Sedimentary rock
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Sedimentary rocks are types of rock formed by the cementation of sediments—i.e. particles made of minerals or organic matter —that have been accumulated or deposited at Earth's surface. Sedimentation
Middle Triassic marginal marine sequence of siltstones (reddish layers at the cliff base) and limestones (brown rocks above), Virgin Formation, southwestern Utah, U.S.
Uluru (Ayers Rock) is a large sandstone formation in Northern Territory, Australia.
Claystone deposited in Glacial Lake Missoula, Montana, United States. Note the very fine and flat bedding, common for deposits coming from lake beds further away from the source of sediment.
Sedimentary rock with sandstone in Malta, southern Europe
Clastic rock
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Clastic rocks are composed of fragments, or clasts, of pre-existing minerals and rock. A clast is a fragment of geological detritus, chunks, and smaller grains of rock broken off other rocks by physic
A thin section of a clast (sand grain), derived from a basalt scoria. Vesicles (air bubbles) can be seen throughout the clast. Plane-polarized light above, cross-polarized light below. Scale box is 0.25 mm.
Conglomerate
Breccia. Notice the angular nature of the large clasts