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Slate is a fine-grained, foliated, homogeneous, metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade, regional metamorphism. It is the finest-grained foliated metamorphic rock. [ 1 ]
Metamorphic rock can be formed locally when rock is heated by the intrusion of hot molten rock called magma from the Earth's interior. The study of metamorphic rocks (now exposed at the Earth's surface following erosion and uplift) provides information about the temperatures and pressures that occur at great depths within the Earth's crust.
A claystone is a lithified and non-cleavable mudrock. In order for a rock to be considered a claystone, it must consist of at least fifty percent clay (phyllosilicates), whose particle measures less than 1/256 of a millimeter in size.
Argillite (/ ˈ ɑːr dʒ ɪ l aɪ t /) is a fine-grained sedimentary rock composed predominantly of indurated clay particles. Argillaceous rocks are basically lithified muds and oozes. They contain variable amounts of silt-sized particles. The argillites grade into shale when the fissile layering typical of shale is developed.
The premise that the processes affecting the earth today are the same as in the past is the basis for determining how sedimentary features in the rock record were formed. By comparing similar features today to features in the rock record—for example, by comparing modern sand dunes to dunes preserved in ancient aeolian sandstones—geologists ...
Psychology Today is an American media organization with a focus on psychology and human behavior. The publication began as a bimonthly magazine, which first appeared in 1967. The print magazine's reported circulation is 275,000 as of 2023. [ 2 ]
Unmetamorphosed sedimentary rocks are found in the rock record from the Cambrian, in the early Paleozoic.The feldspathic quartz sandstone and orthoquartz sandstone of Chequamegon, Devils Island and Orienta formations make up the Bayfield Group which underlies the entire Lake Superior shoreline of the state from Chequamecon Bay to the St. Louis River in the west.
The result is large and small branching fractures throughout the rocks. [1] [2] [3] Shatter cones can range in size from microscopic to several meters. The largest known shatter cone in the world (more than 10 metres in length) is located at the Slate Islands in Terrace Bay, Ontario, Canada. The azimuths of the cones' axes typically radiate ...