The geology of Codfish Island, Stewart Island, New Zealand

Abstract

Codfish Granite, a variably altered biotite granite crosscut by volumetrically minor dike(s) of biotite-garnet-muscovite-bearing granite makes up 70% of the bedrock of Codfish Island. This pluton is part of the Rakeahua Batholith which forms a large part of nearby Stewart Island. Paterson Group metavolcanogenic sediments form a 500 m wide strip along the east coast of Codfish Island. Paterson Group rocks are characterised by heterogeneous foliation development and metamorphism to the upper greenschist or lower amphibolite facies. Rakeahua Batholith and Paterson Group rocks are separated by a kilometre-wide cataclasite zone.