U-Pb geochronology of Lewisian orthogneisses in the Outer Hebrides, Scotland; implications for the tectonic setting and correlation of the South Harris Complex

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doi: 10.1144/0016-764902-140
Authors:Mason, A. J.; Parrish, R. R.; Brewer, T. S.
Author Affiliations:Primary:
University of Leicester, Department of Geology, Leicester, United Kingdom
NERC Isotope Geoscience Laboratory (NIGL), United Kingdom
Volume Title:Journal of the Geological Society of London
Source:Journal of the Geological Society of London, Vol.161(Part 1), p.45-54. Publisher: Geological Society of London, London, United Kingdom. ISSN: 0016-7649
Publication Date:2004
Note:In English. 54 refs.; illus., incl. 1 table, geol. sketch maps
Summary:The South Harris Complex of the Scottish Outer Hebrides forms a distinctive component of the Lewisian Complex and contains three supposedly co-magmatic meta-igneous bodies, a diorite, a "norite" and an anorthosite, believed to be part of a Palaeoproterozoic arc. New U-Pb zircon ages obtained from these bodies of 1888±2 Ma, 1890 +2/-1 Ma, and 2491 +31/-27 Ma, respectively, demonstrate that the anorthosite cannot be related to the younger calc-alkaline diorite and "norite". The diorite and "norite", however, probably are related products of arc magmatism. The spatial association of the diorite and "norite" with the substantially older anorthosite suggests that the younger intrusions were emplaced into continental crust. Any suture associated with the South Harris Complex remains cryptic, and is not marked by an obvious change in protolith ages in the adjacent tonalitic gneisses.
Sections:Age determination; Petrology
Subsections:Igneous petrology
Subjects:Absolute age; Anorthosite; Archean; Dates; Diorites; Gabbros; Geochronology; Gneisses; Igneous rocks; Lewisian; Lewisian Complex; Metamorphic rocks; Nesosilicates; Norite; Orthosilicates; Paleoproterozoic; Pb/Pb; Plutonic rocks; Precambrian; Proterozoic; Protoliths; Silicates; Tectonics; Titanite; Titanite group; Tonalite; U/Pb; Upper Precambrian; Zircon; Zircon group; Europe; Great Britain; Hebrides; Outer Hebrides; Scotland; United Kingdom; Western Europe; South Harris Complex
Coordinates:N564500 N583000 W0061000 W0080000
Abstract Numbers:04M/550
Record ID:2004023606
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from The Geological Society, London, London, United Kingdom
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