Whitesail Lake Map-Area

its core of plutonic rock that has dislocated the Hazelton group rocks near
it, thus the structures on one range are rarely continuous with those of an
adjacent range. Angles of dip are in the order of 30-50 degrees and rarely
exceed 60 degrees.

A number of small fold structures are indicated by the mapping, but
as stated above they are not persistent along the strike.

Between Tahtsa and Nanika Lakes there is a sharp anticline and
complementary syncline, the axes of which trend northwesterly. The north
slope of the Sibola Range is a fairly wide synclinal structure, the axis of .
which strikes north, but the structures on this mountain are interrupted,
warped, and broken by the pluton that forms the core of the range.

Smoke Mountain is an open synclinal structure striking north 65 degrees
east which is at right angles to the common northwesterly trend. West of
Anzac Lake another small synclinal trough lies between two plutonic masses.
This structure also strikes in a northeasterly direction. The attitude indicates
that the stocks and bosses outcrop on anticlinal structures in this part of
the area.

Attitudes in the Shelford Hills indicate the rocks there to be warped into
gentle northwesterly trending folds. The western end of the Mosquito Hills
is represented by a small anticline the axis of which strikes northeasterly.

The attitudes on Whitesail Range do not clearly indicate any definite
structure, the beds altering in strike and dip within short distances.

On Chikamin Range the beds west of the peak form the southwestern
limb of an anticlinal structure that is interrupted to the east by granitic and
dioritic intrusions forming the core of the range. This western limb of the
structure is fractured near the intrusion the fracturing expressing itself in
narrow continuous breaks which in places contain lead-zinc minerals. Near
the head of Whitesail Lake the beds strike northwesterly and dip away from
the main batholithic contact.

The northwestern slope of Key Mountain contains a small synclinal
structure the axis of which trends northwesterly.

The beds on Mount Preston dip 40 degrees to the southwest, and those
on Mount Pondosy dip 50 degrees to the northeast, indicating a synclinal
structure whose axis lies along the valley between Tesla Lake and Pondosy
Bay.

In the Quanchus Range in the eastern part of the map-area the rocks
are again disturbed by intrusions and the structures are mostly local. Where
observed on the western slopes of Mount Wells and Tweedsmuir Peak the
beds dip away from the plutonic mass. In this case the dip is westerly.

46