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27 Cards in this Set
- Front
- Back
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How are magmatic segregation deposits formed? |
Differentiation or direct crystallization of magmas |
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What are the three types of magmatic segregation deposits? |
Mafic segregation deposits Felicity and intermediate intrusions Pegmatites |
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What tectonic environment doe Mafic segregation deposits form in? |
Cratons or continental crust undergoing rifting. |
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What are some examples of mafic segregation deposits? |
Layered mafic intrusions Kimberlites Carbonatites Ophiolites |
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Where can felsic/intermediate segregation deposits be found? |
Orogenic belts |
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What are examples of felsic and intermediate segregation deposits. |
Porphyry base metal deposits Hydrothermal iron Cordilleran veins Skarns |
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What are porphyry base metal deposits? |
Gigantic hydrothermal systems Ringed by outer zones of Pb, Zn,Mn, Ag, Au From shallow seated intrusive activity Most important deposits associated with intrusions. |
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What are some common pegmatitic ore deposits? |
Uranium Thorium Rare earth elements Molybdenum |
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How are solution demobilization deposits formed? |
Circulation fluids that scavenge metallic ions Redeposit them in fractures as vein deposits. |
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What is a common solution demobilization deposit? |
Quartz-carbonate-gold Mother load in California |
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How are epigenetic deposits formed? |
After host rock deposited Heated aqueous fluids or associated with Angelou’s activity |
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What are some examples epigenetic deposits? |
Mississippi Valley Deposits (lead-zinc) Western States Uranium Deposits Athabaskan-type unconformity related uranium |
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Where can MVDs be found? |
Structurally passive areas Mid continent craton US |
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How do MVDs form? |
When warm brines containing metals migrate from basins into carbonate seds at the margins of the basin. |
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What are common MVD deposits? |
Galena Sphalerite Barite-fluorite |
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What are the different categories of Volcanic deposits? |
Subaerial -epithermal and submarine - volcanogenic |
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What is an epithermal deposit? |
Deposits formed from volcanic-related hydrothermal activity at shallow depths. Low temps and pressures |
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Are subaerial volcanic deposits and epithermal deposits related? |
Yes. |
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What are some common characteristics of epithermal deposits? |
Country rock near epithermal veins extensively altered Have a discrete base Covered by iron oxide cap (gossan- pyrite rich) |
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How are volcanogenic deposits formed? |
Stratabound deposits formed underwater by: -volcanic processes -Thermal springs |
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What are some common volcanogenic deposits? |
Volcanogenic Massive Sulfides Branded iron formations Black shale hosted ores |
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What comprises Vocanogenic massive sulfides? |
Cu Zn Pb Ag |
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What comprises Vocanogenic massive sulfides? |
Cu Zn Pb Ag |
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How are massive suffixes created? |
Volcanically heated seawater dissolved elements in magma and mineral rich brine emerges through black smokers |
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How are regional metamorphic deposits formed? |
Under high temps/pressures during regional metamorphism. |
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What are the two types of regional metamorphic deposits? |
New metamorphic rocks/minerals are formed Deposits from mobiles and re-emplaces constituents. |
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What are common metamorphic ores? |
Industrial rocks/minerals (graphite, garnet, asbestos, mica, talc) Gems Uranium |
