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49 Cards in this Set

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aa flow, p 144
a type of lava flow that has a jagged, block surface
can you differentiate between aa lava and pahoehoe lava?
batholith, p 167
a large mass of igeous rock that formed when magma was emplaced at depth, crystallized, and was subsequently exposed by erosion.
block lava
caldera, p 147
A large, basin-shaped depression, more or less circular in form, usually caused by collapse or ejection of the summit area of a volcano. Typically steep-sided, found at the summit of a shield volcano . Calderas are 1 km in diameter or more. See the diagram on p. 689.
what is the difference between volcanoes with craters and volcanoes with calderas at their summits?
cinder cone, p 151
a rather small volcano built primarily of ejected lava fragments that consist mostly of pea-sized to walnut-sized lapilli. See the diagram on p. 690.
columnar joints, p. 166
A pattern of cracks that forms during cooling of molten rock to generat columns.
We'll see these at the Natural History Museum.
composite cone, p 153
A volcano composed of both lava flows and pyroclastic material. See the diagram on p. 690.
concordant, p 163
A term used to describe intrusive igeous masses that form parallel to the bedding of the surrounding rock.
we'll cover this when we do block diagrams on Mar 31
conduit, p 147
a pipelike opening through which magma moves toward Earth's surface. It terminates at a surface opening called a vent.
crater (volcanic), p 147
a depression, either at the summit of a volcano or at a meteorite impact site. Volcanic craters are less than 1 km in diameter.
dike, p 163
a tabular-shaped intrusive igenous feature cutting through the surrounding rock
we'll cover this when we do block diagrams on Mar 31
discordant, p 163
a term used to describe plutons cutting across existing rock structures, such as bedding planes
we'll cover this when we do block diagrams on Mar 31
eruption column, p 142
buoyant plumes of hot ash-laden gases that can rise up to thousands of meters into the atmosphere
airplanes flying through eruption columns have had engine failure from the intake of ash. Plumes don't show up well on radar, so it's a big problem for pilots to avoid atmospheric ash.
fissure, p 159
a crack in a rock that has opened up (some cracks don't open up) so that there is a distinct separation between sides that were once joined
fissure eruption, p. 160
an eruption in which lava is extrudedf from narrow fractures or cracks in the crust
flood basalt, p 160
Flows of basaltic lava issuing from cracks or fissures. Flood basalts usually cover wide areas(some the size of states) to great thickness (hundreds of meters)
fumarole, p 147
a vent in a volcanic area from which fumes and gasses escape
intraplate volcanism, p 174
igenous activity occurring within a tectonic plate far way from plate boundaries (not near the edge of the plate)
we'll cover this when we do plate margins in mid- to late-March
laccolith, p 166
a massive igneous body intruded between preexisiting strata. see diagrm on p 695
we'll cover this when we do block diagrams on Mar 31
lahar, p 157
a debris flow on the slopes of a volcano. Lahars form when layers of unstable ash and debris become saturated with water (and vapor) and flow downslope, usually along stream channels
the lahars during the eruption of Mount St Helens were especially dangerous, They picked up houses and logging trucks and carried them far downstream
lava dome, p 161
a bulbous mass found at the main vent of many old-age volcanoses. Lava domes are produced when thick lava is slowly squeezed from the vent. They sometimes act as plugs, deflecting subsequent eruptions of gas.
a lava dome acts a lot like the dried up toothpaste blocking the opening in your toothpaste dispenser
lava tube, p 144
a tunnel in hardened lava acting as a horizontal conduit for flva flowing from a volcanic vent. Lava tubes allow fluid lavas to advance great distances underground before they surface.
Lava tubes are empty once the lava has moved on. They are a long narrow caves, some with lava stalagmites.
massive pluton, p 163
a pluton that is not tabular in shape, but rather blocky or irregular in shape. Massive plutons are quite large.
we'll cover this when we do block diagrams on Mar 31
nuee ardente, p 156
Hot, hot, volcanic debris buoyed up by incandescent gasses moving downslope in a glowing avalanche called a pyroclastic flow. Temperatures can be 1500 degrees F. Speeds can be 150 miles per hour.
pahoehoe flow, p 144
a lava flow with a smooth surface or a surface that looks like ropes piled up.
parasitic cone, p 157
a volcanic cone that forms on the flank of a larger volcano
parasitic cones are not near the summit crater of the volcano
pillow lava (pillow basalts), p 145
Basaltic lava solidifying underwater. The surface of pillow lavas look like a mass of piled up pillows.
pipe, p 147
a vertical conduit or pipe letting magma escape as lava
pluton, p 162
an igneous structure formed as magma is emplaced and crystalizes as it cools slowly beneath the surface of the earth.
we'll cover this when we do block diagrams on Mar 31
pumice, p 147
light-colored, glassy, vesicular rock with a granitic composition
pyroclastic flow, p 156
a highly heated mixture, largely of ash and pumice fragments. A pyroclastic flow travels down the flanks of a volcano and along the surface of the ground at the base of the volcano.
pyroclastic material, p 146
the volcanic rock ejected during an eruption. Pyroclastics include ash, bombs, and blocks.
scoria, p 147
vesicular ejecta of basaltic composition; also called "cinder"
scoria cone, p 151
same as a "cinder cone"
shield volcano, p148
a broad gently sloping volcano built from fluid basaltic lavas.
Shield volcanoes are the flattest and broadest of the three types of volcanoes
sill, p 164
a tabular igenous body intruded parallel to the horizontal layering of pre-existing rock
we'll cover this when we do block diagrams on Mar 31
stock, p 167
A mini-batholith . . . a pluton similar to a batholith but not as large
we'll cover this when we do block diagrams on Mar 31
stratovolcano, p 153
see "composite cone"
tabular pluton, p 166
an igenous pluton much longer and wider than it is tall
we'll cover this when we do block diagrams on Mar 31
vent, p 147
a surface opening of a volcanic conduit or pipe
viscosity, p 141
a measure of a fluid's resistance to flow. Hot maple syrup is less viscous than cold maple syrup.
volcanic neck, p 162
an isolated, steep-sided, erosional remanant consisting of lava that once occupied the main vent of volcano.
in the movie "Close Encounters of the Third Kind", a volcanic neck was the landing site of the UFO
volcano, p 147
a mountain formed from lava, or pyroclastics, or both.
xenolith, p 168
an inclusion of unmelted country rock (local rock found underground that has broken off) in an igneous pluton
we'll cover this when we do block diagrams on Mar 31
Volcanic ash
The dust-sized, sharp-edged, glassy particles resulting from an explosive volcanic eruption.
Volcanic Bomb
a lump of lava ejected from a volcano that has acquired a characteristic tapering form as a result of its solidification while traveling through the air
Pacific Ring of Fire
The Ring of Fire is a zone of frequent earthquakes and volcanic eruptions that encircles the basin of the Pacific Ocean. It is shaped like a horseshoe and it is 40,000 km long. It is associated with a nearly continuous series of oceanic trenches, island arcs, and volcanic mountain ranges and/or plate movements. It is sometimes called the circum-Pacific belt or the circum-Pacific seismic belt.
Mount St Helens
an active volcano in the Cascade Range in southwestern Washington; erupted violently in 1980 after 123 years of inactivity
Crater Lake, Oregon
A lake of southwest Oregon in a volcanic crater of the Cascade Range. Iis the second-deepest lake in North America and the deepest in the United States.