Permalink : http://hdl.handle.net/2115/36687

The occurrence of cumulus gabbro in the Hidaka Metamorphic Belt has been noted in the Western Zone of the Metamorphic belt as cumulus series of dunite-wehrlite-troctolite-olivine gabbro-anorthosite and various amphibolites which were obducted westward (Miyashita and Hashimoto, 1975). Besides the Western Zone gabbro series, many small bodies of cumulus gabbros have been known as fault bounded blocks throughout the whole metamorphic belt in the Axial and Eastern zones (Hashimoto, 1975). The Ameyama gabbro which occurs as an outlier of the metamorphic belt, is described and is compared with the Western Zone gabbros. Diabase which is accompanied by the Ameyama gabbro is also described. The chemical characteristic of the diabase show that it is nearly the same as the Hidaka Western Marginal Zone diabases but a slight difference in the trend of differentiation is revealed.