title of the thesis - Department of Geology - Queen's University

overprinting (Cochrane, 1991; Coulson 1996). Observed examples of brittle reactivation within
the shear zones include:
Horizontal slickensides along the 400-East Shear Zone. These indicate lateral movement,
overprinting previous vertical displacement.
Brittle fracturing of shotcrete along the strike of the Return Air Raise (2.9A, B) and
Footwall Shear Zones.
Extension in proximity to the Grizzly Shear Zone. This is likely the result of unloading
induced by excavation of a nearby drift.
Normal-sense movement along fractures in proximity to the Plum Shear Zone, as
indicated by displaced dykes and slickensides along the fracture surface (2.10A-H). This
overprints previous ductile, reverse-sense motion along the fracture as indicated by rock
shear-sense indicators.
Late-stage brittle fractures that intersect and displace shear zones (Fig 2.14). Offset
fractures are observed in the Fresh Air Raise-type Shear Zone (Fig. 2.12B).
The geometry of brittle features is incompatible within a single stress regime, requiring a change
in far-field stresses to have occurred. Previous work by Cochrane (1991) on levels above the
Creighton Deep indicates that late-stage faults in Creighton Mine have strike-slip displacement,
overprinting earlier reverse-sense displacement that is recorded by ductile features within the
shear zones. This is supported by near-horizontal slickenlines along late-stage features, similar to
those are observed along the 400-East Shear Zone. Sense-of-shear along late-stage faults was not
determined by Cochrane (1991).
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