Abstract

The Whitehorse Trough is an early Mesozoic marine sedimentary basin, which extends from southern Yukon to Dease Lake in British Columbia. This paper outlines the stratigraphy and structure, and characterises the overall petroleum resource potential of the central Whitehorse Trough. Strata within the central Whitehorse Trough include carbonate rocks of the Upper Triassic Sinwa Formation, and interbedded sandstone, siltstone and argillite of the Lower Jurassic Inklin Formation. The central Whitehorse Trough is structurally dominated by a Middle Jurassic southwest-vergent fold and thrust belt. Programmed pyrolysis data indicate that potential source rocks in the Inklin Formation are gas-prone, and, along the northeastern flank of the central Whitehorse Trough, are within the oil and gas window. Variably tuffaceous feldspathic arenites in the Inklin Formation have fair to good reservoir characteristics, but are a minor component of the stratigraphy. Potential petroleum traps are provided by antiforms, thrust faults and stratigraphic pinch-outs. Three conceptual gas plays for the central Whitehorse Trough are proposed: (1) the Sinwa Structural Gas Play; (2) the Inklin Structural Gas Play; and (3) the Inklin Stratigraphic Gas Play. The Inklin Structural Gas Play presents the greatest potential in the central Whitehorse Trough because levels of organic maturation along the northeastern flank of the basin are favourable and structural traps are readily identifiable. This prospective belt of strata may extend to the northeast beneath the structurally overlying Cache Creek terrane.

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