Geometric consequences of ductile fabric development from brittle shear faults in mafic melt sheets: Evidence from the Sudbury Igneous Complex, Canada

Dating shear zones with plastically deformed titanite: New insights into the orogenic evolution of the Sudbury impact structure (Ontario, Canada)

“…A kinematic domain dominated by thrusting in the western part of the complex and a domain of dextral transpression in the eastern part (Riller et al, 1999). Generally, the following processes have been proposed that influenced the deformation pattern of the South Range during and/or after the impact event : (a) the formation of syn-impact fractures (Siddorn and Ham., 2006), (b) the mechanical weakening of the crust by the impact event (Riller et al, 2010), (c) the orogenic buckling of the Sudbury Igneous Complex in a flexural -slip mode (Mukwakwami et al, 2012), and (d) a tri-shear fault -propagation folding of the crater units (Lenauer and Riller., 2012).…”

Structural controls on the localization of the mineralized Copper Cliff embayment and the Copper Cliff Offset dyke, Sudbury Igneous Complex, Canada

“…Post-cratering events include metamorphism, folding and faulting related to the 1.7-1.6 Yavapai-Mazatzal, the 1.5-1.4 Ga Chieflakian-Pinwarian and the 1.2-1.0 Ga Grenville orogenies (Bailey et al, 2004;Papapavlou et al, 2018Papapavlou et al, , 2017Tschirhart and Morris, 2012). In the study area, the metamorphic facies reaches upper to mid-greenschist (Card, 1978;Fleet et al, 1987) and the crater floor has been tilted from sub-horizontal to 77°NW−45°NW (Dreuse et al, 2010;Grieve et al, 2008) during the folding and thrusting of the SIC (Clendenen et al, 1988;Cowan and Schwerdtner, 1994;Lenauer and Riller, 2017, 2012a, 2012bMilkereit and Green, 1992;Santimano and Riller, 2012).…”

“…However, the study area is located in the South Range, which consists of two tectonically different portions (Santimano and Riller, 2012): 1) the western South Range that formed by thrusting on the SRSZ; and 2) the eastern South Range that underwent dextral transpression (Cowan et al, 1999;Santimano and Riller, 2012) generating the southeastern lobe of the SIC by buckling (Cowan and Schwerdtner, 1994). The study area is located at the western portion of the eastern South Range where, according to lineaments mapped from air photos, NNW-SSE and NE-SW striking sinistral conjugate faults and NW-SE striking dextral faults are consistent with N-S shortening (Lenauer and Riller, 2012a;Santimano and Riller, 2012).…”

“…In the CCE, deformation was mostly accommodated by sub-vertical and E-W-striking faults, and faults and quartz veins have consistent orientations and kinematics, i.e., oblique-slips and reverse-dominated kinematics. Local N-S shortening (Lenauer and Riller, 2012a;Santimano and Riller, 2012) is expected to induce dip-slip dominated reverse motion along E-W-striking planar structures. It is possible that pre-impact E-W striking faults propagated from footwall rocks and into SIC rocks during regional NW-SE shortening (Lenauer and Riller, 2012a), forming oblique-slip E-W striking faults in the CCE.…”

Petrochronology and mineral chemistry of mid-crustal shear zones

“…These two structural domains are characterised by distinct kinematics (Santimano and Riller, 2012): a kinematic domain dominated by thrusting in the western part of the complex and a domain of dextral transpression in the eastern part . Generally, the following processes have been proposed to have influenced the deformation pattern of the South Range during and/or after the impact event : (a) the formation of syn-impact fractures (Siddorn and Ham., 2006), (b) the mechanical weakening of the crust by the impact event (Riller et al, 2010), (c) the orogenic buckling of the Sudbury Igneous Complex in a flexural -slip mode , and (d) a tri-shear fault -propagation folding of the crater units (Lenauer and Riller., 2012).…”