The geology of the Mt. Crawford gneissic granite and its environs.

Abstract

A description of the stratigraphy of the area is given, with associated petrographic notes on each unit of the sequence. The petrology of the Mt. Crawford Gneissic Granite, its variation, the nature of the enclaves and contacts with the surrounding schists is discussed. Descriptive notes on the petrology, mineralogy, and occurrence of various amphiboles and pegmatite dykes, have been added. A study of the variation of minor minerals in the granite and its enclaves, and their relation to the surrounding sediments is presented. The structural geology of the area with special reference to a statistical study of jointing and lineation in the granite, and micro-folding in the surrounding schists is summarised; and a possible theory to explain the evidence is given. Conclusions on the possible origin of the granite, the amphiboles, and a discussion of the metamorphism and metasomatism in the area in the light of the petrological, mineralogical, and structural evidence concludes the paper.