A Xenolithic Minor Intrusion at Slievenagriddle, County Down

Abstract

Examination of a xenolithic minor intrusion of Caledonian age at Slievenagriddle, County Down, has shown the existence of felspathic replacement rims and rheomorphic veins associated with the xenoliths, and derived from them by metasomatic action of the magma. Chemical and spectrographic analyses of the main rock of the intrusion, and of a rheomorphic vein, establish an order of geochemical migration for the metals of the alkali series. In conclusion I wish to express my thanks to Mr. J. J. Hartley, of Queen's University, Belfast, for valuable advice and help in the field work; to Dr. J. E. Richey and other members of the Geological Survey for much useful criticism and assistance; to Dr. D. L. Reynolds for reading this communication in MS., and to Dr. R. L. Mitchell, of the Macaulay Institute for Soil Research, for performing the two spectrographic analyses.