### stone:

Sedimentary rock
* Many sedimentary rocks can absorb soluble salts and be stained.
* Many sedimentary rocks contain rounded lumps called concretions
  - shells, bones, and other remains of living things
* Most sedimentary rocks are clastic rocks
  - come from sediments deposited on the margins of the ocean
  - form under water
  - occur in the form of layers called beds or strata
* Some sedimentary rock can also form from chemical and biological processes.
* Some sedimentary rocks are made of just one type of sediment, all about the same size, such as sand
  - can be porous
* are also the source of most fossils
  - because lots of minerals and other rocks have piled up
  - classified according to the type of material
  - extremely common throughout Iowa
* are formed by the accumulation of sediments
  - from broken pieces of rocks
  - in layers as sediments, usually on the bottom of the ocean
  - hard to date because they're made of particles from older rocks
  - important building materials
  - made of lots of particles that can stick together in all different directions
  - one of the three major rock groups
* are rocks that are laid down or deposited by wind or water
  - form from the accumulation of sediments
* are softer than igneous rocks and erode more easily
  - volcanic ones
  - stones
* are the erosion products of any kind of rock
  - great archive of Earth history
  - most common rocks on Earth
  - richest sources of fossils
* can also hold trace fossils, which record an organism's behavior.
* can change into metamorphic or igneous rock
  - rock or into igneous rock
  - form in one of three main ways
* changes into a different form when it undergoes heat, pressure or other forces.
* contain a layer of iridium, a mineral uncommon on Earth
  - important information about the history of the Earth
  - information about what earth's environment was like in the past
  - the overwhelming majority of fossils
  - valuable resources of oil, gas and mineral deposits
* develop from the lithification of sediments or weather rock debris.
* exhibit either clastic textures or nonclastic textures.
* form at the earth's surface
  - by lithification of sediment at the Earth's surface
  - from loose sediment or fragments that are cemented together and harden
  - layers or stratifications
* form when particles are cemented and bonded together
  - sediment settles under water and becomes compacted
  - sediments accumulate and are then consolidated
* have the appearance of a 'layer cake', at least at the time of deposition
  - lowest average susceptibility and basic igneous rocks, the highest
* includes sandstone, shale, mudstone, limestone, and clay.
* is among the most common rock on the surface of the planet
  - compacted sediment which can come from any of the other rocks
  - created by the bonding of sediment from broken down minerals
  - formed as layers of sediment are pressed together and harden
* is formed by layers of silt or mud on top of each other
  - the deposition of new layers over time
* is formed from earth materials gradually worn down by water, wind, and snow
  - layers of sediments piled on top of each other
  - in water
  - through the cementation of sediments under slight pressure
  - found all over the world
  - layered rocks that are formed by pressure
  - like a sandwich filled with many different layers
  - rock that has been made from sediment
* is rock that has formed from sediment, like sand, mud, small pieces of rocks
  - some kind of sediment
  - round on the ridgetops
* is the best place to look for dinosaur fossils
  - only type of rock to contain fossils
  - where aquifers are usually located
* keep getting pushed further and further down.
* lie uppermost in the crust.
* provide evidence for the long history of the earth.
* provides essential habitat for seabirds and marine mammals
  - evidence of the different changes in the earth's environments
* result from the consolidation of loose sediment that has accumulated in layers.
* tend to form a gradient of grain size and composition.
+ Geology, Types of rock, Sedimentary rock
  * Sedimentary rock is rock that has been made from sediment. Sediment is all solid pieces of stuff that are moved by the wind, water, or glaciers. Sediment can be made from clay, sand, gravel and the bodies and shells of animals. The sediment gets dropped in a layer at the bottom of a river or sea. As the sediment piles up, the lowers layers get squashed together. Slowly they set hard into rock.
  * Sediment is all solid pieces of stuff that are moved by the wind, water, or glaciers. Sediment can be made from clay, sand, gravel and the bodies and shells of animals. The sediment gets dropped in a layer at the bottom of a river or sea. As the sediment piles up, the lowers layers get squashed together. Slowly they set hard into rock. Some sedimentary rocks are made of just one type of sediment, all about the same size, such as sand. Other sedimentary rocks will have large and small lumps, and pieces made of different types of rock. Well-known sedimentary rocks are sandstone and limestone.
+ Rock (geology), Rock classification, Sedimentary rock
  * Sedimentary rocks are the most common rocks on Earth. They form at or near the Earth's surface. Sedimentary rock is formed in layers which were laid down one by one on top of another. Some of the layers are thin, some are thick. Layers are made by deposition of sediment, organic matter, and chemical precipitates. Deposition is followed by squeezing of sediment under its own weight, and cementation
  - cycle, Sedimentary rock
  * Sedimentary rock is compacted sediment which can come from any of the other rocks. It can erode back into sediment, or be pressurized into metamorphic rock