ABSTRACT

Subaqueous slope and base-of-slope depositional systems are a major component of most marine and many lacustrine basin fills, and constitute primary targets for hydrocarbon exploration and development. Seven basic facies building blocks comprise slope systems: (1) turbidite channel fills, (2) turbidite lobes, (3) sheet turbidites, (4) slide, slump, and debris-flow sheets, lobes, and tongues, (5) finegrained turbidite fills and sheets, (6) contourite drifts, and (7) hemipelagic drapes and fills. The grain size of supplied sediment is a primary control on channel and lobe morphologies and on the scale and importance of slump and debris-flow deposits. Two general families of siliciclastic slope systems occur. Constructional (allochthonous) systems, including fans, aprons, and basin-floor channels, are built of sediment supplied from superjacent delta, shore-zone, shelf, or glacial systems. The facies architecture of allochthonous systems is determined jointly by the sediment texture and pattern of supply to the shelf margin. Point sources of supply create fans; line sources create strike-elongate prisms of slope sediment called slope aprons. Shelf-margin deltas provide a particularly common intermediate source geometry, forming offlapping delta-fed aprons. Autochthonous systems, including retrogressive aprons, canyon fills, and megaslump complexes, record slope reworking and resedimentation.

First Page Preview

First page PDF preview
You do not currently have access to this article.