Search results
Results from the WOW.Com Content Network
The tholeiitic magma series (/ ˌθoʊliˈaɪtɪk /) is one of two main magma series in subalkaline igneous rocks, the other being the calc-alkaline series. A magma series is a chemically distinct range of magma compositions that describes the evolution of a mafic magma into a more evolved, silica rich end member. Rock types of the tholeiitic ...
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 ...
Gabbro (/ ˈɡæbroʊ / GAB-roh) is a phaneritic (coarse-grained and magnesium- and iron-rich), mafic intrusive igneous rock formed from the slow cooling magma into a holocrystalline mass deep beneath the Earth 's surface. Slow-cooling, coarse-grained gabbro is chemically equivalent to rapid-cooling, fine-grained basalt.
Model of the crystallization of a subsurface magma chamber. The Skaergaard intrusion was formed 56 million years ago during the opening of the North Atlantic Ocean. [1] The intrusion was emplaced beneath the preexisting rock in the region, including plateau basalt and gneiss. [1][2] The intrusion has a general oval shape, which is atypical in ...
A large igneous province (LIP) is an extremely large accumulation of igneous rocks, including intrusive (sills, dikes) and extrusive (lava flows, tephra deposits), arising when magma travels through the crust towards the surface. The formation of LIPs is variously attributed to mantle plumes or to processes associated with divergent plate ...
The mafic rocks also typically have a higher density than felsic rocks. The term roughly corresponds to the older basic rock class. [9] Mafic lava, before cooling, has a low viscosity, in comparison with felsic lava, due to the lower silica content in mafic magma. Water and other volatiles can more easily and gradually escape from mafic lava.
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.
In essence, fractional crystallization is the removal of early formed crystals from an originally homogeneous magma (for example, by gravity settling) so that these crystals are prevented from further reaction with the residual melt. [3] The composition of the remaining melt becomes relatively depleted in some components and enriched in others ...