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Flow regimes in single-direction (typically fluvial) flow, which at varying speeds and velocities produce different structures, are called bedforms. In the lower flow regime , the natural progression is from a flat bed, to some sediment movement ( saltation etc.), to ripples, to slightly larger dunes.
Antidunes produce sedimentary structures characteristic of their flow regime, which allow sedimentary geologists to understand past flow conditions. Unlike low flow regime bedforms like dunes and ripples which generally produce downstream dipping cross stratification, antidunes produce a mixture of low-angle downstream and upstream dipping ...
In geology, ripple marks are sedimentary structures (i.e., bedforms of the lower flow regime) and indicate agitation by water (current or waves) or directly by wind. Defining ripple cross-laminae and asymmetric ripples
Low-density turbidity current deposits (turbidites) are characterized by a succession of sedimentary structures referred to as the Bouma sequence, which result from decreasing energy within the flow (i.e., waning flow), as the turbidity current moves downslope. [4]
Sedimentary structures can indicate something about the sedimentary environment or can serve to tell which side originally faced up where tectonics have tilted or overturned sedimentary layers. Sedimentary rocks are laid down in layers called beds or strata. A bed is defined as a layer of rock that has a uniform lithology and texture. Beds form ...
In case of volcanic rocks, the lithostratigraphic unit equivalent to a bed is a flow. A flow is “...a discrete, extrusive, volcanic rock body distinguishable by texture, composition, order of superposition, paleomagnetism, or other objective criteria.” A flow is a part of a member as a bed of sedimentary rock is a part of a member. [18] [19]
These phase diagrams [1]: 1 [9] are used for two main purposes: i) for prediction of bed states in a known flow and sediment transport condition, and, ii) as a tool for the reconstruction of paleoenvironments from a known bed state or sedimentary structure. Despite the great utility of such diagrams, they are very difficult to construct, making ...
Bouma A is the first layer deposited by a flow, provided the flow has sufficient energy. Otherwise Bouma B, C or D will be the first layer deposited. Bouma A is deposited when the flow energy is high enough that fluid turbulence is able to keep the coarsest grains in suspension. When energy drops below a critical level, the grains tend to ...