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17 Cards in this Set
- Front
- Back
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magma ascent rates
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vary by method
extrusive magma: 0.001 - 0.015 m/s kimberlites: 10 - 30 m/s |
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dike dimensions
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length (depth to source) : 2 - 6 km
width: avg ~ 1 - 6m, thicker for more viscou lavas width : max ~ 20 - 50m thicker at surface that at depth |
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VEI 0
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nonexplosive
gentle 10^4 m^3 of tephra eruption cloud column height <0.1 km |
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VEI 1
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small
effusive 10^6 m^3 of tephra eruption cloud column height 0.1 -1 km |
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VEI 2
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moderate
explosive 10^7 m^3 of tephra eruption cloud column height 1 - 5 km |
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VEI 3
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moderate-large
explosive 10^8 m^3 of tephra eruption cloud column height 3 - 15 km |
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VEI 4
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large
cataclysmic 10^9 m^3 of tephra eruption cloud column height 10 - 25 km |
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VEI 5
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very large
cataclysmic 10^10 m^3 of tephra eruption cloud column height >25 km |
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VEI 6
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very large
cataclysmic 10^11 m^3 of tephra eruption cloud column height >25 km |
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VEI 7
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very large
cataclysmic 10^12 m^3 of tephra eruption cloud column height >25 km |
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VEI 8
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very large
cataclysmic 10^13 m^3 of tephra eruption cloud column height >25 km |
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bulk density of tephra - ash fall
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600 - 800 kg/m3
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density of molten rock free of bubbles
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2300 - 2700 kg/m3
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How are silicate tetrahedron (SiO4) arranges in:
a) pyroxenes b) amphiboles c) micas |
Silicate Tetrahedra are arranges as follows:
pyroxenes - single chains amphibolde - double chains micas - sheets |
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Highly alkaline rocks have a lot of what?
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Highly alkaline rocks have a lot of sodium and potassium
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Basic rocks are often termed mafic. What is an example of a mafic rock?
What is the most silicic rock? |
Basalt is a mafic rock.
Rhyolite is the most silicic volcanic rock, followed by dacite. These rocks consist mostly of quartz and feldspars. |
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What three key factors influence the melting and freezing points of a magma?
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The solidus and liquidus depend on:
composition, temperature, and pressure. |
