Mixing of supernatant and interstitial fluids in the Rhum layered intrusion

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Authors:Young, I. M.
Author Affiliations:Primary:
Univ. St. Andrews, Dep. Geol., Fife, United Kingdom
Volume Title:origin of the igneous rocks of the Tertiary igneous province
Volume Authors:Walsh, J. N., editor
Source:Mineralogical Magazine, 48 Part 3(348), p.345-350; Thematic meeting of the Mineralogical Society of Great Britain ; The origin of the igneous rocks of the Tertiary igneous province, United Kingdom, May, 1983, edited by J. N. Walsh. Publisher: Mineralogical Society, London, United Kingdom. ISSN: 0026-461X
Publication Date:1984
Note:In English. 21 refs.; illus. incl. 1 table
Summary:An alternative explanation for the occurrence of chrome-spinel layers in the Eastern Layered Series of the Rhum intrusion is suggested by extreme concentrations of chrome-spinel in small-scale structures in the layer at the unit 7-8 boundary (Brown, 1956). These take the form of downward pointing cones several centimetres across and deep, and lined or wholly filled with chrome-spinel; lamination in the underlying allivalite exhibits quaquaversal dips around these cones. By comparing these structures to fluid escape structures in clastic sediments, it is proposed that spinel is the product of mixing and reaction of upward moving interstitial liquid and more primitive liquid newly emplaced in the chamber. Further evidence for the presence of a second liquid during spinel crystallization is provided by spherical silicate inclusions within spinel grains. Complex zoning in feldspars in the underlying allivalite suggests that the newly emplaced primitive liquid was able to penetrate the crystal mush on the intrusion floor. [R.A.H.]
Subjects:Chemical composition; Chrome spinel; Chromite; Fluid phase; Intrusions; Layered intrusions; Magmas; Minerals; Oxides; Petrography; Petrology; Europe; Great Britain; Hebrides; Highland region Scotland; Inner Hebrides; Inverness-shire Scotland; Rhum; Scotland; United Kingdom; Western Europe; Evolution
Coordinates:N565500 N570500 W0061500 W0063500
Abstract Numbers:84M/4360
Record ID:1985028200
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Abstract, Copyright, Mineralogical Society of Great Britain and Ireland
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