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COMFAN (Committee on Deep-Sea Fans) is an informal, international group of scientists that was hosted by Gulf Research & Development Co. in September 1982 to analyze the findings of deep-sea fan research accomplished during previous years. The group also reviewed the future plans for DSDP drilling on the Mississippi fan (Leg 96) and provided recommendations.
It was realized that tectonic setting and sea level variations have major influences on volumes of sediment supply, type of sediment, rates of accumulation, nature of fan growth, facies distribution, and stratigraphic sequences.
Deep-sea fans can be divided into three categories. Elongate fans develop in response to medium to high sediment input dominated by mud and fine sand. These fans have a major river as their primary source (e.g., Mississippi, Bengal, Indus, Amazon, and Rhone fans). Radial fans result from a lower sediment input with higher sand/clay ratios (e.g., La Jolla, Navy, San Lucas, Redondo fans). Slope aprons are a third category that, although not submarine fans, are closely related turbidite systems. Most fans are hybrids rather than true end members.
Three major conclusions were generated: (1) comparing modern fans with ancient turbidite systems is almost impossible because of scale differences and different study techniques; (2) slope failure may be a more direct source of fan deposits rather than deltaic systems; and (3) major fan accumulations most likely occur during the end of a sea level lowering or during the initial period of sea level rise, and sedimentation rates may be very high.
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