Sr isotope data for the Tertiary lavas of Northern Ireland; evidence for open system petrogenesis

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doi: 10.1144/gsjgs.151.5.0869
Authors:Wallace, J. M.; Ellam, R. M.; Meighan, I. G.; Lyle, P.; Rogers, N. W.
Author Affiliations:Primary:
Queen's University, School of Geosciences, Belfast, United Kingdom
Scottish Universities Research and Reactor Centre, United Kingdom
University of Ulster at Jordanstown, United Kingdom
Open University at Milton Keynes, United Kingdom
Volume Title:Journal of the Geological Society of London
Source:Journal of the Geological Society of London, Vol.151(Part 5), p.869-877. Publisher: Geological Society of London, London, United Kingdom. ISSN: 0016-7649
Publication Date:1994
Note:In English. 41 refs.; illus., incl. 3 tables, geol. sketch maps
Summary:New 87Sr/86Sr data for 41 Tertiary rocks from this largest remnant of the British Tertiary igneous province, by virtue of extreme variation, are considered to provide evidence of extensive open system behaviour in the petrogenesis of the flood basalts. To some extent the initial 87Sr/86Sr ratios record the effects of late-stage hydrothermal processes, but leaching experiments allow primary magmatic signatures to be inferred. Coherent increases in initial 87Sr/86Sr ratio with differentiation indices and incompatible trace element ratios imply a role for crustal contamination. Very significant differences in the style of crustal interaction are shown by discrete units within the basalt pile; there are also marked contrasts with Tertiary basalts elsewhere in the United Kingdom. In both cases, such variations appear to respond to changes in the basement geology, reflecting the important control of crustal wall-rocks on the geochemistry of these basalts. [R.A.H.]
Subjects:Absolute age; Alkaline earth metals; Ar-40/Ar-39; Argon; Basalts; Cenozoic; Chemical composition; Dates; Genesis; Igneous rocks; Isotope ratios; Isotopes; Lava; Metals; Neodymium; Noble gases; Open systems; Petrology; Radioactive isotopes; Rare earths; Sr-87/Sr-86; Stable isotopes; Strontium; Tertiary; Trace elements; Volcanic rocks; Antrim Northern Ireland; Europe; Northern Ireland; United Kingdom; Western Europe; Antrim Lava Group; British Tertiary igneous province; Initial neodymium
Abstract Numbers:95M/571
Record ID:1995035202
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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