Brock River Map-area, District of Mackenzie (97 D)

Résumé du livre

Gently folded, unmetamorphosed Upper Proterozoic (Hadrynian or Neohelikian) sedimentary rocks, with a total exposed thickness of about 6,000 feet, underlie most of the map-area; gabbro sills and dykes locally intrude the strata. Paleozoic, marine sedimentary rocks, ranging in age from Cambrian to Middle Devonian, and having an exposed thickness of about 1,700 feet, uncomformably overlie the Proterozoic rocks. Paleozoic rocks are separated by a regional hiatus from the overlying Cretaceous sequence that is about 700 feet thick and composed of quartz sandstones, siltstones, shale and coal. Thick, topographically prominent, Pleistocene glacial deposits obscure bedrock throughout wide regions.