Abstract

The basin floor of Crater Lake (10-km diameter, 600-m water depth) is covered by up to 75 m of sediment–gravity-flow deposits interbedded with mud. In the upper units (8 m (thick), sand and gravel layers with numerous wedging, strong seismic reflectors characterize the base-of-slope aprons at the basin margin. These layers evolve to turbidites of mainly thin, fine-grained, basin-plain type, characterized by numerous flat and weak seismic reflectors in the central basin floor. Many individual debris-chute sources funnel sediment to base-of-slope aprons: there, coarse-grained parts of the sediment–gravity flows deposit nonchannelized beds attributed to the F, A, B turbidite facies. While traversing the base-of-slope aprons, flows evolve to sheet-flow turbidity currents that deposit D-facies beds over the central basin floor. These processes and patterns of deposition characterize small siliciclastic basins without channelized submarine fans and are common in carbonate basins of all sizes.

You do not currently have access to this article.