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Zircon U-Pb Ages from an Ultra-High Temperature Metapelite, Rauer Group, East Antarctica: Implications for Overprints by Grenvillian and Pan-African Events

January 29, 2007

SHRIMP U-Pb dating of zircon from an ultra-high temperature (UHT, ~1000 °C) granulite-facies metapelite
from the Rauer Group, Mather Peninsula, east Antarctica, has yielded evidence for two episodes of metamorphic zircon
growth, at ~1.00 Ga and ~530 Ma, and two episodes of magmatism in the source region for the protolith sediment, at
~2.53 and ~2.65 Ga, were identified from the zircon cores. Successive zircon growth at ~1.00 Ga and ~530 Ma records
a sequence of distinct, widely spaced high-temperature metamorphic and/or anatectic events related to Grenvillian and
Pan-African orogenesis. This study presents the first robust geochronological evidence for the timing of UHT
metamorphism of the Rauer Group, supporting arguments that the peak UHT metamorphic event occurred at ~1.00 Ga
and was overprinted by a separate high-grade event at ~530 Ma. The new age data indicate that the UHT granulites of
the Rauer Group experienced a complex, multi-stage tectonothermal history, which cannot simply be explained via a
single Pan-African (~500 Ma) high-grade tectonic event. This is critical in understanding the role of the eastern Prydz
Bay region during the assembly of the east Gondwana supercontinent, and the newly recognized inherited Archaean
ages (~2.53 and ~2.65 Ga) suggest a close tectonic relationship between the Rauer Group and the adjacent Archaean of
the Vestfold Hills

Publication Year 2007
Title Zircon U-Pb Ages from an Ultra-High Temperature Metapelite, Rauer Group, East Antarctica: Implications for Overprints by Grenvillian and Pan-African Events
DOI 10.3133/ofr20071047SRP023
Authors Yanbin Wang, Laixi Tong, Dunyi Liu
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Open-File Report
Series Number 2007-1047-SRP-023
Index ID ofr20071047SRP023
Record Source USGS Publications Warehouse