A number of modern marine geologic techniques are available for the study of modern deep-sea fan environments. These techniques fall into several basic categories, including (1) acoustic techniques to map the sea-floor bathymetry, the sea floor surface, and define subsurface acoustic reflectors, (2) surface and subsurface sampling techniques, and (3) methods to assess environmental parameters of deep-sea-fan deposition. Modern environmental conditions can be assessed using current meters, suspended sediment measuring devices, and biological sampling techniques. General morphology of deep-sea fans can be studied by echo sounding techniques, TV cameras with videotape recording, and bottom photography (Fig. 2-1). Deep-sea-fan stratigraphy and lithology can be studied by continuous seismic profiling, coring, and deep-sea drilling. These techniques have been used to understand the near-surface environment and sedimentary processes of modern deep-sea fans. Although we know near-surface facies for different modern fan environments, the lateral and vertical continuity and three-dimensional lithofacies of modern systems is poorly known. This results in the lack of an adequate data base to make good comparisons of the modern deep-sea-fan environments with comparable information from ancient deep-sea fan rock sequences.
Echo-sounding techniques (3.5-12 kHz) have been used for several decades to define submarine bathymetry and outline deep-sea fans, fan valleys, and deep-sea channels (Fig. 2-lA) (Menard, 1955). At the lower frequencies, there often is some subsurface penetration as well as the collection of accurate bathymetric profiles. Recently, SEABEAM, a multi-beam precision echo-sounding techniques coupled with onboard, real-time processing and generation of bathymetric charts has been applied to submarine canyon
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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.