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Volcanic rocks (often shortened to volcanics in scientific contexts) are rocks formed from lava erupted from a volcano. Like all rock types, the concept of volcanic rock is artificial, and in nature volcanic rocks grade into hypabyssal and metamorphic rocks and constitute an important element of some sediments and sedimentary rocks. For these ...
Scoria is a pyroclastic, highly vesicular, dark-colored volcanic rock formed by ejection from a volcano as a molten blob and cooled in the air to form discrete grains called clasts. [1] [2] It is typically dark in color (brown, black or purplish-red), and basaltic or andesitic in composition.
Trachybasalt – Volcanic rock – A volcanic rock with a composition between basalt and trachyte Hawaiite – Volcanic rock – a sodic type of trachybasalt, typically formed by ocean island volcanism; Trachyte – Extrusive igneous rock – A silica-undersaturated volcanic rock; essentially a feldspathoid-bearing rhyolite
Pages in category "Volcanic rocks" The following 68 pages are in this category, out of 68 total. This list may not reflect recent changes. ...
Volcanic bombs or volcanic blocks – larger than 64 mm (2.5 inches) in diameter The use of tephra layers, which bear their own unique chemistry and character, as temporal marker horizons in archaeological and geological sites, is known as tephrochronology .
In the 1900s, deep drilling brought up warm water and volcanic rock. He said the top of it sits about 4,000 feet underground. It probably last erupted toward the end of the Cretaceous period which ...
A cinder cone (or scoria cone [1]) is a steep conical hill of loose pyroclastic fragments, such as volcanic clinkers, volcanic ash, or scoria that has been built around a volcanic vent. [2] [3] The pyroclastic fragments are formed by explosive eruptions or lava fountains from a single, typically cylindrical, vent.
Metavolcanic rock is volcanic rock that shows signs of having experienced metamorphism. [1] In other words, the rock was originally produced by a volcano, either as lava or tephra. The rock was then subjected to high pressure, high temperature or both, for example by burial under younger rocks, causing the original volcanic rock to recrystallize.