Dept of Earth & Environmental Sciences
Centre for Environmental and Information Technology (EIT)
200 University Ave. W
Waterloo, Ontario, Canada N2L 3G1
Phone: (519) 888-4567
Clays, Faults and Orogeny
Dr. Ben van der Pluijm
Department of Earth and Environmental Sciences, University of Michigan
Newly-formed, illitic clays are common in foreland fold-thrust belts, and the ages of fault-zone mineralization allow first-order constraints on the timing of regional deformation, fault weakening and fluid pathways. We briefly discuss our method of authigenic clay characterization and analysis, and focus on Ar-encapsulation dating.
Application to foreland fold-thrust belts in the Canadian and US Rockies shows multiple cycles (“pulses”) of orogenic wedge formation, each lasting 4-8 my, separated by longer periods of tectonic quiescence (“stick-slip orogeny”). Fault ages in the eastern Pyrenees, in contrast, preserve progressive faulting over ~20 my, with a much smaller strain rate. Variations in foreland orogenic wedges reflect tectonic setting and deformation style.
FREE ADMISSION ~ REFRESHMENTS
200 University Ave West
Waterloo, ON N2L 3G1