Some aspects of Tertiary acid magmatism in NE Ireland

Abstract

ABSTRACT. Geochemical data (including REE determinations) are presented for all five Mourne Mountains granites and three Northern Ireland rhyolites. These confirm (1) the extremely fractionated nature of some of the rocks (Sr and Ba < 10 ppm, Rb > 400 ppm, Eu/Eu* < 0

The emplacement of the Palaeogene Mourne Granite Centres, Northern Ireland: new results from the Western Mourne Centre

“…Stevenson et al (2007b) outlined the key criteria that Richey (1928) used to invoke cauldron subsidence in this plutonic complex sensu Clough et al (1909). Revisions of Richey's (1928) original mapping in both centres (Emeleus 1955;Hood et al 1981;Meighan et al 1984) involved only minor modifications of Richey's original framework and the ring-dyke cauldron subsidence model persisted (for a summary see Cooper & Johnston 2004, pp. 182-187) until Stevenson et al (2007b) revealed magmatic fabrics in the Eastern Mourne granite using anisotropy of magnetic susceptibility (AMS) measurements.…”

“…1) and heralded the breakup of North America and Eurasia c. 55 Ma (Jolley & Bell 2002). The Mourne Granites are anorogenic and the granitic melt formed by fractionation of basalts derived from plume-driven mantle melting under intact continental lithosphere (Meighan et al 1984;Kent & Fitton 2000) but, as has been shown for other British and Irish Palaeogene Igneous Province centres, may have had melt contributions from crustal contamination sources (e.g. Geldmacher et al 2002;Troll et al 2005).…”

Anorogenic granite magma genesis: new isotopic data for the southern sector of the British Tertiary Igneous Province

“…Meighan 1979, Meighan et al 1984, Thorpe et al 1990), although it must be noted that Stone (1988Stone ( , 1990) assigns general S-type status to the Lundy intrusions. The paucity of published isotopic data factor (Table 3) is particularly serious for parts of this sector, especially for O. Recognising this and the importance of information for several isotopic systems, new data for Arran (O) and northeastern Ireland (O, Nd, Sr) are summarised and discussed in relation to the northern sector.…”

“…Notes'. Major elements and Sr were determined by X-ray fluorescence analysis, Ce, Yb and Eu by neutron activation analysis (as in Meighan et al 1984 on July 5, 2015 specialpapers.gsapubs.org Downloaded from 3.1. O isotopic data: N Arran, Ailsa Craig and northeastern Ireland Table 6 summarises new O isotopic data for the granitic rocks of N Arran (the coarse biotite granite and later, more fractionated, 'fine' biotite granite) and the Mourne Mountains (amphibole-biotite granites G1 and G5 together with the very fractionated biotite granites G2, G3 and G4: McCormick et al under review).…”

“…This has passed into a phase dominated by some degree of "petrogenetic convergence" in which mantle and crustal components are recognised (Meighan et al 1984;Dickin et al 1984) with seemingly no uncontaminated basaltic differentiate granites or "100% crustal melt" granites in the province. For Skye, the basic parent has been identified as the MORB-like Preshal Mhor basalt magma type (Dickin et al 1984) and the BTIP granites in general may contain substantial asthenospheric mantle components (e.g.…”