Marine Sedimentary Processes
Particles in the ocean:
where they accumulate and how they get there
OCEAN 541/OCEAN 411
Andrea Ogston (543-0768; email@example.com; 107A MSB)
Chuck Nittrouer (543-5099; firstname.lastname@example.org; 111B MSB)
Introduction to Marine Sedimentary Processes
Initially, we will introduce basic terms and background, and progress to initial development of the concepts of sediment transport and accumulation.
Mechanics of sediment transport (how particles get there)
The first part of the course will focus on the mechanics of sediment transport the physical processes by which sediment particles are moved in the marine environment. We will start with the removal of sediment from plumes, and progress to resuspension processes where we will study the "Law of the Wall" and methods of evaluating bed shear stress. Threshold of sediment motion will be covered, and then transport as suspended load in the marine environment. The contributions of waves and wave-current interactions, particle aggregation, and density effects will be discussed within the context of experimental studies. Instrumentation and field methods for study of sediment dynamics will also be discussed.
Particle distributions, settling velocity, and particle aggregation
"Law of the Wall" boundary layer velocity profiles
Boundary shear stress & the quadratic stress law
Initiation of sediment motion
Sedimentary environments (where particles accumulate)
The latter part of the course will be an examination of sedimentation in diverse marine environments ranging from the shoreline to the abyssal plains. The concept of sediment accumulation will be addressed, in terms of how deposition, erosion and bioturbation conspire to control the strata formed at particular sites. The impacts of these processes cause local and progressive changes of sedimentary characteristics in the seabed, which will be examined along fluvial dispersal systems from shallow to deep settings. We'll start with beaches and barrier coastlines, where surface gravity waves have a dominant impact. Next the evolution of river mouths from estuaries to deltas will be examined. Continental shelves are areas affected most dramatically by sea-level fluctuation, and thus experience a broad range of terrestrial and marine processes. The steep gradients of continental slopes make gravitational flows common there, especially during low stands of sea level. These flows spread sediment onto the continental rise and into the deep sea, forming abyssal plains. The fundamental mechanisms of fluvial dispersal systems will be contrasted with low-latitude carbonate and high-latitude glacial-marine systems.
Radioisotope techniques for measuring sedimentation
Interactions of sediment mixing, accumulation, and strata formation
Beaches and barrier islands
Estuaries and deltas
Continental slope, rise, and abyssal plain
Carbonate and glacial-marine margins
Organization of the course:
Homework problem sets will be required in the course. During the discussion on sedimentary environments, each student will give a short oral presentation, relating concepts presented in this course to their research interests.
Two exams will be given: one following "mechanics of sediment transport" and the other following "sedimentary environments".
Exam (mid-quarter mechanics of sediment transport) 30%
Exam (final-exam period - sedimentary environments +) 40%
A field trip (potentially: 13-14 May) will allow us to examine sediment transport and accumulation in coastal environments from the Columbia River northward along the Washington coast.
References for Marine Sedimentary Processes: (No text)Davis, R. A., Coastal Sedimentary Environments
Pethick, J., An Introduction to Coastal Geomorphology
Reading, H.G., Sedimentary Environments and Facies
Komar, P., Beach Processes and Sedimentation, Second Edition
Wright, L. D., Morphodynamics of Inner Continental Shelves
Nielsen, P., Coastal Bottom Boundary Layers and Sediment Transport
U.S. Army Corp of Engineers, Shore Protection Manual
Dean, R. G. and Dalrymple, R.A., Water Wave Mechanics for Engineers and Scientists.
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Last modified: 4/04/2006 10:16 AM