Igneous Rocks

Question 1

On which planetary bodies is active volcanism known to exist?

Answer 1

Jupiters moon

Question 2

Where is the largest known volcano in the solar system?

Answer 2

Mars ; Olympus Mons

Question 3

What are the four plate tectonic environments in which most volcanism (on Earth) occurs?

Answer 3

V-HCOP

Volcanism - Hotspots, Continental Rifts, Oceanic Spreading Centers, Plate Subduction Zones

Question 4

What is a pyroclastic flow?

Answer 4

Fast-moving current of superheated gas and rock

Question 5

How do pyroclastic flows compare to lava flows and lahars?

Answer 5

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.

Question 6

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?

Answer 6

120 mph

Question 7

How might volcanoes change global climate, according to scientists? What compounds are emitted during volcanic eruptions that can, at least temporarily, alter climate?

Answer 7

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.

Question 8

What is fluidity?

Answer 8

The property of flowing easily.

Question 9

What is viscosity?

Answer 9

The state of being thick, sticky, and semifluid in consistency, due to internal frictioin.

Question 10

How does the viscosity of orange juice compare to the viscosity of maple syrup?

Answer 10

Maple syrup is much slower; stickier and thicker.

Question 11

What is silicate? Why is it called the “building block” of minerals?

Answer 11

A salt in which the anion contains both silicon and oxygen. SiO4 tetrahedral unit.

Question 12

What are the names, abbreviations, and example minerals of the silicate mineral groups?

Answer 12

Isolated > I > olivine

Single Chain > SC > pyroxene

Double Chain > DC > amphibole

Sheet > S > mica

Framework > F > feldspar, quartz

Question 13

Explain why melts of the various silicate mineral groups exhibit different viscosities. Which compositions exhibit the least viscosity. Which are the greatest viscosity? Why?

Question 14

How does the viscosity of a silicate melt control (in part) the angle of slope of a volcano?

Answer 14

Depending on the viscosity the magma may cool at a faster rate, causing a more slope on a volcano.

Question 15

What are the names of igneous rocks that denote different degrees of color?

Answer 15

Dunite - green

Question 16

Which silicate minerals are found abundantly in the felsic and mafic igneous rocks?

Answer 16

mafic-pyroxene

felsic - granite

Question 17

Is the grain size of igneous minerals that cool from a melt larger or smaller with a faster rate of heat loss.

Answer 17

smaller

Question 18

How can we tell (what is the evidence for) whether an igneous rock was fromed intrusively or extrusively?

Answer 18

The size of the crystals

Question 19

What are the various names for igneous rocks?

Answer 19

Volcanic rocks or Plutonic rocks

Question 20

What are the various textures of igneous rocks? Explain the meaning of vesicular.

Answer 20

Phaneritic-large mineral crystals visible

Aphanitic-small mineral crystals

Glassy-

Vesicular-Having cavities

Pyroclastic-broken in pieces

Question 21

A flood basalt a)exhibits lower or higher viscosity, and b)forms lower angle or higher angle slopes.

Answer 21

low; low

Question 22

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?

Answer 22

Lava and tephra

Question 23

Which igneous rock textures indicate formation in extrusive environments? Intrusive environements?

Answer 23

fine grained for extrusive ; coarse grained for intrusive

Question 24

How and where do pillow lavas form?

Answer 24

Under water by large temperature change

Question 25

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?