ERSC 4P10 Lecture Notes - Lecture 1: Aggradation, Cobequid Bay
22 Jan 2016
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Document Summary
Bed forms and stratification under unidirectional flows: the sequence of bed forms. Water flowing over a flat bed of sand will, with increasing flow strength, develop a sequence of bed forms that differ in terms of morphology and behavior. The sequence shown would develop with increasing velocity and constant flow depth. Note that not all of the lower flow regime bed forms will develop for a given sand size. Gradational transition to 3-d dunes: current from right to left. Scour pits in the trough are typical of 3-d dunes. These intertidal dunes from cobequid bay pond water in their scoured troughs after the ebb tide recedes. Planar tabular cross-stratificaton: bounding surfaces are parallel planes. Bounding surfaces are planes that are not parallel. Trough cross-stratificaton: bounding surfaces are curved or trough shaped. Cross-strata formed by a set of ripples migrating over a bed with low rates of bed aggradation. Cross-section of ripple cross-lamination; current from left to right.
