Petrology of the Elbow Lake stock : Elbow Lake-Grass River area, Manitoba
Quaraishi, Abul Ata.
A stock of quartz diorite, intrusive into greenstone, outcrops just south of Elbow Lake, about 40 miles east of Flin Flon, Manitoba. Field examination established the internal homogeneity of the body, the concentration of inclusions near the contacts and the intrusive character of the contacts. The distribution of joints, faults and foliation was mapped from the areal photographs. A study of thin sections revealed that the texture is hypautomorphic granular, with euhedral plagioclase crystals. This igneous texture is somewhat modified by deuteric alteration. The main minerals are plagioclase and quartz, which occur in proportions which are roughly that of quartz-plagioclase eutectic. The variations of mineral compositions show no regular pattern. Deuteric alteration occurs with a concentric layered distribution pattern, with the most altered rocks in the center of the intrusive body.