U-Pb and Rb-Sr geochronology of magmatism and metamorphism in the Dalradian of Connemara, western Ireland

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doi: 10.1144/gsjgs.153.1.0109
Authors:Cliff, R. A.; Yardley, B. W. D.; Bussy, F. R.
Author Affiliations:Primary:
University of Leeds, Department of Earth Sciences, Leeds, United Kingdom
Other:
Université de Lausanne, Switzerland
Volume Title:Journal of the Geological Society of London
Source:Journal of the Geological Society of London, Vol.153 (Part 1), p.109-120. Publisher: Geological Society of London, London, United Kingdom. ISSN: 0016-7649
Publication Date:1996
Note:In English. 59 refs.; illus., incl. 3 tables, geol. sketch map
Summary:U-Pb zircon data on four intermediate to acid foliated magmatic rocks show important inherited components, but the most concordant fractions demonstrate that major magmatism continued in this area until 465 m.y., whereas the earliest basic magmatism had been dated previously at 490 m.y. Arc magmatism in Connemara therefore spanned a period of ≥ 25 m.y. Recent U-Pb data on titanite from central Connemara are supplemented by U-Pb data on titanite and monazite from metamorphic veins in E Connemara which indicate that low-P, high-T regional metamorphism continued there to 465 m.y., i.e. at least 10 m.y later than in the central region dated previously. New Rb-Sr data on muscovites from coarse-grained segregations range from 475 to 435 m.y., with three ages close to 455 m.y. in the E of the area which is also the site of the lowest-P metamorphism. Thermal modelling indicates that at any one locality the duration of metamorphism was probably as little as 1-2 m.y. The new dates emphasize the complexity in the spatial and temporal distribution of high-level regional metamorphism caused by magmatic activity. [R.A.H.]
Subjects:Absolute age; Actinides; Alkali metals; Alkaline earth metals; Dalradian; Dates; Lead; Magmas; Magmatic associations; Metals; Metamorphism; Rb/Sr; Rubidium; Strontium; U/Pb; Uranium; Connemara; Europe; Galway Ireland; Ireland; Western Europe; Western Ireland
Coordinates:N531500 N534000 W0090000 W0102000
Abstract Numbers:96M/1310
Record ID:1996050147
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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