Refined model of incremental emplacement based on structural evidence from the granodioritic Newry igneous complex, Northern Ireland

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dc.contributor.author Anderson, P. E.
dc.contributor.author Stevenson, C. T.
dc.contributor.author Cooper, M. R.
dc.contributor.author Meighan,I. G.
dc.contributor.author Reavy, R. John
dc.contributor.author Hurley, C. T.
dc.contributor.author Inman, J.
dc.contributor.author Ellam, R. M.
dc.date.accessioned 2018-02-06T13:36:28Z
dc.date.available 2018-02-06T13:36:28Z
dc.date.issued 2017
dc.identifier.citation P.E. Anderson, C.T. Stevenson, M.R. Cooper, I.G. Meighan, R.J. Reavy, C.T. Hurley, J. Inman, R.M. Ellam (2017) 'Refined model of incremental emplacement based on structural evidence from the granodioritic Newry igneous complex, Northern Ireland', Geological Society of America Bulletin. (17pp). doi: 10.1130/B31756.1 en
dc.identifier.startpage 1
dc.identifier.endpage 17
dc.identifier.issn 0016-7606
dc.identifier.uri http://hdl.handle.net/10468/5391
dc.identifier.doi 10.1130/B31756.1
dc.description.abstract Although many intrusions are now known to have been incrementally emplaced, the mechanisms through which this takes place are generally poorly understood. The Newry igneous complex was incrementally emplaced within the Southern Uplands-Down-Longford terrane of Northern Ireland during late Caledonian sinistral transtension. This study uses a variety of new and existing data and techniques to provide a fuller and firmer understanding of incremental emplacement than has previously been available, addressing both deep-crustal processes and those operating within the emplacement site. Host-rock orientations suggest that some of the accommodation space for the Newry igneous complex was generated due to pull-apart tectonics operating within the Southern Uplands-Down-Longford terrane. Local host-rock deflections, concentric igneous foliations, and concentric linear anisotropy of magnetic susceptibility (AMS)fabrics show that inflation due to magma overpressure also generated significant space. Strong AMS fabrics close to the boundaries of some magma pulses in turn suggest that inflation was accomplished by injection of individual magma pulses and was thus incremental. The dome-like orientations of mineral foliations within plutons and the truncation of steep local host-rock tracts by the Newry igneous complex imply that the complex consists of four laccolithic bodies. On a larger scale, it is suggested that the deep-seated Argyll and Newry lineaments represent faults that allowed magma generated at depth to ascend to the crustal level of the Southern Uplands-Down-Longford tract boundaries. It is also inferred that sinistral movement along the Argyll and Newry lineaments may have produced the releasing bend within the Southern Uplands-Down-Longford terrane. Higher in the crust, reduced confining pressure resulted in tectonic opening along this releasing bend. This local stress field induced horizontal magma flow and emplacement of the Newry igneous complex as laccolithic bodies. This study suggests that simplistic emplacement models should largely be abandoned in favor of holistic models incorporating the multiple interdependent processes operating during magma ascent and emplacement. en
dc.description.sponsorship Natural Environment Research Council (NE/H525038/1) en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher Geological Society of America en
dc.relation.uri https://pubs.geoscienceworld.org/gsa/gsabulletin/article/522698
dc.rights © 2017, the Authors. Gold Open Access: This paper is published under the terms of the CC-BY license en
dc.subject Southern Uplands-Down-Longford terrane en
dc.subject Granodioritic Newry igneous complex en
dc.subject magnetic susceptibility en
dc.title Refined model of incremental emplacement based on structural evidence from the granodioritic Newry igneous complex, Northern Ireland en
dc.type Article (peer-reviewed) en
dc.internal.authorcontactother j.reavy@ucc.ie en
dc.internal.availability Full text available en
dc.description.version Published Version en
dc.contributor.funder Geological Survey of Northern Ireland
dc.contributor.funder Scottish Universities Environmental Research Centre
dc.contributor.funder Natural Environment Research Council
dc.description.status Peer reviewed en
dc.identifier.journaltitle Geological Society of America Bulletin en
dc.internal.IRISemailaddress John Reavy, Biological, Earth and Environmental Sciences, University College Cork, Cork, Ireland. +353-21-490-3000 Email: j.reavy@ucc.ie en


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