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Extrusive igneous rock is made from lava released by volcanoes Sample of basalt (an extrusive igneous rock), found in Massachusetts. Extrusive igneous rock, also known as volcanic rock, is 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, rapidly ...
Diorite (/ ˈ d aɪ. ə r aɪ t / DY-ə-ryte) [1] [2] is an intrusive igneous rock formed by the slow cooling underground of magma (molten rock) that has a moderate content of silica and a relatively low content of alkali metals. It is intermediate in composition between low-silica gabbro and high-silica granite.
When rocks are pushed deep under the Earth's surface, they may melt into magma. If the conditions no longer exist for the magma to stay in its liquid state, it cools and solidifies into an igneous rock. A rock that cools within the Earth is called intrusive or plutonic and cools very slowly, producing a coarse-grained texture such as the rock ...
As of 2014 about 6,400 kimberlite pipes are known on Earth including about 900 that have been found to contain diamonds, with mining of diamonds occurring at about 30 pipes. [ 25 ] The discovery of diamond-rich kimberlite pipes in northern Canada during the early 1990s serves as a prime example of how challenging these deposits can be to locate ...
Metamorphic rocks are created by rocks that have been transformed into another kind of rock, usually by some combination of heat, pressure, and chemical alteration. Sedimentary rocks are created by a variety of processes but usually involving deposition, grain by grain, layer by layer, in water or, in the case of terrestrial sediments, on land ...
During retrograde metamorphism, near-isobaric cooling after the peak took place, indicating that the rock stays at the same position while the magma cools. [ 16 ] Intrusion of magma results in a great increment in temperature and a slight increase in pressure experienced by the underlying rocks, which gives prograde metamorphism.
Using lasers to analyze minerals and rocks extracted from the Argyle deposit, the researchers found that the pink diamond-rich site formed during the breakup of an ancient supercontinent, called ...
Cumulate rocks are igneous rocks formed by the accumulation of crystals from a magma either by settling or floating. Cumulate rocks are named according to their texture ; cumulate texture is diagnostic of the conditions of formation of this group of igneous rocks.