Sedimentary rocks are formed on or well-nigh the Earth's surface, in contrast to metamorphic and igneous rocks, which are formed deep inside the Earth. The about important geological processes that atomic number 82 to the creation of sedimentary rocks are erosion, weathering, dissolution, precipitation, and lithification.

Erosion and weathering include the effects of wind and rain, which slowly interruption downward large rocks into smaller ones. Erosion and weathering transform boulders and even mountains into sediments, such as sand or mud. Dissolution is a form of weathering—chemical weathering. With this procedure, h2o that is slightly acidic slowly wears away stone. These three processes create the raw materials for new, sedimentary rocks.

Precipitation and lithification are processes that build new rocks or minerals. Atmospheric precipitation is the formation of rocks and minerals from chemicals that precipitate from water. For example, as a lake dries upward over many thousands of years, it leaves behind mineral deposits; this is what happened in California's Death Valley. Finally, lithification is the procedure by which clay, sand, and other sediments on the bottom of the sea or other bodies of water are slowly compacted into rocks from the weight of overlying sediments.

Sedimentary rocks can exist organized into two categories. The first is detrital rock, which comes from the erosion and aggregating of rock fragments, sediment, or other materials—categorized in total as detritus, or droppings. The other is chemical rock, produced from the dissolution and atmospheric precipitation of minerals.

Detritus can be either organic or inorganic. Organic detrital rocks form when parts of plants and animals decay in the footing, leaving behind biological textile that is compressed and becomes rock. Coal is a sedimentary rock formed over millions of years from compressed plants. Inorganic detrital rocks, on the other hand, are formed from broken up pieces of other rocks, not from living things. These rocks are often called clastic sedimentary rocks. One of the best-known clastic sedimentary rocks is sandstone. Sandstone is formed from layers of sandy sediment that is compacted and lithified.

Chemical sedimentary rocks can be establish in many places, from the ocean to deserts to caves. For case, virtually limestone forms at the bottom of the body of water from the precipitation of calcium carbonate and the remains of marine animals with shells. If limestone is found on country, it can exist assumed that the expanse used to be nether water. Cave formations are also sedimentary rocks, just they are produced very differently. Stalagmites and stalactites form when h2o passes through bedrock and picks up calcium and carbonate ions. When the chemic-rich h2o makes its way into a cave, the water evaporates and leaves behind calcium carbonate on the ceiling, forming a stalactite, or on the floor of the cavern, creating a stalagmite.

Sedimentary Rocks

An example of a sedimentary stone, which is, by definition, composed of many, smaller rocks.

carbonate

describing word, noun

mineral created past the activity of carbon dioxide on a base.

clastic sediment

Substantive

rock composed of fragments of older rocks that have been transported from their identify of origin.

detrital rock

Noun

sedimentary stone produced from small pieces of other rocks

dissolution

Noun

termination or destruction by breaking downwards, disrupting, or dispersing

Noun

act in which world is worn abroad, often by water, air current, or water ice.

geomorphology

Noun

written report of geographic features on the landscape and the forces that create them.

halite

Noun

natural mineral form of salt (sodium chloride.) Too called rock salt.

limestone

Noun

blazon of sedimentary stone mostly made of calcium carbonate from shells and skeletons of marine organisms.

lithify

Verb

to change into rock or stone.

Noun

all forms in which water falls to Earth from the atmosphere.

Noun

solid textile transported and deposited by water, ice, and current of air.

shale

Noun

blazon of sedimentary rock.

stalactite

Noun

rock formed by mineral-rich water dripping from the roof of a cave. The water drips, but the mineral remains similar an icicle.

stalagmite

Substantive

mineral eolith formed on a cavern floor, usually by water dripping from in a higher place.

Noun

the breaking down or dissolving of the Globe's surface rocks and minerals.

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    Director

    Tyson Brown, National Geographic Society

    Author

    National Geographic Society

    Product Managers

    Gina Borgia, National Geographic Club
    Jeanna Sullivan, National Geographic Club

    Program Specialists

    Sarah Appleton, National Geographic Society
    Margot Willis, National Geographic Society

    Producer

    Clint Parks

    Final Updated

    Oct. 22, 2019

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