Level: Master students
Topic: Sedimentology – Sequence Stratigraphy
This video is an experiment done at UNLV. It shows different phases of deltaic sedimentation, erosion, and sequence stratigraphy. The plans for this flume tank are at http://serc.carleton.edu/NAGTWorkshop…
Rivers entering standing water behave as jets, either axial jets where river and standing water are equally dense or as plane jets where the river is lighter (or denser) than the standing water. Lacustrine deltas are deposited from axial jets; they have arcuate development and steep fronts. Mediterranean deltas occur in seas with low tidal ranges where plane jets are formed. Birdsfoot deltas are the ideal type but marine erosion, concentrating at the margin of the delta, can smooth them off into arcuate or classical deltas. Oceanic deltas form under strong tidal influence and are marked by flaring river mouths and concave delta plains.
“Deposition in deltas is concentrated at the delta front, where jet flow is initiated. Sand is laid down in river mouth bars which may coalesce into delta front sand sheets. Beyond the sand finer sediments are deposited in the prodelta, a marine environment wherein 75% of the actual deltamass accumulates. ” Derek Moore (1966)Moore, D. (1966). Deltaic sedimentation. Earth-Science Review vol 1 (2-3), p. 87-104
doi.org/10.1016/0012-8252(66)90001-8