We propose a collaborative thermochronologic study across the Trans-Hudson orogen (THO) in northern Saskatchewan and Manitoba, Canada. The study is specific to the THO, but we believe the results will yield some general insights into the process by which collisional orogens become cratonized. We anticipate four important results: (1) the extent of the time period following terminal collision until the several terranes have been amalgamated into a single craton; (2) which, if any, of the terranes studied were reactivated at a later time; (3) the lateral (geographic) extent of a 1.8 - 1.75 Ga cooling event, specifically how far this cooling event extended into the Archean cratons that bound the THO on the northwest (Hearne Province) and southeast (Superior craton); and (4) a related topic, whether the juvenile terranes of the internides of the THO have the same cooling history as the bounding reworked Archean cratons and the internally incorporated Sask craton microcontinent.

The study will focus upon plutons and paragneisses from most of the internal subdivisions (terranes) of the THO. We will collect suitable samples across the orogen, following as closely as possible the Canadian Lithoprobe Seismic transect, and working in the company of geologists who have done field work in these areas. Samples will be collected to allow ⁴⁰Ar/³⁹Ar analyses of coexisting micas, hornblende, and K-feldspar, and U-Pb analyses of coexisting zircon, monazite, sphene, rutile, and garnet. Using the variable closure temperatures of these minerals and the ages obtained, we will construct time-temperature cooling curves for the several terranes and the bordering Archean cratons.