| Title | Landscape evolution of Antarctica |
| Author | Jamieson, S.S.R.; Sugden, D.E. |
| Author Affil | Jamieson, S.S.R., University of Edinburgh, School of GeoSciences, Edinburgh, United Kingdom. Other: Jet Propulsion Laboratory |
| Source | Antarctica; a keystone in a changing world; online proceedings for the 10th international symposium on Antarctic earth sciences. Open-File Report - U. S. Geological Survey, No.OF2007-1047, p.39-54; [10th international symposium on Antarctic earth sciences; Antarctica; a keystone in a changing world, Santa Barbara, CA, Aug. 26- Sept. 1, 2007]; edited by A. Cooper and C. Raymond. Publisher: U. S. Geological Survey, Reston, VA, United States. ISSN: 0196- 1497 |
| Publication Date | 2007 |
| Notes | In English. Accessed on May 27, 2010. 94 refs. GeoRef Acc. No: 299610. CRREL Acc. No: 64004510 |
| Index Terms | erosion; geomorphology; paleoclimatology; weathering; Antarctica-- Antarctic ice sheet; Antarctic ice sheet; Antarctica; Cenozoic; erosion features; fluvial features; glacial environment; glacial features; landform evolution; landscapes; Quaternary; Tertiary; USGS |
| Abstract | The relative roles of fluvial versus glacial processes in shaping the landscape of Antarctica have been debated since the expeditions of Robert Scott and Ernest Shackleton in the early years of the 20th century. Here we build a synthesis of Antarctic landscape evolution based on the geomorphology of passive continental margins and former northern mid-latitude Pleistocene ice sheets. What makes Antarctica so interesting is that the terrestrial landscape retains elements of a record of change that extends back to the Oligocene. Thus there is the potential to link conditions on land with those in the oceans and atmosphere as the world switched from a greenhouse to a glacial world and the Antarctic ice sheet evolved to its present state. In common with other continental fragments of Gondwana there is a fluvial signature to the landscape in the form of the coastal erosion surfaces and escarpments, incised river valleys, and a continent-wide network of river basins. A selective superimposed glacial signature reflects the presence or absence of ice at the pressure melting point. Earliest continental-scale ice sheets formed around 34 Ma, growing from local ice caps centered on mountain massifs, and featured phases of ice- sheet expansion and contraction. These ice masses were most likely cold-based over uplands and warm-based across lowlands and near their margins. For 20 million years ice sheets fluctuated on Croll-Milankovitch frequencies. At ~14 Ma the ice sheet expanded to its maximum and deepened a preexisting radial array of troughs selectively through the coastal mountains and eroded the continental shelf before retreating to its present dimensions at ~13.5 Ma. Subsequent changes in ice extent have been forced mainly by sea-level change. Weathering rates of exposed bedrock have been remarkably slow at high elevations around the margin of East Antarctica under the hyperarid polar climate of the last ~13.5 Ma, offering potential for a long quantitative record of ice-sheet evolution with techniques such as cosmogenic isotope analysis. |
| URL | http://pubs.usgs.gov/of/2007/1047/ |
| Publication Type | conference paper or compendium article |
| Record ID | 88363 |