Million year old ice found under meter thick debris layer in Antarctica

Bibby, T.; Putkonen, Jaakko; Morgan, Daniel J.; Balco, Greg; Shuster, David L.

doi:10.1002/2016gl069889

Cited by 26 publications

(52 citation statements)

References 33 publications

(52 reference statements)

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“…Nevertheless, boulders can become stable if the rock glacier mobility is very limited (Bibby et al . ). This suggests that CRE ages do not indicate the final activity of the rock glacier or its fossilization, but rather the survival of one of the surfaces of the boulder, which remains permanently exposed on a rock glacier with a large ice layer, but which is static or has low dynamism (Mackay & Marchant ).…”

Section: Discussionmentioning

confidence: 97%

Timing of deglaciation and rock glacier origin in the southeastern Pyrenees: a review and new data

Andrés

Gómez‐Ortiz

Fernández‐Fernández

et al. 2018

Boreas

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The aim of this research is to improve our current understanding of the deglaciation stages in the southeastern Pyrenees and integrate it into reconstructions of the long-term deglaciation in the Iberian mountains since the Last Glaciation. First, we examine the existing chronological data for deglaciation in Iberian mountain ranges, mainly focusing on the Pyrenees and the results derived from cosmic ray exposure dating methods. Then, we recalculate the age of 17 samples from four different areas in the SE Pyrenees (Ar anser, La Llosa and Duran valleys and Malniu-Guils complex) based on the 36 Cl isotope and applying a new age calculator. In addition, we date eight new samples from the Malniu-Guils complex to provide a more accurate chronology for this site. The results do not clarify the timing of the maximum glacier extent, but support an extensive glacial advance followed by multiple small advances and retreats during the Last Glacial Maximum (LGM). Geomorphological and chronological data show evidence of massive deglaciation at the end of the LGM around 18 ka, and deglaciation was practically complete during the Bølling-Allerød interstadial. There is no geomorphological evidence of glacial advances in the cirques during the Younger Dryas. Instead, cirque wallswere coveredwith rock glaciers during the Bølling-Allerød interstadial. The fronts of these rock glaciers stabilized at the end of this period, while their roots remained active until well into the Holocene.Nuria Andr es (nandresp@ucm.es), Jos e M. Fern andez-Fern andez,

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Section: Discussionmentioning

confidence: 97%

Timing of deglaciation and rock glacier origin in the southeastern Pyrenees: a review and new data

Andrés

Gómez‐Ortiz

Fernández‐Fernández

et al. 2018

Boreas

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“…Furthermore, blue ice areas have the potential to contain surface or shallow ice that is older than that recovered from deep drilling projects and can in some cases provide a higher temporal resolution (e.g. Sinisalo et al, 2007;Higgins et al, 2015;Bibby et al, 2016;Kehrl et al, 2018). Equally important, ice is available in large quantities, which is necessary for certain types of measurements, such as the characterization of trapped gasses and their isotopic composition (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Muhs et al, 1999;Curzio et al, 2008), cosmogenic dating of glacial tills (e.g. Bibby et al, 2016), dating by comparison to isotopic variations from ice cores through wigglematching (e.g. Moore et al, 2006) and constraining the terrestrial age from surface meteorites (e.g.…”

Section: Introductionmentioning

confidence: 99%

Unravelling the high-altitude Nansen blue ice field meteorite trap (East Antarctica) and implications for regional palaeo-conditions

Zekollari

Goderis

Debaille

et al. 2019

Geochimica et Cosmochimica Acta

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Antarctic blue ice zones, the most productive locations for meteorite recovery on Earth, contain old ice that is easily accessible and available in large quantities. However, the mechanisms behind these meteorite traps remain a topic of ongoing debate. Here, we propose an interdisciplinary approach to improve our understanding of a meteorite trap in Dronning Maud Land (East Antarctica) on the Nansen blue ice field meteorite trap (2600-3100 m above sea level), where more than half of the Asuka meteorites have been collected. Based on 185 surface blue ice samples, one of the largest observed spatial patterns in oxygen isotopic variation to date is found. Relying on meteorites for which the terrestrial ages are determined using 14 C and 36 Cl, this surface ice is interpreted to date from the Last Interglacial up to the present-day. By combining state-of-the-art satellite derived surface velocities, surface mass balance modelling and ice flow modelling, we estimate that about 75-85% of the meteorites found on the ice field were supplied by ice flow after entering the ice sheet in an accumulation area of a few hundred square kilometres located south (upstream) of the ice field. Less than 0.4 new meteorites per year are supplied to the ice field through ice flow, suggesting that the hundreds of meteorites found 25 years after the first visit to this ice field mostly represent meteorites that were previously not found, rather than newly supplied meteorites. By combining these findings, the infall rate of meteorites from space is estimated, which is in line with values from the literature, but situated at the higher end of the range. A comparison of the oxygen isotopic variation of the surface blue ice to that of the European Project for Ice Coring

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“…CC BY 4.0 License. regions of Antarctica (Fukui et al, 2008;Hassinger and Mayewski, 1983;Bibby et al, 2016). Based on our results, it is likely that many ice-cored rock glaciers elsewhere in Antarctica record past glacial fluctuations, and can therefore be used to study climatic history during the Holocene and Pleistocene.…”

Section: Implications For Mcmurdo Dry Valleys Glaciersmentioning

confidence: 64%

Rock glacier characteristics serve as an indirect record of multiple alpine glacier advances in Taylor Valley, Antarctica

Winsor¹,

Swanger²,

Babcock³

et al. 2019

Preprint

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Abstract. The geomorphic record indicates that alpine glaciers in the McMurdo Dry Valleys of southern Victoria Land, Antarctica appear to advance during interglacial periods in response to ice-free conditions in the Ross Sea. Few records of these advances are preserved and/or subaerially exposed, complicating the interpretations of regional glacier response to climate changes. Here, we present geophysical and geochemical analyses of a rock glacier that originates from icefalls fed by alpine Doran Glacier in central Taylor Valley. The rock glacier exhibits a trend of increased weathering of granitic clasts via ventifaction and grussification down-flow. Meltwater ponds on the rock glacier exhibit variable salinity that ranges from freshwater to higher than seawater, with the highest salinity pond near the rock glacier toe. Ground-penetrating radar analyses reveal the feature to possess a primarily clean ice interior, with layers of englacial debris. Stable isotopic data from three ice cores support a glacial origin for the ice within the rock glacier. These data suggest that the current morphology of the rock glacier is the result of multiple events of increased ice contribution caused by advances of Doran Glacier, which is the main source of the ice that cores the rock glacier. We therefore demonstrate the potential of ice-cored rock glaciers to record multiple advances and retreats of Dry Valley glaciers, permitting the interpretation of glacial responses to Pleistocene and Holocene climate change even where direct records are not present.

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Million year old ice found under meter thick debris layer in Antarctica

Cited by 26 publications

References 33 publications

Timing of deglaciation and rock glacier origin in the southeastern Pyrenees: a review and new data

Timing of deglaciation and rock glacier origin in the southeastern Pyrenees: a review and new data

Unravelling the high-altitude Nansen blue ice field meteorite trap (East Antarctica) and implications for regional palaeo-conditions

Rock glacier characteristics serve as an indirect record of multiple alpine glacier advances in Taylor Valley, Antarctica

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