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Mesozoic (?) Acid Intrusives

The rocks grouped here are of many different tynes,
and occur as batholithic masses and stocks,

The largest body of those rocks oxtends northeasterly
from Babine Lake to Stuart Lako and is 80 square miles in areca,
Diorite is tho normal typo, but with the addition of quartz and
biotite it grades into quartz diorite. Tho rocks arc modium- to
coarse=grainod, green rocks characterized by abundant hornblende,
Stringers of epidote cut them everywhere, The rocks in many
places show well-devoloped foliation, which strikes northwest
conforming with the strike of the Carboniferous rocks they intrude.
Jointing in three directions, two nearly vertical and ono noarly
horizontal, is prevalent. Similar rocks occur noar tho Taltapin
and Radio mines.

A body of muscovite granite occupies 27 square miles
north of Sixteonmile Creek. It is a coarse-grained, white rock
composed of quartz, fcoldspar, and white mica, As it
diorite, and as no sharp contact with tho dioritco has boon
observed, both it and the dioritc may represont difforont p
of the same body.

An irregular area of intrusive rocks, 20 square miles
in size, lies northeast of Wright Bay, Babine Lake, It is
occupied by granite in its western half, and by albite syenite in
the eastern half. Normally the granite is a crey medium-crained,

vi 5 S J <
non-porphyritic rock containing considerable grey-sreen feldspar.
But all gradations between erey, pink, and white varieties aro
found. The pink variety is coarse-grained, porphyritic, and
composed of pink and white feldspar, quartz, biotite, and hornblende,
The pink feldspar usually forms large crystals up to 2 inches in
size; whereas the white feldspar along with the quartz for:
base of the rock, Locally this pink granite is foliated,

strike of the foliation being north 50 degrees cast. The

granitic rocks are non-porphyritic, medium to fine-srained,
contain very little pink feldspar. Stringers and spots of

are present in all the verietics,

The syenite is a mecdium=crained, grey-browm rock, that
weathers to a reddish browm due to the presence of considerable
pyrite. It is composed predominantly of albite and a minor amount
of hornblende.