Term
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Definition
natural compounds of elements
solid
specific composition, which means each mineral:
has specific shape, other specifi physical characteristics, specific conditions it forms at |
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Term
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Definition
mixtures of minerals,
three main types:
sedimentary
igneous
metamorphic |
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Definition
| formed from cemented sediment |
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Term
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Definition
| formed when molten rock (magma) solidifies |
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Definition
| formed by altering pre-existing rock |
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Term
| intrusive (plutonic) rock |
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Definition
magma cools slowly
a few crystals at a time form
resulting rock has visible mineral crystals |
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| extrusive (volcanic) rock |
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Definition
cool rapidly
many crystals form at once
result in microscopic crystals |
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Definition
black to grey in color. <52% silica, 5-20% FeO and MgO
intrusive: gabbro
extrusive: basalt
also called basaltic |
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Term
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Definition
52-63% silica, <10% FeO and MgO, many light colored minerals
intrusive: diorite
extrusive: andesite
also called andesitic |
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Term
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Definition
>63% silica, very little FeO and MgO, many light colored minerals
intrusive: granite
extrusive: dacite and rhyolite |
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Definition
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Definition
granite and diorite
also sedimentary and metamorphic rocks |
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Definition
silica increases viscosity of magma (movement)
as silica concentration increases, tetrahedral link up |
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Term
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Definition
dissolved in magma at depth
released as gases near surface |
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Term
how melting occurs
PRESSURE RELEASE |
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Definition
| bring hot mantle rock up to a depth or pressure it will melt at |
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Term
how melting occurs
FLUX MELTING |
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Definition
| add water to mantle rock to lower its melting temperature |
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Term
how melting occurs
SECONDARY CRUST MELTING |
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Definition
| from contact with pre-existing magma |
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Term
| dry pressure release melting produces.. |
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Definition
| mafic magma, low silica, low viscosity, low amounts of water and CO2 |
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Term
| wet flux melting produces.. |
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Definition
| intermediate magma, higher viscosity, higher amounts of silica, water, and CO@ |
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Term
| secondary melting of continental crust produces.. |
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Definition
| felsic magma, very high viscosity, highest amounts of silica |
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Term
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Definition
magma that reaches the surface
flows along the ground as liquid
the cooled and solidified rock
thick flows cool slowly
vesciles: bubbles left by escaping gas |
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Term
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Definition
very hot ~1,000 to 1,300 degrees C
very fluid - thin flows, flow long distances, can cover large areas, very destructive of property
a'a: lava with sharp jagged crust
pahoehoe: lava with smooth crust |
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Term
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Definition
large eruptions of basal, may cover 1000s of km2, eruptions over thousands to millions
Deccan "traps" - ~65 mil years ago, may have helped trigger a mass extinction |
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Definition
| crust encases flow -> creates a tube, insulates flow, allows flow to travel a longer distance |
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Definition
| semi solid chunks of a flow, break off and roll |
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Definition
| underwater eruptions, lobes of lava quickly cool |
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Definition
| higher viscosity, thicker flows, do not travel as far as basalt |
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Definition
| intermediate felsic. high viscosity, very thick flows, remain close to vent, may form spires and ridges as it erupts. unstable |
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Definition
| rare, usually erupts at ash, flows often stay in vent, obsidian, rhyolitic magma, quenches to glass |
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Term
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Definition
magma thrown through air, can be mixed with volcanic gases, may be fragments of lava or glass.
tuff: a deposit of tephra
spatter: basaltic lava droplets, still liquid when it lands
Pele's tears: drops of lava, quench to glass in mid-air |
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Term
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Definition
| semi-solid vesiculated basaltic lava fragments, known as cinders, vesicles are open |
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Definition
pebble size tephra
may be solid lava fragments or cemented ash |
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Definition
| semi solid fragments, several cms to meters in size |
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Definition
| glassy foam, intermediate and felsic, vesicles sealed - pumice floats |
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| very small pumice fragments, often mixed with gases, sent aloft in eruption column. larger eruptions produce more ash and distribute it further |
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Definition
| ash and hot gas flowing down from vent up to 200km/hr, flows can cross over ridges and across bodies of water. can knock down and ignite forest and buildings |
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Definition
| thick layers of ash and pumice deposited by pyroclastic flows, often "welded" in center |
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Definition
| may be minor, may be only eruptive product |
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Definition
| steam vents, all types of volcanoes, contain sulfur dioxide gas that will deposit sulfur at vent |
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Definition
| geyser-icelandic for "gusher" groundwater heated by hot rock, flash boils and erupts. yellowstone has the most |
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Definition
| huge mudflows created when erupting ash mixes with water from rapidly melting snow and glaciers. can also occur months to years after eruption, heavy rain on thick ash deposits |
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Definition
| failure of the flank of a volcano can cause huge land slide or debris flow |
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Term
| volcano explosivity index (VEI) |
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Definition
| measure of relative violence of eruptions, particular event not for a volcano. scale 0-8. higher VEI, the more material comes out |
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Term
| effusive Hawaiin type eruptions |
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Definition
| not explosive, VEI 0-1. has basaltic lava flows, not limited to Hawaii, often involve eruptions from fissures, fire fountain: gas driven fountain of lava. gentle slope. built from many fluid lava flows. convex shape. build sheild volcanoes |
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Term
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Definition
| VEI 1-3, basaltic magma with slightly more silica and gas, short blasts lasting few seconds, build cinder cones, built from scoria and lava flows |
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Term
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Definition
| VEI of 3-5, intermediate (andesitic-dactic magma), often have high water contents, eruption cloud 3-25km high, bursts may last hours, large blocks (blocks), ash, steam, and gases |
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Term
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Definition
| VEI >5 high silica magma (>65%), high water and CO2 contents, eruption would >25km high, large amounts of ash |
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Term
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Definition
| a series of vulcanian and plinian eruptions, can be several thousand meters tall, consists of alternating ash and lava layers, central or side vents, have snow and ice because altitude is high, water vapor freezes |
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Term
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Definition
| rhyolitic lava builds up near vents to form, domes may also form on stratovolcanoes after large eruptions, eruptions may continue to take place from domes for many years |
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Term
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Definition
collapsed area due to: sinking of shield volcano summit or very large Plinian eruption, most calderas for explosiveley in stratovolcanoes (Crater Lake, OR)
eruptions form continental hotspots may collapse large areas of the crust |
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Term
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Definition
collapsed area due to: sinking of shield volcano summit or very large Plinian eruption, most calderas for explosiveley in stratovolcanoes (Crater Lake, OR)
eruptions form continental hotspots may collapse large areas of the crust |
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Term
| Phreatomagmatic Eruptions |
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Definition
| magma encounters ground or surface water, violent stream explosions result, any type of magma, produces "tuff rings" |
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Definition
| volcanic eruptions cannot be predicted years in advance. but bases on geological data, geologists can say how often and how explosively a volcano erupts |
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Definition
| seismic activity, gas emissions, deformation (swelling) of the volcano, change in groundwater chemistry |
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Definition
| seismometers set-up around volcano, quakes usually first warning sign |
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Definition
| ground rising and sifting due to rising magma, on ground instrumentation: tilt meters and GPS stations, satellite radar interferometry |
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Definition
SO2 in venting steam indicates presence of magma, measured remotely with correlation spectrometer (COSPEC)or direct sampling
CO2 also indicates magma beneath the surface, excess CO2 will kill trees and can be hazardous in confined areas
, clouds of CO2 are known as mazukus |
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Term
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Definition
| collect lava and ash to determine chemistry, provide silica content of magma and clues to magma origins |
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Definition
| hazardous to aircraft, can be tracked by satellite |
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Definition
| examine deposits from past eruptions, identifies potential hazard zones from future eruptions |
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Definition
| Hawaiians attributed volcanic eruptions to this goddess. Pele could take the form of an old woman or a dog, if not treated well she would send lava into offenders' village |
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Definition
| youngest shield on island, historically very active. most past eruptions from summit depression or caldera. 1983 eruption came from rift zone. shattered lava washed up along coast to create unique black sand |
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Definition
| seawater and basaltic lava = acidic steam and scalding water. newly cooled lava benches often collapse. people have fallen into scalding water |
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Definition
| largest shield volcano, 4170 meters above sea level, not as active as Kilauea, last erupted in 1984, may erupt again at any time |
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Definition
| inactive volcano, highest point in Hawaii (4206 m) had an ice cap during last ice age, erosion by ice not covered by new lava |
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Definition
| newest Hawaiian volcano, submarine |
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| on Maui, last recorded eruption out of big island, 1690 Strombolian eruption, "house of the sun" |
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| 1991 Pinatubo, Philippines |
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Definition
| rumbling, earth shook, 3 explosion craters, blast was mountain letting off steam, 400 earthquakes recorded, 10million ppl and 2 US military bases nearby. 6 million evacuate |
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Term
| SO2 aerosol in stratosphere will.. |
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Definition
| cause spectacular sunrises & sunsets, produce unsually colored sun and moon, lower average global temp |
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Definition
| collapse of volcano during Plinian eruption, may form in a stratovolcano or large region |
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Definition
| 1815, largest eruption in 500 yrs. villages buried, outside world knew little about eruption. 1816 - abnormally cold throughout North America. New England had a killing frost every month... snow in Maine even in July |
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| small island between Java and Sumatra, became active in 1883, climatic phase in August. 4 large explosions, largest noise ever recorded! massive ash falls. everyone around the world knew, but it was not as serious as Tambora |
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| 74,000 yrs ago. night-like darkess over a large region for weeks, 9m of ash deposited in India, 900km away, led to a volcanic winter -> followed by coldest 100 years of last Ice Age |
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| created by hotspot below North America, largest volcano on Earth if you consider caldera and surrounding area together, caldera forming eruptions every 600,000 |
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Definition
| caldera complex in eastern Cali, formed 7600 years ago, erupted from 35,00 to about 600 years ago |
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Definition
| most volcanic activity occurs on mid ocean ridges, intermittent eruptions of basalt, associated with unusual organisms |
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Definition
| recycle chemicals necessary for life, replenish soil, gather water in snow, rain, and ice, create valuable ore deposits |
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