Ad
related to: sedimentary flow structures examples animals pictures list
Search results
Results From The WOW.Com Content Network
Sedimentary structures include all kinds of features in sediments and sedimentary rocks, formed at the time of deposition. Sediments and sedimentary rocks are characterized by bedding , which occurs when layers of sediment, with different particle sizes are deposited on top of each other. [ 1 ]
These forms of ripples are constructed by unidirectional flow of the current. Sinuous Sinuous ripples generate cross-laminae that are curvy. They show a pattern of curving up and down as shown in picture. Sinuous ripples produce trough cross lamination. All laminae formed under this type of ripple dip at an angle to the flow as well as downstream.
This turbidite from the Devonian Becke-Oese Sandstone of Germany is an example of a deposit from a sediment gravity flow. Note the complete Bouma sequence.. A sediment gravity flow is one of several types of sediment transport mechanisms, of which most geologists recognize four principal processes.
It is now recognized that the vertical progression of sedimentary structures described by Bouma applies to turbidites deposited by low-density turbidity currents. As the sand concentration of a flow increases, grain-to-grain collisions within the turbid suspension create dispersive pressures that become important in hindering further settling ...
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 ...
Bioturbation is thought to have been an important co-factor of the Cambrian Explosion, during which most major animal phyla appeared in the fossil record over a short time. [2] Predation arose during this time and promoted the development of hard skeletons, for example bristles, spines, and shells, as a form of armored protection. [2]
The term rock formation can also refer to specific sedimentary strata or other rock unit in stratigraphic and petrologic studies. A rock structure can be created in any rock type or combination: Igneous rocks are created when molten rock cools and solidifies, with or without crystallisation. They may be either plutonic bodies or volcanic ...
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]