Riley, Teal RR;
Millar, Ian LL;
Carter, Andrew;
Flowerdew, Michael JJ;
Burton-Johnson, Alex;
Bastias, Joaquin;
Storey, Craig DD;
... Whitehouse, Martin JJ; + view all
(2023)
Evolution of an Accretionary Complex (LeMay Group) and Terrane Translation in the Antarctic Peninsula.
Tectonics
, 42
(2)
, Article e2022TC007578. 10.1029/2022TC007578.
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Tectonics - 2023 - Riley - Evolution of an Accretionary Complex LeMay Group and Terrane Translation in the Antarctic.pdf - Published Version Download (8MB) | Preview |
Abstract
The LeMay Group accretionary complex of Alexander Island (Antarctic Peninsula) comprises a 4 km thick succession of variably deformed turbidites associated with thrust slices of ocean floor basalts. The depositional age and provenance of the succession is uncertain with estimates ranging from Carboniferous to Cretaceous. The accretion history is also poorly established and whether the LeMay Group developed allochthonously and accreted during an episode of Cretaceous terrane translation. We have examined the geochronology and geochemistry of 22 samples from across the entire accretionary complex to determine its depositional, provenance and accretion history. The accretionary complex has been subdivided into four separate groups based on detrital zircon U-Pb age and Lu-Hf provenance analysis. Groups 1 and 2 are interpreted to be a continuation of the extensive Permian accretionary complexes of West Gondwana and have a depositional age of c. 255 Ma, with volcaniclastic input from the extensive silicic volcanism of the Choiyoi Province. Accretion of the LeMay Group to the continental margin developed during the mid-Triassic, potentially related to the Peninsula Orogeny and an episode of flat-slab subduction of the proto-Pacific plate. Group 3 is only identified from an island to the west of Alexander Island and has a mid-Cretaceous depositional age and provenance akin to offshore sequences from Thurston Island. A para-autochthonous origin is suggested, with mid-Cretaceous accretion associated with the melange belts of central Alexander Island. Group 4 is also a distinct unit with an Early Jurassic depositional age and a source more closely related to the Antarctic Peninsula.
| Type: | Article |
|---|---|
| Title: | Evolution of an Accretionary Complex (LeMay Group) and Terrane Translation in the Antarctic Peninsula |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1029/2022TC007578 |
| Publisher version: | https://doi.org/10.1029/2022TC007578 |
| Language: | English |
| Additional information: | © Wiley Periodicals LLC. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited |
| Keywords: | Science & Technology, Physical Sciences, Geochemistry & Geophysics, Gondwana, detrital, zircon, U-Pb geochronology, Lu-Hf isotopes, U-PB AGES, NATURAL REFERENCE MATERIAL, CENTRAL ALEXANDER ISLAND, WEST ANTARCTICA, LU-HF, SOUTHWESTERN GONDWANA, ISOTOPE SYSTEMATICS, ELLSWORTH MOUNTAINS, DETRITAL ZIRCONS, TRACE-ELEMENT |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10171241 |
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