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We applied SHRIMP zircon U-Pb age dating to ultrahigh-temperature (UHT) sapphirine-bearing orthopyroxene garnet (SOG) granulite and biotite-hornblende (Bt-Hbl) gneiss in the Schirmacher Hills, East Antarctica. In the Bt-Hbl gneiss, concordant ages of 657 ± 7.1 and 807 ± 9.1 Ma were obtained from zircon overgrowth rims and zircon cores, with oscillatory and irregular zoning, respectively. The zircon overgrowth rims (657 ± 7.1 Ma) with low Th/U ratios from the Bt-Hbl gneiss are interpreted as having a metamorphic origin. Oscillatory-zoned and/or irregularly zoned zircon cores may have crystallized during an igneous event at 807 ± 9.1 Ma; 800-Ma igneous events have not previously been recognized in central Dronning Maud Land (DML) inland nunatak. Zircons in the SOG granulite yielded a concordant age of 643 ± 6.5 Ma, using analyses of sector-zoned and simple-zoned grains. These zircons have relatively high Th/U ratios with a narrow range, and they occur in association with garnet breaking down to form cordierite. The 643 ± 6.5-Ma age obtained from these zircons is interpreted as the timing of crystallization from a high-Th/U partial melt soon after peak metamorphism. The combination of a ca. 800-Ma igneous age and 660-640-Ma metamorphic ages obtained from Schirmacher Hills is different from that of other neighboring parts of central DML. In addition, a metamorphic PT path involving ultrahigh temperatures at early and subsequent isobaric cooling (IBC) stages at around 650 Ma has not previously been known in the central DML nunatak region. The Ca. 650-Ma UHT metamorphic event probably occurred in a back-arc tectonic setting and predates the main collisional event of central DML (ca. 550-500 Ma). [ABSTRACT FROM AUTHOR]

The article presents a study on the age determination of the rare earth element (REE) distribution in Zircon from a granitoid sample from the Southern Prince Charles Mountains in Eastern Antarctica. It states that the presence of Ruker granite in the area indicates a series of felsic orthogneiss, metasedimentary and volcanic events. The researchers used a titanium geothermometer to estimate the crystallization temperature of zircon in the area. It concludes that the Sodruzhestva Series in the area was formed in the post-Archean time because signs of Archean - Paleoproterozoic tectonothermal processes are absent in the samples.