The Leka ophiolite complex, central Norwegian Caledonides; field characteristics and geotectonic significance

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doi: 10.1144/gsjgs.145.3.0401
Authors:Furnes, H.; Pedersen, R. B.; Stillman, C. J.
Author Affiliations:Primary:
Geol. Inst., Bergen, Norway
Other:
Trinity Coll., United Kingdom
Volume Title:Journal of the Geological Society of London
Source:Journal of the Geological Society of London, Vol.145(Part 3), p.401-412. Publisher: Geological Society of London, London, United Kingdom. ISSN: 0016-7649
Publication Date:1988
Note:In English. 49 refs.; illus. incl. 1 table, sects., chart, geol. sketch maps
Summary:This ophiolite complex of Lower Ordovician age on the island of Leka and its neighbouring islets, W Norway, contains: 1) a lower, strongly deformed harzburgite unit, representing depleted upper mantle; 2) a sequence of ultramafic cumulates overlying the harzburgite tectonite; 3) layered metagabbros, grading upwards to laminated and vari-textured metagabbro which contains 4) metabasalt dykes, increasing upwards from single dykes to a sheeted dyke complex with 5) pillow lavas associated with thick volcaniclastic sediments at apparently higher stratigraphic levels. Geochemically, the metabasalt dykes and pillow lavas range from predominant island arc tholeiite to MORB character: typical boninites are also present. It is considered that the first stages in the formation of the Leka complex was by spreading above a subduction zone. The pillow lavas are of MORB or within-plate basalt type, and these probably represent the later spreading stages of the complex in a back-arc basin. [R.A.H.]
Subjects:Alkali basalts; Basalts; Deformation; Igneous rocks; Lower Ordovician; Ophiolite; Ordovician; Paleozoic; Petrology; Plutonic rocks; Structural geology; Tectonics; Ultramafics; Volcanic rocks; Europe; Norway; Scandinavia; Western Europe; Leka; Leka Ophiolite Complex
Abstract Numbers:89M/1055
Record ID:1988057544
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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