This award, provided by the Office of Polar Programs of the National Science Foundation, supports an international collaborative research project involving New Mexico Institute of Mining and Technology, USA, and the British Antarctic Survey (BAS). The objective is to understand the origin, emplacement, and evolution of Jurassic (180 million year old) basaltic rocks in Antarctica which formed when the Gondwana supercontinent started to disintegrate. The research team will test a new unified model for this 180 million year magmatic activity in which the magmatism is caused by a single mantle superplume and is a major factor in continental rifting. Within Antarctica, the Jurassic basaltic rocks are divided into two provinces: Ferrar Large Igneous Province (FLIP) and the Dronning Maud Igneous Province (DMIP) (the official US name for Dronning Maud Land is Queen Maud Land - the foreign term will be used for purposes here because the project is collaborative with BAS). The origin of the FLIP is problematical and a plume origin has generally been discounted because of its lateral distribution over 3000 km along the Transantarctic Mountains and also in southern Australia. The FLIP is characterized by unusual geochemical compositions, which has been attributed to their origin from an enriched mantle source. In the model being investigated by this research team, the FLIP magma would have been significantly contaminated in an upper continental crustal magma chamber (probably the Dufek Intrusion) whereas the DMIP has distinctly mantle-like chemical characteristics but still shows some evidence of modification by crustal material. In this research, the team will examine and sample the rocks of the DMIP and rocks of the FLIP in the Theron and Pensacola Mountains and Dronning Maud Land. The team will conduct an integrated study of the age, geochemistry, and structural relationships of the FLIP and DMIP. Radiometric age determinations will examine the age relationship between the FLIP and DMIP. Models for upper crustal contamination of the FLIP magmas will be tested using isotopic studies and geochemical modeling. Other studies, conducted by BAS collaborators, include a regional aerogeophysical survey to determine the size and shape of the Dufek Intrusion and a detailed survey will search for a feeder dike system from the body.
