Batholith, lava and destructive margins?

A book reads 'The rising magma at destructive margins is more acidic and flows less easily. Then it may solidify with the mountain mass to form batholith instrusions'.





The 1st question: why is the molten lava at destructive margins is more acidic than anywhere else, say that at convergent margins?


And why more acidic lava flows less easily?





The 2nd question: Batholiths are formed by the process of intrusion and solidification of lava. Do all the fold mountains, created at collision zones, have batholiths?





I've just found these on the Net. Could you help me giving more real examples?


Sierra Nevada Batholith


Panguipulli Batholith


Patagonian Batholith


(Does Himalayas belong to it?)





The 3rd question: Which exact location does the batholith formed - in the asthenosphere, lithosphere or somewhere between them?|||Some confusion in terminology here. Destructive and Convergent boundaries are one and the same thing. Acidic lavas typically have more SiO2 in them, 60%+. The higher the silica content, the more acidic the lava. High mineral content makes the lava more viscous/sticky and can result in explosive volcanic activity.





As the plate descends into the asthenosphere it will take down some water within it. Water lowers the melting temperature of the overlying asthenosphere and causes partial melting. The composition of the resulting volcanic activity will depend upon what lies above: if there is more oceanic crust then the lavas produced will be basaltic and andesitic in composition. The volcanic arc will form a line of islands (e.g. Japan). If the overlying crust is continental then some of the magma produced will be more granitic in composition. There will still be volcanic activity producing basaltic and andesitic lavas, but there will also be more silica-rich lavas such as rhyolites and dacites, as well as the intrusion of granite plutons beneath the surface. Magmas which are richer in silica tend to produce more explosive volcanism.





Batholiths are formed either as one large mass or many smaller masses at great depths in the earth's crust and are exposed at the surface only after considerable erosion of the overlying mountain mass. They are commonly associated with lithospheric plate boundaries, where the interactions between plates can produce sufficient heat to melt crustal rocks on a large scale and form batholiths.





One of the largest single batholiths in North America is the Coast Range batholith of W Canada and Alaska, encompassing an area of about 73,000 sq mi (182,500 sq km). Important batholiths in the United States include the Idaho batholith, 18,000 sq mi (45,000 sq km), and the Sierra Nevada batholith, 16,000 sq mi (40,000 sq km).





The Himalayas do belong to it. The formation of the Rutog pluton suggests flat subduction of the Neo-Tethyan oceanic lithosphere from the south. Crustal thickening may have occurred in the Late Cretaceous prior to the India鈥揂sia collision. The Rutog granitic pluton lies in the Gangdese magmatic arc in the westernmost part of the Lhasa Terrane, NW Tibet.








Granitic Plutons form in Continental Crust.|||1 it forms a shield volcano which means the acid is thick and adic


when a dome volcano forms its runny and not acidic





2 no batholiths are arent formed with certain sorts of rock





himalayas dont belong and the only place i know is dartmoor that was my case study through my gcse years





3 batholith is magma pushing into the earths crust|||1) there is no such thing as a destructive margin. Convergent margins are where subduction of denser oceanic basaltic crust is submerged underneath less dense continental granitic/acidic crust. When a basaltic oceanic crust melts because of pressure and temperature at 750Km into the mantle, because the magma has a lower density then the surrounding mantle material, it starts to rise. as it rises through the mantle crust, it picks up more silica, SiO2. SiO2 increases the viscosity and acidity ( more Si) of the magma. H2O vapor at high pressure in the magma makes it more explosive. Magmas with higher viscosities flow less easily than more basaltic.basic magma with Fe/Mg compounds predominating.





2) Batholiths are formed from magma that fractionally crystallizes as it slowly cools, Some batholiths have not completely fractionally crystallized because they are still cooling down. Most folded mountains do have batholiths, but only those where the pressure and temperatures are high enough to raise the temperature above the melting points of the minerals at the lower lithosphere/crust and asthenosphere boundary.





The sierra Nevada batholith may be still fractionally crystallizing, Yes, the Himalayas will be forming batholiths in the future, but the collision between the Asian and Indo-Australian plates is still young enough that no magma is rising from the collision of two granitic/acidic crusts/mantles. No subduction is taking place because the densities of the colliding crusts/mantles is equal.|||A batholith is formed by the scum and deposit that collects in a ring around the bath if you don't wash it. You can get it from most student's bathrooms.





Lava is the oily stuff they make Lave Lamps with.





Destructive Margins are temper tantrums that geology students get when they try to get others to do their coursework instead of GOING TO THE FECKING LECTURES AND READING THE FECKING TEXTBOOKS.





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