GC100 exam 3 (12-19) questions well
answered to pass
12.) What are the layers of Earth? What is each layer made of? Which are solid and which are
liquid? - correct answer ✔✔Crust- solid (Roughly 95% of the crust is silicate minerals)
Upper Mantle- Solid, (but not completely rigid, olivine silicate minerals)
Lower Mantle- Solid, (rigid rock (due to pressure, olivine, iron magnetism sulfates)
Outer core- liquid (mostly iron, little nickel)
Inner core- solid (iron and nickel)
How do oceanic and continental crusts differ? - correct answer ✔✔- Oceanic crust ; ~7 km thick,
Denser than continental crust, Mostly basaltic rock (magnesium and iron-based silicates)
- Continental crust ; ~35 km thick on average, up to 60km thick under mountains, Less dense
than oceanic crust, More granitic rock (feldspar-based silicate), with some basaltic rock
What are the asthenosphere and lithosphere? - correct answer ✔✔The lithosphere is the brittle
crust and uppermost mantle. The asthenosphere is a solid but it can flow, like toothpaste. The
lithosphere rests on the asthenosphere
What is the Moho? - correct answer ✔✔Crust / Uppermost Mantle boundary
How have scientists determined the structure and composition of the earth's interior? - correct
answer ✔✔We infer information about Earth's interior from other sources
Volcanic lava has same chemical make-up of upper layers
Other bodies in solar system (moon & meteorites) likely have same chemical make-up as total
earth
,Lab experiments squeezing rocks to high temperatures & pressures tell us how core & mantle
behave
Seismic tomography: image earth's interior using earthquake waves • Same principle as an x-ray
or MRI image of the human body
What are isostasy and isostatic rebound? - correct answer ✔✔equilibrium state of the
lithosphere floating on the asthenosphere
here
What are the 2 most common elements in the earth's crust? - correct answer ✔✔Oxygen and
silicon
What is the most common element in the earth as a whole? - correct answer ✔✔Oxygen
What is the rock cycle? - correct answer ✔✔Rocks are constantly being formed, worn down and
then formed again. It takes thousands and millions of years for rocks to change.
What is a mineral? - correct answer ✔✔a naturally occurring, inorganic solid that has a crystal
structure and a definite chemical composition
What is a rock? - correct answer ✔✔an assemblage of minerals bound together, Most contain
two or more minerals, but some contain only one mineral
What are igneous rocks? - correct answer ✔✔rocks formed directly from magma or lava
How are intrusive and extrusive igneous rocks formed? - correct answer ✔✔Formed from
magma that cools and solidifies slowly, below the surface.
, And formed from lava that has reached the surface, as lava flow or volcanic eruption; cools
quickly
How does the crystal size differ between intrusive and extrusive rocks? - correct answer
✔✔Intrusive igneous rocks cool slowly, large grain-size Extrusive igneous rocks cool quickly,
small grain-size
How does mineral composition affect the density and melting point of igneous rocks? (Be able
to identify sills, dikes, and laccoliths in pictures.) - correct answer ✔✔melting point decreases
allowing the mineral to melt at lower temperatures
What are sedimentary rocks? - correct answer ✔✔made from accumulation of sediment,
Particles of minerals, rocks, organic matter are: Disintegrated or dissolved from an existing rock-
form, by weathering, Picked up (eroded) and moved (transported) by wind, water, or ice,
Deposited as sediments, Lithified into rock
What is lithification (and what are the sub-processes of lithification)? - correct answer
✔✔process of cementation, compaction, and hardening that turns loose sediment into rock
Compaction: as layers of clastic sediment accumulate, lower layers are compressed by weight of
upper layers, Amount of pore space decreases, as air & water are expelled
Cementation: dissolved minerals precipitate out of solution, recrystallizing in pore spaces and
forming a natural cement that holds the clasts together
How are clastic sedimentary rocks formed? How are chemical sedimentary rocks formed? -
correct answer ✔✔made from fragments or clasts of rocks,
dissolved minerals are transported, then recrystallize from solution
What are metamorphic rocks? How are they formed? - correct answer ✔✔rocks that have been
created from transformation, by heat and/or pressure from existing rocks
answered to pass
12.) What are the layers of Earth? What is each layer made of? Which are solid and which are
liquid? - correct answer ✔✔Crust- solid (Roughly 95% of the crust is silicate minerals)
Upper Mantle- Solid, (but not completely rigid, olivine silicate minerals)
Lower Mantle- Solid, (rigid rock (due to pressure, olivine, iron magnetism sulfates)
Outer core- liquid (mostly iron, little nickel)
Inner core- solid (iron and nickel)
How do oceanic and continental crusts differ? - correct answer ✔✔- Oceanic crust ; ~7 km thick,
Denser than continental crust, Mostly basaltic rock (magnesium and iron-based silicates)
- Continental crust ; ~35 km thick on average, up to 60km thick under mountains, Less dense
than oceanic crust, More granitic rock (feldspar-based silicate), with some basaltic rock
What are the asthenosphere and lithosphere? - correct answer ✔✔The lithosphere is the brittle
crust and uppermost mantle. The asthenosphere is a solid but it can flow, like toothpaste. The
lithosphere rests on the asthenosphere
What is the Moho? - correct answer ✔✔Crust / Uppermost Mantle boundary
How have scientists determined the structure and composition of the earth's interior? - correct
answer ✔✔We infer information about Earth's interior from other sources
Volcanic lava has same chemical make-up of upper layers
Other bodies in solar system (moon & meteorites) likely have same chemical make-up as total
earth
,Lab experiments squeezing rocks to high temperatures & pressures tell us how core & mantle
behave
Seismic tomography: image earth's interior using earthquake waves • Same principle as an x-ray
or MRI image of the human body
What are isostasy and isostatic rebound? - correct answer ✔✔equilibrium state of the
lithosphere floating on the asthenosphere
here
What are the 2 most common elements in the earth's crust? - correct answer ✔✔Oxygen and
silicon
What is the most common element in the earth as a whole? - correct answer ✔✔Oxygen
What is the rock cycle? - correct answer ✔✔Rocks are constantly being formed, worn down and
then formed again. It takes thousands and millions of years for rocks to change.
What is a mineral? - correct answer ✔✔a naturally occurring, inorganic solid that has a crystal
structure and a definite chemical composition
What is a rock? - correct answer ✔✔an assemblage of minerals bound together, Most contain
two or more minerals, but some contain only one mineral
What are igneous rocks? - correct answer ✔✔rocks formed directly from magma or lava
How are intrusive and extrusive igneous rocks formed? - correct answer ✔✔Formed from
magma that cools and solidifies slowly, below the surface.
, And formed from lava that has reached the surface, as lava flow or volcanic eruption; cools
quickly
How does the crystal size differ between intrusive and extrusive rocks? - correct answer
✔✔Intrusive igneous rocks cool slowly, large grain-size Extrusive igneous rocks cool quickly,
small grain-size
How does mineral composition affect the density and melting point of igneous rocks? (Be able
to identify sills, dikes, and laccoliths in pictures.) - correct answer ✔✔melting point decreases
allowing the mineral to melt at lower temperatures
What are sedimentary rocks? - correct answer ✔✔made from accumulation of sediment,
Particles of minerals, rocks, organic matter are: Disintegrated or dissolved from an existing rock-
form, by weathering, Picked up (eroded) and moved (transported) by wind, water, or ice,
Deposited as sediments, Lithified into rock
What is lithification (and what are the sub-processes of lithification)? - correct answer
✔✔process of cementation, compaction, and hardening that turns loose sediment into rock
Compaction: as layers of clastic sediment accumulate, lower layers are compressed by weight of
upper layers, Amount of pore space decreases, as air & water are expelled
Cementation: dissolved minerals precipitate out of solution, recrystallizing in pore spaces and
forming a natural cement that holds the clasts together
How are clastic sedimentary rocks formed? How are chemical sedimentary rocks formed? -
correct answer ✔✔made from fragments or clasts of rocks,
dissolved minerals are transported, then recrystallize from solution
What are metamorphic rocks? How are they formed? - correct answer ✔✔rocks that have been
created from transformation, by heat and/or pressure from existing rocks
