Sequence stratigraphy and evolution of the Paleoproterozoic intracontinental Baker Lake and Thelon basins, western Churchill Province, Nunavut, Canada

The Kivalliq Igneous Suite: Anorogenic bimodal magmatism at 1.75Ga in the western Churchill Province, Canada

“…Nueltin Granite intrusions in the Hearne Province are uniformly coarse grained, with no volcanic equivalents. The Rae Province additionally contains exposures of subvolcanic intrusions, volcanic deposits, and dyke swarms of the same age (Peterson and van Breemen, 1999;Rainbird et al, 2003;Rainbird and Davis, 2007). The north-south variation in depth of erosion reflects younger vertical movements on reactivated faults and crustal flexure associated with deposition of the overlying Thelon Formation.…”

“…2 and 3). The Dubawnt Supergroup (DSG) comprises three first-order sequences of continental facies supracrustal rocks spanning a minimum of 300 million years, and contains two regional angular unconformities that bound the Wharton Group (Rainbird et al, 2003). The lowermost Baker Lake Group, deposited in active strike-slip extensional basins, includes alluvial fan, fluviatile, and minor lacustrine deposits partly sourced from and interbedded with ultrapotassic volcanic rocks (minettes) dated at about 1.83 Ga (Peterson et al, 1994;Rainbird et al, 2006).…”

The Great Grenvillian Sedimentation Episode: Record of Supercontinent Rodinia's assembly

“…Some of the thickest and most extensive of these dominantly terrestrial deposits occur above regionally extensive unconformities that are developed on the crystalline rocks of broad and stable Precambrian cratons (Eriksson and Donaldson, 1986). This period is marked by Earth's earliest examples of thick (sometimes exceeding 1000 m), widespread deposits of mature sandstone (mainly quartzarenite), many of which show evidence of deposition in broad, braided river channels (e.g., Athabasca Group of northern Saskatchewan, Ramaekers and Catuneanu, 2004), Dubawnt Supergroup of Thelon and Baker basins (Rainbird et al, 2003); Baraboo interval of north-central United States (Medaris et al, 2003(Medaris et al, , 2007; Roraima Supergroup of southern Venezuela (Santos et al, 2003); and the Huron Supergroup of south-central Canada , to name a just a few (North American examples located on Figure 29.2). These deposits contain a relatively high proportion of coarse, bedload material and there is little evidence of the existence of deep channels.…”

“…Evidence for their formerly greater extent includes the presence of small outliers of sandstone, well beyond the present-day basin margins, and numerous exposures of regolith that show evidence of reworking by formerly overlying fluvial deposits (Hadlari et al, 2004). The basins record a composite history and are localized at the sites of earlier, syn-orogenic extension and related subsidence and sedimentation events (Aspler et al, 2004;Rainbird et al, 2003;Ramaekers et al, 2007). The sequence stratigraphy, sedimentology and depositional age of the basins' fill are similar and can be correlated between depocenters that are thousands of kilometers apart.…”

A high resolution multi-proxy record of pronounced recent environmental change at Baker Lake, Nunavut

“…Instrumental records indicate a polar climate with a mean July temperature of 11.4°C and total annual precipitation averaging 156.7 mm. The bedrock geology of the region is of Proterozoic-Neoarchean origin generally characterized by weathered Archean granitoid gneiss overlain by feldspathic sandstone (Rainbird et al 2003). Catchment vegetation includes dwarf shrubs (Salix spp.…”