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A lava spine or lava spire is a growth that can form on the top of a lava dome. A lava spine can increase the instability of the underlying lava dome. A recent example of a lava spine is the spine formed in 1997 at the Soufrière Hills Volcano on Montserrat.
Lava domes are formed by the extrusion of viscous felsic magma. They can form prominent rounded protuberances, such as at Valles Caldera. As a volcano extrudes silicic lava, it can form an inflation dome or endogenous dome, gradually building up a large, pillow-like structure which cracks, fissures, and may release cooled chunks of rock and rubble.
Lava domes are common features on volcanoes around the world. Lava domes are known to exist on plate margins as well as in intra-arc hotspots, and on heights above 6000 m and in the sea floor. [1] Individual lava domes and volcanoes featuring lava domes are listed below.
The dome growth has been both endogenous and exogenous. The former implies dome interior expansion to accommodate new lava and the latter refers to superficial piling up of lava. Activity has been concentrated at several different vents, and Santiaguito now has the appearance of several overlapping domes. [16] At the beginning of dome growth ...
The volume of Chao is exceptional for a lava dome structure, although the lava flux rate generating it is low in comparison to a basaltic eruption like Laki in Iceland. This low flux rate is insufficient to cause caldera formation. Cerro Chao is the largest Quaternary silicic lava flow in the world. [1]
The Rockland complex formed between 825,000 and 609,000 years ago. It was the source of lava domes and lava flows of dacitic composition. Around 610,000 years ago over 130 km 3 [19] of rhyolite magma violently erupted onto the surface, producing massive pyroclastic flows and an ash plume several tens of kilometers high.
The six rhyodacite lava domes of Chaos Crags, where C and F are behind D and E. Between 385,000 and 315,000 years ago, volcanic activity in the Lassen volcanic center shifted dramatically from building andesitic stratovolcanoes to producing lava domes made of dacite. These eruptions formed the Lassen dome field, staged as andesite lava flows ...
In 1992, Coffin and Eldholm initially defined the term "large igneous province" as representing a variety of mafic igneous provinces with areal extent greater than 100,000 km 2 that represented "massive crustal emplacements of predominantly mafic (magnesium- and iron-rich) extrusive and intrusive rock, and originated via processes other than 'normal' seafloor spreading."