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Porphyritic granite

Grid Ref (WGS84 Lat/Long in decimal degrees)

-17.546821, 31.462503
Near the Shamva Road
Chinamora Granite

The outcrop  is part of the Chinamora Porphyritic Granite which Baldock (1991) assigned to the Chinamora Igneous Complex. This was first described by Snowden (1976) who recognised some 45 different granitic types and Snowden and Bickle (1976) later grouped these into old gneisses, gneissic granites and late granites. The Chinamora Porphyritic Granite is part of the “late granites”.

The megacrysts are dominantly of microcline and occur in very variable quantities from dense to widely dispersed and in many localities, they are aligned. This alignment was attributed to two regional deformations by Snowden and Bickle (1976), partly because of their parallelism to similar megacrysts in sparse mafic xenoliths. However, the Granite is not foliated and Baldock suggested that upward diapiric movement could have caused the alignment.

Author Credit: 
Tony Martin