A metamorphic perspective on the Pan African overprint in the Amery area of Mac Robertson Land, East Antarctica

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Authors:Scrimgeour, Ian; Hand, Martin
Author Affiliations:Primary:
University of Adelaide, Department of Geology and Geophysics, Adelaide, South Aust., Australia
Volume Title:Antarctic Science
Source:Antarctic Science, 9(3), p.313-335. Publisher: Blackwell, Oxford, United Kingdom. ISSN: 0954-1020
Publication Date:1997
Note:In English. 74 refs.; illus., incl. 5 tables, sketch maps
Summary:The Amery area of Mac. Robertson Land lies between the early Palaeozoic granulite terrain of Prydz Bay and Meso-Neoproterozoic granulites in northern Prince Charles Mountains (nPCM). In contrast to the nPCM which shows an apparently simple near-isobaric history, granulites exposed in the Amery area contain reaction textures suggesting a more complex evolution. Peak-M1 Mesoproterozoic assemblages formed at c. 700 MPa and 800°C and initially underwent a near-isobaric cooling. A subsequent increase in temperature (M2) resulted in the formation of cordierite-spinel assemblages at ca. 450 MPa and 700°C in metapelite. The timing of M2 is not firmly established, however existing data strongly suggest it is an early Palaeozoic event coeval with tectonism in Prydz Bay to the northeast. Thus the metamorphic evolution of granulites in the Amery area reflects a terrain-scale thermal interference pattern between two unrelated orogenic events. (Auth. mod.)
Subjects:Decompression; Granulites; Lower Paleozoic; Mesoproterozoic; Metamorphic rocks; Metamorphism; Metapelite; Metasedimentary rocks; Mineral assemblages; Overprinting; P-T conditions; Paleozoic; Pan-African Orogeny; Petrography; Precambrian; Proterozoic; Textures; Upper Precambrian; Antarctica; East Antarctica; Mac Robertson Land
Abstract Numbers:98M/1037
Record ID:1998001474
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from the Antarctic Bibliography, United States
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