The mineral chemistry of dolerites and gabbros from the central Complex of Slieve Gullion, NE Ireland

Abstract

The dolerites and gabbros of the Tertiary central complex of Slieve Gullion, NE Ireland, represent a suite of tholeiitic magmas (varying from tholeiitic basalt to tholeiitic andesite, Gamble 1979 a ) which crystallized in the root-zone of a shield volcano. The ubiquity of biotite suggests that the magmas were hydrous and, in addition, both silicate (olivine) and oxide (Ti-magnetite) phases show evidence for oxidation at high temperatures.