High-Resolution Studies of Amazon Fan Distributary Channels and Growth Pattern Using GLORIA, SEA BEAM, and Seismic Reflection Data: ABSTRACT

Abstract

Deep-sea fans have become increasingly important targets for exploration because their facies associations can provide the necessary geologic factors for hydrocarbon generation and accumulation. We need to acquire a better understanding of channel morphology, vertical and lateral facies distributions, and growth pattern of modern deep-sea fans to successfully exploit the hydrocarbon potential of both ancient and modern fans. To this end we have developed a series of studies to investigate the structure of the Amazon Fan. Long-range side-scan sonar (GLORIA) and single-channel seismic records have revealed that the fan is composed of relatively few channel/levee systems. The channels (width 1.5 to 0.5 km or .9 to .3 mi) are intensely meandering with sinuosities up to 2.5. C toff meanders, channel branchings, and overflow deposits are associated with these channels. GLORIA sonographs and seismic reflection profiles show a probable growth pattern for the fan. Apparently only one major channel is active at a given time. In early 1984 we will conduct multi-narrow-beam bathymetric swath mapping (SEA BEAM) and high-resolution seismic (watergun) studies of critical channel segments in order to further resolve the bifurcation and meandering patterns of the channels. We will collect quantitative data on channel development across the fan, and on channel/levee structure, including depths, widths, and intra-channel topography (terraces, point bars). These data should provide important new insight into the origin and evolution of fan channels and associated inter-chann l deposits. Detailed studies such as these should provide new information for predicting the distribution of hydrocarbon reservoir rocks in fan deposits. End_of_Article - Last_Page 799------------