General Geology

complex. Numerous dykes and small cupolas of granitic and dioritic ma-
terial are also included (see Plate VI A). Hornblende, epidote, and chlorite
are common minerals. Hornblende is particularly abundant where the
original rock was of volcanic origin and in some instances it comprises the
whole rock. Epidote is widespread and chlorite is ever present as an
alteration product of ferromagnesian minerals. Commonly greenstones or
metamorphosed lava flows have become coarse grained and dioritic in
character, resembling intrusive diorite. Some limestones have recrystallized
without the production of skarn, but others have produced wide bands con-
taining typical skarn minerals.

The range in age of the various rocks comprising this complex is not
definitely known. Most of the rocks are in part correlative with the Hazelton
group, but the possibility that some may be as early as Paleozoic must be
entertained. Recent work by the author in the Terrace area to the northwest
has shown the presence of Palzozoic rocks in metamorphosed zones similarly
related to the main mass of Coast Intrusions.

Copper, lead, zinc, gold and silver have been reported from quartz veins,
in the areas of these metamorphic rocks that are readily accessible. Much of
the main belt of these rocks, however, covers rugged country, difficult of
access, along the crest of the Coast Mountains and any mapping or prospecting
done so far must be regarded largely as reconnaissance. Some mineral
deposits have been found in the main belt, copper and gold being the principal
economic elements, but, generally speaking, the belt has not been prospected.

Takla Group

The Takla group was defined by Armstrong (1946, Map 844A) as a
series of volcanic and lesser sedimentary rocks about 5,000 feet thick which
range in age from Upper Triassic to Upper Jurassic. Tipper (unpublished
report), however, pointed out that the original locality from which the group
was named and described contained fossils of only Upper Triassic and Lower
Jurassic age and that the component of Upper Jurassic age is the result of
work by Lord (1948, pp. 19-25) in McConnell Creek map-area. There,
Lord included with the Takla group, as an upper member, certain Middle
and Upper Jurassic strata. Though he distinguished between the Upper
Triassic—Lower Jurassic beds and the Middle Jurassic—Upper Jurassic beds
he included them all with the Takla group. Based on this information
Armstrong extended the Takla group to include Upper Jurassic strata even
though the highest beds in the type locality are of Lower Jurassic age.

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