Stratigraphic and Geochemical Expression of Early Cretaceous Environmental Change in Arctic Svalbard
The Arctic is climatically sensitive to global change and therefore climate records from this region are of key importance. Little, however, is known of the state of the Arctic in the traditionally “greenhouse” period of the Cretaceous. Climate conditions are often assumed to have been warm-temperat...
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ftunivplympearl:oai:pearl.plymouth.ac.uk:10026.1/10041 2023-05-15T14:48:23+02:00 Stratigraphic and Geochemical Expression of Early Cretaceous Environmental Change in Arctic Svalbard Vickers, Madeleine Larissa Price, Gregory Faculty of Science and Engineering 2017 http://hdl.handle.net/10026.1/10041 en eng University of Plymouth 10472477 http://hdl.handle.net/10026.1/10041 2018-10-10T14:53:33Z 12 months Stratigraphy Palaeoclimate Geochemistry Sedimentology Early Cretaceous PhD Thesis Doctorate 2017 ftunivplympearl 2021-03-09T18:35:26Z The Arctic is climatically sensitive to global change and therefore climate records from this region are of key importance. Little, however, is known of the state of the Arctic in the traditionally “greenhouse” period of the Cretaceous. Climate conditions are often assumed to have been warm-temperate as evidenced by the presence of conifers and dinosaur trackways on Svalbard and other Arctic localities. However, isotopic evidence for cooling episodes, sequence stratigraphic evidence for interpreted glacio-eustatic sea-level falls, and the presence of more enigmatic deposits such as dropstones and glendonites has led to a re-evaluation of the question of climatic dynamism during the Cretaceous. This project evaluates the climatic and environmental character of Arctic Svalbard during the Early Cretaceous (palaeo-latitude of c. 65 °N), via a multiproxy sedimentological, geochemical, sequence- and chemo- stratigraphic study of Berriasian–Albian strata from the Central Basin of Svalbard. The “outsized clasts” recorded on Spitsbergen do not show evidence that they were rafted by glacial ice (e.g. surface striations), although could have been rafted by seasonal sea-ice. The results show that regionally widespread cold water conditions were the most likely control on ikaite formation and glendonite preservation. This counters recent studies that suggest a methane-seep driver for Mesozoic glendonites, and supports the global extent of Valanginian to Hauterivian and Late Aptian global cooling. Surface temperatures during cool episodes of < 14 °C, as implied by the presence of glendonites at the seafloor, are consistent with Polar (90 °N) temperatures being below freezing (even given reduced pole-to-equator temperature gradients). This study therefore supports the hypothesis that small polar ice-caps developed during the Valanginian – Hauterivian and Late Aptian cooling events. Thesis Arctic Sea ice Svalbard Spitsbergen PEARL (Plymouth Electronic Archiv & ResearchLibrary, Plymouth University) Arctic Svalbard Central Basin ENVELOPE(43.000,43.000,73.500,73.500) |
institution |
Open Polar |
collection |
PEARL (Plymouth Electronic Archiv & ResearchLibrary, Plymouth University) |
op_collection_id |
ftunivplympearl |
language |
English |
topic |
Stratigraphy Palaeoclimate Geochemistry Sedimentology Early Cretaceous PhD |
spellingShingle |
Stratigraphy Palaeoclimate Geochemistry Sedimentology Early Cretaceous PhD Vickers, Madeleine Larissa Stratigraphic and Geochemical Expression of Early Cretaceous Environmental Change in Arctic Svalbard |
topic_facet |
Stratigraphy Palaeoclimate Geochemistry Sedimentology Early Cretaceous PhD |
description |
The Arctic is climatically sensitive to global change and therefore climate records from this region are of key importance. Little, however, is known of the state of the Arctic in the traditionally “greenhouse” period of the Cretaceous. Climate conditions are often assumed to have been warm-temperate as evidenced by the presence of conifers and dinosaur trackways on Svalbard and other Arctic localities. However, isotopic evidence for cooling episodes, sequence stratigraphic evidence for interpreted glacio-eustatic sea-level falls, and the presence of more enigmatic deposits such as dropstones and glendonites has led to a re-evaluation of the question of climatic dynamism during the Cretaceous. This project evaluates the climatic and environmental character of Arctic Svalbard during the Early Cretaceous (palaeo-latitude of c. 65 °N), via a multiproxy sedimentological, geochemical, sequence- and chemo- stratigraphic study of Berriasian–Albian strata from the Central Basin of Svalbard. The “outsized clasts” recorded on Spitsbergen do not show evidence that they were rafted by glacial ice (e.g. surface striations), although could have been rafted by seasonal sea-ice. The results show that regionally widespread cold water conditions were the most likely control on ikaite formation and glendonite preservation. This counters recent studies that suggest a methane-seep driver for Mesozoic glendonites, and supports the global extent of Valanginian to Hauterivian and Late Aptian global cooling. Surface temperatures during cool episodes of < 14 °C, as implied by the presence of glendonites at the seafloor, are consistent with Polar (90 °N) temperatures being below freezing (even given reduced pole-to-equator temperature gradients). This study therefore supports the hypothesis that small polar ice-caps developed during the Valanginian – Hauterivian and Late Aptian cooling events. |
author2 |
Price, Gregory Faculty of Science and Engineering |
format |
Thesis |
author |
Vickers, Madeleine Larissa |
author_facet |
Vickers, Madeleine Larissa |
author_sort |
Vickers, Madeleine Larissa |
title |
Stratigraphic and Geochemical Expression of Early Cretaceous Environmental Change in Arctic Svalbard |
title_short |
Stratigraphic and Geochemical Expression of Early Cretaceous Environmental Change in Arctic Svalbard |
title_full |
Stratigraphic and Geochemical Expression of Early Cretaceous Environmental Change in Arctic Svalbard |
title_fullStr |
Stratigraphic and Geochemical Expression of Early Cretaceous Environmental Change in Arctic Svalbard |
title_full_unstemmed |
Stratigraphic and Geochemical Expression of Early Cretaceous Environmental Change in Arctic Svalbard |
title_sort |
stratigraphic and geochemical expression of early cretaceous environmental change in arctic svalbard |
publisher |
University of Plymouth |
publishDate |
2017 |
url |
http://hdl.handle.net/10026.1/10041 |
long_lat |
ENVELOPE(43.000,43.000,73.500,73.500) |
geographic |
Arctic Svalbard Central Basin |
geographic_facet |
Arctic Svalbard Central Basin |
genre |
Arctic Sea ice Svalbard Spitsbergen |
genre_facet |
Arctic Sea ice Svalbard Spitsbergen |
op_relation |
10472477 http://hdl.handle.net/10026.1/10041 |
op_rights |
2018-10-10T14:53:33Z 12 months |
_version_ |
1766319467706449920 |