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Dike (geology) A magmatic dike (vertical) cross-cutting horizontal layers of sedimentary rock, in Makhtesh Ramon, Israel. In geology, a dike or dyke is a sheet of rock that is formed in a fracture of a pre-existing rock body. Dikes can be either magmatic or sedimentary in origin. Magmatic dikes form when magma flows into a crack then solidifies ...
A composite dike can include rocks as different as granophyre and diabase. [37] While there is often little visual evidence of multiple injections in the field, there is geochemical evidence. [38] Zircon zoning provides important evidence for determining if a single magmatic event or a series of injections were the methods of emplacement.
Dike swarm. A dike swarm (American spelling) or dyke swarm (British spelling) is a large geological structure consisting of a major group of parallel, linear, or radially oriented magmatic dikes intruded within continental crust or central volcanoes in rift zones. Examples exist in Iceland [1] and near other large volcanoes, (stratovolcanoes ...
QAPF diagram for the classification of plutonic rocks Devils Tower, United States, an igneous intrusion exposed when the surrounding softer rock eroded away. Intrusive rock is formed when magma penetrates existing rock, crystallizes, and solidifies underground to form intrusions, such as batholiths, dikes, sills, laccoliths, and volcanic necks.
Igneous rock (igneous from Latin igneus 'fiery'), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rocks are formed through the cooling and solidification of magma or lava. The magma can be derived from partial melts of existing rocks in either a planet 's mantle or crust.
A sheeted dyke complex, or sheeted dike complex, is a series of sub-parallel intrusions of igneous rock, forming a layer within the oceanic crust. [1] At mid-ocean ridges , dykes are formed when magma beneath areas of tectonic plate divergence travels through a fracture in the earlier formed oceanic crust, feeding the lavas above and cooling ...
Table 1: Geometry of dykes [17] Feature Description Shape: Dykes are in sheet-like and planar shape. Thick dykes are usually straight, but most dykes are sinuous. Length and thickness: Dykes are very thin when comparing to their length. Some megadykes can be 500 to 1000 km long, and some can be 100 to 200 m thick. Segmentation
Sill (geology) Illustration showing the difference between a dike and a sill. In geology, a sill is a tabular sheet intrusion that has intruded between older layers of sedimentary rock, beds of volcanic lava or tuff, or along the direction of foliation in metamorphic rock. A sill is a concordant intrusive sheet, meaning that it does not cut ...