Geology Chapter Four Flashcards

A broad constructive magnetic anomaly near the center of the caldera could additionally be caused by a thick part of magnetic volcanic move lying east of the projected Hilton Creek fault and underlying much of the eastern basin. Viscosity is a key soften property in understanding the behaviour of magmas. The viscosity is usually decided by composition but can also be depending on temperature. The tendency of felsic lava to be cooler than mafic lava increases the viscosity difference. Where two tectonic plates converge, if one or both of the plates is oceanic lithosphere, a subduction zone will kind. An oceanic plate will sink back into the mantle.

D. There just isn’t sufficient information to ascertain the relative viscosities of these magmas. ________ lava is basically restricted to slim zones alongside convergent plate boundaries. Most of the basalt and gabbro on the ocean ground is created at mid oceanic ridges, which are additionally ____. On its sluggish journey via the crust, mafic magma evolves into intermediate magma by differentiation and assimilation of ______. Hawaii and __________ eruptions are associated to intraplate igneous exercise.

Water acts as a community modifier, and dissolved water drastically reduces soften viscosity. Carbon dioxide neutralizes community modifiers, so dissolved carbon dioxide will increase the viscosity. Higher-temperature melts are much less viscous, since extra thermal power is available to break bonds between oxygen and network formers. Between rock-forming minerals, these parts aren’t markedly redistributed upon reasonable fractional crystallization of melts and, subsequently, include data on the subcrustal circumstances of such a process.

This ends in plug circulate of partially crystalline magma. A acquainted instance of plug move is toothpaste squeezed out of a toothpaste tube. The toothpaste comes out as a semisolid plug, as a end result of shear is concentrated in a thin layer within the toothpaste subsequent to the tube, and only right here does the toothpaste behave as a fluid. Thixotropic habits additionally hinders crystals from settling out of the magma. Once the crystal content material reaches about 60%, the magma ceases to behave like a fluid and begins to behave like a strong. Such a mix of crystals with melted rock is typically described as crystal mush.

Deposits of coal have been found beneath the ice of Antarctica. Use Wegener’s speculation to explain how coal might be found so near where does an mpls label go in a pdu? to the South Pole. _____ is/are widespread in the last stages of development of a typical protect volcano.

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