| Summary: | Naturally occurring hydrocarbon seeps and shows have been documented along the coast of western Newfoundland through the 1800s. Historically, hydrocarbon exploration and drilling have targeted conventional oil and gas resources within Cambrian–Ordovician sedimentary rocks of the western (outer) part of the Humber (tectonostratigraphic) Zone. However, to date, the hydrocarbon potential of western Newfoundland has not been fully evaluated, even though much of the Cambro- Ordovician rocks of the outer Humber Zone reside within the oil-window. Earlier studies described and illustrated a successful petroleum play within the western part of the zone and proposed two petroleum fairways; one extensional, the other inversional, with reservoirs anticipated to be principally in the lower autochthonous Paleozoic shelf rocks. The Cambro-Ordovician Green Point shale (part of the Green Point Formation, Cow Head Group of the Taconic Humber Arm Allochthon) is the principal source rock for hydrocarbons in western Newfoundland; thick sections of these rocks are known, and have potential as an unconventional shale resource. Previous geochemical studies have shown that the shales are rich in Type BI organic matter of mostly algal origin and Type I/II Kerogen and that the chemistry of its oils are similar to those of the oil seeps and is consistent with a pre-Devonian clastic source rock. Regional geochemistry studies indicate that the shale ranges from thermally immature to mature (possibly ranging up to overmature) and that thermal maturity increases (at surface) from west to east and from south to north (late mature); Green Point shale, occurring north of Parson’s Pond, may reside in the gas window. The Green Point shale was complexly deformed during multiple tectonic events and its distribution, stratigraphy and structure are generally poorly understood. There is no robust model of the subsurface because of limited onshore mapping, the scarcity of well data, and the fine-grained nature of the rocks that make seismic resolution and interpretation difficult. Further study of the stratigraphy, sedimentology, geochemistry, maturity, and mineralogy, together with structural and mapping studies of the Green Point Formation and associated rocks, would lead to a better understanding of the shale’s hydrocarbon potential.
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