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GEOREF RECORD

The gabbro-dyke transition zone demonstrated on Tviberg, Solund-Stavfjord ophiolite complex

K. P. Skjerlie and H. Furnes
The gabbro-dyke transition zone demonstrated on Tviberg, Solund-Stavfjord ophiolite complex
Geological Magazine (September 1996) 133 (5): 573-582

Abstract

On the island of Tviberg, off W Norway, the transition zone between gabbro and dykes is complicated due to several different lithologies with different and complex contact relationships. The fine-grained to pegmatitic rocks of the plutonic complex vary in composition from Fe-Ti basaltic to quartz dioritic, and the felsic varieties are produced by fractional crystallization of basaltic magma. Patches of fractionated dioritic rocks may show both gradual and intrusive relationships with the surrounding host gabbro, showing that late-stage liquids commonly left the source region and locally intruded the surrounding parent rocks. The high-level plutonic rocks are cut by dykes of granoblastic epidote and quartz and are associated with irregular bodies of plagioclase-porphyritic diabase with a high MgO content; these diabase bodies either represent early local intrusions of the first magma to fill the magma chamber or are the lower part of dykes. The plutonic complex locally shows intrusive relationships with the overlying 100% dyke complex, but is itself cut by two dyke swarms; dykes of both swarms carry large quantities of glomeroporphyritic aggregates of plagioclase and altered clinopyroxene, indicating that the source area of the dykes intermittently was a crystal mush.


ISSN: 0016-7568
EISSN: 1469-5081
Coden: GEMGA4
Serial Title: Geological Magazine
Serial Volume: 133
Serial Issue: 5
Title: The gabbro-dyke transition zone demonstrated on Tviberg, Solund-Stavfjord ophiolite complex
Affiliation: Geologisk Institut, Bergen University, Bergen, Norway
Pages: 573-582
Published: 199609
Text Language: English
Publisher: Cambridge University Press, London, United Kingdom
References: 22
Accession Number: 1997-010789
Categories: Igneous and metamorphic petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. geol. sketch map
N58°00'00" - N71°00'00", E04°00'00" - E31°00'00"
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United KingdomTwickenhamUKUnited Kingdom
Update Code: 199704
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