ABSTRACT: Submarine Fan "Lobes"

SHANMUGAM, G., Mobil Research and Development Corp., Dallas, TX

Numerous submarine fan "lobe" terminologies, implying widely different reservoir properties, have been introduced into the sedimentologic literature. Three of the commonly used terms--suprafan lobes, depositional lobes, and fanlobes--are specifically defined. Braided suprafan lobes refer to channel-mouth deposits of sand-rich fans composed of gravel and coarse-grained sand; they are characterized by stacked channel sand bodies with good lateral and vertical communication. Depositional lobes are considered to be sheetlike turbidite sand bodies, composed of medium- to fine-grained sand, and they develop at the mouths of channels. They have good lateral and moderate vertical communication. Fanlobes refer to the entire meandering channel-levee system of large mud-rich submarine fans, such as the Mississippi Fan, and are characterized by offset stacked channel sand bodies with poor lateral and vertical communication. External mounded reflections in seismic profiles are often interpreted as "lobes" or sand-rich "basin-floor fans"; however, there are no definite seismic criteria to delineate mud-rich lobes from sand-rich lobes.

AAPG Search and Discovery Article #91012©1992 AAPG Annual Meeting, Calgary, Alberta, Canada, June 22-25, 1992 (2009)