Megacrysts and associated xenoliths; evidence for migration of geochemically enriched melts in the upper mantle beneath Scotland

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doi: 10.1093/petrology/40.6.935
Authors:Upton, B. G. J.; Hinton, R. W.; Aspen, P.; Finch, A. A.; Valley, John W.
Author Affiliations:Primary:
Edinburgh University, Department of Geology and Geophysics, Edinburgh, United Kingdom
Other:
Luton University, United Kingdom
University of Wisconsin, United States
Volume Title:Journal of Petrology
Source:Journal of Petrology, 40(6), p.935-956. Publisher: Clarendon Press, Oxford, United Kingdom. ISSN: 0022-3530
Publication Date:1999
Note:In English. 69 refs.; illus., incl. 6 tables, geol. sketch map
Summary:Megacrysts, mainly anorthoclase, Fe-rich biotite, clinopyroxene, magnetite, zircon and apatite, occur in Scottish alkaline basalts, mostly of Carboniferous to Permian age, both as discrete and composite assemblages including syenite (anorthoclasite) xenoliths which were pegmatite veins traversing pyroxenitic wall-rocks in the shallow mantle. The anorthoclasites crystallized from highly trace element enriched melts which at their extremes were also peraluminous with corundum and Nb-rich oxides including ilmenorutile. The syenitic facies crystallized from felsic melts of metasomatized mantle lithologies with the peraluminous nature resulting from loss of alkalies to fugitive carbonatite fractions. Major, trace and REE plus some O isotope data (for silicates and zircon) are given for anorthoclase, sanidine, corundum, clinopyroxene, biotite, apatite and the Nb oxides, columbite, yttro-niobate and samarskite. [B.E.L.]
Sections:Geochemistry
Subsections:Igneous rocks
Subjects:Alkalic composition; Basalts; Geochemistry; Igneous rocks; Inclusions; Lithogeochemistry; Mantle; Megacrysts; Melts; Metals; Plutonic rocks; Rare earths; Syenites; Upper mantle; Volcanic rocks; Xenoliths; Europe; Great Britain; Scotland; United Kingdom; Western Europe
Abstract Numbers:00M/1777
Record ID:1999051831
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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