Quantifying channelized submarine depositional systems from bed to basin scale
Lyons, William J.
MetadataShow full item record
LocationZerissenne Turbidite System, Namibia
The challenges of directly observing active turbidity currents necessitates the consideration of preserved deposits for deciphering the behavior of these systems. In this thesis, I take advantage 3-D subsurface seismic data and outcrop exposures to study turbidites at scales ranging from bed to basin. At the basin scale, I develop a method to estimate the time-frame over which sedimentation and subsidence come into equilibrium. Using seismic data from the Fisk Basin, Gulf of Mexico, I find that, during periods of broadly distributed, sheet-like deposition, equilibrium time is on the order of 4.6 x 105 years. In contrast, during periods of confined channel development, that time drops to 2.0 x 105 years. Identifying these equilibrium times is critical because, at times below equilibrium, autogenic and allogenic stratigraphic signals cannot be distinguished. At the scale of turbidite beds, detailed grainsize analyses of sediment samples from the Capistrano Formation, San Clemente, California reveal the potential for misinterpretation that arises when deposits are studied without consideration for the dynamics of sedimentation. Previously interpreted as the result of anomalous sandy turbidites, using simple bed shear calculation and Froude scaling, I show that these coarse sediments are consistent with classical muddy, low-density turbidity currents. Finally, at the scale of amalgamated turbidite beds, I use outcrop mapping and aerial photography of the Zerissenne Turbidite System, Namibia to provide a measure of lateral and vertical continuity of a deepwater turbidite system. Previous studies have been hampered by limited exposure while the extensive continuous exposure of the Zerissenne show that correlation lengths of these systems can exceed 1.5 km.
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2004
Showing items related by title, author, creator and subject.
Experimental and seismological constraints on the rheology, evolution, and alteration of the lithosphere at oceanic spreading centers deMartin, Brian J. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2007-02)Oceanic spreading centers are sites of magmatic, tectonic, and hydrothermal processes. In this thesis I present experimental and seismological constraints on the evolution of these complex regions of focused crustal ...
Ecology of chemical defenses of algae against the herbivorous snail, Littorina littorea, in the New England rocky intertidal community Geiselman, Joy Ann (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1980-02)In the New England rocky intertidal community, space is dominated by two perennial plant types, brown fucoid algae (Ascophyllum nodosum and several species of Fucus) in the mid zones and the red alga Chondrus crispus ...
Lipoproteins and heat shock proteins as measures of reproductive physiology in the soft shell clam, Mya arenaria Clayton, Maureen E. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1996-06)Reproduction is an important physiological process in marine bivalve molluscs. Experiments were designed to examine the role of lipoproteins and heat shock proteins in normal physiological processes of the soft shell ...