Many of the basic problems about mode of generation and physical properties of turbidity currents are no better understood now than they were 10 to 20 years ago. Even within the past 10 years, there have been few new laboratory experiments on the phenomena of turbidity currents because of the basic scaling problem and inability to relate laboratory studies to events in nature. Thus, a review of the older work remains pertinent to provide a framework for understanding the processes depositing deep-sea-fan sediment.
In both modern and ancient deep-sea-fan deposits, graded beds that are coarser-grained than the interbedded muds are observed to contain displaced shallow-water plant and animal remains. They are obviously the product of resedimentation of shallow-water debris to basin depths. These graded beds in both modern and ancient deposits often occur in cone-shaped sediment deposits with channel and interchannel areas. (Nelson and Kulm, 1973; Walker and Mutti, 1973). The resedimented deposits of deep-sea fans are inferred to be the product of various types of turbidity currents that occur on a wide variety of scales and densities of flows. These inferences are based on actual observations of some types of turbid flows, although many types of the family of turbidity-current events have not been measured in natural events.
Observations of actual turbidity currents have been most commonly made in lakes. The studies began in the late 19th century and continue to the present modern events. Movements of turbid water traced in Lake Mead revealed that 12 major turbidity currents
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Modern and Ancient Deep-Sea Fan Sedimentation
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.