Pleistocene uplift and palaeoenvironments of Macquarie Island: evidence from palaeobeaches and sedimentary deposits
Macquarie Island (54°30'S, 159°00'E) is an emergent part of the Macquarie Ridge Complex composed of ocean-floor rocks of Miocene age now 4000 m above the ocean floor. A number of landforms, including palaeobeaches now above sea level (a.s.l.)on Macquarie Island, were formed by marine erosi...
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ftunivtasmania:oai:eprints.utas.edu.au:14429 2023-05-15T17:09:54+02:00 Pleistocene uplift and palaeoenvironments of Macquarie Island: evidence from palaeobeaches and sedimentary deposits Adamson, DA Selkirk, PM Price, DM Ward, N Selkirk, JM 1996 application/pdf https://eprints.utas.edu.au/14429/ https://eprints.utas.edu.au/14429/4/1996-Adamson-Pleistocene.pdf en eng https://eprints.utas.edu.au/14429/4/1996-Adamson-Pleistocene.pdf Adamson, DA, Selkirk, PM, Price, DM, Ward, N and Selkirk, JM 1996 , 'Pleistocene uplift and palaeoenvironments of Macquarie Island: evidence from palaeobeaches and sedimentary deposits' , Papers and Proceedings of the Royal Society of Tasmania, vol. 130, no. 2 , pp. 25-32 , doi:10.26749/rstpp.130.2.25 <http://dx.doi.org/10.26749/rstpp.130.2.25>. cc_utas Royal Society of Tasmania RST Van Diemens Land natural history science ecology taxonomy botany zoology geology geography papers & proceedings Australia UTAS Library Article PeerReviewed 1996 ftunivtasmania https://doi.org/10.26749/rstpp.130.2.25 2020-05-30T07:28:10Z Macquarie Island (54°30'S, 159°00'E) is an emergent part of the Macquarie Ridge Complex composed of ocean-floor rocks of Miocene age now 4000 m above the ocean floor. A number of landforms, including palaeobeaches now above sea level (a.s.l.)on Macquarie Island, were formed by marine erosion during uplift of the island. During the last Pleistocene period of low sea level (c. 20 ka) the island was three times larger than now. Thermoluminescence (TL) dating of two palaeobeaches indicates Pleistocene ages: 172 ± 40 ka for one at 100 m a.s.l. and 340 ± 80 ka for another at 263 m a.s.l. Matching the altitude sequence of palaeobeaches on Macquarie Island with the pattern of peaks in world sea level determined from deep sea cores allows an independent estimate of beach ages. Comparison of the altitude and sea level sequences most plausibly places the 100 m palaeobeach in Oxygen Isotope Stage 5e (130-125 ka) and the 263 m palaeobeach in Stage 9 (340-330 ka), matching reasonably with the TL dates. Other palaeobeaches at about 50 m and 170-190 m a.s.l. then correlate with high sea levels. We calculate an average rate of uplift forthe island of 0.8 mma-I . At this rate, 4000 m of Macquarie Ridge uplift would have taken about five million years and the top of the island may first have emerged some 700 to 600 ka. During the six Pleistocene glacial-interglacial cycles since then, there has been periglacial rather than glacial activity on cold uplands, but conditions suitable for vegetation of the present type persisted close to sea level. Article in Journal/Newspaper Macquarie Island University of Tasmania: UTas ePrints Papers and Proceedings of the Royal Society of Tasmania 130 2 25 32 |
institution |
Open Polar |
collection |
University of Tasmania: UTas ePrints |
op_collection_id |
ftunivtasmania |
language |
English |
topic |
Royal Society of Tasmania RST Van Diemens Land natural history science ecology taxonomy botany zoology geology geography papers & proceedings Australia UTAS Library |
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Royal Society of Tasmania RST Van Diemens Land natural history science ecology taxonomy botany zoology geology geography papers & proceedings Australia UTAS Library Adamson, DA Selkirk, PM Price, DM Ward, N Selkirk, JM Pleistocene uplift and palaeoenvironments of Macquarie Island: evidence from palaeobeaches and sedimentary deposits |
topic_facet |
Royal Society of Tasmania RST Van Diemens Land natural history science ecology taxonomy botany zoology geology geography papers & proceedings Australia UTAS Library |
description |
Macquarie Island (54°30'S, 159°00'E) is an emergent part of the Macquarie Ridge Complex composed of ocean-floor rocks of Miocene age now 4000 m above the ocean floor. A number of landforms, including palaeobeaches now above sea level (a.s.l.)on Macquarie Island, were formed by marine erosion during uplift of the island. During the last Pleistocene period of low sea level (c. 20 ka) the island was three times larger than now. Thermoluminescence (TL) dating of two palaeobeaches indicates Pleistocene ages: 172 ± 40 ka for one at 100 m a.s.l. and 340 ± 80 ka for another at 263 m a.s.l. Matching the altitude sequence of palaeobeaches on Macquarie Island with the pattern of peaks in world sea level determined from deep sea cores allows an independent estimate of beach ages. Comparison of the altitude and sea level sequences most plausibly places the 100 m palaeobeach in Oxygen Isotope Stage 5e (130-125 ka) and the 263 m palaeobeach in Stage 9 (340-330 ka), matching reasonably with the TL dates. Other palaeobeaches at about 50 m and 170-190 m a.s.l. then correlate with high sea levels. We calculate an average rate of uplift forthe island of 0.8 mma-I . At this rate, 4000 m of Macquarie Ridge uplift would have taken about five million years and the top of the island may first have emerged some 700 to 600 ka. During the six Pleistocene glacial-interglacial cycles since then, there has been periglacial rather than glacial activity on cold uplands, but conditions suitable for vegetation of the present type persisted close to sea level. |
format |
Article in Journal/Newspaper |
author |
Adamson, DA Selkirk, PM Price, DM Ward, N Selkirk, JM |
author_facet |
Adamson, DA Selkirk, PM Price, DM Ward, N Selkirk, JM |
author_sort |
Adamson, DA |
title |
Pleistocene uplift and palaeoenvironments of Macquarie Island: evidence from palaeobeaches and sedimentary deposits |
title_short |
Pleistocene uplift and palaeoenvironments of Macquarie Island: evidence from palaeobeaches and sedimentary deposits |
title_full |
Pleistocene uplift and palaeoenvironments of Macquarie Island: evidence from palaeobeaches and sedimentary deposits |
title_fullStr |
Pleistocene uplift and palaeoenvironments of Macquarie Island: evidence from palaeobeaches and sedimentary deposits |
title_full_unstemmed |
Pleistocene uplift and palaeoenvironments of Macquarie Island: evidence from palaeobeaches and sedimentary deposits |
title_sort |
pleistocene uplift and palaeoenvironments of macquarie island: evidence from palaeobeaches and sedimentary deposits |
publishDate |
1996 |
url |
https://eprints.utas.edu.au/14429/ https://eprints.utas.edu.au/14429/4/1996-Adamson-Pleistocene.pdf |
genre |
Macquarie Island |
genre_facet |
Macquarie Island |
op_relation |
https://eprints.utas.edu.au/14429/4/1996-Adamson-Pleistocene.pdf Adamson, DA, Selkirk, PM, Price, DM, Ward, N and Selkirk, JM 1996 , 'Pleistocene uplift and palaeoenvironments of Macquarie Island: evidence from palaeobeaches and sedimentary deposits' , Papers and Proceedings of the Royal Society of Tasmania, vol. 130, no. 2 , pp. 25-32 , doi:10.26749/rstpp.130.2.25 <http://dx.doi.org/10.26749/rstpp.130.2.25>. |
op_rights |
cc_utas |
op_doi |
https://doi.org/10.26749/rstpp.130.2.25 |
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Papers and Proceedings of the Royal Society of Tasmania |
container_volume |
130 |
container_issue |
2 |
container_start_page |
25 |
op_container_end_page |
32 |
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1766066264450531328 |