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The sedimentary rock cover of the continents of the Earth's crust is extensive (73% of the Earth's current land surface), [1] but sedimentary rock is estimated to be only 8% of the volume of the crust. [2] Sedimentary rocks are only a thin veneer over a crust consisting mainly of igneous and metamorphic rocks.
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 beds range from millimeters to centimeters ...
Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand and silt can be carried in suspension in river water and on reaching the sea bed deposited by ...
Sedimentology encompasses the study of modern sediments such as sand, [1] silt, and clay, [2] and the processes that result in their formation (erosion and weathering), transport, deposition and diagenesis. [3] Sedimentologists apply their understanding of modern processes to interpret geologic history through observations of sedimentary rocks ...
Conglomerate (/ kənˈɡlɒmərɪt /) is a sedimentary rock made up of rounded gravel -sized pieces of rock surrounded by finer-grained sediments (such as sand, silt, or clay). The larger fragments within conglomerate are called clasts, while the finer sediment surrounding the clasts is called the matrix. The clasts and matrix are typically ...
Sand blowing off a crest in the Kelso Dunes of the Mojave Desert, California. Aeolian or eolian (depending on the parsing of æ) is the term for sediment transport by wind. This process results in the formation of ripples and sand dunes. Typically, the size of the transported sediment is fine sand (<1 mm) and smaller, because air is a fluid ...
Slate is a fine-grained, foliated, homogeneous, metamorphic rock derived from an original shale -type sedimentary rock composed of clay or volcanic ash through low-grade, regional metamorphism. It is the finest-grained foliated metamorphic rock. [1] Foliation may not correspond to the original sedimentary layering, but instead is in planes ...
Metamorphic rocks are formed by subjecting any rock type—sedimentary rock, igneous rock or another older metamorphic rock—to different temperature and pressure conditions than those in which the original rock was formed. This process is called metamorphism, meaning to "change in form". The result is a profound change in physical properties ...