Organic maturation and thermal history of Queen Charlotte Islands

Conference · Fri Sep 01 00:00:00 EDT 1989 · AAPG Bulletin (American Association of Petroleum Geologists); (USA)

OSTI ID:5631957

Bustin, R M; Vellutini, D ^[1]

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1. Univ. of British Columbia, Vancouver (Canada)

The level of organic maturation and thermal history of Mesozoic and Tertiary strata of the Queen Charlotte Islands have been determined with vitrinite reflectance (R{sub 0}), numerical modeling (modified Arrhenius model), and Rock-Eval Pyrolysis. The level of organic maturation increases from northern Graham to southern Moresby Island, which primarily reflects high heat flow resulting from Middle to Late Jurassic and Eocene to Oligocene plutonism and cospatial dyking. Upper Triassic-Lower Jurassic and most Cretaceous strata are overmature on Moresby Island, with R{sub 0} values ranging from 2.40 to 5.80%. Jurassic, Cretaceous, and Tertiary strata are immature to overmature on Graham Island, with R{sub 0} values ranging from 0.15% (Skonun Formation) to 2.4% (Haida Formation). Locally, R{sub 0} values up to 3.2% on Graham Island and 8.3% on Moresby Island occur adjacent to igneous intrusives. Modeling measured levels of organic maturation suggests that elevated geothermal gradients ranging from 83{degree} to 150{degree}C/km existed during Yakoun (183-178 Ma) and Masset (35-10 Ma) volcanism on Graham Island. Numerical modeling further suggests that Triassic strata on Fredrick Island and Kennecott Point (Graham Island) entered the oil window during the early Miocene, whereas Jurassic strata at Rennell Junction and Cumshewa Inlet entered the oil window during the Bajocian. Cretaceous strata on north and south Graham Island entered the oil window during the early Miocene and are currently within the oil window. The Tertiary Skonun Formation is generally immature except for strata on west and northeast Graham Island, which entered the oil window in the late Miocene.

• OSTI ID: 5631957
• Report Number(s): CONF-8910195-; CODEN: AABUD
• Journal Information: AAPG Bulletin (American Association of Petroleum Geologists); (USA), Vol. 73:9; Conference: AAPG Rocky Mountain Section meeting, Albuquerque, NM (USA), 1-4 Oct 1989; ISSN 0149-1423
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
BRITISH COLUMBIA
PETROLEUM DEPOSITS
SOURCE ROCKS
MATURATION
CRETACEOUS PERIOD
GEOLOGIC FORMATIONS
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GEOTHERMAL GRADIENTS
JURASSIC PERIOD
MATHEMATICAL MODELS
OPTICAL PROPERTIES
SEDIMENTARY BASINS
TERTIARY PERIOD
TRIASSIC PERIOD
VITRINITE
CANADA
CENOZOIC ERA
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
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TEMPERATURE GRADIENTS
020200* - Petroleum- Reserves
Geology
& Exploration