georefid:2012-050595SEDIS Publication Catalogue

ana.macario@awi.de

http://sedis.iodp.org/pub-catalogue/informationpointOfContact2013-07-08T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=10.1016/j.quascirev.2010.06.0372010-01-01publicationgeorefid:2012-050595doi:10.1016/j.quascirev.2010.06.037Muratli, Jesse M.Oregon State University, College of Oceanic and Atmospheric Sciences, Corvallis, OR, United StatesauthorChase, ZannaauthorMcManus, JamesauthorMix, AlanauthorElsevier, InternationalpublisherdocumentHardcopyQuaternary Science Reviews29 (23-24)3230-3239Bulk 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 36 degrees S, 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 41 degrees S 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 36 degrees S, Andean-sourced sediment decreased as Andean mountain glaciers retreated after approximately 17.6 ka, coincident with local oceanic warming and southward retreat of the Patagonian Forest and, by inference, westerly winds. At 41 degrees S Andean sediment dominance peaks and then rapidly declines at approximately 19 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 41 degrees S 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. Abstract Copyright (2010) Elsevier, B.V.completedQuaternary geologyIsotope geochemistryalkaline earth metalsaluminumAndesCenozoiccentral Chilechemical compositionChileEast Pacificerosionfluvial environmentglacial geologyHoloceneice sheetsisotope ratiosisotopesLeg 202magnesiummarine sedimentsmetalsMg/AlO-18/O-16Ocean Drilling ProgramODP Site 1233ODP Site 1234ODP Site 1235oxygenPacific OceanpaleoenvironmentPatagonian ice sheetPleistoceneQuaternarysedimentsSouth AmericaSouth PacificSoutheast Pacificsouthern Chilestable isotopesstream sedimentsupper Pleistoceneurn:org.iodp:exp:202urnlargerWorkCitationcampaignurn:org.iodp:exp:202:site:1233urnlargerWorkCitationstudyurn:org.iodp:exp:202urnlargerWorkCitationcampaignurn:org.iodp:exp:202:site:1234urnlargerWorkCitationstudyurn:org.iodp:exp:202urnlargerWorkCitationcampaignurn:org.iodp:exp:202:site:1235urnlargerWorkCitationstudyurn:org.iodp:exp:202urnlargerWorkCitationcampaignEnglishgeoscientificInformation-74.2700-73.3400-41.0000-36.1000Supplemental information/data is available in the online version of this article; includes appendix; NSF grants OCE-0526278, OCE-0753487, AGS-0602395