GEOL 3233 Lecture Notes - Lecture 4: Point Bar, Cyanobacteria, Desiccation
11 Oct 2017
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Document Summary
Sand moves parallel to beach-waves and longshore current ; Distributary channel not very broad, usually secondary. Beach ridges/barrier islands - cover a large area. Facies: delta front sheet sands elongate bars coarsening upward \bars migrate laterally \and seaward abundant burrowing. Tidal flats occur on low slope \ coasts\ marked tidal range\ high sediment inlfux wave energy? commonly in estuaries. North coast of germnay (german bay) some barriers protect the flats. Netherlands bodnesee (van stratten) barriers protect. Bay of fundy (klein) very high tidal range not common. Zones within a tidal flat (5-7 km wide) subtidal sand flat. Tidal channels like fluvial, fine upward point bar. 68% in german flats are reworked in 100 years may get bimodal currents herringbone but on channel can be unidirectional. Mixed flats; flaser to wavy to lenticular bedding as move landward. Arid bare except for blue green algae can get gypsum dessication cracks common.
