Volume 20, 1970 - The Arctic Circle - Home

VOL. XX THE ARCTjC CIRCI"JI,ARL2REPCRTl{ishli hts of Field Activrties of the Geolosical Surve ofCanada in the North i969.By R.G. Blacka-dar, Geoiogicai Surve.r* of Canada, Ottawa.The Geological Siurvey i-s one of Canadats oldestscientific agencies and is, am'Jng cther things, responsible forproviding geological info::mation that can be used in evaluatingthe Nation's mineral irotential. In support of this objectivethe Surt'ev has been active i n irnexplored frontier-areas fromthe days of its first director, Sir l{illiam Logan, w}ro in the1840s examined ttre ir'ilderness cf the upper Ottawa Valley andthe nortitern snores o{' Lakc Superior. Geological studies wereextended to the Arctic in thc late 19th century and the namesof A.P. Low, J.B. Ti'rrell and Robert Bell are faniliar to thoseversed in northern explorati.on. ltiith the increasing interestin our North these studi es have expandecl and in 1969 there weremore than 30 field prcjects i.n various parts of the NorthwestTerritories. in Januarv 1970 the Geological Survey pubtishedits I'Report of Activities, Aprii to October 1969" (paper T0-1,Part A) and that report forms the basis for the following briefnotes on some oF the Si;rveyt.s northern work, notes that aredesigned to alert those iriterested in specific areas or subjects.Scveral ircli copter-supported geological reconnaissancest{ere carriecl out, tiic two lirrgest F-reas covered being parts ofthe western District of li;rckenzic r'rnd Southamnton Island.Opcrat-ion Norrnatr, a three-season project begun in1968 and lvhich ivj.11 cover 145,0OO^square miles between 64'N andthe arctic coast ancl 119'ailtl i32ul!', combines bcdrock mapping,stratigraphic studies ancl investigations of surficial deposits.Tlie 1969 lvork rvas i.n the llackenzie l'lountains, the lr{ackenzievalley, tlte l.'lcConnell Range anci the plains south of Great BearLake. Thirty-sn* strati rrirpiri c uni ts t^iere mapired and it wasdetermined that 1;ronounceci regional unconformities occur at thebase of the Cret.aceous, L-ievonian, Upper Ordovician to LowerSi lurian, and Ilicidlc-: Ciimtir j an to Lolver 0rdovician successions .In the Niackenzie lr.iver valley thcre is evidence thatcompressive det-ornation c.cntlnued into the Tertiary whereassouthof Great Bear Lake the last significant deformation waspre-Canbrian. In I'iackenzie ltlountajns the last orogenicmovement appears to have been nre-l'jiddle Canbrian; pre-Tertiary,pre-Cretaceous, pre-Devonian and pr"e-Upper Ordovician uplifts