SUP18229T1.csv (3.12 kB)

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

Download (3.12 kB)
posted on 21.06.2016 by Morag A. Hunter, David J. Cantrill, Michael J. Flowerdew, Ian L. Millar

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.