Cyclic sequences occur worldwide in nearly every stratigraphic sequence; they are particularly well developed in deposits associated with large river systems. Superimposed on cycles attributed to shifting sites of deposition are those related to high frequency sea level changes. The large data base for this study (including 471 deep foundation borings, thousands of line kilometers of high-resolution seismic, and sedimentological and dating analyses) represents the best information on high resolution chrono- and lithostratigraphy that is available on any modern continental shelf/upper slope. These data are used to document sedimentological characteristics, spatial depositional patterns, and seismic/lithofacies response during three complete sea level cycles over the entire continental shelf/upper slope of offshore Louisiana.

Sedimentation during periods of high sea level is characterized by: (a) thin, slowly accumulated depositional sequences referred to as condensed section, (b) calcareous-rich deposits, including hemipelagics and shell hashes, (c) wide lateral continuity, and (d) high amplitude acoustic response. Sedimentation during periods of low sea level are characterized by: (a) variable-thickness, rapidly accumulated sequences referred to as expanded sections, (b) coarse-grained clastic deposits, including abundant sands and gravels, (c) well-defined depositional trends, and (d) a wide variety of seismic responses.

Even though the data set covers only a short period of geologic time (240,000 years), these high frequency events are responsible for the deposition of excellent reservoir quality facies in well-defined and predictable trends. An understanding of the facies relationships resulting from these high frequency events will aid in the interpretation of the complex sequence of deeply buried Neogene sediments in the northern Gulf of Mexico basin and aid in correlation of the various lithofacies.

End_of_Record - Last_Page 8---------------