Metamorphic evolution of the Maud Belt:: P-T-t path for high-grade gneisses in Gjelsvikfjella, Dronning Maud land, East Antarctica

被引:19
作者
Bisnath, A [1 ]
Frimmel, HE [1 ]
机构
[1] Univ Cape Town, Dept Geol Sci, ZA-7701 Cape Town, South Africa
关键词
Maud Belt; Gjelsvikfjella; Pan-African orogeny; P-T-t path; East Antarctica;
D O I
10.1016/j.jafrearsci.2005.09.007
中图分类号
P [天文学、地球科学];
学科分类号
07 ;
摘要
A metamorphic petrological study, in conjunction with recent precise geochronometric data, revealed a complex P-T-t path for high-grade gneisses in a hitherto poorly understood sector of the Mesoproterozoic Maud Belt in East Antarctica. The Maud Belt is all extensive high-grade, polydeformed, metamorphic belt, which records two significant tectono-thermal episodes, once towards the end of the Mesoproterozoic and again towards the late Neoproterozoic/Cambrian. In contrast to previous models, most of the metamorphic mineral assemblages are related to a Pan-African tectono-thermal overprint, with only very few relics of late Mesoproterozoic granulite-facies mineral assemblages (M-1) left in strain-protected domains. Petrological and mineral chemical evidence indicates a clockwise P-T-t path for the Pan-African orogeny. Peak metamorphic (M-2b) conditions recorded by most rocks in the area (T = 709-785 degrees C and P = 7.0-9.5 kbar) during the Pan-African orogeny were attained subsequent to decompression from probably eclogite-facies metamorphic conditions (M-2a). The new data acquired in this Study, together with recent geochronological and geochemical data, permit the development of a geodynamic model for the Maud Belt that involves volcanic arc formation during the late Mesoproterozoic followed by extension at 1100 Ma and subsequent high-grade tectono-thermal reworking once during continent-continent collision at the end of the Mesoproterozoic (M-1; 1090-1030 Ma) and again during the Pan-African orogeny (M-2a, M-2b) between 565 and 530 Ma. Post-peak metamorphic K-metasomatism under amphibolite-facies conditions (M-2c) followed and is ascribed to post-orogenic bimodal magmatism between 500 and 480 Ma. (c) 2005 Elsevier Ltd. All rights reserved.
引用
收藏
页码:505 / 524
页数:20
相关论文
共 73 条
[1]   SUBDUCTION AND EDUCTION OF CONTINENTAL-CRUST - MAJOR MECHANISMS DURING CONTINENT-CONTINENT COLLISION AND OROGENIC EXTENSIONAL COLLAPSE, A MODEL BASED ON THE SOUTH NORWEGIAN CALEDONIDES [J].
ANDERSEN, TB ;
JAMTVEIT, B ;
DEWEY, JF ;
SWENSSON, E .
TERRA NOVA, 1991, 3 (03) :303-310
[2]  
Arima M., 2001, MEMORIAL NATL I POLA, V55, P1
[3]   U-PB ZIRCON AGE AND ND ISOTOPIC COMPOSITION OF GRANITOIDS, CHARNOCKITES AND SUPRACRUSTAL ROCKS FROM HEIMEFRONTFJELLA, ANTARCTICA [J].
ARNDT, NT ;
TODT, W ;
CHAUVEL, C ;
TAPFER, M ;
WEBER, K .
GEOLOGISCHE RUNDSCHAU, 1991, 80 (03) :759-777
[4]   Geochemical correlation between metasediments of the Mfongosi Group of the Natal sector of the Namaqua-Natal Metamorphic Province, South Africa and the Ahlmannryggen Group of the Grunehogna Province, Antarctica [J].
Basson, IJ ;
Perritt, S ;
Watkeys, MK ;
Menzies, AH .
GONDWANA RESEARCH, 2004, 7 (01) :57-73
[5]   Late mesoproterozoic arc and back-arc volcanism in the Heimefrontfjella (East Antarctica) and implications for the palaeogeography at the southeastern margin of the Kaapvaal-Grunehogna craton [J].
Bauer, W ;
Jacobs, J ;
Fanning, CM ;
Schmidt, R .
GONDWANA RESEARCH, 2003, 6 (03) :449-465
[6]   The neoproterozoic suture between east and west Gondwana - New results from central Dronning Maud Land, Antarctica [J].
Bauer, W ;
Jacobs, J .
GONDWANA RESEARCH, 2001, 4 (02) :147-149
[7]  
Bisnath A., 2004, AGE TECTONOTHERMAL E, P60
[8]   Pan-African tectonism in the Western Maud Belt:: P-T-t path for high-grade gneisses in the HU Sverdrupfjella, East Antarctica [J].
Board, WS ;
Frimmel, HE ;
Armstrong, RA .
JOURNAL OF PETROLOGY, 2005, 46 (04) :671-699
[9]  
Bucher K., 1994, PETROGENESIS METAMOR, P318, DOI 10.1007/978-3-662-03000-4
[10]   GRANULITES AND GRANET CORDIERITE GNEISSES FROM DRONNING MAUD LAND, ANTARCTICA [J].
BUCHERNURMINEN, K ;
OHTA, Y .
JOURNAL OF METAMORPHIC GEOLOGY, 1993, 11 (05) :691-703