Annual report . Mines No. 4 magma itself. The rock is essentially a biotite gneiss, with little biotite andlarge quartz-content. It is pinkish in colour to the east of Freda station, and inplaces shows a porphyritic texture with orthoclase phenocrysts; and in some partsit increases in coarseness to a pegmatitic facies containing anhedrons up to threeinches in diameter. To the west of Freda station the inclusions of basic rock aremuch more numerous, and the magma itself finer-grained and of a greyer colour,probably due to assimilation of basic material or to basic differentiation near thecontac
Annual report . Mines No. 4 magma itself. The rock is essentially a biotite gneiss, with little biotite andlarge quartz-content. It is pinkish in colour to the east of Freda station, and inplaces shows a porphyritic texture with orthoclase phenocrysts; and in some partsit increases in coarseness to a pegmatitic facies containing anhedrons up to threeinches in diameter. To the west of Freda station the inclusions of basic rock aremuch more numerous, and the magma itself finer-grained and of a greyer colour,probably due to assimilation of basic material or to basic differentiation near thecontact with the roof. About a mile northward there are in addition to thebasic inclusions others that appear to represent acid rocks, possibly sandstoneor quartz porphyry now much altered. The inclusions here show a considerableamount of contortion due to fiowage of the gneiss, and are less markedly angularthan near Freda. The surface is therefore representative of a lower horizonwithin the batholith. >*iB|»»
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectminesandmineralresou
