The metamorphic evolution of mafic rocks in the Tugela Terrane, Natal Belt, South Africa

被引:6
作者
Bisnath, A. [1 ]
McCourt, S. [2 ]
Frimmel, H. E. [3 ]
Buthelezi, S. B. N. [2 ]
机构
[1] Council Geosci, Pietermaritzburg, South Africa
[2] Univ KwaZulu Natal, Sch Geol Sci, Durban, South Africa
[3] Univ Cape Town, Dept Geol Sci, ZA-7701 Rondebosch, South Africa
关键词
D O I
10.2113/gssajg.111.4.369
中图分类号
P5 [地质学];
学科分类号
0709 ; 081803 ;
摘要
New petrological and mineral chemical data indicate a clockwise P-T path for medium- to high-grade metamorphic mafic rocks in different thrust sheets of the Tugela Terrane within the Mesoproterozoic Natal Belt in KwaZulu-Natal (eastern South Africa). There metamorphic stages are distinguished: (i) an early upper amphibolite- to lower granulite-facies metamorphic event (M(1)) is indicated by rare relies of clinopyroxene: (ii) mineral chemical and textural equilibration during M(2) at calculated pressure-temperature condition of 4.5 to 6 kbar and 693 to 750 degrees C; and (iii) partial diffusional resetting of mineral compositions during subsequent uplift and exhumation (M(3)) under lower amphibolite- to greenschist-facies conditions. No major differences were noted in the tectono-thermal regimes at which each of the respective thrust sheets were deformed suggesting the Tugela Terrane was a homogenous package and experience uniform P-T conditions. The new data acquired in this study contribute to an improvement in the ongoing development of a tectono-thermal and geodynamic model for the Natal Belt.
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页码:369 / 386
页数:18
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