The contribution of glacial erosion to shaping the hidden landscape of East Antarctica

Stuart N. Thomson; Peter W. Reiners; Sidney R. Hemming; George E. Gehrels

doi:10.1038/ngeo1722

The contribution of glacial erosion to shaping the hidden landscape of East Antarctica

Stuart N. Thomson, Peter W. Reiners, Sidney R. Hemming, George E. Gehrels

Geosciences

Research output: Contribution to journal › Article › peer-review

72 Scopus citations

Abstract

The subglacial topography in East Antarctica has been revealed by airborne radar surveys^1-3. However, how this ice-hidden landscape has evolved over time is less well known^2-12. Low pre-glacial erosion rates since the Permian period have been reported¹², challenging arguments for enhanced erosion during the Cretaceous period^4,6. Here we present a record of long-term East Antarctic erosion by applying multiple dating techniques to over 1,400 detrital mineral grains from onshore moraines and offshore sediments of Cretaceous to Quaternary age in the region of Lambert Glacier and Prydz Bay. Ages from pre-glacial sediments support overall low erosion rates before the expansion of the ice sheet, apart from a discrete interval of magmatic heating about 115 Myr ago that is inconsistent with widespread Cretaceous erosion. We find a shift towards younger and broader age distributions since ∼34 Myrago that necessitates spatially localized erosion of over 2 km in the Lambert Glacier catchment over this time. We infer that the trough containing Lambert Glacier was incised almost entirely by selective glacial erosion following initial expansion of the East Antarctic ice sheet. This implies that the early ice sheet was dynamic with ice flow concentrated along fixed ice streams.

Original language	English (US)
Pages (from-to)	203-207
Number of pages	5
Journal	Nature Geoscience
Volume	6
Issue number	3
DOIs	https://doi.org/10.1038/ngeo1722
State	Published - Mar 2013

ASJC Scopus subject areas

General Earth and Planetary Sciences

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10.1038/ngeo1722

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title = "The contribution of glacial erosion to shaping the hidden landscape of East Antarctica",

abstract = "The subglacial topography in East Antarctica has been revealed by airborne radar surveys1-3. However, how this ice-hidden landscape has evolved over time is less well known2-12. Low pre-glacial erosion rates since the Permian period have been reported12, challenging arguments for enhanced erosion during the Cretaceous period4,6. Here we present a record of long-term East Antarctic erosion by applying multiple dating techniques to over 1,400 detrital mineral grains from onshore moraines and offshore sediments of Cretaceous to Quaternary age in the region of Lambert Glacier and Prydz Bay. Ages from pre-glacial sediments support overall low erosion rates before the expansion of the ice sheet, apart from a discrete interval of magmatic heating about 115 Myr ago that is inconsistent with widespread Cretaceous erosion. We find a shift towards younger and broader age distributions since ∼34 Myrago that necessitates spatially localized erosion of over 2 km in the Lambert Glacier catchment over this time. We infer that the trough containing Lambert Glacier was incised almost entirely by selective glacial erosion following initial expansion of the East Antarctic ice sheet. This implies that the early ice sheet was dynamic with ice flow concentrated along fixed ice streams.",

author = "Thomson, {Stuart N.} and Reiners, {Peter W.} and Hemming, {Sidney R.} and Gehrels, {George E.}",

note = "Funding Information: This work was supported by NSF Polar Programs award ANT 0838722. We thank D. Harwood for supplying samples from the Pagodroma Group, E. Pierce and T. Williams for help with data compilation, L. Hill and P. Gou for help with sample preparation, U. Chowdhury and S. Nicolescu for (U–Th)/He analytical assistance, and M. Pecha and the Arizona LaserChron Center staff for support with U–Pb analysis.",

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N1 - Funding Information: This work was supported by NSF Polar Programs award ANT 0838722. We thank D. Harwood for supplying samples from the Pagodroma Group, E. Pierce and T. Williams for help with data compilation, L. Hill and P. Gou for help with sample preparation, U. Chowdhury and S. Nicolescu for (U–Th)/He analytical assistance, and M. Pecha and the Arizona LaserChron Center staff for support with U–Pb analysis.

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N2 - The subglacial topography in East Antarctica has been revealed by airborne radar surveys1-3. However, how this ice-hidden landscape has evolved over time is less well known2-12. Low pre-glacial erosion rates since the Permian period have been reported12, challenging arguments for enhanced erosion during the Cretaceous period4,6. Here we present a record of long-term East Antarctic erosion by applying multiple dating techniques to over 1,400 detrital mineral grains from onshore moraines and offshore sediments of Cretaceous to Quaternary age in the region of Lambert Glacier and Prydz Bay. Ages from pre-glacial sediments support overall low erosion rates before the expansion of the ice sheet, apart from a discrete interval of magmatic heating about 115 Myr ago that is inconsistent with widespread Cretaceous erosion. We find a shift towards younger and broader age distributions since ∼34 Myrago that necessitates spatially localized erosion of over 2 km in the Lambert Glacier catchment over this time. We infer that the trough containing Lambert Glacier was incised almost entirely by selective glacial erosion following initial expansion of the East Antarctic ice sheet. This implies that the early ice sheet was dynamic with ice flow concentrated along fixed ice streams.

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The contribution of glacial erosion to shaping the hidden landscape of East Antarctica

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