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Lewisian complex
About: Lewisian complex is a research topic. Over the lifetime, 258 publications have been published within this topic receiving 9083 citations.
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TL;DR: In this article, ion microprobe zircon geochronology for three samples from the late Archaean Lewisian gneiss complex at Gruinard Bay, northwestern Scotland, in an attempt to resolve the discrepancy between SmNd and Pb-Pb isochron ages for trondhjemite and hornblendite components.
303 citations
TL;DR: In this article, the authors describe the metamorphic history of two areas of Lewisian gneiss in the North-West Highlands of Scotland and describe the first time from the Loch Torridon area.
Abstract: Summary The paper describes the metamorphic history of two areas of Lewisian gneiss in the North-West Highlands of Scotland. Metamorphosed sedimentary rocks are described for the first time from the Loch Torridon area. It is shown that both in the Loch Torridon and the Scourie districts the gneisses have been produced in two separate periods of metamorphism, migmatization and deformation. These two metamorphic episodes, which are named the Scourian and Laxfordian episodes, are separated in time by a period of uplift and tension during which a series of uniform dolerite dykes was intruded. Since a very great interval of time appears to have elapsed between the two metamorphic episodes, it is suggested that the rocks produced during these episodes should be regarded as members, not of a single formation as heretofore, but of two distinct chronological units.
301 citations
TL;DR: Lead isotope ratios, together with uranium and lead analyses, are reported for thirty-seven whole rock samples from the Precambrian Lewisian basement complex of Northwest Scotland as discussed by the authors, which can help to decide whether a given crustal segment represents essentially juvenile addition of material from the upper mantle, or reworked older crust.
260 citations
TL;DR: The early Proterozoic Loch Maree Group (LMG) of the Lewisian complex consists of a supracrustal sequence of metasedimentary schists and associated tholeiitic metavolcanic amphibolites within the Archaean basement.
256 citations
TL;DR: In this paper, isotope systematics of Lewisian gneisses from North-west Scotland suggest that their igneous calc-alkaline precursors separated from previously undifferentiated mantle 2,920±50 Myr ago.
Abstract: Sm—Nd isotope systematics of Lewisian gneisses from North-west Scotland suggest that their igneous calc-alkaline precursors separated from previously undifferentiated mantle 2,920±50 Myr ago. Approximately 200 Myr elapsed before this material was finally differentiated and stabilised as granulite and amphibolite fades crust.
241 citations