Sea level controls on the textural characteristics and depositional architecture of the Hueneme and associated submarine fan systems, Santa Monica Basin, California

摘要: Hueneme and Dume submarine fans in Santa Monica Basin consist of sandy channel muddy levee facies on the upper fan, lenticular sand sheets middle thinly bedded turbidite hemipelagic elsewhere. Fifteen widely correlatable key seismic reflections high-resolution airgun deep-towed boomer profiles subdivide fan basin deposits into time-slices that show different thickness seismic-facies distributions, inferred to result from changes Quaternary sea level sediment supply. At times low level, highly efficient turbidity currents generated by hyperpycnal flows or failures at river deltas carry well out onto middle-fan area. Thick, formed rapidly prograding high levees mainly western (right-hand) side three valleys fed times; most recently active lowstand valleys, valley, now heads Canyon. receive canyons intercept littoral-drift cells mixed earthquake-triggered slumps. Turbidity are confined ‘underfit’ talweg channels steep, small, basin-margin like fan. Mud is effectively separated moves basinward across shelf plumes storm-generated lutite flows, contributing a basin-floor blanket locally thicker than contemporary onlaps older margin. The infilling has involved both aggradation accompanied landward shifts. Progradation was restricted downslope growth periodic advance toe steeper sandier Although region tectonically active, major sedimentation can be related eustatic sea-level changes. primary controls shifts appear an interplay texture source sediment, efficiency with which transport sand, effects delta distributary switching, all reflect