Caledonian transpressional terrane accretion along the Laurentian margin in Co. Mayo, Ireland

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doi: 10.1144/gsjgs.152.5.0797
Authors:Harris, D. H. M.
Author Affiliations:Primary:
University of Keele, Department of Geology, Keele, United Kingdom
Volume Title:Journal of the Geological Society of London
Source:Journal of the Geological Society of London, Vol.152(Part 5), p.797-806. Publisher: Geological Society of London, London, United Kingdom. ISSN: 0016-7649
Publication Date:1995
Note:In English. 49 refs.; illus., incl. block diags., 1 table, geol. sketch maps
Summary:The Highland Border-Fair Head-Clew Bay-Baie Verte-Brompton Suture (Clew Bay Suture) on Achill Island, western Ireland is an E-W-trending zone of vertical, ductile dextral transpression bounding the southern edge of the Dalradian terrane. The Achill Dalradian, a sequence of coarse-grained psammite overlain by conglomerate, quartzite, schist and limestone, disposed in recumbent curvilinear folds, represents Laurentian continental margin deposits which were translated westward during deformation, parallel to the suture trace. Studies of fabric development and albite porphyroblast growth indicate that E-W dextral transpression and west-directed recumbent folding were synchronous, and are interpreted as separate expressions of the same NW-directed terrane impingement event. This process of terrane-docking was marked by a c. 4 kbar phase of decompression. Within the suture, four separate terrane-slivers are recognized. The presence of pyrope-garnet and crossite-amphibole within two imply the Clew Bay Zone experienced sufficient displacement of exhume rocks from deep lithospheric-levels. In addition, the extensive retrogression and destruction suffered by these remnant high pressure mineral assemblages during the albite-generating transpressional phase, implies that ductile deformation was enhanced by the introduction of fluid into and along the suture zone during impingement.
Subjects:Accretion; Caledonian Orogeny; Dalradian; Deformation; Faults; Folds; Laurentia; Paleozoic; Plate tectonics; Terranes; Transpression; Europe; Ireland; Mayo Ireland; Western Europe; Achill Island
Abstract Numbers:96M/951
Record ID:1996011181
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data supplied by Institute of Geological and Nuclear Sciences Limited (GNS Science), Lower Hutt, New Zealand
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