Has the formation of a slab window below the Antarctic Peninsula controlled its topographic evolution?
Twinn, Gary Peter (2024) Has the formation of a slab window below the Antarctic Peninsula controlled its topographic evolution? PhD thesis, Birkbeck, University of London.
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Abstract
This thesis presents apatite (U-Th)/He and apatite fission-track thermochronology data to understand spatial and temporal changes in rock uplift and exhumation along and across the Antarctic Peninsula to determine how and when its high elevation developed. This is important to test tectonic models and to understand the elevation history as a precursor to ice nucleation and expansion in the Cenozoic. Easterly-directed subduction of the Phoenix Plate, including ridge-trench collisions, has been taking place along its western margin since the Late Cretaceous. Data from four east-west transects show how cooling rates varied with distance from the trench as well as with respect to the timing of the ridge-trench collisions on a south-north basis. Eastern Palmer Land preserves a record of uplift during the Late Cretaceous that coincides with changes in Phoenix Plate convergence rates and direction. In contrast, western Palmer Land and Alexander Island experienced a period of increased rates of cooling between c. 25 and 15 Ma. This younger phase of exhumation is bounded by major fault zones related to the extension and rifting that formed the present-day George VI Sound. It was probably triggered by cessation of subduction owing to trench collision of a ridge segment NE of the Heezen fracture zone. Samples from Adelaide Island and the Trinity Peninsula show a similar period of cooling during the Late Cretaceous but recent cooling is consistent with the onset of glaciation in Antarctica. Patterns of cooling show no evidence for the influence of a slab window in any part of the region.
Metadata
| Item Type: | Thesis |
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| Copyright Holders: | The copyright of this thesis rests with the author, who asserts his/her right to be known as such according to the Copyright Designs and Patents Act 1988. No dealing with the thesis contrary to the copyright or moral rights of the author is permitted. |
| Depositing User: | Acquisitions And Metadata |
| Date Deposited: | 12 Mar 2024 17:58 |
| Last Modified: | 13 Mar 2024 13:26 |
| URI: | https://eprints.bbk.ac.uk/id/eprint/53226 |
| DOI: | https://doi.org/10.18743/PUB.00053226 |
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