Shale

Shale is a fine-grained sedimentary rock whose original constituents were clays or muds. It is characterized by thin laminae breaking with an irregular curving fracture, often splintery, and parallel to the often indistinguishable bedding planes. Non-fissile rocks of similar composition but made of particles smaller than 1/16 mm are mudstones. Rocks with similar particle sizes but with less clay and therefore grittier are siltstones.

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The fine particles that compose shale can remain suspended in water long after the larger and denser particles of sand have deposited out. Shales are typically deposited in very slow moving water and are often found in lake and lagoonal deposits, in river deltas, on floodplains, and offshore of beach sands.

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Fossils, animal tracks/burrows, and even raindrop impact craters are sometimes preserved on shale bedding surfaces. Shales may also contain concretions.

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Shales that are subject to heat and pressure alter into a hard, fissile, and metamorphic material known as slate that is often used in building construction.

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Sedimentary rock: Sedimentary rock is one of the three main rock groups (along with igneous and metamorphic rocks) and is formed in three main ways—by the deposition of the weathered remains of other rocks (known as clastic sedimentary rocks); by the deposition of the results of biogenic activity; and by precip...

Clay: :For the town in the United States, see Clay, New York....

Mud: :This article is about a type of online computer game. For other uses of the word "mud," see mud...

Shale related Images and Photos (experimental)

Adam's Island Shale