Late Archaean granulite facies metamorphism in the Vestfold Hills, East Antarctica

AbstractThe 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 pressure–temperature determinations suggest that the Highjump Archipelago attained slightly higher temperature and pressure conditions than previously proposed and that the rocks probably experienced a clockwise pressure–temperature evolution.

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Granulite-Facies Metamorphism at Molodezhnaya Station, East Antarctica

Journal of Petrology ◽

10.1093/petrology/22.3.297 ◽

1981 ◽

Vol 22 (3) ◽

pp. 297-336 ◽

Cited By ~ 43

Author(s):

E. S. GREW

Keyword(s):

Granulite Facies ◽

East Antarctica ◽

Granulite Facies Metamorphism ◽

Facies Metamorphism

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Chlorine-rich fluid or melt activity during granulite facies metamorphism in the Late Proterozoic to Cambrian continental collision zone—An example from the Sør Rondane Mountains, East Antarctica

Precambrian Research ◽

10.1016/j.precamres.2012.10.006 ◽

2013 ◽

Vol 234 ◽

pp. 229-246 ◽

Cited By ~ 24

Author(s):

Fumiko Higashino ◽

Tetsuo Kawakami ◽

M. Satish-Kumar ◽

Masahiro Ishikawa ◽

Kenshi Maki ◽

...

Keyword(s):

Granulite Facies ◽

Continental Collision ◽

East Antarctica ◽

Granulite Facies Metamorphism ◽

Late Proterozoic ◽

Collision Zone ◽

Facies Metamorphism

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Dating of late Archaean crustal mobilisation north of Qugssuk, Godthåbsfjord, southern West Greenland

Rapport Grønlands Geologiske Undersøgelse ◽

10.34194/rapggu.v128.7922 ◽

1986 ◽

Vol 128 ◽

pp. 23-36

Author(s):

A.A Garde ◽

O Larsen ◽

A.P Nutman

Keyword(s):

Granulite Facies ◽

Isotopic Data ◽

Zircon Age ◽

Granulite Facies Metamorphism ◽

Late Archaean ◽

West Greenland ◽

Facies Metamorphism ◽

The Common

The Taserssuaq tonalite, which is slightly younger than or coeval with the common grey gneisses north of Godthåbsfjord, has yielded a zircon U-Pb age of 2982 ± 7 Ma, and an apparent Rb-Sr whole-rock age of 2882 ± 36 Ma (MSWD = 1.57, initial 87Sr/86Sr = 0.7017). The minerals were isotopicaIly equilibrated at 2500 Ma, and finally biotite was reset at 1700 Ma. The Qugssuk granite, an adjacent granitic mobilisate, has yielded a Rb-Sr age of 2969 ± 32 Ma (MSWD = 1.09, initial 87Sr/86Sr = 0.7020). The intrusion of the Taserssuaq tonalite is probably dated by its zircon age, which broadly correlates it with the Nilk gneisses. Field relations and microtextures strongly suggest that the Qugssuk granite is younger than the Taserssuaq tonalite and post-dates granulite facies metamorphism in the area, and its formation may be related to the extensive retrogression of the Taserssuaq tonalite. Isotopic data may support this interpretation in spite of the apparent inconsistencies in the age values.

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