Date of Award


Degree Type


Degree Name

Doctor of Philosophy


The greater than 1.4 Ga old Wernecke Supergroup is subdivided, from oldest to youngest, into the Fairchild Lake Group, the Quartet Group and the Gillespie Lake Group. The 4 km thick Fairchild Lake Group, is fine siliciclastic sediments with some intercalated carbonate. Locally phyllites and schists are present. This sequence is tentatively subdivided into five formations: F-1, F-2, F-3, F-4 and F-TR. F-1, F-2 and F-3 were deposited in a basin supplied by abundant fine-grained detritus from a major river. F-4 was probably deposited on a shallow marine shelf. F-TR accumulated in an anoxic basin partially fringed by a carbonate shelf.;The approximately 5 km thick Quartet Group is siltstone, fine sandstone, mudstone and claystone. Fine-grained, carbonaceous sediments comprising Q-1 accumulated in an anoxic, stagnant basin. The thick Q-2 was deposited on a broad, shallow marine shelf.;There is a gradational contact between Q-2 and the overlying 4 km thick Gillespie Lake Group which is dolomite, dolomite-terrigenous admixtures, limestone, and fine-grained siliciclastics. This sequence is tentatively subdivided into seven units of formational rank: G-TR, G-2, G-3, G-4, G-5, G-6 and G-7. Facies changes are common. G-TR to G-4 is finegrained siliciclastic-carbonate admixtures deposited in a progressively deepening basin. G-5 records the evolution from a gentle carbonate slope fringed by a stromatolite reef complex to an intertidal and subtidal regime. G-6 was deposited on a periodically exposed mixed carbonate-siliciclastic shelf. G-7 accumulated on a rimmed carbonate shelf.;Dykes and sills of diorite, gabbro, peridotite and lamprophyre, of several ages, intrude the Wernecke Surgroup. Gabbro and diorite, the most common varieties, have immobile trace element contents similar to mid-ocean ridge basalts.;The Wernecke Supergroup hosts numerous discordant breccia complexes which are of variable size and shape. Breccias were formed by the interaction of faulting, hydraulic stopping and the intrusion of gas-charged fluids.;Breccias are locally enriched in uranium, copper, barium, cobalt or iron. Stratbound and fracture-hosted copper, lead, silver and zinc are in some formations of the Gillespie Lake Group.;The Wernecke Supergroup was deposited along a complex, arcuate continental margin which was convex to the southwest.



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