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TitleInfluence of igneous intrusions on the thermal maturity of organic matter in the Sverdrup Basin, Arctic Canada
AuthorGoodarzi, F; Gentzis, T; Dewing, KORCID logo
SourceInternational Journal of Coal Geology vol. 213, 103280, 2019 p. 1-14,
Alt SeriesNatural Resources Canada, Contribution Series 20200355
PublisherElsevier BV
Mediapaper; on-line; digital
File formatpdf; html
ProvinceNunavut; British Columbia
NTS93L/11; 49G; 49H; 340B
AreaCanadian Arctic Archipelago; Ellesmere Island; Ellef Ringnes Island; Melville Island; Sabine Peninsula
Lat/Long WENS -88.0000 -80.0000 80.5000 79.0000
Lat/Long WENS-127.5000 -127.0000 54.7500 54.5000
Subjectsfossil fuels; economic geology; geochemistry; tectonics; Science and Technology; Nature and Environment; petroleum resources; petroleum generation; petroleum occurrence; hydrocarbon migration; thermal maturation; coal seams; bitumen; pyrobitumen; tectonic history; thermal history; burial history; magmatism; intrusions; sills; metamorphism; alteration; carbonization; microscopic analysis; pyrolysis; organic geochemistry; vitrinite reflectance; bedrock geology; lithology; sedimentary rocks; igneous rocks; intrusive rocks; diabases; granodiorites; aureoles; gas analyses; Sverdrup Basin; Panarctic Chads Creek B-64 Well; Panarctic Drake Point D-68 Well; Romulus C-42 Well; Helicopter J-12 Well; Phanerozoic; Mesozoic; Cretaceous; Jurassic; Paleozoic; Permian; Carboniferous; Pennsylvanian
Illustrationsgeoscientific sketch maps; stratigraphic columns; geophysical logs; tables; plots; photomicrographs; profiles; spectra
ProgramGeoscience for New Energy Supply (GNES) Shale Reservoir Characterization
Released2019 08 31
AbstractThe influence of igneous intrusions on the trend of thermal maturity with depth in two drillholes, one on Ellesmere Island and the other on Ellef Ringnes Island, Arctic Canada, was assessed using vitrinite and solid bitumen reflectance, Rock-Eval pyrolysis/TOC, and gas composition analysis in order to assess the impact of igneous intrusions on the hydrocarbon system in the area. Thick sequences of Permo-Pennsylvanian strata in Sabine Peninsula, Melville Island, were intruded by two igneous intrusions in the Panarctic Chads Creek B-64 (influenced by one intrusion) and the Panarctic Drake Point D-68 (influenced by two intrusions). Sedimentary strata in Chads Creek B-64 were intruded by a 120 m-thick diabase sill (with temperature of ~1100°C) of unknown age. This resulted in increased reflectance of vitrinite from 0.90% to 1.65% and of pyrobitumen from 2.90% to almost 5.80% near the sill contact at depth of 3600 m. Solid bitumen outside of the thermal aureole zones and having reflectance values <1.50% followed the extrapolated trend for solid bitumen present in the country rocks. In Panarctic Drake Point D-68, the intrusives are granodiorite sills of 45 m and 75 m thickness and were emplaced during the Upper Jurassic (152 Ma) and Lower Cretaceous (131 Ma). The intrusion temperature was 800°C. The Vitrinite Rr prior to sill emplacement was <1.0% outside the aureole and increased to approximately 2.0% near the intrusive zone. The rocks were well-lithified prior to sill emplacement. Solid bitumen underwent carbonization after being exposed to a temperature of at least 800°C. Solid bitumen reflectance also showed a sudden increase from a minimum of 1.50% outside the aureole to approximately 7.0% near the sill contact, a 5x increase as compared to an increase of 2x for vitrinite. This indicates that solid bitumen is a very sensitive indicator of temperature variation, more sensitive than vitrinite. Solid bitumen reflectance prior to the sill emplacement can only be inferred from the solid bitumen below the lower, younger sill because of poor control on solid bitumen in the interval just above the upper, older sill. Reflectance trends above and below the sills appear to be symmetrical despite the superimposition of the effects of one sill on the other. The metamorphic effects of the sill, as determined vertically by the reflectance trend, can be observed for a distance of up to seven times its thickness. The upper, older sill is approximately 45 m thick and the thermal aureole zone above it has a width of 330 m. The thickness of the aureole below the sill is difficult to establish because it has been obliterated by the effect of the lower, younger sill. The thickness of the lower sill is 75 m. An additional factor that influenced solid bitumen reflectance in this case may have been the thickness of the sill, which, in turn, affects the cooling time of the intrusive body. The granodiorite sills are approximately 45-75 m thick and the diabase sill is almost 120 m.
Summary(Plain Language Summary, not published)
Paper discusses role of igneous intrusion in productivity of oil shale in Arctic.

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