GEO 401 EXAM 2 | FROM PRACTICE TO PERFECTION
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The Earth's upper mantle is mainly made of peridotite, an ultramafic igneous rock with
lots of olivine crystals. Which type of magma can be produced when the upper mantle
undergoes decompression melting of the upper mantle peridotite at mid-ocean ridges? -
Answer: Basaltic
Seismic studies of the earth have shown that the platnet's interior is made of a few
layers with distinct seismic signatures and chemical compositions. The major layers of
the planet include (from innermost to the outermost layers) ____________. - Answer:
inner core, outer core, mantle, crust
Melting occurs when a solid (rock) becomes a liquid (melt: magma). There are a number
of pressure, temperature, and compostioinal conditions that can cause a rock to melt.
Which one of the following conditions can cause a rock to melt in the Eath's deep
interior? - Answer: All of the above
-addition of volatiles such as water inti the rock
- decompression (a decrease in pressure)
- and increase in temperature
The mineralogy of terrestrial planets evolves as a consequence of a range of physical,
chemical, and biological processes. Based on the statement, the number of minerals in
the Earth would ________ as the planet evolves through time. - Answer: increase
Which of the following metamorphic facies represents the highest temp? - Answer:
Granulite
A geothermometer is ____________. - Answer: a mineral assemblage that reveals the
maximum temp attained by a rock
1
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, A number of geological principles such as Principle of Superpostion, Principle of
Original Horizontality, and Principle of Faunal Succession have been used to
understand geological records in rock formations. Based on these principles, which one
of the following statements is TRUE? - Answer: In a sequence of undisturbed layered
rock, the oldest rocks are on the bottom
Fossils are most common in which types of rocks? - Answer: sedimentary
Unconformity is the surface between two layers that were laid down in a broken
sequence. Which of the following statements about the unconformity are TRUE? -
Answer: All of the Above
- Angular unconformity is an unconformity in which younger sediments rest upon the
eroded surface of tilted or folded older rocks
- Disconformity is an unconformity between beds that are parallel
- Nonconformity is an unconformity between stratified rocks above and unstratified
igneous or metamorphic rocks below
The principle of superposition states that _______________. - Answer: undisturbed
sedimentary layers get progressively younger from bottom to top
Which of the following radioactive isotopes is the most useful for dating very young
(<10,000 years old) wood and charcoal? - Answer: carbon-14
A rock formed with 100 atoms of a radioactive parent element but contains only 25
radioactive parent atoms today. Let's assume that the rock did not contain any daughter
isotopes to start with. If the half-life for the radioactive element is two billion years, how
old is the rock? - Answer: 4 billion years old
Radioactive isotope dating is commonly used in geology to understand the ages of
minerals and rocks. The parent radioactive isotope decays into the daughter isotope at
a constant rate. The decay rate is measured by the amount of time required for half the
2
APPHIA - Crafted with Care and Precision for Academic Excellence.
| GUARANTEED SUCCESS!
The Earth's upper mantle is mainly made of peridotite, an ultramafic igneous rock with
lots of olivine crystals. Which type of magma can be produced when the upper mantle
undergoes decompression melting of the upper mantle peridotite at mid-ocean ridges? -
Answer: Basaltic
Seismic studies of the earth have shown that the platnet's interior is made of a few
layers with distinct seismic signatures and chemical compositions. The major layers of
the planet include (from innermost to the outermost layers) ____________. - Answer:
inner core, outer core, mantle, crust
Melting occurs when a solid (rock) becomes a liquid (melt: magma). There are a number
of pressure, temperature, and compostioinal conditions that can cause a rock to melt.
Which one of the following conditions can cause a rock to melt in the Eath's deep
interior? - Answer: All of the above
-addition of volatiles such as water inti the rock
- decompression (a decrease in pressure)
- and increase in temperature
The mineralogy of terrestrial planets evolves as a consequence of a range of physical,
chemical, and biological processes. Based on the statement, the number of minerals in
the Earth would ________ as the planet evolves through time. - Answer: increase
Which of the following metamorphic facies represents the highest temp? - Answer:
Granulite
A geothermometer is ____________. - Answer: a mineral assemblage that reveals the
maximum temp attained by a rock
1
APPHIA - Crafted with Care and Precision for Academic Excellence.
, A number of geological principles such as Principle of Superpostion, Principle of
Original Horizontality, and Principle of Faunal Succession have been used to
understand geological records in rock formations. Based on these principles, which one
of the following statements is TRUE? - Answer: In a sequence of undisturbed layered
rock, the oldest rocks are on the bottom
Fossils are most common in which types of rocks? - Answer: sedimentary
Unconformity is the surface between two layers that were laid down in a broken
sequence. Which of the following statements about the unconformity are TRUE? -
Answer: All of the Above
- Angular unconformity is an unconformity in which younger sediments rest upon the
eroded surface of tilted or folded older rocks
- Disconformity is an unconformity between beds that are parallel
- Nonconformity is an unconformity between stratified rocks above and unstratified
igneous or metamorphic rocks below
The principle of superposition states that _______________. - Answer: undisturbed
sedimentary layers get progressively younger from bottom to top
Which of the following radioactive isotopes is the most useful for dating very young
(<10,000 years old) wood and charcoal? - Answer: carbon-14
A rock formed with 100 atoms of a radioactive parent element but contains only 25
radioactive parent atoms today. Let's assume that the rock did not contain any daughter
isotopes to start with. If the half-life for the radioactive element is two billion years, how
old is the rock? - Answer: 4 billion years old
Radioactive isotope dating is commonly used in geology to understand the ages of
minerals and rocks. The parent radioactive isotope decays into the daughter isotope at
a constant rate. The decay rate is measured by the amount of time required for half the
2
APPHIA - Crafted with Care and Precision for Academic Excellence.
