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SHRIMP U-Pb zircon and Sm-Nd garnet ages from the granulite-facies basement of SE Kenya; evidence for Neoproterozoic polycyclic assembly of the Mozambique Belt

Christoph A. Hauzenberger, Holger Sommer, Harald Fritz, Andreas Bauernhofer, Alfred Kroener, Georg Hoinkes, Eckart Wallbrecher and Martin Thoeni
SHRIMP U-Pb zircon and Sm-Nd garnet ages from the granulite-facies basement of SE Kenya; evidence for Neoproterozoic polycyclic assembly of the Mozambique Belt
Journal of the Geological Society of London (January 2007) 164 (1): 189-201

Abstract

The Taita Hills-Galana River region is a key area to demonstrate the polycyclic nature of the Mozambique Belt in SE Kenya. On the basis of petrological and tectonic data, this area is composed of two different granulite-facies terranes, which are separated by the 20-30 km wide Galana Shear Zone. The Taita Hills and adjoining Sagala Hills exhibit a metamorphic overprint at 630-645 Ma, similar to areas in Tanzania. An emplacement age for the magmatic precursor rocks of 850-960 Ma was derived from zircon cores. Sm-Nd garnet-whole-rock analyses give an age of 585 Ma, interpreted as the cooling age after 630-645 Ma metamorphism. Nd crustal residence ages are between 1000 and 1500 Ma. The Galana Shear Zone east of the Taita Hills contains strongly deformed tonalitic migmatites with interlayered pegmatites that date a younger tectonometamorphic event at 560-580 Ma. East of the shear zone only a young metamorphic age of 550 Ma was found. The Nd model ages are c. 1500 Ma to c. 2900 Ma. In a continental configuration prior to Gondwana break-up our study area was located close to Madagascar, where several large shear zones are observed. One of these shear zones (Ranotsara Shear Zone) may be a continuation of the Galana Shear Zone.


ISSN: 0016-7649
EISSN: 2041-479X
Coden: JGSLAS
Serial Title: Journal of the Geological Society of London
Serial Volume: 164
Serial Issue: 1
Title: SHRIMP U-Pb zircon and Sm-Nd garnet ages from the granulite-facies basement of SE Kenya; evidence for Neoproterozoic polycyclic assembly of the Mozambique Belt
Affiliation: Universitaet Graz, Institut fuer Erdwissenschaften, Graz, Austria
Pages: 189-201
Published: 200701
Text Language: English
Publisher: Geological Society of London, London, United Kingdom
References: 56
Accession Number: 2007-008444
Categories: Igneous and metamorphic petrologyGeochronology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. geol. sketch maps, sect., 2 tables, anals.
S03°49'60" - S03°00'00", E38°10'00" - E38°49'60"
Secondary Affiliation: Universitaet Mainz, DEU, Federal Republic of GermanyUniversitaet Wien, AUT, Austria
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data from The Geological Society, London, London, United Kingdom
Update Code: 200704
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