Stratigraphy and timing of eolianite deposition
Over 100 whole-rock amino acid racemization (AAR) ratios from outcrops around Rottnest Island (32.0 ° S Latitude near Perth) indicate distinct pulses of eolian deposition during the late Quaternary. Whole-rock D-alloisoleucine/L-isoleucine (A/I) ratios from bioclastic carbonate deposits fall into th...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.596.8808 2023-05-15T17:35:55+02:00 Stratigraphy and timing of eolianite deposition Paul J. Hearty The Pennsylvania State University CiteSeerX Archives 2003 application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.596.8808 http://www.uow.edu.au/content/groups/public/@web/@sci/@eesc/documents/doc/uow014944.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.596.8808 http://www.uow.edu.au/content/groups/public/@web/@sci/@eesc/documents/doc/uow014944.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://www.uow.edu.au/content/groups/public/@web/@sci/@eesc/documents/doc/uow014944.pdf Western Australia Late Quaternary Whole-rock amino acid racemization Carbonate eolianite Sea-level changes text 2003 ftciteseerx 2016-01-08T13:46:42Z Over 100 whole-rock amino acid racemization (AAR) ratios from outcrops around Rottnest Island (32.0 ° S Latitude near Perth) indicate distinct pulses of eolian deposition during the late Quaternary. Whole-rock D-alloisoleucine/L-isoleucine (A/I) ratios from bioclastic carbonate deposits fall into three distinct modal classes or “aminozones. ” The oldest, Aminozone E, averages 0.33 0.04 (n 21). Red palaeosol and thick calcrete generally cap the Aminozone E deposits. A younger Aminozone C averages 0.22 0.03 (n 63); comprising two submodes at 0.26 0.01 (n 14) and 0.21 0.02 (n 49). Multiple dune sets of this interval are interrupted by relatively weak, brown to tan “protosols. ” A dense, dark brown rendzina palaeosol caps the Aminozone C succession. Ratios from Holocene dune and marine deposits (“Aminozone A”) center on 0.11 0.02 (n 15), comprising submodes of 0.13 0.01 (9) and 0.09 0.01 (6). Calibration of A/I averages from Aminozones E and A are provided by U/Th and 14C radiometric ages of 125,000 yr (marine oxygen isotope stage (MIS) 5e and 2000–6000 14C yr B.P. (MIS 1), respectively. The whole-rock A/I results support periodic deposition initiated during MIS 5e, continuing through MIS 5c, and then peaking at the end of MIS 5a, about 70,000–80,000 yr ago. Oceanographic evidence indicates the area was subjected to much colder conditions during MIS 2–4 (10,000 to 70,000 yr ago), greatly slowing the epimerization rate. Eolianite deposition resumed in the mid Holocene (6000 yr ago) up to the present. The A/I epimerization pathway constructed from Rottnest Island shows remarkable similarity to that of Bermuda in the North Atlantic (32 ° N Latitude). These findings suggest that, like Bermuda, the eolian activity on Rottnest occurred primarily during or shortly after interglacial highstands when the shoreline was near the present datum, rather than during glacial lowstands when the coastline was positioned 10–20 km to the west. Text North Atlantic Unknown |
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Open Polar |
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Unknown |
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ftciteseerx |
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English |
topic |
Western Australia Late Quaternary Whole-rock amino acid racemization Carbonate eolianite Sea-level changes |
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Western Australia Late Quaternary Whole-rock amino acid racemization Carbonate eolianite Sea-level changes Paul J. Hearty Stratigraphy and timing of eolianite deposition |
topic_facet |
Western Australia Late Quaternary Whole-rock amino acid racemization Carbonate eolianite Sea-level changes |
description |
Over 100 whole-rock amino acid racemization (AAR) ratios from outcrops around Rottnest Island (32.0 ° S Latitude near Perth) indicate distinct pulses of eolian deposition during the late Quaternary. Whole-rock D-alloisoleucine/L-isoleucine (A/I) ratios from bioclastic carbonate deposits fall into three distinct modal classes or “aminozones. ” The oldest, Aminozone E, averages 0.33 0.04 (n 21). Red palaeosol and thick calcrete generally cap the Aminozone E deposits. A younger Aminozone C averages 0.22 0.03 (n 63); comprising two submodes at 0.26 0.01 (n 14) and 0.21 0.02 (n 49). Multiple dune sets of this interval are interrupted by relatively weak, brown to tan “protosols. ” A dense, dark brown rendzina palaeosol caps the Aminozone C succession. Ratios from Holocene dune and marine deposits (“Aminozone A”) center on 0.11 0.02 (n 15), comprising submodes of 0.13 0.01 (9) and 0.09 0.01 (6). Calibration of A/I averages from Aminozones E and A are provided by U/Th and 14C radiometric ages of 125,000 yr (marine oxygen isotope stage (MIS) 5e and 2000–6000 14C yr B.P. (MIS 1), respectively. The whole-rock A/I results support periodic deposition initiated during MIS 5e, continuing through MIS 5c, and then peaking at the end of MIS 5a, about 70,000–80,000 yr ago. Oceanographic evidence indicates the area was subjected to much colder conditions during MIS 2–4 (10,000 to 70,000 yr ago), greatly slowing the epimerization rate. Eolianite deposition resumed in the mid Holocene (6000 yr ago) up to the present. The A/I epimerization pathway constructed from Rottnest Island shows remarkable similarity to that of Bermuda in the North Atlantic (32 ° N Latitude). These findings suggest that, like Bermuda, the eolian activity on Rottnest occurred primarily during or shortly after interglacial highstands when the shoreline was near the present datum, rather than during glacial lowstands when the coastline was positioned 10–20 km to the west. |
author2 |
The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Paul J. Hearty |
author_facet |
Paul J. Hearty |
author_sort |
Paul J. Hearty |
title |
Stratigraphy and timing of eolianite deposition |
title_short |
Stratigraphy and timing of eolianite deposition |
title_full |
Stratigraphy and timing of eolianite deposition |
title_fullStr |
Stratigraphy and timing of eolianite deposition |
title_full_unstemmed |
Stratigraphy and timing of eolianite deposition |
title_sort |
stratigraphy and timing of eolianite deposition |
publishDate |
2003 |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.596.8808 http://www.uow.edu.au/content/groups/public/@web/@sci/@eesc/documents/doc/uow014944.pdf |
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North Atlantic |
genre_facet |
North Atlantic |
op_source |
http://www.uow.edu.au/content/groups/public/@web/@sci/@eesc/documents/doc/uow014944.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.596.8808 http://www.uow.edu.au/content/groups/public/@web/@sci/@eesc/documents/doc/uow014944.pdf |
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Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
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