The Paleoproterozoic structural history of metamorphosed and polydeformed basement and cover rocks in the Ptarmigan Fiord area, Baffin Island, Nunavut: a tectonic component of the Quebec-Baffin segment of the Paleoproterozoic Trans-Hudson orogen

The structural geometry and Paleoproterozoic deformation history of the Ptarmigan Fiord area is based on mapping and structural analyses, integrated with published petrology and geochronology data. Early thrust repetition, of 80-200 m-thick sheets of Archean orthogneiss basement with Paleoproterozoic cover of the Lake Harbour Group, results in belts of basement-cover couplets. This was followed by DP2 penetrative transposition that occurred at amphibolite-facies at ca. 1850-1820 Ma. The major structure in the SE part of the map is an upright ~ NW- striking, tight F2b syncline that folded three basement-cover couplets. The fold has a wavelength of ~ 3 km, occurs over a strike length of ~ 11 km, and has been refolded. The NW part of the map area comprises a NW-dipping panel of basement rocks and three belts of basement-cover couplets. This NW-dipping panel was juxtaposed against the F2b syncline by a moderately NW-dipping, T3c reverse shear zone.