sheets undergoing intense surface melting. The lack of postglacial river erosion in our seven gorges implicates subglacial meltwater as a key driver of valley deepening on the Baltic Shield over multiple glacial cycles.
Asynchronous glacier dynamics during the Antarctic Cold Reversal in central Patagonia
Publisher: Elsevier BV
Date: 11-2018
Glacial lake evolution and Atlantic-Pacific drainage reversals during deglaciation of the Patagonian Ice Sheet
Publisher: Elsevier BV
Date: 2019
NICKPOINT RECESSION IN KARST TERRAINS: AN EXAMPLE FROM THE BUCHAN KARST, SOUTHEASTERN AUSTRALIA
Publisher: Wiley
Date: 05-1996
DOI: 10.1002/(SICI)1096-9837(199605)21:5<453::AID-ESP608>3.0.CO;2-4
Lowland river responses to intraplate tectonism and climate forcing quantified with luminescence and cosmogenic 10Be
Publisher: Elsevier BV
Date: 03-2013
Weathering fluxes and sediment provenance on the SW Scottish shelf during the last deglaciation
Publisher: Elsevier BV
Date: 08-2018
Ice-stream demise dynamically conditioned by trough shape and bed strength
Publisher: American Association for the Advancement of Science (AAAS)
Date: 05-04-2019
Abstract: We show how the shape and strength of an ice stream’s bed can drive step changes in retreat rate and hasten ice loss to the ocean.
Erratum: Holocene chronology of the Brattforsheden delta and inland dune field, SW Sweden
Publisher: Walter de Gruyter GmbH
Date: 19-05-2015
A new Scandinavian reference 10Be production rate
Publisher: Elsevier BV
Date: 08-2015
A detailed Pleistocene cosmogenic nuclide chronology of Patagonian Ice-Sheet expansions in north-eastern Patagonia (43°S)
Publisher: Copernicus GmbH
Date: 03-03-2021
DOI: 10.5194/EGUSPHERE-EGU21-2820
Abstract: & & The former Patagonian Ice Sheet was the most extensive Quaternary ice sheet of the southern hemisphere outside of Antarctica. Against a background of Northern Hemisphere-dominated ice volumes, it is essential to document how the Patagonian Ice Sheet and its outlet glaciers & #64258 uctuated throughout the Quaternary. This information can help us investigate the climate forcing mechanisms responsible for ice sheet & #64258 uctuations and provide insight on the causes of Quaternary glacial cycles at the southern mid-latitudes. Patagonia is part of the only continental landmass that fully intersects the precipitation-bearing Southern Westerly Winds and is thus uniquely positioned to study past climatic fluctuations in the southern mid-latitudes. While Patagonian palaeoglaciological investigations have increased, there remains few published studies investigating glacial deposits from the north-eastern sector of the former ice sheet, between latitudes 41& #176 S and 46& #176 S. Palaeoglaciological reconstructions from this region are required to understand the timing of Pleistocene glacial expansion and retreat, and to understand the causes behind potential latitudinal asynchronies in glacial advances throughout Patagonia. Here, we reconstruct the glacial history and chronology of a previously unstudied region of north-eastern Patagonia that formerly hosted the R& #237 o Corcovado (43& #176 S, 71& #176 W) palaeo ice-lobe. Here we present a new set of cosmogenic & sup& & /sup& Be exposure ages from presumed pre-LGM moraine boulder and glaciofluvial outwash surface cobble s les, establishing for the first time a comprehensive chronology for pre-LGM glacial margins of the R& #237 o Corcovado palaeo-glacier. This new dataset completes our effort to date the entire preserved moraine record of the R& #237 o Corcovado valley: which captures at least seven distinct Pleistocene glacial events. Our results allow answering questions on the timing of the maximum local ice extent of the last glacial cycle as well as older, pre-last glacial cycle glaciations, for which few robust glacier chronologies exist in the Southern Hemisphere. The most informative cosmogenic nuclide-derived glacial chronologies with the capacity to resolve questions on interhemispheric phasing of climate change require unambiguous dating of glacial margins spanning the entirety of the last glacial cycle and ideally earlier glacial cycles. Therefore, our findings have significant implications for understanding past climate fluctuations at the southern mid-latitudes, former Southern Westerly Winds behaviour and interhemispheric climate linkages throughout the Pleistocene. They also provide further evidence supporting the proposed latitudinal asynchrony in the timing of Patagonian Ice Sheet expansion during the last glacial cycle and enable novel glacio-geomorphological interpretations for the studied region.& &
Response to Bromley et al. “Comment on ‘Was Scotland deglaciated during the Younger Dryas?’ By Small and Fabel (2016)”
Publisher: Elsevier BV
Date: 11-2016
Devising quality assurance procedures for assessment of legacy geochronological data relating to deglaciation of the last British-Irish Ice Sheet
Publisher: Elsevier BV
Date: 2017
The use of in-situ produced cosmogenic radionuclides in glaciology and glacial geomorphology
Publisher: International Glaciological Society
Date: 1999
DOI: 10.3189/172756499781821968
Abstract: The usefulness of in-situ produced cosmogenic radionuclides in constraining glacial chronologies through exposure-age dating has been demonstrated in numerous studies. However, an understanding of cosmogenic radionuclide techniques and their uncertainties opens up a wide range of other potential applications in glaciology and glacial geomorphology. Recently developed applications include: estimation of spatial and temporal variations in the depth of glacial erosion from cosmogenic radionuclide inheritance, which provides important constraints on process-based erosion models and burial dating, which can provide chronological control for glacial advances and the onset of till deposition. An interesting new application, currently at the level of theoretical model development, concerns the unraveling of complex exposure and burial histories. Overall, in-situ produced cosmogenic radionuclide techniques provide a means with which to constrain a wide range of ice-sheet and glacial models over time-scales of a thousand to a few million years.
Deglaciation of Fennoscandia
Publisher: Elsevier BV
Date: 09-2016
Lateglacial surface exposure dating in the Monadhliath Mountains, Central Highlands, Scotland
Publisher: Elsevier BV
Date: 05-2012
Slow, patchy landscape evolution in northern Sweden despite repeated ice-sheet glaciation
Publisher: Geological Society of America
Date: 2006
Supplementary material to "Arctic-alpine blockfields in northern Sweden: Quaternary not Neogene"
Publisher: Copernicus GmbH
Date: 10-02-2014
Quantifying the erosional impact of the fennoscandian ice sheet in the torneträsk–narvik corridor, northern sweden, based on cosmogenic radionuclide data
Publisher: Informa UK Limited
Date: 10-2002
Supplementary material to "Growing topography due to contrasting rock types in a tectonically dead landscape"
Publisher: Copernicus GmbH
Date: 25-08-2020
Episodic intraplate deformation of stable continental margins: evidence from Late Neogene and Quaternary marine terraces, Cape Liptrap, Southeastern Australia
Publisher: Elsevier BV
Date: 2009
The evolution of the terrestrial‐terminating Irish Sea glacier during the last glaciation
Publisher: Wiley
Date: 07-07-2020
DOI: 10.1002/JQS.3229
Abstract: Here we reconstruct the last advance to maximum limits and retreat of the Irish Sea Glacier (ISG), the only land‐terminating ice lobe of the western British Irish Ice Sheet. A series of reverse bedrock slopes rendered proglacial lakes endemic, forming time‐transgressive moraine‐ and bedrock‐dammed basins that evolved with ice marginal retreat. Combining, for the first time on glacial sediments, optically stimulated luminescence (OSL) bleaching profiles for cobbles with single grain and small aliquot OSL measurements on sands, has produced a coherent chronology from these heterogeneously bleached s les. This chronology constrains what is globally an early build‐up of ice during late Marine Isotope Stage 3 and Greenland Stadial (GS) 5, with ice margins reaching south Lancashire by 30 ± 1.2 ka, followed by a 120‐km advance at 28.3 ± 1.4 ka reaching its 26.5 ± 1.1 ka maximum extent during GS‐3. Early retreat during GS‐3 reflects piracy of ice sources shared with the Irish‐Sea Ice Stream (ISIS), starving the ISG. With ISG retreat, an opportunistic readvance of Welsh ice during GS‐2 rode over the ISG moraines occupying the space vacated, with ice margins oscillating within a substantial glacial over‐deepening. Our geomorphological chronosequence shows a glacial system forced by climate but mediated by piracy of ice sources shared with the ISIS, changing flow regimes and fronting environments.
Early to middle Holocene valley glaciations on northernmost Greenland
Publisher: Elsevier BV
Date: 12-2010
Quantifying soil loss with in-situ cosmogenic10Be and14C depth-profiles
Publisher: Elsevier BV
Date: 04-2015
Late Holocene glacier activity at inner Hornsund and Scottbreen, southern Svalbard
Publisher: Wiley
Date: 05-2017
DOI: 10.1002/JQS.2944
Investigating the glacial history of the northern sector of the Cordilleran Ice Sheet with cosmogenic 10Be concentrations in quartz
Publisher: Elsevier BV
Date: 12-2010
Arctic-alpine blockfields in northern Sweden: Quaternary not Neogene
Publisher: Copernicus GmbH
Date: 10-02-2014
Abstract: Abstract. Slowly-eroding, blockfield-mantled, non-glacial surface remnants may serve as markers against which to determine Quaternary glacial erosion volumes in high latitude mountain settings. To investigate this potential utility of these surfaces, chemical weathering, erosion rates, and origins of mountain blockfields are investigated in northern Sweden. This is done, firstly, by assessing the intensity of regolith chemical weathering along altitudinal transects descending from three blockfield-mantled summits. Clay/silt ratios, secondary mineral assemblages determined through X-ray diffraction, and the presence of chemically weathered grains visible on scanning electron microscopy, in fine matrix s les collected from pits excavated along the transects are each used for this purpose. Secondly, erosion rates and total surface histories of two of the summits are inferred from concentrations of in situ-produced cosmogenic 10Be and 26Al in quartz at the blockfield surface. An interpretative model is adopted that includes temporal variations in nuclide production rates through surface burial by glacial ice and glacial isostasy-induced elevation changes of the blockfield surfaces. Together, our data indicate that these blockfields are not derived from remnants of intensely weathered Neogene weathering profiles, as is commonly considered. Evidence for this interpretation includes minor chemical weathering in each of the three examined blockfields, despite some differences according to slope position. In addition, average erosion rates of ∼16.2 mm ka−1 and ∼6.7 mm ka−1, calculated for two blockfield-mantled summits, are low but of sufficient magnitude to remove present blockfield mantles, of up to a few meters in thickness, within a late-Quaternary timeframe. Hence, blockfield mantles appear to be replenished by regolith formation through, primarily physical, weathering processes that have operated during the Quaternary. Erosion rates remain low enough, however, for blockfield-mantled, non-glacial surface remnants to provide reasonable landscape markers against which to contrast Quaternary erosion volumes in surrounding glacial landscape elements. The persistence of blockfield mantles over a number of glacial-interglacial cycles and an apparently low likelihood that they can re-establish on glacially eroded bedrock, also discounts the operation of a "glacial buzz-saw" on surface remnants that are presently perceived as non-glacial. These interpretations are tempered though by outstanding questions concerning the composition of preceding Neogene regoliths and why they have apparently been comprehensively removed from these remnant non-glacial surfaces. It remains possible that periglacial erosion of perhaps more intensely weathered Neogene regoliths was high during the Pliocene–Pleistocene transition to colder conditions and that periglacial processes reshaped non-glacial surface remnants largely before the formation of blockfield armours.
Trough geometry was a greater influence than climate-ocean forcing in regulating retreat of the marine-based Irish-Sea Ice Stream
Publisher: Geological Society of America
Date: 28-05-2018
DOI: 10.1130/B31852.1
Cosmogenic21Ne analysis of individual detrital grains: Opportunities and limitations
Publisher: Wiley
Date: 2010
DOI: 10.1002/ESP.1815
A cosmogenic nuclide-derived chronology of pre-Last Glacial Cycle glaciations during MIS 8 and MIS 6 in northern Patagonia
Publisher: Copernicus GmbH
Date: 06-01-2023
Abstract: Abstract. The precise environmental mechanisms controlling Quaternary glacial cycles remain ambiguous. To address this problem, it is critical to better comprehend the drivers of spatio-temporal variability in ice-sheet evolution by establishing reliable chronologies of former outlet-glacier advances. When spanning multiple glacial cycles, such chronologies have the capacity to contribute to knowledge on the topic of interhemispheric phasing of glaciations and climate events. In southern Argentina, reconstructions of this kind are achievable, as Quaternary expansions of the Patagonian Ice Sheet have emplaced a well-preserved geomorphological record covering several glacial cycles. Moreover, robust ice-sheet reconstructions from Patagonia are powerful barometers of former climate change, as Patagonian glaciers are influenced by the Southern Westerly Winds and the Antarctic Circumpolar Current coupled to them. It is essential to better constrain former shifts in these circulation mechanisms as they may have played a critical role in pacing regional and possibly global Quaternary climate change. Here, we present a new set of cosmogenic 10Be and 26Al exposure ages from pre-Last Glacial Cycle moraine boulder, glaciofluvial outwash cobble, and bedrock s les. This dataset constitutes the first direct chronology dating pre-Last Glacial Maximum (LGM) glacier advances in northern Patagonia and completes our effort to date the entire preserved moraine record of the Río Corcovado valley system (43∘ S, 71∘ W). We find that the outermost margins of the study site depict at least three distinct pre-Last Glacial Cycle stadials occurring around 290–270, 270–245, and 130–150 ka. Combined with the local LGM chronology, we discover that a minimum of four distinct Pleistocene stadials occurred during Marine Isotope Stages 8, 6, and 2 in northern Patagonia. Evidence for Marine Isotope Stage 4 and 3 deposits were not found at the study site. This may illustrate former longitudinal and latitudinal asynchronies in the Patagonian Ice Sheet mass balance during these Marine Isotope Stages. We find that the most extensive middle-to-late Pleistocene expansions of the Patagonian Ice Sheet appear to be out of phase with local summer insolation intensity but synchronous with orbitally controlled periods of longer and colder winters. Our findings thus enable the exploration of the potential roles of seasonality and seasonal duration in driving the southern mid-latitude ice-sheet mass balance, and they facilitate novel glacio-geomorphological interpretations for the study region. They also provide empirical constraints on former ice-sheet extent and dynamics that are essential for calibrating numerical ice-sheet and glacial isostatic adjustment models.
Landscape preservation under Fennoscandian ice sheets determined from in situ produced 10Be and 26Al
Publisher: Elsevier BV
Date: 07-2002
Younger Dryas and early Holocene age glacier advances in Patagonia
Publisher: Elsevier BV
Date: 12-2012
Reconstructing the erosion history of glaciated passive margins: applications of in situ produced cosmogenic nuclide techniques
Publisher: Geological Society of London
Date: 2002
Be‐10 Dating of Ice‐Marginal Moraines in the Khumbu Valley, Nepal, Central Himalaya, Reveals the Response of Monsoon‐Influenced Glaciers to Holocene Climate Change
Publisher: American Geophysical Union (AGU)
Date: 08-2022
DOI: 10.1029/2022JF006645
Abstract: The dynamic response of large mountain glaciers to climatic forcing operates over timescales of several centuries and therefore understanding how these glaciers change requires observations of their behavior through the Holocene. We used Be‐10 exposure‐age dating and geomorphological mapping to constrain the evolution of glaciers in the Khumbu Valley in the Everest region of Nepal. Khumbu and Lobuche Glaciers are surrounded by high‐relief lateral and terminal moraines from which seven glacial stages were identified and dated to 7.4 ± 0.2, 5.0 ± 0.3, 3.9 ± 0.1, 2.8 ± 0.2, 1.3 ± 0.1, 0.9 ± 0.02, and 0.6 ± 0.16 ka. These stages correlate to each of the seven latest Holocene regional glacial stages identified across the monsoon‐influenced Himalaya, demonstrating that a coherent record of high elevation terrestrial palaeoclimate change can be extracted from dynamic mountain landscapes. The time‐constrained moraine complex represents a catchment‐wide denudation rate of 0.8–1.4 mm a −1 over the last 8 kyr. The geometry of the ablation area of Khumbu Glacier changed around 4 ka from a broad, shallow ice tongue to become narrower and thicker as restricted by the topographic barrier of the terminal moraine complex.
Supplementary material to A cosmogenic nuclide-derived chronology of pre-Last Glacial Cycle glaciations during MIS 8 and MIS 6 in northern Patagonia
Publisher: Copernicus GmbH
Date: 25-04-2022
Revised Quaternary glacial succession and post-LGM recession, southern Wind River Range, Wyoming, USA
Publisher: Elsevier BV
Date: 07-2018
Current stability to improve AMS precision for cosmogenic 10Be applications
Publisher: Copernicus GmbH
Date: 04-03-2021
DOI: 10.5194/EGUSPHERE-EGU21-16090
Abstract: & & With the present AMS & sup& & /sup& Be uncertainties (~2% best case scenario) and the increasing need for more precise cosmogenic & sup& & /sup& Be data it has become imperative to improve AMS measurements. Precision depends on counting statistics which in turn depend on ion beam current stability and s le longevity. The ion beam currents are dependent on the metal matrix in which BeO is dispersed the matrix:BeO ratio homogeneity of the mixture and the packing of the AMS cathode. We aim to understand the effect of cathode homogeneity in generating stable beam currents. We have performed a series of experiments using different metal matrices (Nb, Ag, Fe) in different forms (solid and in solution). The metals have been added to different stages of the s le precipitation process and both BeO and Be(OH)& sub& & /sub& have been pressed into AMS cathodes and analysed at SUERC. We will discuss results of these experiments and introduce an innovative use of polyoxometalates (molibdanate and niobate) to create a homogeneous compound that has the potential to generate stable ion beam currents from sputter ion sources.& &
Surface uplift of the Eastern Alps. Much faster than we thought?
Publisher: Copernicus GmbH
Date: 15-05-2023
DOI: 10.5194/EGUSPHERE-EGU23-2346
Abstract: We present cosmogenic nucleide data that help to understand the ill-constrained & uplift history of the Eastern Aps. Well accepted, but indirect evidence & for this uplift history includes: (a) the onset of flexural subsidence of the foreland basins, or (b) the formation of the Periadriatic line (recording the onset of continent-continent collision in the Alps). Both are often used to suggest about 30 Ma as the starting date for the surface uplift of the range. Since this time the fine interplay of many kilometres of upwards rock uplift and downwards erosion resulted in net surface uplift of some 2-3 kilometres but reference frames that allow to discern between rock uplift and surface uplift are often hard to identify. One way of measuring surface uplift rates is through the study of areas where erosion did not occur. That is, dating and identifying relicts of ancient base levels for ex le in caves, sediments or paleosurfaces.In this contribution we present 10Be, 21Ne, 26Al cosmogenic nucleide data of fluvial sediments s led in some 50 caves across the Eastern Alps from elevations between 300 and 2500 m surface elevation. We collected s les that were interpreted to have been deposited during cave formation at the vadose-phreatic transition. As such, they form markers for base level and & the age of their burial into the cave may be interpreted as the time the cave was at base level some few hundreds of meters above sea level. Interpretation of our data indicates that the uplift rate of the Eastern Alps may be in the order of 200 m & #8211 500 m per Million years for much of the Pliocene. As such, much of the observed surface uplift of the Eastern Alps may have occurred since the late Miocene and surface uplift is thus much faster than previously thought.&
Palaeoglaciation in the low latitude, low elevation tropical Andes, northern Peru
Publisher: Copernicus GmbH
Date: 04-03-2021
DOI: 10.5194/EGUSPHERE-EGU21-7580
Abstract: & & Palaeo-glaciological studies of former ice thickness and extent within the tropical Andes have tended to focus on locations where glaciers are currently present, or in high elevation locations where evidence exists of recently deglaciated cirques. Few studies have focussed on low elevation regions due to the presumption that glaciers could not have existed at such low altitudes within the tropics. A latitudinal & #8216 data gap& #8217 exists between Ecuador and more central and southern Peru where evidence for former glaciation is abundant. To fill this gap we present rare evidence of past glaciation from the Las Huaringas region, northern Peru, located in a relatively low elevation massif (& m).& & & & Within Las Huaringas a large valley glacier existed, extending N-S ~12 km down valley to ~2900 m in elevation while glacial cirques existed exhibiting an E-W orientation on the western facing hillslope of the massif with pronounced moraine complexes and bedrock erosion. We used high-resolution remotely sensed imagery, a 30 m ALOS DEM, and preliminary field observations to identify and map an abundance of geomorphic evidence of glaciation. These include moraines at different stages of preservation and predominance, eroded bedrock surfaces, cirque landforms and overdeepened valleys to develop the first glacial geomorphological map of the region. We performed morphometric analysis (e.g. width, length, altitude, azimuth) of the mapped glacial landforms and cirques along with hypsometric analysis of the main valley of Laguna Shimbe, yielding a hypsometric maxima of 3250 m. Using the geomorphological map, we determine the former extent and thickness of palaeoglaciers in the area and use delineated glacial outlines of their furthest extent to reconstruct Equilibrium Line Altitudes (ELAs) of these ice masses using a combination of ELA estimation techniques.& & & & Ongoing research aims to determine whether the palaeoglacial evidence is consistent with formation by valley glaciers or an icecap and whether the timing of the local Last Glacial Maximum (LGM) was synchronous with the global timing. A set of hypotheses for the timing and drivers of the reconstructed extent of former glaciers in the area will be presented. Our analysis confirms the presence of former glaciers in a low elevation and low latitude region of the tropical Andes. Our ongoing work aims to unveil the timing of the glacial events and the drivers of the glacial and climate history seen within this important region.& &
10Be chronology of deglaciation and ice-dammed lake regression in the vicinity of the Mylodon Cave (Cerro Benítez, Patagonia, Chile)
Publisher: Elsevier BV
Date: 02-2022
Extent and retreat history of the Barra Fan Ice Stream offshore western Scotland and northern Ireland during the last glaciation
Publisher: Elsevier BV
Date: 12-2018
Characterization, Quantification and Compound-specific Isotopic Analysis of Pyrogenic Carbon Using Benzene Polycarboxylic Acids (BPCA)
Publisher: MyJove Corporation
Date: 16-05-2016
DOI: 10.3791/53922
The evolution of the terrestrial-terminating Irish Sea glacier during the last glaciation
Publisher: Copernicus GmbH
Date: 23-03-2020
DOI: 10.5194/EGUSPHERE-EGU2020-9438
Abstract: & & Comprehensive mapping and the Briticechrono geochronology provides a reconstruction of the last advance and retreat of the only land-terminating ice lobe of the western British Irish Ice Sheet. The Irish Sea Glacier was fed by ice from Lake District, Irish Sea and Wales, and extended to maximum limits in the English Midlands. During ice retreat after 27 kyrs, a series of reverse bedrock slopes rendered proglacial lakes endemic in the land-system. Not resembling the more extensive definitions of the classical & #8216 Glacial Lake Lapworth& #8217 , these ice contact lakes were smaller time transgressive moraine- and bedrock-dammed basins that evolved with ice marginal retreat. Combining, for the first time on glacial sediments, OSL bleaching profiles for cobbles with single grain and small aliquot OSL measurements on sands, has produced a coherent chronology from these heterogeneously bleached s les, and constrained for the Irish Sea Glacier a post 30ka ice maximum advance, 26.5& #177 .8ka maximum extent, and 25.3& #177 .6 to 20.6& #177 .2ka retreat vacating the region. With retreat of the Irish Sea Glacier an opportunistic Welsh re-advance 19.7& #177 .5ka took advantage of the vacated space and rode over Irish Sea Glacier moraines. Our geomorphological chronosequence shows a glacial system forced by climate, but mediated by piracy of ice sources shared with the larger and marine terminating Irish Sea Ice Stream to the west. The Irish Sea Glacier underwent changes flow regime and fronting environments driven by stagnation and decline as the primary impetus to advance was erted. Ultimately, the glacier of the English Midlands display complex uncoupling and realignment during deglaciation and ice margin retreat towards upland hinterlands ~17.8 kyrs (Lake District and Pennines) and asynchronous behaviour as in idual adjacent ice lobes became increasingly important in driving the landform record.& &
Plio-/Pleistocene landscape evolution in the Eastern Alps: new insights from cosmogenic nuclide dating
Publisher: Copernicus GmbH
Date: 28-03-2022
DOI: 10.5194/EGUSPHERE-EGU22-9531
Abstract: & & The Eastern Alps hold an abundance of landscapes with noticeably low topographic gradients at higher elevations above much steeper slopes. Many of these elevated low-relief landscapes (ELRL) are organized in distinct surface levels. Sub-horizontal cave systems can often be found at similar elevations. Utilizing spatial statistics of these ELRL and over 15000 caves, we show that the formation of both the surface and sub-surface landscapes is connected and can help deciphering the landscape evolution of the Eastern Alps from the Late Neogene until today. New cosmogenic nuclide data (& sup& & /sup& Be, & sup& & /sup& Ne, & sup& & /sup& Al) of allogenic quartzous sediments from caves and surfaces of distinct elevation levels in the Eastern Alps are used to quantify the incision and ultimately surface uplift history. Burial ages of cave sediments scatter between 0.5 and over 5 Ma. The preliminary data indicate a mean surface uplift of some 0.15 & #8211 0.25 mm/year for much of the Pliocene. We also show that most ELRL in the Eastern Alps can be interpreted in terms of pre-Pleistocene relict landscapes, especially in the only minorly glaciated eastern part. & However, the data also show some impact of the Pleistocene glacial cycles on the ELRL and the mobilization of sediments associated with them.& &
Pliocene−Pleistocene incision of the Green River, Kentucky, determined from radioactive decay of cosmogenic 26Al and 10Be in Mammoth Cave sediments
Publisher: Geological Society of America
Date: 07-2001
Inceptions: mechanisms, patterns and timing of ice sheet inception
Publisher: Elsevier BV
Date: 09-2002
Growth and decay of a marine terminating sector of the last British–Irish Ice Sheet: a geomorphological reconstruction
Publisher: Elsevier BV
Date: 2014
New 10be cosmogenic ages from the vimmerby moraine confirm the timing of scandinavian ice sheet deglaciation in southern sweden
Publisher: Informa UK Limited
Date: 06-2009
Old orogen - young topography: Landscape Rejuvenation in the Bohemian Massif
Publisher: Copernicus GmbH
Date: 15-05-2023
DOI: 10.5194/EGUSPHERE-EGU23-2068
Abstract: The Bohemian Massif is the relic of a major Paleozoic mountain range that is known to have exhumed and its surface levelled in the Permian. The southern part of the Bohemian Massif with high grade metamorphic rocks and magmatic intrusions dips towards the south under the weakly consolidated Neogene sediments of the Molasse Basin. However, Neogene landscape evolution is largely unconstrained, but the occurrence of marine sediments several hundred meters above sea level is a clear indication of significant surface uplift during the last few million years. The landscape is characterized by rolling hills and extended planation surfaces above an elevation of about 500 m. However, at lower elevations deeply incised gorges confined by steep hillslopes are abundant and contrast impressively with the low relief landscapes above. A continental drainage ide follows the central ridge of the Bohemian Massif with the Vlatava (Moldau) and the Danube (Donau) draining the regions north and south of the drainage ide. In this study we aim quantifying spatial and temporal variations of landscape change in the Bohemian Massif during the last few million years. To characterize the two contrasting landscape states, we computed landscape metrics based on digital elevation models (e.g. normalized steepness index, geophysical relief). To determine the rate landscape change we determined catchment-wide erosion rates from the concentration of cosmogenic 10Be in river sands.Results show that the landscape is characterized by out-of-equilibrium river profiles with knickpoints abundantly occurring at elevations between 450 m and 550 m separating steep channel segments at lower elevations from less steep channels at higher elevations. Hypsometric maxima at or close above knickpoint elevations along with high and low values in geophysical relief downstream and upstream of major knickpoints support the idea of landscape bimodality. Furthermore, we found a strong drainage ide asymmetry, which evidences for the reorganization of the drainage network of the region. Across- ide gradients in channel steepness predict the northward migration of the Danube-Vltava drainage ide including growth and shrinkage of tributary catchments. Erosion rates of the 20 investigated catchments are very low (20 & #8211 50 m per million year) compared to the Alps or other active mountain ranges. The lowest erosion rates occur in catchments with a large fraction of planation surfaces at mid-altitudes. Highest erosion rates occur in elongated catchments of Danube tributaries. Based on our results we suggest that the occurrence of contrasting bedrock properties between Molasse sediments and the crystalline basement represents a superior control on the topographic evolution of the entire region. The transition from soft sediments of the Molasse basin to much less erodible basement rocks during progressive river incision in a setting of low but long last uplift distinctly changes the channel steepness and relief, the course of the receiving streams, and their susceptibility to sudden changes in flow direction (river capture) of the million years& #8217 time scale.
A relict landscape in the centre of Fennoscandian glaciation: cosmogenic radionuclide evidence of tors preserved through multiple glacial cycles
Publisher: Elsevier BV
Date: 04-2002
Expression of the Younger Dryas cold event in the Carpathian Mountains, Ukraine?
Publisher: Elsevier BV
Date: 04-2012
New age constraints for the limit of the British–Irish Ice Sheet on the Isles of Scilly
Publisher: Wiley
Date: 2017
DOI: 10.1002/JQS.2922
Cosmogenic nuclide exposure ages from the ‘Parallel Roads’ of Glen Roy, Scotland
Publisher: Wiley
Date: 25-08-2009
DOI: 10.1002/JQS.1318
A Lateglacial 10Be production rate from glacial lake shorelines in Scotland
Publisher: Wiley
Date: 08-2015
DOI: 10.1002/JQS.2804
Pleistocene dynamics of the interior East Antarctic ice sheet
Publisher: Geological Society of America
Date: 08-2010
DOI: 10.1130/G31172X.1
Ice margin oscillations during deglaciation of the northern Irish Sea Basin
Publisher: Wiley
Date: 31-07-2018
DOI: 10.1002/JQS.3057
Drumlin formation time: evidence from northern and central sweden
Publisher: Informa UK Limited
Date: 06-2004
Deglaciation of coastal south‐western Spitsbergen dated with in situ cosmogenic 10Be and 14C measurements
Publisher: Wiley
Date: 06-08-2018
DOI: 10.1002/JQS.3058
Early deglaciation of the British-Irish Ice Sheet on the Atlantic shelf northwest of Ireland driven by glacioisostatic depression and high relative sea level
Publisher: Elsevier BV
Date: 03-2019
A cosmogenic nuclide-derived chronology of pre-Last Glacial Cycle glaciations during MIS 8 and MIS 6 in northern Patagonia
Publisher: Copernicus GmbH
Date: 25-04-2022
DOI: 10.5194/CP-2022-32
Abstract: Abstract. The precise environmental mechanisms controlling Quaternary glacial cycles remain ambiguous. To address this problem, it is critical to better comprehend the drivers of spatio-temporal variability in ice-sheet evolution by establishing reliable chronologies of former outlet-glacier advances. When spanning multiple glacial cycles, such chronologies have the capacity to resolve conundrums on interhemispheric phasing of glaciations and climate events. In southern Argentina, reconstructions of this kind are achievable, as Quaternary expansions of the Patagonian Ice Sheet have emplaced a well-preserved geomorphological record covering several glacial cycles. Moreover, robust ice-sheet reconstructions from Patagonia are powerful barometers of former climate change, as Patagonian glaciers are influenced by the Southern Westerly Winds and its coupled Antarctic Circumpolar Current. Former shifts in these circulation mechanisms are essential to better constrain, as they may have played a critical role in pacing regional and possibly global Quaternary climate change. Here, we present a new set of cosmogenic 10Be and 26Al exposure ages from pre-Last Glacial Cycle moraine boulder, glaciofluvial outwash cobble and bedrock s les. This dataset constitutes the first direct chronology dating pre-LGM glacier advances in northern Patagonia, and completes our effort to date the entire preserved moraine record of the Río Corcovado valley system (43° S, 71° W). We find the outermost margins of the study site depict at least three distinct pre-Last Glacial Cycle glaciations occurring at 284 ± 7 ka, 257 ± 7 ka, and 147 ± 4 ka. Combined with the local LGM chronology, we discover that a minimum of four distinct Pleistocene glaciations occurred during Marine Isotope Stages eight, six, and two in northern Patagonia. Evidence for stage four and three deposits were not found at the study site, which illustrates former longitudinal and latitudinal asynchronies in Patagonian Ice Sheet mass balance during these stages. We find the most extensive middle-to-late Pleistocene expansions of the Patagonian Ice Sheet appear to be out-of-phase with local summer insolation intensity, but synchronous with orbitally-controlled periods of longer and colder winters. Our findings thus enable to explore the potential roles of seasonality and seasonal duration in driving southern mid-latitude ice-sheet mass balance and facilitate novel glacio-geomorphological interpretations for the study region. They also provide empirical constraints of former ice-sheet extent and dynamics that are essential to calibrating numerical ice-sheet and glacial isostatic adjustment models.
Does decreasing paraglacial sediment supply slow knickpoint retreat?
Publisher: Geological Society of America
Date: 06-2011
DOI: 10.1130/G32018.1
Sedimentation during Marine Isotope Stage 3 at the eastern margins of the Glacial Lake Humber basin, England
Publisher: Wiley
Date: 07-09-2018
DOI: 10.1002/JQS.3066
Cosmogenic exposure age constraints on deglaciation and flow behaviour of a marine-based ice stream in western Scotland, 21–16 ka
Publisher: Elsevier BV
Date: 07-2017
Late Quaternary glaciation in the Hebrides sector of the continental shelf: cosmogenic nuclide dating of glacial events on the St Kilda archipelago
Publisher: Wiley
Date: 25-04-2017
DOI: 10.1111/BOR.12242
The coastal landslides of Shetland
Publisher: Informa UK Limited
Date: 03-04-2018
Final deglaciation of the Malin Sea through meltwater release and calving events
Publisher: Geological Society of London
Date: 06-05-2020
DOI: 10.1144/SJG2019-010
Ice marginal dynamics of the last British-Irish Ice Sheet in the southern North Sea: Ice limits, timing and the influence of the Dogger Bank
Publisher: Elsevier BV
Date: 10-2018
Late-Pleistocene geomorphological and geochronological history of the former Patagonian Ice Sheet in north-eastern Patagonia (43°S)
Publisher: Copernicus GmbH
Date: 23-03-2020
DOI: 10.5194/EGUSPHERE-EGU2020-2384
Abstract: & & The former Patagonian Ice Sheet was the most extensive Quaternary ice sheet of the southern hemisphere outside of Antarctica. Against a background of Northern Hemisphere-dominated ice volumes, it is essential to document how the Patagonian Ice Sheet and its outlet glaciers & #64258 uctuated throughout the Quaternary. This information can help us investigate the climate forcing mechanisms responsible for ice sheet & #64258 uctuations and provide insight on the causes of Quaternary glacial cycles at the southern mid-latitudes. Moreover, Patagonia is part of the only continental landmass that fully intersects the precipitation-bearing southern westerly winds and is thus uniquely positioned to study past climatic fluctuations in the southern mid-latitudes. While Patagonian palaeoglaciological investigations have increased, there remains few published studies investigating glacial deposits from the north-eastern sector of the former ice sheet, between latitudes 41& #176 S and 46& #176 S. Palaeoglaciological reconstructions from this region are required to understand the timing of late-Pleistocene glacial expansion and retreat, and to understand the causes behind potential latitudinal asynchronies in the glacial records throughout Patagonia. Here, we reconstruct the glacial history and chronology of a previously unstudied region of north-eastern Patagonia that formerly hosted the Rio Huemul and Rio Corcovado (43& #176 S, 71& #176 W) palaeo ice-lobes. We present the first detailed glacial geomorphological map of the valley enabling interpretations of the region& #8217 s late Quaternary glacial history. Moreover, we present new cosmogenic 10Be exposure ages from moraine boulders, palaeolake shoreline surface cobbles and ice-moulded bedrock. This new dataset establishes a high-resolution reconstruction of the local LGM through robust dating of five distinct moraines limits of the Rio Corcovado palaeo-glacier. Our results demonstrate that, in its north-eastern sector, the Patagonian Ice Sheet reached its last maximum extent during MIS 2, thus contrasting with the MIS 3 maxima found for the southern parts of the ice sheet. We also present geomorphological evidence along with chronological data for the formation of two ice-dammed proglacial lake phases in the valley caused by LGM ice-extent fluctuations and final glacial recession. Furthermore, this dataset allows us to determine the timing and onset of glacial termination 1 in the region. Finally, our findings include the reconstruction of a proglacial lake drainage and Atlantic/Pacific drainage reversal event caused by ice sheet break-up in western Patagonia. Such findings have significant implications for climate fluctuations at the southern mid-latitudes, former Southern Westerly Winds behaviour and interhemispheric climate linkages during and following the local LGM. They provide further evidence supporting the proposed latitudinal asynchrony in the timing of expansion of the Patagonian Ice Sheet during the last glacial cycle and enable glacio-geomorphological interpretations for the studied region.& &
In situ cosmogenic exposure ages from the Isle of Skye, northwest Scotland: implications for the timing of deglaciation and readvance from 15 to 11 ka
Publisher: Wiley
Date: 08-08-2011
DOI: 10.1002/JQS.1522
Spatial Patterns of Glacial Erosion at a Valley Scale Derived From Terrestrial Cosmogenic10Be and26Al Concentrations in Rock
Publisher: Informa UK Limited
Date: 06-2200
Discordance between cosmogenic nuclide concentrations in amalgamated sands and individual fluvial pebbles in an arid zone catchment
Publisher: Elsevier BV
Date: 02-2014
A topographic hinge-zone divides coastal and inland ice dynamic regimes in East Antarctica
Publisher: Springer Science and Business Media LLC
Date: 05-01-2023
DOI: 10.1038/S43247-022-00673-6
Abstract: The impact of late Cenozoic climate on the East Antarctic Ice Sheet is uncertain. Poorly constrained patterns of relative ice thinning and thickening impair the reconstruction of past ice-sheet dynamics and global sea-level budgets. Here we quantify long-term ice cover of mountains protruding the ice-sheet surface in western Dronning Maud Land, using cosmogenic Chlorine-36, Aluminium-26, Beryllium-10, and Neon-21 from bedrock in an inverse modeling approach. We find that near-coastal sites experienced ice burial up to 75–97% of time since 1 Ma, while interior sites only experienced brief periods of ice burial, generally % of time since 1 Ma. Based on these results, we suggest that the escarpment in Dronning Maud Land acts as a hinge-zone, where ice-dynamic changes driven by grounding-line migration are attenuated inland from the coastal portions of the East Antarctic Ice Sheet, and where precipitation-controlled ice-thickness variations on the polar plateau taper off towards the coast.
Apatite Deposition on NaOH‐Treated PEEK and UHMWPE Films for Sclera Materials in Artificial Cornea Implants
Publisher: Wiley
Date: 07-2010
Was Scotland deglaciated during the Younger Dryas?
Publisher: Elsevier BV
Date: 08-2016
Advance and retreat of the marine-terminating Irish Sea Ice Stream into the Celtic Sea during the Last Glacial: Timing and maximum extent
Publisher: Elsevier BV
Date: 06-2019
Investigating the last deglaciation of the Scandinavian Ice Sheet in southwest Sweden with 10Be exposure dating
Publisher: Wiley
Date: 07-10-2011
DOI: 10.1002/JQS.1536
New constraints on Plio-Pleistocene East Antarctic Ice Sheet thickness: cosmogenic exposure data from western Dronning Maud Land
Publisher: Copernicus GmbH
Date: 23-03-2020
DOI: 10.5194/EGUSPHERE-EGU2020-17965
Abstract: & & & span& Reconstructing past ice surface changes is key to test and improve ice-sheet models. Yet, data constraining the past behaviour of the East Antarctic Ice Sheet are sparse, limiting our understanding of its response to past and future climate changes. Here, we attempt to test whether the ice-sheet margin in western Dronning Maud Land has thinned since the last glacial maximum or whether it perhaps thickened in places due to increased precipitation associated with warmer climates. We report cosmogenic multi-nuclide (& sup& & /sup& Be, & sup& & /sup& Al, & sup& & /sup& Cl,& sup& 21& /sup& Ne) data from bedrock and erratics on nunataks along Jutulstraumen ice stream and the Penck Trough in western Dronning Maud Land, East Antarctica. Spanning elevations between 751-2387 m above sea level, and between 5 and 450 m above the contemporaneous local ice sheet surface, the s les record apparent exposure ages between 2 ka and 5 Ma. The highest bedrock s le indicates (near-) continuous exposure since at least the Pliocene, with a very low apparent erosion rate of 15& /span& & span& & #177 & /span& & span& cm Ma& sup& -1& /sup& . However, there are also clear indications of a thicker-than-present ice sheet within the last glacial cycle, thinning ~35-120 m at several nunataks during the Holocene (~2-11 ka). Owing to difficulties in retrieving suitable s le material from the often rugged and quartz-poor mountain summits, and due to the presence of inherited nuclides in many of our s les, we are unable to present robust thinning estimates from elevational profiles. Nevertheless, the results clearly indicate ice-surface fluctuations of several hundred meters within the last glacial cycle in this sector of the EAIS, between the current grounding line and the edge of the polar plateau. & /span& & span& Finally, inverse modelling of the cosmogenic multi-nuclide inventories in bedrock yields estimates of total erosion and ice cover across multiple glacial cycles. Our results show that the EAIS in western Dronning Maud Land was thicker than present during most of the Quaternary, covering s le sites up to 200 m above the present-day ice sheet for ~80 % of this period. Thinning of the ice since the last glacial maximum, combined with a long-term record of thicker-than-present ice, indicate that the ice sheet below the polar plateau in western Dronning Maud Land generally expands and thickens during climate cooling, despite decreasing precipitation associated with a cooler Southern Ocean.& /span& & &
A Younger Dryas re-advance of local glaciers in north Greenland
Publisher: Elsevier BV
Date: 09-2016
Investigating absolute chronologies of glacial advances in the NW sector of the Cordilleran Ice Sheet with terrestrial in situ cosmogenic nuclides
Publisher: Elsevier BV
Date: 05-2014
Trimlines, blockfields, mountain-top erratics and the vertical dimensions of the last British–Irish Ice Sheet in NW Scotland
Publisher: Elsevier BV
Date: 11-2012
Internal dynamics condition centennial-scale oscillations in marine-based ice-stream retreat
Publisher: Geological Society of America
Date: 29-07-2017
DOI: 10.1130/G38991.1
Rapid ice sheet response to deglacial and Holocene paleoenvironmental changes in eastern Prydz Bay, East Antarctica
Publisher: Elsevier BV
Date: 03-2022
Very low inheritance in cosmogenic surface exposure ages of glacial deposits: A field experiment from two Norwegian glacier forelands
Publisher: SAGE Publications
Date: 18-01-2017
Abstract: Terrestrial cosmogenic nuclide dating has been widely used to estimate the surface exposure age of bedrock and boulder surfaces associated with deglaciation and Holocene glacier variations, but the effect of inherited age has been rarely directly addressed. In this study, small clasts, embedded in flute surfaces on two cirque glacier forelands in Jotunheimen, southern Norway and deposited within the last ~60 years, were used to test whether such clasts have the modern surface exposure age expected in the absence of inheritance. Two different approaches were taken involving dating of (1) a single clast of cobble size from the proglacial area of Austanbotnbreen, and (2) 75 clasts mostly of pebble size from the proglacial area of Storbreen crushed and treated as a single s le. 10 Be surface exposure ages were 99 ± 98 and 368 ± 90 years, respectively, with 95% confidence (±2σ). It is concluded that (1) these small glaciers have eroded and deposited rock fragments with a cosmogenic zero or near-zero concentration, (2) the likelihood of inherited cosmogenic nuclide concentrations in similar rock fragments deposited by larger warm-based glaciers and ice sheets should be small, and (3) combining a large number of small rock particles into one s le rather than using single large clasts of boulder size may provide a viable alternative to the commonly perceived need for five or more independent estimates of exposure age per site.
Lake Store Finnsjøen – a key for understanding Lateglacial/early Holocene vegetation and ice sheet dynamics in the central Scandes Mountains
Publisher: Elsevier BV
Date: 08-2015
Dating Pleistocene deltaic deposits using in-situ 26Al and 10Be cosmogenic nuclides
Publisher: Elsevier BV
Date: 06-2015
Geomorphology and 10Be chronology of the Last Glacial Maximum and deglaciation in northeastern Patagonia, 43°S-71°W
Publisher: Elsevier BV
Date: 11-2021
New evidence for the incision history of the Liuchong River, Southwest China, from cosmogenic 26Al/10Be burial ages in cave sediments
Publisher: Elsevier BV
Date: 09-2013
A 10B e‐based reconstruction of the last deglaciation in southern S weden
Publisher: Wiley
Date: 04-06-2013
DOI: 10.1111/BOR.12027
Late-glacial to Neoglacial evolution of glacier extent and surface mass balance in the Cordillera Blanca, Peruvian Andes
Publisher: Copernicus GmbH
Date: 27-03-2022
DOI: 10.5194/EGUSPHERE-EGU22-4999
Abstract: & & Cordillera Blanca glaciers represent the greatest glacial freshwater reserve in tropical South America and have been shrinking substantially over recent decades, posing a threat to future water resources in the Peruvian Ancash region. A crucial step to better understand the evolution of these glaciers under changing conditions is to establish robust reconstructions of their past response to climate fluctuations. Such reconstructions are limited in the tropical Andes, which inhibits our understanding of the climatic drivers of tropical glacier length and surface mass balance changes. The relative importance of temperature versus precipitation rate changes on glacier length changes is therefore still debated in the region. Here, we present 42 cosmogenic & sup& & /sup& & em& Be& /em& exposure ages from moraine boulder s les, establishing for the first time a comprehensive chronology for Late-glacial, Holocene and Neoglacial advances of four distinct Cordillera Blanca mountain glaciers. We use this chronology to constrain a series of moraine-matching numerical model-run simulations conducted for each dated glacier advance using a spatially-distributed ice-flow model coupled with a positive degree-day surface mass balance parameterisation. These simulations aim at modelling and estimating former three-dimensional glacier geometries, equilibrium line altitudes, surface mass balance properties and their evolution through time. This analysis also enables us to use glacier surface mass balance as a proxy for past atmospheric temperature and precipitation variations at the time of the reconstructed glacier advances. This new, multi-method glacier reconstruction enables, for the Cordillera Blanca: 1) novel glacio-geomorphological interpretations, 2) an improved understanding of glacier extent, surface mass balance and volume change during the Late-glacial, Holocene and Neoglacial phases of advance, and 3) new estimations of paleoclimate conditions required for the reconstructed glacier events to occur. & & & &
Cosmogenic nuclide evidence for minimal erosion across two subglacial sliding boundaries of the late glacial Fennoscandian ice sheet
Publisher: Elsevier BV
Date: 04-2006
The importance of lithology and throw rate on bedrock river behaviour and evolution in the Gediz (Alaşehir) Graben, Turkey.
Publisher: Copernicus GmbH
Date: 23-03-2020
DOI: 10.5194/EGUSPHERE-EGU2020-10246
Abstract: & & The Gediz (Ala& #351 ehir) Graben is located in the highly tectonically active and seismogenic region of Western Turkey, which has been experiencing high-angle normal faulting since ~ 2 Ma.& Rivers upstream of the normal fault-bounded graben each contain a lithologic knickpoint related to the change in bedrock geology (from soft sediments to hard metamorphic rocks) and a non-lithologic knickpoint, caused by an increase in fault slip rate at ~ 0.8 Ma.& Therefore, this system represents an ideal natural laboratory to investigate the relative roles of bedrock lithology / rock strength and rates of faulting on the behaviour and evolution of bedrock river systems. Our results show that metamorphic rocks in the catchments are 2-3 times harder than the sedimentary rocks. Stream power increases downstream reaching local maxima upstream of the fault within the metamorphic bedrock but declines rapidly once softer sedimentary rocks are encountered. We also demonstrate a positive correlation between throw rate and stream power in the metamorphic rocks characteristic of rivers obeying a detachment-limited model of erosion. In sedimentary rocks stream powers are invariant with throw rate but do scale with the river& #8217 s sediment transport capacity. We also present new Be& sup& & /sup& denudation rates that show correlations with calculated stream power and fault throw rates. This study demonstrates that the strength of underlying bedrock is a major influence on river evolution and that the nature of the underlying lithology profoundly influences the way in which the river behaves.& &
Discussion. Denudational isostatic rebound of intraplate highlands: The Lachlan river valley, Australia
Publisher: Wiley
Date: 12-1993
Related Organisations
University Of Glasgow
Location: United Kingdom of Great Britain and Northern Ireland
Scottish Universities Environmental Research Centre
Location: United Kingdom of Great Britain and Northern Ireland
Australian National University Research School Of Earth Sciences
Location: Australia
Related Funding Activities
Cosmogenic Isotope Analysis Facility
Start Date: 2006
End Date: 2019
Funder: Natural Environment Research Council
View Funded ActivityBRITICE-CHRONO
Start Date: 2012
End Date: 2017
Funder: Natural Environment Research Council
View Funded ActivitySea-level Change In The Australasian Region During The Past 6000 Years: Understanding The Past To Predict The Future
Start Date: 2007
End Date: 2009
Funder: Australian Research Council
View Funded ActivityAltitude And Configuration Of The Last British-Irish Ice Sheet: Testing The Nunatak Hypothesis Using Cosmogenic Be-10 Exposure Dating
Start Date: 2010
End Date: 2011
Funder: Natural Environment Research Council
View Funded ActivityScotIce - How Fast Could Ice Caps Collapse?
Start Date: 2019
End Date: 2022
Funder: Natural Environment Research Council
View Funded ActivityLooking Back To See The Future: Change In The Lambert Glacier And The East Antarctic Ice Sheet
Start Date: 2003
End Date: 2006
Funder: Australian Research Council
View Funded ActivityProduction And Transport Of Soil And Sediments, Determined By Cosmogenic Radionuclides And Noble Gases
Start Date: 2003
End Date: 2005
Funder: Australian Research Council
View Funded ActivityDiscovery Projects - Grant ID: DP0342704
Start Date: 2003
End Date: 12-2007
Amount: $530,000.00
Funder: Australian Research Council
View Funded ActivityDiscovery Projects - Grant ID: DP0342689
Start Date: 2003
End Date: 12-2005
Amount: $295,000.00
Funder: Australian Research Council
View Funded ActivityDiscovery Projects - Grant ID: DP0773019
Start Date: 07-2007
End Date: 07-2011
Amount: $361,000.00
Funder: Australian Research Council
View Funded Activity