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A delta-slope-submarine fan model for maestrichtian part of Great Valley sequence, Sacramento and San Joaquin Basins, California

Journal Article · · Am. Assoc. Pet. Geol., Bull.; (United States)
OSTI ID:6741227

Shoaling of the Great Valley fore-arc basin, which began in the northern Sacramento basin during the Campanian Stage, shifted southward in the Maestrichtian to the southern Sacramento and northern San Joaquin basins, where a regressive sequence of submarine fan, slope, and deltaic deposits aggregates 6,500 ft in thickness. Water depth decreased to sea level as ponded submarine fans aggraded the basin floor, and slope and deltaic systems prograded basinward over them. The central part of the fore-arc basin was filled by the end of the Cretaceous; the southern part was not filled until the middle Eocene. Deltas prograded westward and southwestward from the Sierran magmatic arc. The Roberts Island slope system comprises several thick shale sections deposited during progradational events. Benthic foraminifera grade upward from abundant, varied, lower bathyal species to sparse upper bathyal or neritic species. The Union Island submarine fan system consists of several fans; most are elongate parallel to the southeasterly trend of the basin. Fans consist of upper, middle, and lower segments. Gas is produced from deltaic and submarine fan deposits. Delta-front sand beds form very small reservoirs where growth faults provide subtle structural traps. Distributary-channel sand beds are highly productive.

Research Organization:
Stanford Univ., Stanford, CA
OSTI ID:
6741227
Journal Information:
Am. Assoc. Pet. Geol., Bull.; (United States), Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Vol. 67:5; ISSN AAPGB
Country of Publication:
United States
Language:
English