Universität zu Köln

Kroener, Alfred, Hoffmann, J. Elis ORCID: 0000-0001-6670-1393, Xie, Hangqiang, Wu, Fuyuan, Muenker, Carsten, Hegner, Ernst, Wong, Jean, Wan, Yusheng and Liu, Dunyi (2013). Generation of early Archaean felsic greenstone volcanic rocks through crustal melting in the Kaapvaal, craton, southern Africa. Earth Planet. Sci. Lett., 381. S. 188 - 198. AMSTERDAM: ELSEVIER SCIENCE BV. ISSN 1385-013X

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Abstract

High-potassium felsic volcanic rocks interlayered with basalt and komatiite in early Archaean greenstone sequences in the Barberton Greenstone Belt of South Africa and Swaziland, previously considered to be derived from melting of mafic precursors, are shown to be the result of melting of significantly older felsic crust. This is documented by a combination of SHRIMP zircon dating with Hf-in-zircon and whole-rock Lu-Hf and Sm-Nd isotopic data. Zircons from felsic rocks of the oldest Barberton unit, the 3.53 Ga Theespruit Formation, yielded predominantly negative epsilon(Hf(t))-values, whereas whole-rock epsilon(Hf(t))- and epsilon(Nd(t))-data are slightly negative to slightly positive. Similar results were obtained for ca. 3.45 Ga felsic rocks in the Hoeggenoog and Noisy Formations higher up in the greenstone stratigraphy. These data rule out derivation of the felsic units from melting of basaltic precursors and favor a crustal source, most likely of TTG composition. The isotopic data are not compatible with an entirely oceanic origin of the Barberton greenstone sequences and favor a pre-greenstone basement beneath the volcanic rocks. Crustal melting of Eo- to Paleoarchaean lower crust probably generated the felsic volcanic rocks and is likely to have been responsible for gradual stabilization of the Kaapvaal craton. (C) 2013 Elsevier B.V. All rights reserved.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Kroener, Alfred UNSPECIFIED UNSPECIFIED UNSPECIFIED Hoffmann, J. Elis UNSPECIFIED orcid.org/0000-0001-6670-1393 UNSPECIFIED Xie, Hangqiang UNSPECIFIED UNSPECIFIED UNSPECIFIED Wu, Fuyuan UNSPECIFIED UNSPECIFIED UNSPECIFIED Muenker, Carsten UNSPECIFIED UNSPECIFIED UNSPECIFIED Hegner, Ernst UNSPECIFIED UNSPECIFIED UNSPECIFIED Wong, Jean UNSPECIFIED UNSPECIFIED UNSPECIFIED Wan, Yusheng UNSPECIFIED UNSPECIFIED UNSPECIFIED Liu, Dunyi UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-472531
DOI:	10.1016/j.epsl.2013.08.029
Journal or Publication Title:	Earth Planet. Sci. Lett.
Volume:	381
Page Range:	S. 188 - 198
Date:	2013
Publisher:	ELSEVIER SCIENCE BV
Place of Publication:	AMSTERDAM
ISSN:	1385-013X
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language ANCIENT GNEISS COMPLEX; S-TYPE GRANITES; HF-ISOTOPE; U-PB; CONTINENTAL-CRUST; PILBARA CRATON; ZIRCON AGES; BELT; EVOLUTION; ND Multiple languages Geochemistry & Geophysics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/47253