Sedimentary environments (where particles accumulate)
Half of the course will be an examination of sedimentation in diverse coastal environments ranging from the shoreline to the continental shelf. 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 the evolution of river mouths from estuaries to deltas, and move to continental shelves. These are areas affected most dramatically by sea-level fluctuation, and thus experience a broad range of terrestrial and marine processes. And in association with the fieldtrip, we’ll return to consider beach, barrier coastlines, and lagoonal/intertidal environments.
Discussion topics:
- Basic terms and background
- Concept of sediment accumulation
- Radioisotope techniques for measuring sedimentation
- Interactions of sediment mixing, accumulation, and strata formation
- Sedimentary environments
- Estuaries and deltas
- Continental shelf
- Beaches, barrier islands, lagoons, marshes/flats
Mechanics of sediment transport (how particles get there)
The other half 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.
Discussion topics:
- 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
- Suspended-sediment load
- Density effects
Organization of the course:
There will be three homework problem sets during the course.
Two exams will be given. The first will follow Sedimentary Environments. The second will be during the final-exam period, and will include material from Sediment Transport and Beaches et cetera.
Grading breakdown:
- Homework 30%
- Exam (25 Apr) – Sedimentary Environments 30%
- Exam (final-exam period) – Sediment Transport + 40%
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.
Lecture Notes
Lecture 2
Lecture 3
Lecture 4
Lecture 5
Lecture 6
Lecture 7
Lecture 8
Lecture 9
Lecture 10
Lecture 11
Lecture 12
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