Whitesail Lake Map-Area
Metamorphism

The proximity of the main mass of Coast Intrusions and the widespread
injection of granitic material have caused much alteration of the Hazelton
group within the area.

Epidote and chlorite are common alteration products, imparting a
general green coloration, particularly to the altered volcanic rocks. In other
places amphibole is developed to the extent of forming most of the rock.
This development of amphibole is dominant near the main batholithic masses,
particularly near the heads of Morice and Tahtsa Lakes. Commonly near
contacts with granitic masses, rocks of the Hazelton group have been altered
to schists and gneisses and hybrid types intermediate in character between
regular volcanic rocks and typical granitic rocks. Feldspathic material
developed along minute fractures in volcanic rocks, commonly bordered
by an alteration rim of epidote. The rocks of this zone appear to be more
siliceous than is normal for the Hazelton group.

Where the Hazelton group rocks contain limy members adjacent to
tongues and cupolas of granitic rocks it is common for contact metamorphism
to have produced skarn zones of significant extent. Thus on the mountain
east of Sandifer Lake, a skarn zone at least 400 feet long and 60 feet wide
contains well-developed crystals of epidote, specular hematite, garnet, a little
chalcopyrite and minor bismuthinite. Except for the bismuthinite similar
mineralization and alteration were observed alongside the intrusion on
Chikamin Range. Where argillites of the group are in close contact with
granitic masses they have in places been altered to andalusite schists. An
example of this alteration is exposed on Lindquist Peak on the property of
Deer Horn Mines Limited.

Environment of Deposition

The preponderance of volcanic material, particularly of the fragmental
variety, together with marine sediments as expressed by the argillites, grey-
wackes, and reworked volcanic material, suggests that rocks of this group
were deposited in a shallow sea within a region of volcanic activity. Rocks
composing the Hazelton group together with associated batholithic rocks
typify those found in eugeosynclinal conditions as outlined by Kay and the
whole map-area is included in Kay’s Fraser Eugeosynclinal (Kay, 1947).

Of the sediments in geosynclines Kay (1951, pp. 85-86) said, in part,

.., rocks in eugeosynclines pass on the one hand into lavas, tuffs, and
coarser fragmental rocks, and the derivatives of the weathering of volcanic islands,
and on the other hand into terrigenous sediments eroded from tectonic lands.

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