Host-rock deformation during the emplacement of the Mourne Mountains granite pluton: Insights from the regional fracture pattern
| العنوان: | Host-rock deformation during the emplacement of the Mourne Mountains granite pluton: Insights from the regional fracture pattern |
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| المؤلفون: | Mattsson, Tobias, Burchardt, Steffi, 1982, Mair, Karen, Place, Joachim |
| المصدر: | Geosphere. 16(1):182-209 |
| مصطلحات موضوعية: | Geovetenskap med inriktning mot mineralogi, petrologi och tektonik, Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics |
| الوصف: | The Mourne Mountains magmatic center in Northern Ireland consists offive successively intruded granites emplaced in the upper crust. The Mournegranite pluton has classically been viewed as a type locality of a magma bodyemplaced by cauldron subsidence. Cauldron subsidence makes space formagma through the emplacement of ring dikes and floor subsidence. However,the Mourne granites were more recently re-interpreted as laccoliths andbysmaliths. Laccolith intrusions form by inflation and dome their host rock.Here we perform a detailed study of the deformation in the host rock to theMourne granite pluton in order to test its emplacement mechanism. We use thehost-rock fracture pattern as a passive marker and microstructures in the contact-metamorphic aureole to constrain large-scale magma emplacement-relateddeformation. The dip and azimuth of the fractures are very consistent onthe roof of the intrusion and can be separated into four steeply inclined setsdominantly striking SE, S, NE, and E, which rules out pluton-wide doming. Incontrast, fracture orientations in the northeastern wall to the granites suggestshear parallel to the contact. Additionally, contact-metamorphic segregationsalong the northeastern contact are brecciated. Based on the host-rock fracturepattern, the contact aureole deformation, and the north-eastward–inclinedgranite-granite contacts, we propose that mechanisms involving either asymmetric“trap-door” floor subsidence or laccolith and bysmalith intrusion alongan inclined or curved floor accommodated the emplacement of the granitesand led to deflection of the northeastern wall of the intrusion. |
| وصف الملف: | electronic |
| URL الوصول: | https://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-396235 https://doi.org/10.1130/GES02148.1 https://uu.diva-portal.org/smash/get/diva2:1367050/FULLTEXT01.pdf |
| قاعدة البيانات: | SwePub |
| تدمد: | 20150393 |
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| DOI: | 10.1130/GES02148.1 |