Stratigraphy and timing of eolianite deposition on Rottnest Island, Western Australia
Abstract 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...
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crcambridgeupr:10.1016/s0033-5894(03)00063-2 2024-06-09T07:48:22+00:00 Stratigraphy and timing of eolianite deposition on Rottnest Island, Western Australia Hearty, Paul J. 2003 http://dx.doi.org/10.1016/s0033-5894(03)00063-2 http://api.elsevier.com/content/article/PII:S0033589403000632?httpAccept=text/xml http://api.elsevier.com/content/article/PII:S0033589403000632?httpAccept=text/plain https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033589400012436 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Quaternary Research volume 60, issue 2, page 211-222 ISSN 0033-5894 1096-0287 journal-article 2003 crcambridgeupr https://doi.org/10.1016/s0033-5894(03)00063-2 2024-05-15T13:11:44Z Abstract 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 14 C radiometric ages of 125,000 yr (marine oxygen isotope stage (MIS) 5e and 2000–6000 14 C 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. Article in Journal/Newspaper North Atlantic Cambridge University Press Quaternary Research 60 2 211 222 |
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Cambridge University Press |
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English |
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Abstract 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 14 C radiometric ages of 125,000 yr (marine oxygen isotope stage (MIS) 5e and 2000–6000 14 C 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. |
format |
Article in Journal/Newspaper |
author |
Hearty, Paul J. |
spellingShingle |
Hearty, Paul J. Stratigraphy and timing of eolianite deposition on Rottnest Island, Western Australia |
author_facet |
Hearty, Paul J. |
author_sort |
Hearty, Paul J. |
title |
Stratigraphy and timing of eolianite deposition on Rottnest Island, Western Australia |
title_short |
Stratigraphy and timing of eolianite deposition on Rottnest Island, Western Australia |
title_full |
Stratigraphy and timing of eolianite deposition on Rottnest Island, Western Australia |
title_fullStr |
Stratigraphy and timing of eolianite deposition on Rottnest Island, Western Australia |
title_full_unstemmed |
Stratigraphy and timing of eolianite deposition on Rottnest Island, Western Australia |
title_sort |
stratigraphy and timing of eolianite deposition on rottnest island, western australia |
publisher |
Cambridge University Press (CUP) |
publishDate |
2003 |
url |
http://dx.doi.org/10.1016/s0033-5894(03)00063-2 http://api.elsevier.com/content/article/PII:S0033589403000632?httpAccept=text/xml http://api.elsevier.com/content/article/PII:S0033589403000632?httpAccept=text/plain https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033589400012436 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Quaternary Research volume 60, issue 2, page 211-222 ISSN 0033-5894 1096-0287 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1016/s0033-5894(03)00063-2 |
container_title |
Quaternary Research |
container_volume |
60 |
container_issue |
2 |
container_start_page |
211 |
op_container_end_page |
222 |
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1801380048498851840 |