Glacial erosion of East Antarctica in the Pliocene: a comparative study of multiple marine sediment provenance tracers
File(s)Cook et al., accepted manuscript.pdf (2.48 MB)
Accepted version
Author(s)
Type
Journal Article
Abstract
The history of the East Antarctic ice sheet provides important understanding of its potential future behaviour in a warming world. The provenance of glaciomarine sediments can provide insights into this history, if the underlying continent eroded by the ice sheet is made of distinct geological terranes that can be distinguished by the mineralogy, petrology and/or geochemistry of the eroded sediment. We here present a multi-proxy provenance investigation on Pliocene sediments from Integrated Ocean Drilling Program (IODP) Site U1361, located offshore of the Wilkes Subglacial Basin, East Antarctica. We compare Nd and Sr isotopic compositions of < 63 μm detrital fractions, clay mineralogy of < 2 μm fractions, 40Ar/39Ar ages of > 150 μm ice-rafted hornblende grains, and petrography of > 2 mm ice-rafted clasts and > 150 μm mineral grains. Pliocene fine-grained marine sediments have Nd and Sr isotopic compositions, clay mineralogy, and clast characteristics that can be explained by mixing of sediments eroded from predominantly proximal crystalline terranes with material derived from inland sources from within the currently glaciated Wilkes Subglacial Basin. Conversely, evidence for such an inland source is absent from ice-rafted hornblende ages. We render a lithological bias against hornblende grains in the doleritic and sedimentary units within the basin the most likely explanation for this observation. 40Ar/39Ar hornblende ages however record additional provenance from the distal margins of the Ross Sea, and possibly even the West Antarctic area of Marie Byrd Land. The latter lies > 2000 km to the east and hints at significant iceberg release from the West Antarctic ice sheet during warm intervals of the Pliocene. Together our results make a strong case for combining geochemical and mineralogical signatures of coarse- and fine-grained glaciomarine sediment fractions in order to derive robust provenance interpretations in ice covered areas.
Date Issued
2017-06-08
Date Acceptance
2017-06-07
Citation
Chemical Geology, 2017, 466, pp.199-218
ISSN
1872-6836
Publisher
Elsevier
Start Page
199
End Page
218
Journal / Book Title
Chemical Geology
Volume
466
Copyright Statement
© 2017 Elsevier Ltd. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/
Sponsor
Commission of the European Communities
Natural Environment Research Council (NERC)
Natural Environment Research Council (NERC)
Grant Number
PIRG03-GA-2008-230828
NE/H014144/1
NE/H025162/1
Subjects
Science & Technology
Physical Sciences
Geochemistry & Geophysics
East Antarctic ice sheet
Provenance
Marine sediment
Pliocene warmth
Radiogenic isotopes
Thermochronology
NORTHERN VICTORIA LAND
DEEP-SEA SEDIMENTS
CENTRAL TRANSANTARCTIC MOUNTAINS
LARGE IGNEOUS PROVINCE
ZIRCON U-PB
ICE-SHEET
WILKES LAND
BYRD-LAND
SOUTHERN-OCEAN
ROSS SEA
0402 Geochemistry
0403 Geology
0406 Physical Geography And Environmental Geoscience
Publication Status
Published