080121-08MN006-Sabina Hackett River Project Proposal ... - NIRB

Description of the Existing Environment6.1.4 Regional Surface and Bedrock GeologyThe Property is underlain by metasedimentary and metavolcanic rocks of the YellowknifeSupergroup (Wardrop, 2007). This occurs in the eastern part of the Archean to Proterozoic-ageSlave Province. Within the Property area, the Yellowknife Supergroup is comprised of threeconformable formations which include the Hackett River, the oldest formation, the Beechy Lake,which is younger, and the Back River Group, the youngest. The Hackett River Group isdominant in the Project area. It consists of three formations of which the Siorak is the oldest, theNauna is younger, with the youngest being the Ignerit Formation. The Ignerit Formation gradesinto the overlying Beechy Lake Group.The Siorak Formation is comprised of gneissic and schistose metavolcanic and metasedimentaryrocks. These are in contact with the underlying Hackett River gneiss dome, assumed to be anintrusive into the Hackett River Group. The overlying Nauna Formation is comprised ofmetamorphosed mafic and felsic flows and pyroclastic rocks. This unit does not appear to bepresent on the Property area where the Ignerit Formation rests with apparent conformity upon theSiorak Formation. The Ignerit Formation contains known sulphide-bearing stratigraphy and iscomprised of basic to felsic pyroclastics, tuffs, reworked volcanic sediments, and exhalativechemical sediments. These include limestone, chert, sulphide facies iron formation, andsulphide-bearing volcaniclastic rocks (Wardrop, 2007).Within the Property area, the Ignerit Formation is comprised of basal rhyolitic pyroclastics thatare overlain by andesitic and dacitic pyroclastics. These are overlain by rhyolitictuffs andsediments and are capped by clastic sediments. The Lower Rhyolitic Pyroclastic Section is atleast 450 m thick and is comprised of fragmental agglomerate to tuff with internal gradations tofiner argillaceous tuffite and chert. The overlying Andesitic Pyroclastic Section is from 60 to180 m thick and is overlain by the Dacitic Pyroclastic Section that ranges from 180 to 240 m inthickness.The Upper Rhyolitic Tuff Section contains the known sulphide deposits. It overlies a MineralHorizon member that ranges from 120 to 180 m in thickness. The Mineral Horizon member isbetween 3 and 100 m in thickness. It is comprised of fine-grained rhyolitic pyroclastics andargillaceous and cherty tuffite. Pyroclastic material increases in abundance east and west of theMain Zone area.A variety of surficial materials occur throughout the Project area. Morainal deposits arepervasive in the region, ranging from blankets (>1 m depth) to veneers (