GEOLOGY 201 FINAL EXAM QUESTIONS WITH
VERIFIED ANSWERS
Definition of a mineral
A naturally occurring inorganic solid that has a specific elemental composition and a specific
arrangement of atoms.
Composition of intrusive rocks and their extrusive equivalents
Silicic - (Granite-intrusive, Rhyolite-extrusive)
Intermediate - (Diorite-intrusive, Andesite-extrusive)
Mafic - (Gabbro-intrusive, Basalt-extrusive)
Ultramafic - (Periodotite-intrusive, Komatiite-extrusive)
Partial Melting
When a given mass of rock within the Earth is subjected to conditions that cause melting, the
minerals with the LOWEST melting points melt first (Bowen's Reaction Series)
Bowen's Reaction Series
High Temp: Olivine (first to crystallize)
Pyroxene
Amphibole
Biotite
Potassium Feldspar
Muscovite
Low Temp: Quartz (Last to crystallize)
Intrusive Igneous Rock
A rock that forms from cooled Magma.
Extrusive Igneous Rock
A rock that forms from cooled Lava.
Magma
Molten rock below the earth's surface.
Lava
Molten rock above the earth's surface.
How and Where Magma forms.
, Forms by Partial Melting in...
1) Subduction Zones: Oceanic Lithosphere is forced into mantle.
2) Dewatering of the down going slab: Water is released from the subducted plate and goes into
the mantle wedge/asthenosphere
3) Decompression Melting: Rocks rising to fill space decompress, and remain warm, but lower
pressure at shallower depths lowers their melting point.
4)Hot Spot volcanoes
Definition of Soil
Where the atmosphere, hydrosphere, lithosphere, and biosphere interact.
Assigning names to detrital sedimentary rocks.
Names based on Clast Size, median diameters larger than 2 mm, clast shape
Breccia: Angular Clasts, closest to source than conglomerate
Conglomerate: Round Clasts
Implications regarding depositional environment of clast size and clast shape
Shear traction at channel bottom determines size of largest clast that will be transported. The
further away from the source the clast is, the smoother and smaller it will get. (breccia,
conglomerate, sandstone, siltstone, shale, mudstone)
Difference between Slate and Schist.
Slate: has crystals that are too small to see without magnification.
Schist: has crystals that are visible to the the naked eye.
Metamorphic Index Minerals
Indicate the temperature and pressure in the rock when metamorphism occurred. (used to define
metamorphic facies)
Naming Metamorphic Rocks
-Contact metamorphic rocks (country rock-rocks magma moved into)
-Hydrothermal metamorphic rocks (water is abundant and close to heat source)
-Regional metamorphic rocks (deep burial during mtn building events, presence of foliation)
Foliation
Orientation of platy or elongate minerals that crystalize during metamorphism.
Everything about Blueschist/Glaucophane
VERIFIED ANSWERS
Definition of a mineral
A naturally occurring inorganic solid that has a specific elemental composition and a specific
arrangement of atoms.
Composition of intrusive rocks and their extrusive equivalents
Silicic - (Granite-intrusive, Rhyolite-extrusive)
Intermediate - (Diorite-intrusive, Andesite-extrusive)
Mafic - (Gabbro-intrusive, Basalt-extrusive)
Ultramafic - (Periodotite-intrusive, Komatiite-extrusive)
Partial Melting
When a given mass of rock within the Earth is subjected to conditions that cause melting, the
minerals with the LOWEST melting points melt first (Bowen's Reaction Series)
Bowen's Reaction Series
High Temp: Olivine (first to crystallize)
Pyroxene
Amphibole
Biotite
Potassium Feldspar
Muscovite
Low Temp: Quartz (Last to crystallize)
Intrusive Igneous Rock
A rock that forms from cooled Magma.
Extrusive Igneous Rock
A rock that forms from cooled Lava.
Magma
Molten rock below the earth's surface.
Lava
Molten rock above the earth's surface.
How and Where Magma forms.
, Forms by Partial Melting in...
1) Subduction Zones: Oceanic Lithosphere is forced into mantle.
2) Dewatering of the down going slab: Water is released from the subducted plate and goes into
the mantle wedge/asthenosphere
3) Decompression Melting: Rocks rising to fill space decompress, and remain warm, but lower
pressure at shallower depths lowers their melting point.
4)Hot Spot volcanoes
Definition of Soil
Where the atmosphere, hydrosphere, lithosphere, and biosphere interact.
Assigning names to detrital sedimentary rocks.
Names based on Clast Size, median diameters larger than 2 mm, clast shape
Breccia: Angular Clasts, closest to source than conglomerate
Conglomerate: Round Clasts
Implications regarding depositional environment of clast size and clast shape
Shear traction at channel bottom determines size of largest clast that will be transported. The
further away from the source the clast is, the smoother and smaller it will get. (breccia,
conglomerate, sandstone, siltstone, shale, mudstone)
Difference between Slate and Schist.
Slate: has crystals that are too small to see without magnification.
Schist: has crystals that are visible to the the naked eye.
Metamorphic Index Minerals
Indicate the temperature and pressure in the rock when metamorphism occurred. (used to define
metamorphic facies)
Naming Metamorphic Rocks
-Contact metamorphic rocks (country rock-rocks magma moved into)
-Hydrothermal metamorphic rocks (water is abundant and close to heat source)
-Regional metamorphic rocks (deep burial during mtn building events, presence of foliation)
Foliation
Orientation of platy or elongate minerals that crystalize during metamorphism.
Everything about Blueschist/Glaucophane
