Zonation and emplacement of the Newry igneous complex, Nothern Ireland

[摘要] The Newry Igneous Complex (NIC) in Northern Ireland comprises three largely granodioritic plutons, together with an intermediate-ultramafic body at its northeast end. Geochronology shows that the NIC becomes broadly younger to the southwest and towards the centres of individual plutons. Geophysical results from the recent Tellus Survey of Northern Ireland have been combined with petrology and geochemistry to establish 17 distinct zones within the NIC, which are interpreted to represent separately intruded magma pulses. A combination of Anisotropy of Magnetic Susceptibility (AMS), petrographical and field data shows that the NIC was emplaced as a series of laccoliths into a tension-releasing bend on a strike-slip fault. This regime is proposed to have been facilitated by two deep-seated crustal lineaments. Inflation is suggested to have occurred due to magma pressure during emplacement of each individual zone. At least five constituent parts of the NIC are interpreted to have been emplaced separately at successively higher crustal levels. Thus the intrusion is thought to represent a series of stacked laccoliths, produced by a southwestward migrating source.

[发布机构] University:University of Birmingham;Department:School of Geography, Earth and Environmental Sciences

[关键词] G Geography. Anthropology. Recreation;G Geography (General)