Skip to Main Content
Book Chapter

Archean magmatic granulites, diapirism, and Proterozoic reworking in the Northern Marginal Zone of the Limpopo Belt

By
T.G. Blenkinsop
T.G. Blenkinsop
School of Earth and Environmental Science, James Cook University, Townsville QLD 4811, Australia
Search for other works by this author on:
Published:
February 01, 2011

The Northern Marginal Zone (NMZ) of the Limpopo Belt, southern Africa, is a high-grade gneiss belt dominated by magmatic granulites of the charnoenderbite suite, which intruded minor mafic-ultramafic and metasedimentary rocks between 2.74 and 2.57 Ga. The intrusive rocks have crustal and mantle components, and occur as elliptical bodies interpreted as diapirs. Peak metamorphism (P ≤800 MPa, T = 800–850 °C) occurred at ca. 2.59 Ga. The highly radiogenic nature of the rocks in the NMZ, supplemented by heat from mantle melts, led to heating and diapirism, culminating in the intrusion of distinctive porphyritic charnockites and granites. Horizontal shortening and steep extrusion of the NMZ, during which crustal thickening was limited by high geothermal gradients, contrast with overthickening and gravitational collapse observed particularly in more recent orogens. The granulites were exhumed by the end of the Archean. The pervasive late Archean shortening over the whole of the NMZ contrasts with limited deformation on the Zimbabwe Craton, possibly owing to the strengthening effect of early crust in the craton. In the southeast of the NMZ, strike-slip kinematic indicators occur within the Transition Zone and the Triangle Shear Zone, where dextral shearing reworked the Archean crust at ca. 1.97 Ga.

You do not currently have access to this article.

Figures & Tables

Contents

GSA Memoirs

Origin and Evolution of Precambrian High-Grade Gneiss Terranes, with Special Emphasis on the Limpopo Complex of Southern Africa

Dirk D. van Reenen
Dirk D. van Reenen
Department of Geology, University of Johannesburg, Auckland Park, South Africa
Search for other works by this author on:
Jan D. Kramers
Jan D. Kramers
Department of Geology, University of Johannesburg, and School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa
Search for other works by this author on:
Stephen McCourt
Stephen McCourt
School of Geological Sciences, University of KwaZulu Natal, Durban, South Africa
Search for other works by this author on:
Leonid L. Perchuk
Leonid L. Perchuk
Department of Petrology, Moscow State University, and the Institute of Experimental Mineralogy, Russian Academy of Sciences, Chernogolovka, Moscow District, Russia
Search for other works by this author on:
Geological Society of America
Volume
207
ISBN print:
9780813712079
Publication date:
February 01, 2011

References

Related

Citing Books via

Related Articles
Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal