Search results
Results from the WOW.Com Content Network
Diorite is an intrusive igneous rock composed principally of the silicate minerals plagioclase feldspar (typically andesine), biotite, hornblende, and sometimes pyroxene.The chemical composition of diorite is intermediate, between that of mafic gabbro and felsic granite.
Diorite – Igneous rock type Napoleonite, also known as corsite – Variety of diorite with orbicular structure; Dunite – Ultramafic and ultrabasic rock from Earth's mantle which is made of the mineral olivine; Essexite – Igneous rock type; Foidolite – Igneous rock rich in feldspathoid minerals; Gabbro – Coarse-grained mafic intrusive rock
Examples of phaneritic igneous rocks are gabbro, diorite, and granite. Porphyritic textures develop when conditions during the cooling of magma change relatively quickly. The earlier formed minerals will have formed slowly and remain as large crystals, whereas, sudden cooling causes the rapid crystallization of the remainder of the melt into a ...
Hooiberg is a Cretaceous-era tonalitic batholith that outcrops on Aruba consisting of tonalite with subordinate and comagmatic trondhjemite, diorite, gabbro, norite, and a dark-colored (melanocratic), hydrous, igneous rock termed hooibergite, or hornblende-rich mela-diorite.
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 ...
The Crazy Mountains have assemblages of diorite, gabbro, and peridotite as a result from laccoliths, sills and dikes. [7] This region's extensive subcontinental mantle is similar to mid-ocean ridge and ocean island basalt sources. [8]
The mountain is composed mostly of feldspar- and hornblende-rich diorite. [5] It is thought to have been formed during the Jurassic period (155–170 Ma) by invasive volcanic flows creating batholithic masses of diorite, which also helped to create the island arcs associated with the San Juan Islands. By the end of the late Jurassic period the ...
Dike swarms (also called dike complexes) are exposed in the eroded rift zones of Hawaiian volcanoes. As with most other magmatic dikes, these were fissures through which lava reached the surface. The swarms are typically 2.5 to 5 km in width, with individual dikes about a meter in width.