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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.
After magma is generated, magma will migrate out of its source region by the process of magma segregation and extraction. These processes define the resulting composition of the magma. Depending on the efficiency of the segregation and extraction, there will be different structures of the volcanic and igneous plumbing systems. [6]
The Salinan and Chumash tribes consider Morro Rock to be a sacred site. The Salinan name for Morro Rock is Le'samo and the Chumash name is Lisamu. [10]The Chumash had an important nearby prehistoric settlement at least as early as the Millingstone Horizon (6500-2000 B.C.E.), and the village was near the mouth of Morro Creek, at the current site of Morro Bay High School.
This volcanic plug, roughly 300 metres (980 feet) in diameter, has a potassium–argon date of 1.6 ± 0.2 million years which may be due to excess argon. [ 103 ] [ 107 ] The eruptions during Ice Peak time deposited 76.7 cubic kilometres (18.4 cubic miles) of volcanic material, making the Ice Peak Formation the most voluminous geological ...
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 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 ...
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Cabezon Peak is the solidified core of a volcano that erupted 2.658 ± 0.032 million years ago, based on argon-argon dating. The eruption at this volcano likely began with lava fountains from the vent, which built up a scoria cone. Lava later ponded in the interior of the cone, solidifying into a massive plug.