SHRIMP U-Pb zircon geochronology of granites from Sansom Island, Prydz Bay, East Antarctica

Sansom Island consists of two low nunataks in Sandefjord Bay, a marginal gulf of Prydz Bay, East Antarctica. These nunataks are composed of two kinds of undeformed biotite granites, and these granites have been dated by ion-microprobe U-Pb zircon geochronology. The zircons from these two samples yield SHRIMP zircon U-Pb concordant ages of 516±5 Ma and 495.8±4.2 Ma, respectively. The results indicate that these granites were emplaced in two pulses in the Cambrian, and further demonstrates the Pan-African event that has overprinted this area. The age of ca. 516 Ma suggests that the undeformed Sansom Island Granite had a different geological history from the Landing Bluff Granite, which contains deformed granite xenoliths dated at ca. 503 Ma, and probably indicates regional variations in the age and intensity of deformation. Citation : Cui Y C, Liu X C, Liu C G, et al. SHRIMP U-Pb zircon geochronology of granites from Sansom Island, Prydz Bay, East Antarctica. Adv Polar Sci, 2018, 29 (2): 135-143, doi:10.13679/j.advps.2018.2.00135