Seismic stratigraphy of the Adare Trough area, Antarctica

• Published in: Marine Geology
• Main Authors: Whittaker, J, Muller, RD
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier Science Bv 2006
• Subjects: Earth Sciences; Geology; Marine Geoscience; Adare; Adare Basin; Adare Trough; Antarctic; Antarctic Peninsula; Cape Adare; Ross Sea; Weddell; Weddell Sea; West Antarctica; Antarc*; Antarctica; Sea ice
• Online Access: https://doi.org/10.1016/j.margeo.2006.05.002; http://ecite.utas.edu.au/84446

The Adare Trough, located 100 km NE of Cape Adare, Antarctica, is the extinct third arm of a Tertiary spreading ridge thatseparated East from West Antarctica. We use seismic reflection data, tied to DSDP Site 274, to link our seismic stratigraphicinterpretation to changes in ocean-bottom currents, Ross Sea ice cover, and regional tectonics through time. Two extendedunconformities are observed in the seismic profiles. We suggest that the earliest hiatus (early Oligocene to Mid-Miocene) is relatedto low sediment supply from the adjacent Ross Shelf, comprised of small, isolated basins. The later hiatus (mid-Miocene to lateMiocene) is likely caused by strong bottom currents sourced from the open-marine Ross Sea due to increased Antarctic glaciationinduced by mid-Miocene cooling (from Mi-3). Further global cooling during the Pliocene, causing changes in global oceancirculation patterns, correlates with Adare Basin sediments and indicate the continuing but weakened influence of bottom currents.The contourite/turbidite pattern present in the Adare Trough seismic data is consistent with the 3-phase contourite growth systemproposed for the Weddell Sea and Antarctic Peninsula. Multibeam bathymetry and seismic reflection profiles show ubiquitousvolcanic cones and intrusions throughout the Adare Basin that we interpret to have formed from the Oligocene to the present.Seismic reflection profiles reveal trans-tensional/strike-slip faults that indicate oblique extension dominated Adare Trough tectonicsat 3215 Ma. Observed volcanism patterns and anomalously shallow basement depth in the Adare Trough area are most likelycaused by mantle upwelling, an explanation supported by mantle density reconstructions, which show anomalously hot mantlebeneath the Adare Trough area forming in the Late Tertiary.