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A diagram of various depositional environments. In geology, depositional environment or sedimentary environment describes the combination of physical, chemical, and biological processes associated with the deposition of a particular type of sediment and, therefore, the rock types that will be formed after lithification, if the sediment is preserved in the rock record.
There must be repeated depositional events with changes in precipitation of materials over time. The thickness of graded beds ranges from 1 millimeter to multiple meters. There is no set time limit in which the layers are formed. Uniformity of size and shape of materials within the bed form must be present on a present or previously horizontal ...
These structures are within sedimentary bedding and can help with the interpretation of depositional environment and paleocurrent directions. They are formed when the sediment is deposited. Cross-bedding Cross-bedding is the layering of beds deposited by wind or water inclined at an angle as much as 35° from the horizontal. [1]
Whether formed by chance or necessity, by headward erosion or downslope convergence, whether inherited or newly formed. [1] Depending on different geological factors such as weathering, erosion, depositional environment, and sediment type, different types of channel patterns can form.
Robert J. Dunham published his classification system for limestone in 1962. [2] The original Dunham classification system was developed in order to provide convenient depositional-texture based class names that focus attention on the textural properties that are most significant for interpreting the depositional environment of the rocks.
The geologic subdiscipline of stratigraphy is primarily concerned with depositional contacts, [4] while faults and shear zones are of particular interest in structural geology. Faults and shear zones can be regarded as a form of secondary structure in the rock beds. [5]
Figure 1 illustrates this relationship between sediment grain size and the depth of the marine environment. Figure 1. Illustrating the sediment size distribution over a shoreline profile, where finer sediments are transported away from high energy environments and settle out of suspension, or deposit in calmer environments.
In sedimentology, imbrication is a primary depositional fabric consisting of a preferred orientation of clasts such that they overlap one another in a consistent fashion, rather like a run of toppled dominoes. Imbrication is observed in conglomerates and in some volcaniclastic deposits. [1] [2]