Geologic observations across a tectono-metamorphic boundary in the Babangu area, Giyani (Sutherland) greenstone belt, South Africa

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doi: 10.1016/0301-9268(92)90018-J
Authors:de Wit, Maarten J.; van Reenen, Dirk D.; Roering, Chris
Author Affiliations:Primary:
Univ. Cape Town, Rondebosch, South Africa
Other:
Univ. Cape Town, South Africa
Rand Afrikaans Univ., South Africa
Volume Title:Special issue; The Archaean Limpopo granulite belt; tectonics and deep crustal processes
Volume Authors:van Reenen, Dirk D., editor; Ashwal, L. D.; de Wit, Maarten J.
Source:Precambrian Research, 55(1-4), p.111-122; Granulites and deep crustal tectonics, June 21-July 1, 1990, edited by Dirk D. van Reenen, Chris Roering, L. D. Ashwal and Maarten J. de Wit. Publisher: Elsevier, Amsterdam, International. ISSN: 0301-9268
Publication Date:1992
Note:In English. 9 refs. Geol. map 1:27,500; illus. incl. 2 tables, sect., sketch maps
Summary:A narrow corridor across the tectono-metamorphic transition between 'low-grade' and 'high-grade' granite-greenstone terrains, respectively, from the Giyani greenstone belt into the hydrated granulites of the S marginal zone of the Limpopo belt, has been mapped in detail. The two terrains are separated by a sharp tectonic (mylonitic) break. The low-grade greenstone terrain to the S of this break is part of a S-dipping flattened antiformal thrust-stack, and is thus probably allochthonous. The greenstone belt may lie on a flattish S-dipping sole-thrust,lubricated by synkinematic granitic rocks in the foot and hanging walls. The N margin of the greenstones is abruptly terminated by a late, steeply oriented shear zone, defined by mylonites. N of the shear zone high-grade granite-greenstone terrain rocks (hydrated granulites) have been juxtaposed against and across the low-grade greenstone terrain. The tectonic break is either part of a transcurrent fault or a lateral ramp as part of a late S-directed overthrust system. Although the rocks of the low-grade terrain have retained their early tectonic fabrics, their metamorphic character more reflects that of the overriding hydrated granulites. [R.E.S.]
Subjects:Electron probe data; Fabric; Geologic maps; Granites; Granulites; Greenstone; High-grade metamorphism; Igneous rocks; Low-grade metamorphism; Maps; Metamorphic rocks; Metamorphism; Plutonic rocks; Schists; Structural geology; Tectonics; Terrains; Africa; South Africa; Southern Africa; Babangu; Giyani greenstone belt; Sutherland greenstone belt; Geologic map
Abstract Numbers:93M/1146
Record ID:1992015354
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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