Geo Ch. 4
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This 3 page Bundle was uploaded by Jamila Ruffin on Thursday January 7, 2016. The Bundle belongs to GEO 101 at University of Alabama - Tuscaloosa taught by Laura Whitaker in Spring2015. Since its upload, it has received 19 views.
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Date Created: 01/07/16
Geo. Ch. 4 Notes Minerals— Mafic: o Simpler structure o Dark colored; more dense o Contain iron and magnesium Felsic: o More complex o Light colored; less dense o No iron or magnesium Nonsilicate minerals: 1. Hematite (oxide) 2. Halite (NaCl) 3. Native copper (Cu) 4. Carbonates (Co3) 5. Sphalerite (Zn, Fe) The Rock Cycle o Illustrates the different processes and paths as Earth materials change both on the surface and inside the Earth What was early Earth like? 1. The earth is a big rock called magma; crystallized to solid state where exposed to lower temperatures 2. Had no water; surface temperature higher at boiling point 3. Atmosphere Earth’s layers: 1. Crust; oceanic 2. Mantle; plastic 3. Core; outer is liquid and inner is solid *Igneous rocks are rocks that have formed by crystallization of magma Partial melting of rocks at depth is called magma Magma at surface is called lava Lava = extrusive or volcanic rocks Magma= intrusive rocks What is magma made of? 1. Liquid portion melt 2. Solids mineral crystals and rock bits 3. Volatiles dissolved gases Factors affecting magma transformations: 1. Heat temperature increases in upper crust 2. Pressure increases in pressure b/c increase in rock’s melting temperature 3. Volatiles causes rock to melt at lower temperature Magma crystallization magma becomes solid The rate of magma cooling and crystallization determines the final composition of the solid rock A slow cooling rate promotes an interlocking mass of mineral crystals visible to the eye A rapid rate of cooling doesn’t allow the mineral crystal to grow large enough to see visible to the eye If lava cools too rapidly, then the crystalline structure associated with minerals doesn’t have time to form Igneous Rock Classification: Texture depends on how large the individual mineral grains are in the final solid rock When cooled in depth: intrusive When cooled on the surface: extrusive Igneous Textures: 1. Aphanitic (fine grained): texture lava cools near the surface 2. Phaneritic (course gained): texture lava cools at depth slowly 3. Porphyritic: indicates two stages of cooling 4. Glassy: texture very rapid cooling; resulting rock called obsidian 5. Pyroclastic: texture debris of explosive volcanoes 6. Pegmatitic: texture very low cooling; forms in late stage of crystallization Magma changes in physical state and chemical composition Magma Composition Bowen’s Reaction Series: o All magmas derived from a parent magma o As temperature decreases, mineral crystallization occurs o SUMMARY: mafic minerals crystallize first then felsic minerals *Minerals don’t crystallize simultaneously, but in predictable sequencefractional crystallization
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