New constraints on metamorphism in the Highjump Archipelago, East Antarctica

Naomi M. Tucker, Martin Hand

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)

Abstract

The age and conditions of metamorphism in the Highjump Archipelago, East Antarctica, are investigated using samples collected during the 1986 Australian Antarctic expedition to the Bunger Hills-Denman Glacier region. In situ U-Pb dating of monazite from three metasedimentary rocks yields ages between c. 1240-1150 Ma and a weighted mean 207Pb/206Pb age of 1183±8 Ma, consistent with previous constraints on the timing of metamorphism in this region and Stage 2 of the Albany-Fraser Orogeny in south-Western Australia. This age is interpreted to date the development of garnet ± sillimanite ± rutile-bearing assemblages that formed at c. 850-950°C and 6-9 kbar. Peak granulite facies metamorphism was followed by decompression, evidenced largely by the partial replacement of garnet by cordierite. These new pressureerature determinations suggest that the Highjump Archipelago attained slightly higher temperature and pressure conditions than previously proposed and that the rocks probably experienced a clockwise pressureerature evolution.

Original languageEnglish
Pages (from-to)487-503
Number of pages17
JournalAntarctic Science
Volume28
Issue number6
DOIs
Publication statusPublished - 1 Dec 2016
Externally publishedYes

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