Magma Ascent along a Major Terrane Boundary: Crustal Contamination and Magma Mixing at the Drumadoon Intrusive Complex, Isle of Arran, Scotland
2009 (English)In: Journal of Petrology, ISSN 0022-3530, E-ISSN 1460-2415, Vol. 50, no 12, 2345-2374 p.Article in journal (Refereed) Published
The composite intrusions of Drumadoon and An Cumhann crop outon the SE coast of the Isle of Arran, Scotland and form partof the larger British and Irish Palaeogene Igneous Province,a subset of the North Atlantic Igneous Province. The intrusions(shallow-level dykes and sills) comprise a central quartz–feldspar-phyricrhyolite flanked by xenocryst-bearing basaltic andesite, withan intermediate zone of dark quartz–feldspar-phyric dacite.New geochemical data provide information on the evolution ofthe component magmas and their relationships with each other,as well as their interaction with the crust through which theytravelled. During shallow-crustal emplacement, the end-membermagmas mixed. Isotopic evidence shows that both magmas werecontaminated by the crust prior to mixing; the basaltic andesitemagma preserves some evidence of contamination within the lowercrust, whereas the rhyolite mainly records upper-crustal contamination.The Highland Boundary Fault divides Arran into two distinctterranes, the Neoproterozoic to Early Palaeozoic Grampian Terraneto the north and the Palaeozoic Midland Valley Terrane to thesouth. The Drumadoon Complex lies within the Midland ValleyTerrane but its isotopic signatures indicate almost exclusiveinvolvement of Grampian Terrane crust. Therefore, although themagmas originated at depth on the northern side of the HighlandBoundary Fault, they have crossed this boundary during theirevolution, probably just prior to emplacement.
Place, publisher, year, edition, pages
2009. Vol. 50, no 12, 2345-2374 p.
Arran; Palaeogene Igneous Province; crustal contamination; magma mixing; Sr isotopes; Nd isotopes; assimilation; Highland Boundary Fault
Research subject Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
IdentifiersURN: urn:nbn:se:uu:diva-119245DOI: 10.1093/petrology/egp081ISI: 000273704800007OAI: oai:DiVA.org:uu-119245DiVA: diva2:299895