P-Total of an intrusive porphyritic dyke B. M. S. 12

Abstract

A quartz-feldspar porphyry dyke in the B.M.S. No. 12 deposit is late D1, which was the most intense deformation in the area (Luff, 1973). Ore textures in samples adjacent to the dyke show features typical of static recrystallization; this annealing event may be due to contact metamorphism associated with dyke emplacement or it may be related to the post-D1 regional metamorphic peak. Microprobe analysis of sphalerites, however are more compatible with the regional metamorphism, post-intrusion and post-D1. Total pressure during metamorphism was slightly greater than 5 kb. based on sphalerite geobarometry.