Physical Exam II Study Guide - Spring 2008

Physical Exam II Study Guide - Spring 2008 - Physical...

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Physical Geology Exam II Study Guide Spring 2008 Rock Cycle/Igneous rocks Rock Cycle Intrusive vs. Extrusive Intrusive o Magma cools and solidifies inside earth Extrusive o Formed at earth’s surface Volcanic vs. Plutonic Volcanic o Rocks formed from lava Plutonic o Rocks formed from magma at depth Three Components of Magma Melt Solids Volatiles Igneous Rock Textures Phaneritic o Visible, large crystals Aphanitic o Not visible, small crystals Glassy o Nearly instant cooling Poryphyritic o Large and Small Crystals Pegmatic o Very large crystals Pyroclastic o Fragmental apperance Crystal Size Factors o Slow Rate = Large Crystals o Fast Rate = Small Crystals Interpretations Mafic vs Felsic Mafic o Dark o Very dense o Olivine, Biotite Mica Felsic o Light Colored o Quartz, Muscovite Mica Silica and Melting Points Igneous Rock Naming Texture and Composition
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Magma Origin Magma Formation Decompression melting Divergent plate boundary o Primarily in mid-Ocean ridges from a mantle plume o Created Hawaiian Islands Decrease in pressure Bowens Reaction Series Magmatic Differentiation Formation of secondary magma from single parent magma Assimilation Incorporation of surrounding rock bodies into a magma Magma mixing Mixing of chemically distinct magmas Partial Melting Incomplete melting of rock and incorporation of melt Viscosity of Magma Resistance to Flow Increases with increased silica Crystal Settling (Fractional Crystallization) Minerals that form at high temperatures are separated Volcanism and Igneous Activity Viscosity and Silica Tetrahedra Amount and Arrangement o More viscosity = more explosive o More complex arrangement = harder flow Composition of Resulting Rocks Type of Eruption o Mafic – Mild o Felsic - Explosive Openings in volcanoes Crater o Less than 1 km diameter Caldera o Greater than 1 km diameter o Formed after eruption, when empty space below causes surface to cave in Fumarole o Doesn’t connect to magma chamber Vent o Opening that connects to magma chamber Types of Volcanoes Shield o Shallow sides o Tallest o Magic lava spreads out
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Cinder Cone o Steep sides o Shortest o Felsic lava Composite o Size varies o Causes lots of damage o Both types of lava, but at different times
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Physical Exam II Study Guide - Spring 2008 - Physical...

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