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

2.4.2 Evolving Stress System in the Sudbury Basin
The geometry and kinematics of the shear zones in the Creighton Deep are not compatible with
either the Andersonian (Anderson, 1951) or Riedel faulting model (Freund, 1974), particularly the
reverse sense along the NW-trending Footwall Shear Zone.
Fault geometry and kinematics
within Creighton Mine are best explained by an evolving stress system. Table 2.4 summarizes
tectonic events that have affected the Sudbury Basin.
Changes in the stress tensor are recorded in the tectonic history of regional-scale faults. The
Creighton Fault was formed as a normal fault and was reactivated as a reverse fault during the
Penokean Orogeny and subsequently reactivated as a strike-slip fault in the Neoproterozoic
(Zolnai et al., 1984; Rousell et al., 1997; Table 2.4). Such changes along regional-scale faults
may provide insight into the faulting history of mine-scale shear zones in the Creighton Deep, as
shown in Table 2.4, though ages for mine-scale shear zones in Creighton Mine are unknown. An
age of 1.7-1.6 Ga was determined by Bailey et al. (2004) for steeply-dipping reverse-sense shear
zones in the Thayer Lindsley mine, also located on the southern rim of the Sudbury Igneous
Complex. Similar to shear zones in the Creighton Deep, the Thayer Lindsley shear zones are
steeply-dipping, strongly-foliated, and biotite-rich and have mineral lineations with steep rakes.
The Thayer Lindsley shear zones are associated with the South Range Shear Zone (Fig. 2.1),
whose formation has been linked to the Mazatzal and Labradorian Orogenies (Bailey et al., 2004)
and Penokean Orogeny (Shanks and Schwerdtner 1991).
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