eCite Digital Repository

Ice-sheet control of continental erosion in central and southern Chile (36°-41°S) over the last 30,000 years

Citation

Muratli, JM and Chase, Z and McManus, J and Mix, A, Ice-sheet control of continental erosion in central and southern Chile (36 -41 S) over the last 30,000 years , Quaternary Science Reviews , 29, (23-24) pp. 3230-3239. ISSN 0277-3791 (2010) [Refereed Article]


Preview
PDF
Restricted - Request a copy
1Mb
  

Copyright Statement

The definitive version is available at http://www.sciencedirect.com

Official URL: http://www.sciencedirect.com

DOI: doi:10.1016/j.quascirev.2010.06.037

Abstract

Bulk sediment chemistry from three Chilean continental margin Ocean Drilling Program sites constrains regional continental erosion over the past 30,000 years. Sediments from thirteen rivers that drain the (mostly igneous) Andes and the (mostly metamorphic) Coast Range, along with existing rock chemistry datasets, define terrestrial provenance for the continental margin sediments. Andean river sediments have high Mg/Al relative to Coast-Range river sediments. Near 36S, marine sediments have high-Mg/Al (i.e. more Andean) sources during the last glacial period, and lower-Mg/Al (less Andean) sources during the Holocene. Near 41S a Ti-rich source, likely from coast-range igneous intrusions, is prevalent during Holocene time, whereas high-Mg/Al Andean sources are more prevalent during the last glacial period. We infer that there is a dominant ice-sheet control of sediment sources. At 36S, Andean-sourced sediment decreased as Andean mountain glaciers retreated after w17.6 ka, coincident with local oceanic warming and southward retreat of the Patagonian Forest and, by inference, westerly winds. At 41S Andean sediment dominance peaks and then rapidly declines at w19 ka, coincident with local oceanic warming and the earliest deglacial sea-level rise. We hypothesize that this decreased flux of Andean material in the south is related to rapid retreat of the marine-based portion of the Patagonian Ice Sheet in response to global sea-level rise, as the resulting flooding of the southern portion of the Central Valley created a sink for Andean sediments in this region. Reversal of the decreasing deglacial Mg/Al trend at 41S from 14.5 to 13.0 ka is consistent with a brief re-advance of the Patagonian ice sheet coincident with the Antarctic Cold Reversal.

Item Details

Item Type:Refereed Article
Research Division:Earth Sciences
Research Group:Physical Geography and Environmental Geoscience
Research Field:Palaeoclimatology
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Earth Sciences
Author:Chase, Z (Associate Professor Zanna Chase)
ID Code:67345
Year Published:2010
Web of Science® Times Cited:7
Deposited By:IMAS Research and Education Centre
Deposited On:2011-03-02
Last Modified:2011-05-30
Downloads:3 View Download Statistics

Repository Staff Only: item control page