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A volcanic plug, also called a volcanic neck or lava neck, is a volcanic object created when magma hardens within a vent on an active volcano. When present, a plug can cause an extreme build-up of high gas pressure if rising volatile -charged magma is trapped beneath it, and this can sometimes lead to an explosive eruption.
Two models of lopolith formation: the cantilevel model and the pistol model (After Cruden & Weinberg, 2018). [4] In the Cantilever model, lopoliths form by tilting of the floor. In the Pistol model, lopoliths form.by vertical subsidence of the floor. [4] Lopoliths are lenticular concordant intrusive masses that display a convex-down shape. It ...
Volcanic necks are feeder pipes for volcanoes that have been exposed by erosion. Surface exposures are typically cylindrical, but the intrusion often becomes elliptical or even cloverleaf-shaped at depth. Dikes often radiate from a volcanic neck, suggesting that necks tend to form at intersections of dikes where passage of magma is least ...
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 .
Morro Rock (Salinan: Le'samo; Chumash: Lisamu'; Spanish: El Morro) [4] [5] [6] is a volcanic plug in Morro Bay, California, on the Pacific Coast at the entrance to Morro Bay harbor. A causeway connects it with the shore, making it a tied island. The rock is protected as the Morro Rock State Preserve. [7]
A dike of lamprophyre near the Shiprock volcanic plug, New Mexico, that has resisted the erosion that removed some of the softer rock into which the dike was originally intruded. A magmatic dike is a sheet of igneous rock that cuts across older rock beds. It is formed when magma fills a fracture in the older beds and then cools and solidifies.
Volcanic pipes or volcanic conduits are subterranean geological structures formed by the violent, supersonic eruption of deep-origin volcanoes. They are considered to be a type of diatreme . Volcanic pipes are composed of a deep, narrow cone of solidified magma (described as "carrot-shaped"), and are usually largely composed of one of two ...
Volcanic rock types found on the Canary Islands are typical of oceanic islands. The volcanic rocks include alkali basalts, basanites, phonolites, trachytes, nephelinites, trachyandesites, tephrites and rhyolites. [19] [3] There are lava flows as well as deposits of pyroclastic material, such as tuff (made of volcanic ash or lapilli).