Geodynamic model for the Weddell Sea using aeromagnetic and palaeomagnetic data

• Main Author: König, Matthias
• Format: Conference Object
• Language: unknown
• Published: 2003
• Subjects: Antarctic; Antarctic Peninsula; Argentina; Byrd; Dronning Maud Land; Lazarev; Riiser-Larsen; Riiser-Larsen Sea; The Antarctic; Thurston; Thurston Island; Weddell; Weddell Sea; Antarc*; Antarctica
• Online Access: https://epic.awi.de/id/eprint/10076/; https://hdl.handle.net/10013/epic.20571

The results of a new aeromagnetic compilation for the Weddell , Lazarev and Riiser-Larsen Sea, joining the EMAGE (East-Antarctic Margin Aeromagnetic and Gravity Experiment, Jokat et al. 2003), USAC (U.S. Argentina Chile, LaBrecque et al. 1989) and shipborne magnetic data from the NGDC (National Geophysical Data Center, Boulder, Colorado), give refined constraints on the early development of the Weddell Sea and adjacent areas during the initial stages of Gondwana break-up.Clear coast parallel sea floor spreading anomalies off the west coast of Dronning Maud Land and another pattern of clearly discernible spreading anomalies in the Riiser-Larsen Sea could be used for magnetic modelling. This led to a well constrained age model from the beginning of seafloor spreading in the Riiser-Larsen Sea at ca. 155 Ma and the eastern Weddell Sea at about 144 Ma to the final separation of South America from Africa about 130 Ma ago. The linear trend of the magnetic anomalies together with their detailed age determination allowed the calculation of new rotation poles for the times when Antarctica and Africa began to drift away from their Early Jurassic position within Gondwana and South America and Antarctica separated through the opening of the Weddell Sea.For the Early Jurassic no constraints on the position of East- and West-Gondwana (Antarctica, Madagascar, India, Australia and South America, Africa) and the West Antarctic microplates (Antarctic Peninsula - AP, Ellsworth-Withmore Mountains block,Thurston Island block, Mary Byrd Land) can be derived from magnetic seafloor spreading anomalies since no ocean floor exists from this period. For these times palaeomagnetic pole positions give the best information about palaeogeography.Palaeomagnetic poles from Grunow (1993, 1999) show relative movements of the Antarctic Peninsula and the other West-Antarctic microplates just prior and during the early opening of the Weddell Sea. In these models the AP forms the southern continuation of the Permo-Triassic subduction zone of South ...