GEOLOGY 201 MIDTERM 2 EXAM
QUESTIONS AND ANSWERS
What is Foliation? - Answer- Layers within a metamorphic rock consisting of similarly
orientated platy and elongate minerals.
What is slate? - Answer- metamorphic rocks that have crystals that are too small to see
without magnification
What is a Normal Fault? - Answer- hanging wall moving down relative to the footwall.
Form as a result of tension. Normal faults extend and thin the Earth's crust. "dip-slip"
faults
What is a Reverse Fault? - Answer- hanging wall moving up relative to the footwall.
Form as a result of compression. They shorten and thicken Earth's crust. "dip-slip" faults
What is a Strike-Slip Fault? - Answer- formed as a consequence of horizontal shear
stress in Earth's crust
What are Transform faults? - Answer- plate boundaries within continental crust where
two plates move past each other. Consist of overlapping and curved faults.
What is Brittle Strain? - Answer- change in shape or position accommodated along
fractures
What is Elastic Strain? - Answer- said of a body in which strains are instantly and totally
recovered
Faults that exists in restraining bends? - Answer- form at left bends or steps along right
lateral faults, because fault geometry causes localized compression and shortening.
Also form in left lateral systems (figure out geometry yourself or see BB
posting<transform_fault.pdf>).
Faults that exists in releasing bends? - Answer- form at right bends or steps along right
lateral strike-slip faults, because fault geometry causes localized tension and extension.
Also form in left lateral systems (figure out geometry yourself or see BB posting
<transform_fault.pdf>).
What is Mechanical Weathering? - Answer- The physical disintegration of rocks-
breaking rocks into smaller pieces. No chemical change occurs
, What causes sheeting and exfoliation? - Answer- Driven by pressure release and
expansion; in many mountainous locations rocks are exhumed from depths of 10s of
km. at rates of 10mm per year
Occurs only in massive Homogenous rocks.
Parallel to surface
What minerals are most and least susceptible to chemical weathering? - Answer-
Olive<Pyroxene (Calcium Feldspar)<Amphibole<Biotite (Sodium Feldspar) < Potassium
feldspar< Muscovite< Quartz
In order of least resistant to most resistant
What drives chemical weathering? - Answer- Primary rock-forming minerals are in
disequilibrium with near surface conditions (more O2 and H2O in near surface
conditions)
Minerals and compounds formed during chemical weathering are more stable in near
surface environments than primary rock-forming minerals.
Soil - Answer- where the atmosphere, hydrosphere, lithosphere, and biosphere interact.
What is translocation and know what the definitive soil-forming process. - Answer- The
definitive pedogenic process. Translocation is the downward movement of solid soil
particles or dissolved ions.
Pedogenesis: the process of soil formation.
What are the soil master horizons, and what the 4 types of B horizons? - Answer- A:
addition organic material, mostly vegetation, is the fundamental process. However, the
"mineral fraction" is dominant. This horizon is usually dark.
B: where weathering product and translocated particles accumulate. This is the horizon
which is most useful to geologists and geomorphologists. B horizons are useful because
in many instances weathering product and translocated particle accumulate in a
predictable and quantifiable manner, and thereby provide a means to establish the
chronological or relative age of the land
Bt: Clay
Bk: calcium carbonate (CaCO3)
Bs: In tropical climates concentrations of Al oxides (sesquioxides)
Bh:in humid, cold climates, especially where there are forests (accumulation of OM)
C: unweathered parent material if the soil is formed in unconsolidated sediment.
E: a bleached lower A horizon. It forms below the A horizon, and it is typically white, and
often consists mostly of quartz.
What are vertisols? - Answer- soils which shrink and swell
Inverted soils
QUESTIONS AND ANSWERS
What is Foliation? - Answer- Layers within a metamorphic rock consisting of similarly
orientated platy and elongate minerals.
What is slate? - Answer- metamorphic rocks that have crystals that are too small to see
without magnification
What is a Normal Fault? - Answer- hanging wall moving down relative to the footwall.
Form as a result of tension. Normal faults extend and thin the Earth's crust. "dip-slip"
faults
What is a Reverse Fault? - Answer- hanging wall moving up relative to the footwall.
Form as a result of compression. They shorten and thicken Earth's crust. "dip-slip" faults
What is a Strike-Slip Fault? - Answer- formed as a consequence of horizontal shear
stress in Earth's crust
What are Transform faults? - Answer- plate boundaries within continental crust where
two plates move past each other. Consist of overlapping and curved faults.
What is Brittle Strain? - Answer- change in shape or position accommodated along
fractures
What is Elastic Strain? - Answer- said of a body in which strains are instantly and totally
recovered
Faults that exists in restraining bends? - Answer- form at left bends or steps along right
lateral faults, because fault geometry causes localized compression and shortening.
Also form in left lateral systems (figure out geometry yourself or see BB
posting<transform_fault.pdf>).
Faults that exists in releasing bends? - Answer- form at right bends or steps along right
lateral strike-slip faults, because fault geometry causes localized tension and extension.
Also form in left lateral systems (figure out geometry yourself or see BB posting
<transform_fault.pdf>).
What is Mechanical Weathering? - Answer- The physical disintegration of rocks-
breaking rocks into smaller pieces. No chemical change occurs
, What causes sheeting and exfoliation? - Answer- Driven by pressure release and
expansion; in many mountainous locations rocks are exhumed from depths of 10s of
km. at rates of 10mm per year
Occurs only in massive Homogenous rocks.
Parallel to surface
What minerals are most and least susceptible to chemical weathering? - Answer-
Olive<Pyroxene (Calcium Feldspar)<Amphibole<Biotite (Sodium Feldspar) < Potassium
feldspar< Muscovite< Quartz
In order of least resistant to most resistant
What drives chemical weathering? - Answer- Primary rock-forming minerals are in
disequilibrium with near surface conditions (more O2 and H2O in near surface
conditions)
Minerals and compounds formed during chemical weathering are more stable in near
surface environments than primary rock-forming minerals.
Soil - Answer- where the atmosphere, hydrosphere, lithosphere, and biosphere interact.
What is translocation and know what the definitive soil-forming process. - Answer- The
definitive pedogenic process. Translocation is the downward movement of solid soil
particles or dissolved ions.
Pedogenesis: the process of soil formation.
What are the soil master horizons, and what the 4 types of B horizons? - Answer- A:
addition organic material, mostly vegetation, is the fundamental process. However, the
"mineral fraction" is dominant. This horizon is usually dark.
B: where weathering product and translocated particles accumulate. This is the horizon
which is most useful to geologists and geomorphologists. B horizons are useful because
in many instances weathering product and translocated particle accumulate in a
predictable and quantifiable manner, and thereby provide a means to establish the
chronological or relative age of the land
Bt: Clay
Bk: calcium carbonate (CaCO3)
Bs: In tropical climates concentrations of Al oxides (sesquioxides)
Bh:in humid, cold climates, especially where there are forests (accumulation of OM)
C: unweathered parent material if the soil is formed in unconsolidated sediment.
E: a bleached lower A horizon. It forms below the A horizon, and it is typically white, and
often consists mostly of quartz.
What are vertisols? - Answer- soils which shrink and swell
Inverted soils
