Morphologic studies of submarine sediment drainage

This thesis examines the morphologic imprint of submarine sediment drainage on the continental slope and rise along three segments of the U.S. continental margin; the central California margin, the New Jersey margin, and the eastern Louisiana margin. In these regions the erosion, transport and deposition of clastic sediments derived from the adjacent continent has often led to the formation of networks of submarine canyons and deep-sea channels that effectively constitute submarine drainage systems. Regional bathymetric grids along with other data types are used to analyze the sea floor morphology in these areas to better understand the processes by which submarine drainage systems form.;In the study of the central California margin, geomorphic measures of the networks of submarine canyons and deep-sea channels that feed the Monterey Fan are found to be quantitatively indistinguishable from those made of a variety of river networks from the continental U.S. The remarkable similarity of the Monterey submarine drainage system to its terrestrial counterparts implies that drainage development beneath the sea parallels that on land.;On the New Jersey continental slope, existing submarine canyons are discovered to have exploited lower slope conduits previously eroded by older canyons now buried beneath the upper slope. The re-use of the lower slope conduits suggests that the present canyons were initiated by downslope eroding sediment flows that interacted with sea floor topography in the same way that surface waters interact with and erode land topography.;Surprisingly little evidence is seen of submarine sediment drainage on the eastern Louisiana slope, where despite the voluminous input of materials to this region during the Plio-Pleistocene, no trace could be found of sediment pathways that once connected submarine canyons now buried along the shelf edge to channel-levee complexes abandoned at the foot of the slope on the Mississippi Fan. This region appears to represent the rare case of a continental slope where the morphologic effects of submarine sediment drainage have been erased by a competing process shaping the sea floor.