We have presented a number of models for deep-sea-fan sedimentation based on studies of both modern and ancient fans. The models presented have basically been variations based on the type of sediment being supplied to the fans, yielding sand-rich (radial), mud-rich (elongate), and mixed-sediment (not yet distinguished in modern deposits) types of fans. Debris apron models need to be applied where nonchannelized sediment cones develop and for most systems supplied with carbonate detritus (Cook et al., 1981).
Many other basic tectonic, sediment-source, and sea-level factors combine to control the size, geometry, and growth history of deep-sea fans (Fig. 11-1) (Table 11-1). We will discuss some examples of these combined factors and their influence on source bed, reservoir, and the petroleum potential of deep-sea fans. We realize, however, that each system has its individual complexities, and we can only cite a few examples limited by our experience. Nevertheless, based on the controlling factors and petroleum potential, we will suggest some general strategies for exploration and secondary recovery of petroleum.
One of the most important tectonic parameters is the basin shape which also influences basin size and gradient to which channel systems adjust. The geometry of the tectonic setting influences the ultimate shape of the turbidite deposit and determines whether it is called a deep-sea fan, trench or channel deposit. Typically, in deep-sea channels and trench systems, the axial channel facies and entire deposit are linear and narrowly confined by tectonic setting; Astoria and Nitinat Fans, however (Fig. 5-23), are examples with
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This course of modern and ancient deep-sea fan sedimentation provides the framework for understanding the morphology, physiography, geometry, depositional processes and reservoir potential of deep-sea fan deposits. Focus is chiefly on the principles that control fan sedimentation and the resultant morphology of fans deposited in various types of settings. Through the comparison of modern and ancient examples of deep-sea fan sedimentation, the authors hope to increase understanding of the principal characteristics of fans. The course is divided into four parts (1) the Introduction, which covers the organization of the course and history of fan studies, (2) modern deep-sea fan deposits, (3) ancient deep-sea fan deposits, and (4) the synthesis, in which the results of the separate modern and ancient examinations of deep-sea fan deposits are synthesized into models that may be applicable to petroleum exploration.