The oldest ice on Earth in Beacon Valley, Antarctica: new evidence from surface exposure dating

Schäfer, Jörg M.; Baur, H.; Denton, George H.; Ivy‐Ochs, Susan; Marchant, D. R.; Schlüchter, Christian; Wieler, R.

doi:10.1016/s0012-821x(00)00095-9

Cited by 87 publications

(78 citation statements)

References 18 publications

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“…We conclude that noncosmogenic 3 He fractions are negligible and report total 3 He as the cosmogenic component in Table 3. 22 Ne/ 20 Ne and 21 Ne/ 20 Ne ratios are higher than atmospheric throughout, ranging from 0.1043 to 0.951 and from 0.00443 to 0.801, respectively, and generally increasing with extraction temperature, again in agreement with the degassing systematics reported in [15]. Trapped Ne is very similar to atmospheric, as shown by the crushing extraction of sample 444.…”

supporting

confidence: 83%

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The production rate of cosmogenic 38Ar from calcium in terrestrial pyroxene

Niedermann

Schaefer

Wieler

et al. 2007

Earth and Planetary Science Letters

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Pyroxene separated from dolerite surfaces, which were exposed to cosmic ray irradiation for Ar (normalized to Ca) to total 3 He and to cosmogenic 21 Ne normalized to Mg, respectively, are excellent. However, various currently used methods to derive the 3 He and 21 Ne production rates in pyroxene lack consistency. Depending on the method chosen, the 38 Ar production rate derived here ranges between (191 ± 21) atoms (g Ca) -1 a -1 and (254 ± 28) atoms (g Ca) -1 a -1 at sea level (standard atmospheric pressure) and high latitude. A more accurate value may be calculated from our data as soon as the He and Ne production rates from pyroxene are known more reliably. Our production rate determination is largely independent of past geomagnetic field variations and of the scaling method used.

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supporting

confidence: 83%

“…3 He/ 4 He ratios vary from 0.859×10 -6 to 331×10 -6 ; they typically decrease with increasing temperature, confirming the predominant release of cosmogenic He from pyroxene below 600°C [15]. To calculate the concentration of cosmogenic 3 He, the contributions of trapped and radiogenic He have to be known.…”

Section: Helium and Neonmentioning

confidence: 99%

The production rate of cosmogenic 38Ar from calcium in terrestrial pyroxene

Niedermann

Schaefer

Wieler

et al. 2007

Earth and Planetary Science Letters

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“…Examples of where the preservation of buried-ice has been permitted on longer timescales include formerly glaciated continental settings (e.g. Ingólfsson and Lokrantz, 2003;Murton et al, 2005), and cold deserts where buried-ice is suggested to have existed for several millennia under permafrost conditions (Sugden et al, 1995;Schäfer et al 2000). Waller et al (2012) highlighted that the preservation of buried-ice may be permitted on geological timescales if it is located at depths unaffected by seasonal thaw.…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

Ice-cored moraine degradation mapped and quantified using an unmanned aerial vehicle: A case study from a polythermal glacier in Svalbard

et al. 2016

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“…In this study, observations on moraine transformation are extended beyond the 2-year study period previously reported (Irvine-Fynn et al, 2011) to facilitate understanding of the evolution of high-Arctic glacial landforms on a decadal scale through the use of high-resolution LiDAR and UAV-SfM (structure-from-motion) derived topographic data sets (techniques demonstrated to be of value in glacial environments by Bhardwaj et al, 2016aBhardwaj et al, , 2016b. The burial and long-term preservation of relict ice is of interest as a potential palaeoglaciological and palaeoenvironmental archive (e.g., Sugden et al, 1995;Schäfer et al, 2000;Murton et al, 2005;Waller et al, 2012). In addition, understanding the preservation history of buried ice will also assist with appropriate landform age determination (e.g., Kirkbride and Winkler, 2012;Çiner et al, 2015;Tonkin et al, 2017;Crump et al, 2017) and assist with former glacier reconstruction (e.g., Benn and Hulton, 2010;Pellitero et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Evolution of high-Arctic glacial landforms during deglaciation

et al. 2018

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Glacial landsystems in the high-Arctic have been reported to undergo geomorphological transformation during deglaciation. This research evaluates moraine evolution over a decadal timescale at Midtre Lovénbreen, Svalbard. This work is of interest because glacial landforms developed in Svalbard have been used as an analogue for landforms developed during Pleistocene mid-latitude glaciation. Ground penetrating radar was used to investigate the subsurface characteristics of moraines. To determine surface change, a LiDAR topographic data set (obtained 2003) and a UAV-derived (obtained 2014) digital surface model processed using structure-from-motion (SfM) are also compared. Evaluation of these data sets together enables subsurface character and landform response to climatic amelioration to be linked. Ground penetrating radar evidence shows that the moraine substrate at Midtre Lovénbreen includes ice-rich (radar velocities of 0.17 m ns (mean thresholded rate of −4.39 m over the 11-year observation period). However, the debris-rich zones show a relatively low rate of surface change (mean thresholded rate of −0.98 m over the 11-year observation period), and the morphology of the debris-rich landforms appear stable over the observation period. A complex response of proglacial landforms to climatic warming is shown to occur within and between glacier forelands as indicated by spatially variable surface lowering rates. Landform response is controlled by the ice-debris balance of the moraine substrate, along with the topographic context (such as the influence of meltwater). Site-specific characteristics such as surface debris thickness and glaciofluvial drainage are, therefore, argued to be a highly important control on surface evolution in ice-cored terrain, resulting in a diverse response of high-Arctic glacial landsystems to climatic amelioration. These results highlight that care is needed when assessing the long-term preservation potential of contemporary landforms at high-Arctic glaciers. A better understanding of ice-cored terrain facilitates the development of appropriate age and climatic interpretations that can be obtained from palaeo ice-marginal landsystems.

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The oldest ice on Earth in Beacon Valley, Antarctica: new evidence from surface exposure dating

Cited by 87 publications

References 18 publications

The production rate of cosmogenic 38Ar from calcium in terrestrial pyroxene

The production rate of cosmogenic 38Ar from calcium in terrestrial pyroxene

Ice-cored moraine degradation mapped and quantified using an unmanned aerial vehicle: A case study from a polythermal glacier in Svalbard

Evolution of high-Arctic glacial landforms during deglaciation

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