Anomalous Geochemical Provenance and Weathering History of Plio-Pleistocene Glaciomarine Fjord Strata, Bardin Bluffs Formation, East Antarctica
Major and trace element chemical analyses of the Plio-Pleistocene Bardin Bluffs Formation, on the margin of a major ice-stream of the East Antarctic Ice Sheet, yield an anomalous chemically altered sediment composition. The Bardin Bluffs Formation of the Pagodroma Group is one of the key deposits on...
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ftmontclairstuni:oai:digitalcommons.montclair.edu:earth-environ-studies-facpubs-1154 2023-07-23T04:14:38+02:00 Anomalous Geochemical Provenance and Weathering History of Plio-Pleistocene Glaciomarine Fjord Strata, Bardin Bluffs Formation, East Antarctica Passchier, Sandra Whitehead, Jason M. 2006-08-01T07:00:00Z https://digitalcommons.montclair.edu/earth-environ-studies-facpubs/155 https://doi.org/10.1111/j.1365-3091.2006.00796.x unknown Montclair State University Digital Commons https://digitalcommons.montclair.edu/earth-environ-studies-facpubs/155 doi:10.1111/j.1365-3091.2006.00796.x Department of Earth and Environmental Studies Faculty Scholarship and Creative Works Antarctica Geochemistry Glaciomarine environment Pleistocene Pliocene text 2006 ftmontclairstuni https://doi.org/10.1111/j.1365-3091.2006.00796.x 2023-07-03T21:47:52Z Major and trace element chemical analyses of the Plio-Pleistocene Bardin Bluffs Formation, on the margin of a major ice-stream of the East Antarctic Ice Sheet, yield an anomalous chemically altered sediment composition. The Bardin Bluffs Formation of the Pagodroma Group is one of the key deposits on the Antarctic continent recording glaciomarine sedimentation under open marine fjord conditions as recently as the Plio-Pleistocene. In modern fjords occupied by outlet glaciers of ice sheets, the composition of fine-grained terrigenous sediments approaches that of unweathered rock types exposed upstream. In the Bardin Bluffs Formation, average abundances of stable elements (Ti, Al, Zr) approach average upper crustal compositions and the element ratios are consistent with sediments with a cratonic source, implying glacial dispersal from a large shield area through the Lambert Glacier drainage system. Interestingly, the chemical index of alteration (CIA) of these sediments has values similar to those of average shales formed under conditions of chemical weathering. The sediments are particularly depleted in silicate Ca, which has been observed elsewhere in glacial muds sourced from pre-glacial saprolites. The anomalous chemistry of the Bardin Bluffs Formation can be explained by a sequence of events, involving chemical weathering prior to glacial expansion and erosion. The presence of a remnant 1·5 m deep late Neogene weathering profile at the base of the Bardin Bluffs sequence corroborates this conclusion. Supply of large quantities of chemically weathered materials to Antarctic marginal basins requires at least partial deglaciation of the continent and was previously regarded as uncharacteristic for late Neogene Antarctica. Text Antarc* Antarctic Antarctica East Antarctica Ice Sheet Lambert Glacier Montclair State University Digital Commons Antarctic The Antarctic East Antarctica East Antarctic Ice Sheet Lambert Glacier ENVELOPE(67.490,67.490,-73.065,-73.065) Bardin Bluffs ENVELOPE(68.133,68.133,-70.819,-70.819) Sedimentology 53 4 929 942 |
institution |
Open Polar |
collection |
Montclair State University Digital Commons |
op_collection_id |
ftmontclairstuni |
language |
unknown |
topic |
Antarctica Geochemistry Glaciomarine environment Pleistocene Pliocene |
spellingShingle |
Antarctica Geochemistry Glaciomarine environment Pleistocene Pliocene Passchier, Sandra Whitehead, Jason M. Anomalous Geochemical Provenance and Weathering History of Plio-Pleistocene Glaciomarine Fjord Strata, Bardin Bluffs Formation, East Antarctica |
topic_facet |
Antarctica Geochemistry Glaciomarine environment Pleistocene Pliocene |
description |
Major and trace element chemical analyses of the Plio-Pleistocene Bardin Bluffs Formation, on the margin of a major ice-stream of the East Antarctic Ice Sheet, yield an anomalous chemically altered sediment composition. The Bardin Bluffs Formation of the Pagodroma Group is one of the key deposits on the Antarctic continent recording glaciomarine sedimentation under open marine fjord conditions as recently as the Plio-Pleistocene. In modern fjords occupied by outlet glaciers of ice sheets, the composition of fine-grained terrigenous sediments approaches that of unweathered rock types exposed upstream. In the Bardin Bluffs Formation, average abundances of stable elements (Ti, Al, Zr) approach average upper crustal compositions and the element ratios are consistent with sediments with a cratonic source, implying glacial dispersal from a large shield area through the Lambert Glacier drainage system. Interestingly, the chemical index of alteration (CIA) of these sediments has values similar to those of average shales formed under conditions of chemical weathering. The sediments are particularly depleted in silicate Ca, which has been observed elsewhere in glacial muds sourced from pre-glacial saprolites. The anomalous chemistry of the Bardin Bluffs Formation can be explained by a sequence of events, involving chemical weathering prior to glacial expansion and erosion. The presence of a remnant 1·5 m deep late Neogene weathering profile at the base of the Bardin Bluffs sequence corroborates this conclusion. Supply of large quantities of chemically weathered materials to Antarctic marginal basins requires at least partial deglaciation of the continent and was previously regarded as uncharacteristic for late Neogene Antarctica. |
format |
Text |
author |
Passchier, Sandra Whitehead, Jason M. |
author_facet |
Passchier, Sandra Whitehead, Jason M. |
author_sort |
Passchier, Sandra |
title |
Anomalous Geochemical Provenance and Weathering History of Plio-Pleistocene Glaciomarine Fjord Strata, Bardin Bluffs Formation, East Antarctica |
title_short |
Anomalous Geochemical Provenance and Weathering History of Plio-Pleistocene Glaciomarine Fjord Strata, Bardin Bluffs Formation, East Antarctica |
title_full |
Anomalous Geochemical Provenance and Weathering History of Plio-Pleistocene Glaciomarine Fjord Strata, Bardin Bluffs Formation, East Antarctica |
title_fullStr |
Anomalous Geochemical Provenance and Weathering History of Plio-Pleistocene Glaciomarine Fjord Strata, Bardin Bluffs Formation, East Antarctica |
title_full_unstemmed |
Anomalous Geochemical Provenance and Weathering History of Plio-Pleistocene Glaciomarine Fjord Strata, Bardin Bluffs Formation, East Antarctica |
title_sort |
anomalous geochemical provenance and weathering history of plio-pleistocene glaciomarine fjord strata, bardin bluffs formation, east antarctica |
publisher |
Montclair State University Digital Commons |
publishDate |
2006 |
url |
https://digitalcommons.montclair.edu/earth-environ-studies-facpubs/155 https://doi.org/10.1111/j.1365-3091.2006.00796.x |
long_lat |
ENVELOPE(67.490,67.490,-73.065,-73.065) ENVELOPE(68.133,68.133,-70.819,-70.819) |
geographic |
Antarctic The Antarctic East Antarctica East Antarctic Ice Sheet Lambert Glacier Bardin Bluffs |
geographic_facet |
Antarctic The Antarctic East Antarctica East Antarctic Ice Sheet Lambert Glacier Bardin Bluffs |
genre |
Antarc* Antarctic Antarctica East Antarctica Ice Sheet Lambert Glacier |
genre_facet |
Antarc* Antarctic Antarctica East Antarctica Ice Sheet Lambert Glacier |
op_source |
Department of Earth and Environmental Studies Faculty Scholarship and Creative Works |
op_relation |
https://digitalcommons.montclair.edu/earth-environ-studies-facpubs/155 doi:10.1111/j.1365-3091.2006.00796.x |
op_doi |
https://doi.org/10.1111/j.1365-3091.2006.00796.x |
container_title |
Sedimentology |
container_volume |
53 |
container_issue |
4 |
container_start_page |
929 |
op_container_end_page |
942 |
_version_ |
1772186205437296640 |