Petrogenesis of Ordovician igneous rocks in the southern part of the Welsh Basin

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Authors:Bevins, R. E.; Lees, G. J.; Roach, R. A.
Author Affiliations:Primary:
National Musuem of Wales, Department of Geology, Cardiff, United Kingdom
Other:
British Geological Survey, United Kingdom
University of Keele, United Kingdom
Volume Title:Special issue on the Palaeozoic Welsh Basin
Volume Authors:Woodcock, N. H., editor; Fletcher, C. J. N.
Source:Geological Magazine, 129(5), p.615-624; Review meeting on the Welsh Basin, Aberystwyth, United Kingdom, Nov. 15-18, 1991, edited by N. H. Woodcock and C. J. N. Fletcher. Publisher: Cambridge University Press, London, United Kingdom. ISSN: 0016-7568
Publication Date:1992
Note:In English. 35 refs.; illus., incl. strat. col., geol. sketch map
Summary:During the early Ordovician, volcanic and high-level intrusive activity occurred at numerous centres across N Pembrokeshire. Previous work suggested a geochemical transition in this activity from calc-alkaline through to tholeiitic with time. However, new data indicate more extensive calc-alkaline magmatism and that both magma types were coeval. The origin of the calc-alkaline magmas remains equivocal, but the tholeiitic magmas appear to have been derived from a source similar to N-type MORB, variably modified by supra-subduction zone fluids, combined with some fractionation during ascent. These data are consistent with emplacement in a suprasubduction zone marginal basin. [Authors' abstract] [C.H.D.]
Subjects:Basins; Genesis; Geochemistry; Igneous rocks; Lithogeochemistry; Metals; Ordovician; Paleozoic; Rare earths; Sedimentary basins; Europe; Great Britain; Pembrokeshire Wales; United Kingdom; Wales; Welsh Basin; Western Europe; Aber Mawr Formation; Dyfed Wales; Fishguard volcanic complex; Igneous activity; Sealyham Group
Coordinates:N513000 N533000 W0024000 W0051500
Abstract Numbers:93M/3506
Record ID:1996005476
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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