Substantial spatial variation in glacial erosion rates in the Dronning Maud Land Mountains, East Antarctica

Hallgeir Sirevaag,Joachim Jacobs,Anna K Ksienzyk

doi:10.1038/s43247-021-00315-3

Hallgeir Sirevaag, Joachim Jacobs + Show 1 more

Open Access

https://doi.org/10.1038/s43247-021-00315-3

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Abstract

The coast-parallel Dronning Maud Land (DML) mountains represent a key nucleation site for the protracted glaciation of Antarctica. Their evolution is therefore of special interest for understanding the formation and development of the Antarctic ice sheet. Extensive glacial erosion has clearly altered the landscape over the past 34 Myr. Yet, the total erosion still remains to be properly constrained. Here, we investigate the power of low-temperature thermochronology in quantifying glacial erosion in-situ. Our data document the differential erosion along the DML escarpment, with up to c. 1.5 and 2.4 km of erosion in western and central DML, respectively. Substantial erosion at the escarpment foothills, and limited erosion at high elevations and close to drainage divides, is consistent with an escarpment retreat model. Such differential erosion suggests major alterations of the landscape during 34 Myr of glaciation and should be implemented in future ice sheet models.

Highlights

The coast-parallel Dronning Maud Land (DML) mountains represent a key nucleation site for the protracted glaciation of Antarctica
The lowest apatite fission-track (AFT) and apatite (U–Th)/He dating (AHe) ages are commonly found at low elevations, at the foothill of the DML escarpment, as well as on the eastern side of Jutulstraumen, while the oldest ages are found on mountain tops along the crest of the escarpment, as well as close to ice divides
DML is a classic example of a glaciated passive continental margin, showing substantial variability in the amount of glacial erosion

Summary

Introduction

The coast-parallel Dronning Maud Land (DML) mountains represent a key nucleation site for the protracted glaciation of Antarctica. Substantial erosion at the escarpment foothills, and limited erosion at high elevations and close to drainage divides, is consistent with an escarpment retreat model Such differential erosion suggests major alterations of the landscape during 34 Myr of glaciation and should be implemented in future ice sheet models. A uniform erosion of 400–500 m over all of DML is highly unlikely though, as the landscape shows clear signs of strongly focused erosion, including the deep incision of Paleozoic paleosurfaces that is mainly ascribed to wet-based glacial erosion of a pre-existing fluvial or tectonic morphology prior to or during the Oligocene[9] This morphology has later been preserved by cold-based ice sheets[9]. Detailed thermal history modeling of low-temperature thermochronological data has proven to be useful for quantifying erosion in situ in areas with long-lasting glaciations

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