igneousII

igneousII - Physical Geology 101 9. Igneous Rocks II (p....

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Physical Geology 101 1 9. Igneous Rocks II (p. 104-114; 116-119; 149-153) Textures of Igneous Rocks The rate of cooling and crystal size determines the texture of an igneous rock. What is the definition of rock texture? _______________________________________ ______________________________________________________________________ We define two types of igneous rocks on the basis of grain size: 1. ____________________: rapid cooling at the Earth's surface small mineral grains. Forms from ______________. Also called: __________________ 2. ____________________: slow cooling inside the Earth large mineral grains Forms from ______________. Also called: __________________ Types of Rock Textures Magma that rises to the Earth's surface erupts as lava and immediately starts to cool due to contact with either the atmosphere or sea water. What are the two ways lava erupts onto the Earth's surface? _______________________________ (volcanic mountains) _______________________________ (big cracks in the crust) Bulbous pods of chilled lava are formed whenever lava erupts onto the ocean bottom or in a lake. What do we call this type of lava? ______________________ What is the general name given to the volcanic glass that forms due to very rapid cooling of lava? _______________. What sort of texture does it have? _____________ When small crystals develop from cooling of lava , the texture is called: ______________________ (also called ___________________) When big crystals develop from cooling of magma , the texture is called: ______________________ (also called ___________________)
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Physical Geology 101 2 Crystals start to grow in magma before it erupts, so volcanic rocks often contain these larger-sized crystals, called __________________, that then become embedded in a matrix of much smaller grained crystals (called ___________________) that grew after the lava erupted. This type of texture is called a __________________ texture. What are gas bubbles in lava called when they are frozen in place? ________________
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This note was uploaded on 01/13/2012 for the course GEOL 101 taught by Professor Williams,t during the Fall '08 term at Idaho.

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igneousII - Physical Geology 101 9. Igneous Rocks II (p....

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