Mid-Jurassic age for the Botany Bay Group: implications for Weddell Sea Basin creation and southern hemisphere biostratigraphy

New U–Pb zircon ion-microprobe ages from the alluvial conglomerates and flood plain sediments of the Botany Bay Group demonstrate that sedimentation occurred at c. 167 Ma, coeval with rift-related silicic volcanism in the northern Antarctic Peninsula. In contrast, rift-related volcanism and sediment...

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Bibliographic Details
Published in:Journal of the Geological Society
Main Authors: Hunter, Morag A., Cantrill, David J., Flowerdew, Michael J., Millar, Ian L.
Format: Article in Journal/Newspaper
Language:unknown
Published: Geological Society of London 2005
Subjects:
Earth Sciences
Antarctic
Antarctic Peninsula
Botany Bay
Latady
The Antarctic
Weddell
Weddell Sea
Antarc*
Online Access:http://nora.nerc.ac.uk/id/eprint/1818/
Description
Summary:New U–Pb zircon ion-microprobe ages from the alluvial conglomerates and flood plain sediments of the Botany Bay Group demonstrate that sedimentation occurred at c. 167 Ma, coeval with rift-related silicic volcanism in the northern Antarctic Peninsula. In contrast, rift-related volcanism and sedimentation in the southern Antarctic Peninsula (Latady Basin) occurred at c. 183 Ma. The new data indicate that syn-rift sedimentation and volcanism was diachronous from south to north, consistent with early opening of the Weddell Sea embayment by anti-clockwise rotation of the Antarctic Peninsula in the Mid-Jurassic. A definitive date for the Botany Bay Group floras has important implications for Southern Hemisphere biostratigraphic correlations.

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