Sequence Stratigraphy of Neogene Sediments of the East-Central Mississippi Canyon Area, Northern Gulf of Mexico

John G. Roesink, Paul Weimer, and Renaud Bouroullec
University of Colorado, Boulder, Colorado

This study presents the sequence stratigraphic and structural framework of the east central Mississippi Canyon, northern deep Gulf of Mexico. Interpretation is based on 2600 miles of 2 dimensional seismic data, wireline logs from 26 wells, and biostratigraphy from17 wells. The Mississippi Canyon slope consists of several complex allochthonous salt systems including the Rum Roho, Thunder Horse, Metallica, and Mica, several isolated salt stocks, and the Sigsbee salt nappe. Multiple, deep, intra-slope minibasins are present between the salt systems. The bulk of Miocene-Pleistocene sediments that filled these minibasins are turbidites comprising sheet sands, channel-fill, and overbank deposits, all sourced from the Mississippi delta.

Ten depositional sequences were recognized, age-dated and correlated in the study area: 24.7, 15.3, 13.05, 10.75, 9.0, 7.45, 6.2, 5.4, 4.1, 3.6, and 1.3 Ma. Each sequence was characterized in detail with seismic facies, isopach, and geologic facies maps. The middle Miocene sequences contain the most sand. These occur where sand flows ponded in the salt-withdrawal basin. The sequences become more shale-rich in late Miocene and Pliocene time as the coarse-grained sediments largely bypass through the downdip area. 

The study area includes seven fields. They produce from amalgamated sheets, the Mensa; from single and multi-story channel-fill at Thunder Horse, Kepler, and Na Kika; and from thin overbank beds at Gemini. Traps consist of turtle structures and combined stratigraphic and structural traps along the flanks of salt diapirs.

AAPG Search and Discovery Article #90032©2004 GCAGS 54th Annual Convention, San Antonio, Texas, October 10-12, 2004