Metasomatism and self-organization of dolerite dyke-marble contacts; Beinn an Dubhaich, Skye

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doi: 10.1046/j.1525-1314.2000.00244.x
Authors:Holness, M. B.
Author Affiliations:Primary:
University of Cambridge, Department of Earth Sciences, Cambridge, United Kingdom
Volume Title:Journal of Metamorphic Geology
Source:Journal of Metamorphic Geology, 18(1), p.103-118. Publisher: Blackwell, Oxford, United Kingdom. ISSN: 0263-4929
Publication Date:2000
Note:In English. 36 refs.; illus., incl. 7 tables, geol. sketch map
Summary:Dolerite dykes which intrude dolomitic marble in the aureole of the Benin an Dubhaich granite have developed metasomatized margins close to the contact with the granite in the southern part of Torrin Quarry. These margins display well-defined mineralogical zones which can be divided into two groups on the basis of composition. Chlorite-bearing margins display the sequence dolerite/diopside + spinel/chlorite + calcite + magnetite/olivine + calcite + spinel/dolomite, whereas phlogopite-bearing sequences have a phlogopite+calcite ± fluorapatite layer in place of the chlorite-bearing layer. No spatial pattern is seen in the distribution of the two margin types, but textural and compositional evidence point to the importance of metasomatism by localized infiltration of magmatic fluids in the development of the phlogopite-bearing sequences. Extensive patterning of the phlogopite-bearing margins by a process of self-organization during grain growth has resulted in the formation of alternating silicate-only/calcite-only layers parallel to the dyke margin on a mm to cm scale. Early development of chlorite-bearing sequences at the dolerite-dolomite contact during contact metamorphism was followed by metasomatism-controlled growth of phlogopite and patterning at, or after, the peak of metamorphism associated with the expulsion of aqueous fluids from the crystallizing pluton. [P.J.T.]
Subsections:Metamorphism: thermal, metasomatic
Subjects:Contact metamorphism; Diabase; Dikes; Granites; Igneous rocks; Intrusions; Marbles; Metamorphic rocks; Metamorphism; Metasomatism; Mica group; Mineral assemblages; Phlogopite; Plutonic rocks; Sheet silicates; Silicates; Europe; Great Britain; Hebrides; Highland region Scotland; Inner Hebrides; Inverness-shire Scotland; Isle of Skye; Scotland; United Kingdom; Western Europe
Coordinates:N570000 N574000 W0054000 W0064500
Abstract Numbers:01M/994
Record ID:2000034617
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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