Igneous Rocks Flashcards
On which planetary bodies is active volcanism known to exist?
Jupiters moon
Where is the largest known volcano in the solar system?
Mars ; Olympus Mons
What are the four plate tectonic environments in which most volcanism (on Earth) occurs?
V-HCOP
Volcanism - Hotspots, Continental Rifts, Oceanic Spreading Centers, Plate Subduction Zones
What is a pyroclastic flow?
Fast-moving current of superheated gas and rock
How do pyroclastic flows compare to lava flows and lahars?
Pyroclastc flows are lava and hot ash blown in the air and lahars are the mud flow created from the cool ash on the earths surface.
If erupted ash from a volcanic eruption were carried by atmospheric wind about 1,200 miles in 12 hours, at what approximate speed, in miles per hour, did the ash move?
120 mph
How might volcanoes change global climate, according to scientists? What compounds are emitted during volcanic eruptions that can, at least temporarily, alter climate?
The ash and sulfur dioxide that blast into the atmosphere can reduce the amount of solar radiation reaching the Earth’s surface, lowering temperatures in the troposphere.
What is fluidity?
The property of flowing easily.
What is viscosity?
The state of being thick, sticky, and semifluid in consistency, due to internal frictioin.
How does the viscosity of orange juice compare to the viscosity of maple syrup?
Maple syrup is much slower; stickier and thicker.
What is silicate? Why is it called the “building block” of minerals?
A salt in which the anion contains both silicon and oxygen. SiO4 tetrahedral unit.
What are the names, abbreviations, and example minerals of the silicate mineral groups?
Isolated > I > olivine
Single Chain > SC > pyroxene
Double Chain > DC > amphibole
Sheet > S > mica
Framework > F > feldspar, quartz
Explain why melts of the various silicate mineral groups exhibit different viscosities. Which compositions exhibit the least viscosity. Which are the greatest viscosity? Why?
How does the viscosity of a silicate melt control (in part) the angle of slope of a volcano?
Depending on the viscosity the magma may cool at a faster rate, causing a more slope on a volcano.
What are the names of igneous rocks that denote different degrees of color?
Dunite - green
Which silicate minerals are found abundantly in the felsic and mafic igneous rocks?
mafic-pyroxene
felsic - granite
Is the grain size of igneous minerals that cool from a melt larger or smaller with a faster rate of heat loss.
smaller
How can we tell (what is the evidence for) whether an igneous rock was fromed intrusively or extrusively?
The size of the crystals
What are the various names for igneous rocks?
Volcanic rocks or Plutonic rocks
What are the various textures of igneous rocks? Explain the meaning of vesicular.
Phaneritic-large mineral crystals visible
Aphanitic-small mineral crystals
Glassy-
Vesicular-Having cavities
Pyroclastic-broken in pieces
A flood basalt a)exhibits lower or higher viscosity, and b)forms lower angle or higher angle slopes.
low; low
What are the two styles of eruptions and what factors cause or control whether a given volcano erupts with one of the styles or the other?
Lava and tephra
Which igneous rock textures indicate formation in extrusive environments? Intrusive environements?
fine grained for extrusive ; coarse grained for intrusive
How and where do pillow lavas form?
Under water by large temperature change
In which three types of plate tectonic regions do most of the worlds volcanoes occur? In what features do these volcanic regions differ from each other?
