Ees 101 Iii--6Th Column

Front 1

Polymerizing

Back 1

as you add more silica to magma, it becomes more viscous

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Partial Melting

Back 2

some minerals melt while others remain solid due to differences in their melting point

Front 3

Assimilation

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magma can melt surrounding rock, and assimilates new compounds into mixture produced in the upper mantle.

Front 4

Magma Mixing

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magma can mix with other bodies of magma or separate

Front 5

Decompression

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hot magma rises, pressure is lowered at shallow depths, therefore lowering its melting point. This causes melting.

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Volatiles

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Volatiles in a magma with a high viscosity, generally felsic with a higher silica (SiO2) content, tend to produce eruptions that are explosive. Volatiles in a magma with a low viscosity, generally mafic with a lower silica content, tend to vent and can give rise to a lava fountain.

Front 7

Magma Composition

Back 7

Si, O, Ca, Al, Fe, Na, Mg, K

Front 8

Weight Percent

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Earth is very felsic on the outside, very magic on inside.

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Intrusions

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is liquid rock that forms under Earth's surface. Magma from under the surface is slowly pushed up from deep within the earth into any cracks or spaces it can find, sometimes pushing existing country rock out of the way, a process that can take millions of years. As the rock slowly cools into a solid, the different parts of the magma crystallize into minerals. Many mountain ranges, such as the Sierra Nevada in California, are formed mostly by intrusive rock, large granite (or related rock) formations.

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Fractional Crystallization

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is the removal and segregation from a melt of mineral precipitates; except in special cases, removal of the crystals changes the composition of the magma. Fractional crystallization in silicate melts (magmas) is complex compared to crystallization in chemical systems at constant pressure and composition, because changes in pressure and composition can have dramatic effects on magma evolution.

Front 11

Dike

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A dike or dyke in geology is a type of sheet intrusion referring to any geologic body that cuts discordantly across

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Sill

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a sill is a tabular sheet intrusion that has intruded between older layers of sedimentary rock, beds of volcanic lava or tuff, or even along the direction of foliation in metamorphic rock. The term sill is synonymous with concordant intrusive sheet. This means that the sill does not cut across preexisting rocks, in contrast to dikes which do cut across older rocks.

Front 13

Laccolith

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A laccolith is a sheet intrusion (or concordant pluton) that has been injected between two layers of sedimentary rock. The pressure of the magma is high enough that the overlying strata are forced upward, giving the laccolith a dome or mushroom-like form with a generally planar base.

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Pluton

Back 14

A pluton in geology is a body of intrusive igneous rock (called a plutonic rock) that crystallized from magma slowly cooling below the surface of the Earth. Plutons include batholiths, dikes, sills, laccoliths, lopoliths, and other igneous bodies. In practice, "pluton" usually refers to a distinctive mass of igneous rock, typically several kilometers in dimension, without a tabular shape like those of dikes and sills.

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Batholith

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is a large emplacement of igneous intrusive (also called plutonic) rock that forms from cooled magma deep in the Earth's crust. Batholiths are almost always made mostly of felsic or intermediate rock-types, such as granite, quartz monzonite, or diorite

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Xenolith

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s a rock fragment which becomes enveloped in a larger rock during the latter's development and hardening. In geology, the term xenolith is almost exclusively used to describe inclusions in igneous rock during magma emplacement and eruption. Xenoliths may be engulfed along the margins of a magma chamber, torn loose from the walls of an erupting lava conduit or explosive diatreme or picked up along the base of a flowing lava on Earth's surface.