--> Deposition and Exploration Analogs for Miocene and Early Pliocene Intraslope Fans of the Central Gulf of Mexico, by C. E. Helsing and J. C. Johnson; #90986 (1994).

Datapages, Inc.Print this page

Abstract: Deposition and Exploration Analogs for Miocene and Early Pliocene Intraslope Fans of the Central Gulf of Mexico

Carl E. Helsing, John C. Johnson

The Mississippi River and its ancestors have provided sediments for deep water fan deposition in the Central Gulf of Mexico (CGOM) since Jurassic time. Recent studies have proposed deposition and exploration analogs using the Mississippi Fan for late Pliocene and Pleistocene intraslope and basin floor fans in the CGOM. This study extends the use of these analogs to Miocene and early Pliocene intraslope fans in the CGOM.

The Pleistocene Mississippi Fan has four key depositional features: submarine canyon, leveed-channel complexes (LCC), debris flows, and sheet sands. Using state-of-the-art reflection seismic and well log data, these features were observed in intraslope fans throughout the Mississippi Canyon and Viosca Knoll Areas of the CGOM. These intraslope fans range from Miocene to early Pliocene.

The two main exploration targets within the intraslope fans are sheet sands and LCC. Sheet sands are associated with the distal edges of the fans. These sands produce a seismic response of continuous, coherent reflectors, thick in the center while thinning towards the edges. Because of their larger areal extent, sheet sands are often the primary exploration target. The LCC are characteristic of mid-fan deposits and produce chaotic seismic responses as a result of the constant channel meanderings. Within a leeved-channel complex, continuous high-amplitude seismic reflectors are associated with channel sands, point bars, and splays. Because they are generally limited in size, these individual features may not be economical targets in deep water. However, when of sufficient size or found stacked vertically with similar deposits or sheet sands, they are often excellent exploration targets.

The previously discussed analogies have illustrated the consistencies in intraslope fan deposition through time. Therefore, the deposition and exploration concepts developed from the Pleistocene Mississippi Fan can be applied to Miocene and early Pliocene intraslope fans throughout the CGOM.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994