Posamentier, Henry W.1
(1) Anadarko Canada Corporation, Calgary, AB
ABSTRACT: The Stratigraphy and Evolution of the Mississippi Canyon, Gulf of Mexico
The Mississippi canyon is a significant conduit of sediment from the shelf to the basin floor. It is deeply incised into shelf and slope sediments, with relief of greater than 1 km m, and width of up to 7 km. It consists of a principal conduit with multiple tributaries and extends more than 150 km in length from the outer shelf to the basin floor of the Gulf of Mexico.
Analysis of 3D seismic data suggests that the bulk of the canyon fill comprises mud-prone mass transport deposits. Relatively minor amounts of sand-prone sediments in the form of turbidity flow channels are observed at the canyon axis as well as erosional remnants on canyon terraces. In addition minor deposits of channel sands are observed imbedded within the overall canyon fill. These channels vary from moderate to high sinuosity. With the exception of two channel systems, one at the base of the canyon and one at the base of a rejuvenated canyon cut higher within the canyon fill section, the channels are only partially preserved, reflecting successive cannibalization by younger flows.
The fill sequence of this canyon appears to be one of repeated cut and fill. The predominance of mud-prone seismic facies within the middle and upper section of the canyon fill suggests that much of this part of the canyon fill has been deposited during times when a direct feed from distributaries of the Mississippi delta was not available. This would argue that the bulk of canyon fill is associated with transgressive and highstand systems tract time when distributary mouths were at the inner shelf.
AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.