Shear zone research

Ductile shear zones are common features of exhumed middle to lower crust and upper mantle, and are delineated by an increase in amount of apparent finite strain relative to wall rock. Essentially, shear zones accommodate varying amounts of displacement, can often juxtapose distinctive packages or rocks and terranes, facilitate fluid and magma flow, and thus are central to our understanding of plate tectonics and crustal evolution. Shear zones range in size (structural thickness/width), deformation mechanisms, coaxiality, length, and displacement that impart a first order control on the rheological and mechanical characteristics of a given region. My research program in shear zones is focused on the development and tectonic implications for geometric features of shear zones and petrochronology of these important features. Research in the Athabasca Granulite terrane, Adirondack Mountains, and northern Cordillera all have aspects focused on understanding shear zones, and collectively provide natural laboratories to compare shear zone development and evolution at various crustal levels.

Several cm-thick granulite-facies shear zone in the ca. 1150 Ma Marcy anorthosite massif
Intrafolial fold in the 5 km wide Cora Lake shear zone, northern Saskatchewan
Samples from a 5 m thick strain gradient in pera autochthonous North America, eastern Alaska
Mutually off-setting (conjugate) granulite- to amphibolite-facies shear zones in the Marcy anorthosite massif, southern Grenville Province


Valdez Creek shear zone, Clearwater Mountains, AK – timing and origin of an inverted metamorphic gradient along the boundary of North America and Wrangellia Composite Terrane.

Para autochthonous North America structurally below accreted Yukon Tanana terrane – development of mid crustal shear zones during accretionary tectonics and gravitational collapse

Athabasca granulite terrane/Snowbird Tectonic Zone – shear zones in lower continental crust

Adirondack Mountains – very hot lower to middle orogenic crust

Porphyroclastic amphibolite-facies tectonite displaying beautiful top to the Southeast kinematic indicators.
Tectonite analysis integrating multi-scale WDS mapping with in-situ isotopic dating