Dudley D. Rice, 1983. "General Characteristics of the Cretaceous Western Interior Seaway and Basin", Patterns of Sedimentation, Diagenesis, and Hydrocarbon Accumulation in Cretaceous Rocks of the Rocky Mountains, Dudley D. Rice, Donald L. Gautier
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Cretaceous rocks of the Rocky Mountain area were formed from sediments deposited in an elongate, asymmetrical foreland basin that was periodically occupied by a shallow epicontinental seaway. The basin formed in Late Jurassic time by subduction of the oceanic crust beneath the North American craton. The area of both maximum subsidence (related to crustal loading by thrust plates) and sedimentation (related to erosion and redistribution of the load) was located on the west side of the basin adjacent to the Cordillera thrust belt. Further east in the foreland basin, deposition was affected by recurrent movement of tectonic features, such as the Transcontinental Arch. The Cretaceous section is characterized by large-scale cyclothems (transgressive-regressive oscillations) that were controlled by (1) global sea-level changes, and (2) major episodes of thrusting in the Cordillera. The cyclothems are strongly asymmetric with the volumetrically largest part of the sequence representing deposition during progradation. Consistent patterns of sedimentation were established that were controlled mainly by the supply of clastics from the west. In general, facies belts are aligned in a north-south direction with coarser grained clastics to the west and thinner sequences of carbonate-rich rocks to the east. Carbonate-rich facies were deposited in the central part of the basin only during times of maximum transgression.
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Patterns of Sedimentation, Diagenesis, and Hydrocarbon Accumulation in Cretaceous Rocks of the Rocky Mountains
In the Rocky Mountains from western Canada to Mexico, Cretaceous rocks are major sources and reservoirs for oil and natural gas, accounting for about 40% of the cumulative production to date. Resources estimates indicate that large amounts of hydrocarbons remain to be discovered in these rocks. The purpose of this volume is to examine the relationship of reservoir quality, resource evaluation, and exploration strategy to depositional environment, thermal maturity, and diagenetic history of Cretaceous rocks in the Rocky Mountain area. Chapters deal with the general characteristics of the Cretaceous Western Interior Basin and seaway, the application of organic geochemistry to hydrocarbon occurrence and exploration, principle aspects of diagenesis that affect reservoir quality and source-rock potential, and the five main depositional facies which can be recognized from west to east across the basin.