Classified Rocks Sedimentary, Igneous, metamorphic

Sedimentary rocks are types of rock that are formed by the deposition and cementation of that material at the Earth's surface and within loads of water. Sedimentation is the name for processes that cause mineral and/or organic particles to settle in place.

Different kind of sedimentary rocks

The particles that form a sedimentary rock by accumulating are called sediment. Before being deposited, the sediment was formed by weathering and erosion from the source area, and then transported to the place of deposition by water, wind, ice, mass movement or glaciers, which are called agents of denudation. Sedimentation may also occur as minerals precipitate from water solution or shells of aquatic creatures settle out of suspension. The sedimentary rock cover of the Earth's crust. Sedimentary rocks are only a thin veneer over a crust consisting mainly igneous and metamorphic rocks. sedimentary rocks are deposited in layers as strata, forming a structure called bedding. The different types of sedimentary rocks are inorganic (classtic) sedimentary rocks, chemical (crystal) sedimentary rocks, and organic (bioclastic) sedimentary rocks.

Clastic Sedimentary Rocks

Clastic sedimentary rocks form by weathering processes which break down rocks into pebble, sand, or clay particles by exposure to wind, ice, and water. Clastic and nonclastic sedimentary rocks are the only members of the rock family that contain fossils as well as indicators of the climate that was present when the rock was formed.If the sediment is buried deeply, it becomes compacted and cemented, forming sedimentary rock. Clastic sedimentary rocks may have particles ranging in size from microscopic clay to huge boulders. Their names are based on their clast or grain size.

Inorganic Sedimentary Rocks

Chemical sedimentary rocks form by precipitation of minerals from water. Precipitation is when dissolved materials come out of water. In inorganic rocks pieces of organic rocks are found in them. Inorganic sedimentary rocks are made of other fragments that are caused by weathering. These rocks are classified by their grain size. These are formed by compaction and cementation of the fragments deposited usually by running water entering calm water. The fragments are deposited in horizontal layers called beds or strata.

Organic Sedimentary Rocks

The sediment in an organic sedimentary rock is made of fossils! The hard parts of animals, such as bones and shells, can become cemented together over time to make rock. Usually the bones and shells are made of calcite, or similar minerals, and the organic rock that is made from them is called limestone.
On the rock cycle, what is squared is where sedimentary rocks are located on the cycle.
On the map,shows where the sedimentary rocks are located.

The layers are deposited in many environments including oceans, rivers and deserts. These layers of sand and mud are later buried. The weight of overlying layers compresses the mud and sand to form solid rock. Because sedimentary rocks begin to form at the Earth's surface

Igenous Rocks

Igneous rock is formed through the cooling and solidification of magma or lava. The magma can be derived from partial melts of existing rocks in either a planet's mantle or crust. Typically, the melting is caused by one or more of three processes: an increase in temperature, a decrease in pressure, or a change in composition. Solidification into rock occurs either below the surface as intrusive rocks or on the surface as extrusive rocks. Igneous rock may form with crystallization to form granular, crystalline rocks, or without crystallization to form natural glasses.

Igneous rocks can be either intrusive (plutonic) or extrusive (volcanic).

Intrusive Rocks

Intrusive igneous rocks are formed from magma that cools and solidifies within the crust of a planet, surrounded by pre-existing rock (called country rock); the magma cools slowly and, as a result, these rocks are coarse-grained. The mineral grains in such rocks can generally be identified with the naked eye. Intrusive rocks can also be classified according to the shape and size of the intrusive body and its relation to the other formations into which it intrudes. Typical intrusive formations are batholiths, stocks, laccoliths, sills and dikes. When the magma solidifies within the earth's crust, it cools slowly forming coarse textured rocks, such as granite, gabbro, or diorite.

The central cores of major mountain ranges consist of intrusive igneous rocks, usually granite. When exposed by erosion, these coresmay occupy huge areas of the Earth's surface.


Extrusive igneous rocks, also known as volcanic rocks, are formed at the crust's surface as a result of the partial melting of rocks within the mantle and crust. Extrusive igneous rocks cool and solidify quicker than intrusive igneous rocks. They are formed by the cooling of molten magma on the earth's surface. The magma, which is brought to the surface through fissures or volcanic eruptions, solidifies at a faster rate. Hence such rocks are smooth, crystalline and fine-grained.

Basalt is a common extrusive igneous rock and forms lava flows, lava sheets and lava plateaus. Some kinds of basalt solidify to form long polygonal columns.
On the rock cycle,what is squared is where the igneous rock is located on the cycle.

Metamorphic Rocks

A metamorphic rock is a result of a transformation of a pre-existing rock. The original rock is subjected to very high heat and pressure, which cause obvious physical and/or chemical changes.Fossils can sometimes be found in it but they are often squashed.Metamorphic rock is formed under extreme pressure combined with heat over time.Metamorphic rocks make up a large part of the Earth's crust and form 12% of the Earth's current land surface.They are classified by texture and by chemical and mineral assemblage . They may be formed simply by being deep beneath the Earth's surface, subjected to high temperatures and the great pressure of the rock layers above it. They are also formed when rock is heated up by the intrusion of hot molten rock,magma, from the Earth's interior. The study of metamorphic rocks provides information about the temperatures and pressures that occur at great depths within the Earth's crust.

Examples of these rock types include marble, slate, gneiss, schist.

Marble-Marble is a metamorphic rock that forms when limestone is subjected to the heat and pressure of metamorphism. It is composed primarily of the mineral calcite and usually contains other minerals, such as clay minerals.Under the conditions of metamorphism, the calcite in the limestone recrystallizes to form a rock that is made of interlocking calcite crystals.

Most marble forms at convergent plate boundaries where large areas of Earth's crust are exposed to regional metamorphism. Some marble also forms by contact metamorphism when a hot magma body heats adjacent limestone.

Gneiss-Gneiss is a high grade metamorphic rock,so that it has been featured to higher temperatures and pressures than schist. It is formed by the metamorphosis of granite, or sedimentary rock. Gneiss displays represents alternating layers made of different minerals.

Gneiss is a metamorphic rock form characterized by banding caused by segregation of different types of rock, typically light and dark silicates. Rather than an indication of specific mineral composition, the term is an indication of texture. The "gneissic texture" refers to the segregation of light and dark minerals.

Slate-Slate is a fine-grained, metamorphic rock that is created by the alteration of shale by low-grade metamorphism. It is popular for a use towards variety of uses such as roofing, flooring, and flagging because of its attractive appearance.Slate is composed mainly of micas, depending upon the metamorphism to which it has been opposed to. The original clay minerals in shale alter to micas with increasing levels of heat and pressure. Slate can also contain quartz and amounts of feldspar, calcite, pyrite, and other minerals.

Most slates are gray in color and range in a continuum of shades from light to dark gray. Slate also occurs in shades of green, red, black, purple, and brown. The color of slate is often determined by the amount and type of iron and organic material that is visible to the eye in the rock.
On the map,what is shaded pink is where metamorphic rocks are located in the U.S.
On the rock cycle,what is squared is where metamorphic rocks are located on the cycle.

Made with Adobe Slate

Make your words and images move.

Get Slate

Report Abuse

If you feel that this video content violates the Adobe Terms of Use, you may report this content by filling out this quick form.

To report a Copyright Violation, please follow Section 17 in the Terms of Use.