LAB Metamorphic Rock Identification
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School
Pace University *
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Course
101
Subject
Geology
Date
Feb 20, 2024
Type
Pages
3
Uploaded by DeanFishPerson1150
Vocabulary
Foliation: The parallel alignment or arrangement of mineral crystals or mineral bands
within a metamorphic rock. This alignment is a result of the intense pressure and heat
during the rock's formation, causing the minerals to align in a preferred orientation.
Banded: The appearance of alternating layers or bands of different minerals or mineral
compositions within a rock. These bands are a result of the metamorphic process,
where mineral crystals segregate into distinct layers based on their composition or size.
Parent Rock: Also known as the protolith, is the original rock from which a metamorphic
rock forms.The characteristics of the parent rock influence the type of metamorphic rock
that will be formed.
Discussion Questions
Why do you seldom see fossils in metamorphic rock?
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Fossils are rarely found in metamorphic rocks because the intense heat and
pressure involved in the metamorphic process typically destroy or alter the
original organic remains. The conditions under which metamorphic rocks form
are not conducive to preserving the delicate structures of fossils.
Why is a quartzite very hard and denser than its parent rock?
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Quartzite is formed from the metamorphism of sandstone, where the original
quartz grains recrystallize and interlock due to heat and pressure. This process
results in a rock that is more compact and has a higher density than its parent
rock. The recrystallization of quartz also contributes to the hardness of quartzite.
How can you differentiate between white marble and white quartzite?
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White marble and white quartzite can look similar, but they have different mineral
compositions. Marble is primarily composed of calcite, while quartzite is
composed mainly of quartz. One way to differentiate them is by performing a
simple acid test: marble will react with dilute hydrochloric acid, producing bubbles
of carbon dioxide, while quartzite will not react.
Why do metamorphic rocks often rearrange in layers?
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The layering in metamorphic rocks, known as foliation, is a result of the parallel
alignment of mineral crystals under the influence of directed pressure during
metamorphism. This alignment can occur due to the shearing forces or
differential pressure acting on the rock, causing minerals to orient themselves in
a preferred direction. The layering enhances the strength and durability of the
rock.
Why are metamorphic rocks formed by contact metamorphism usually not as dense as
those formed by regional metamorphosis?
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In summary, rocks formed by regional metamorphism generally experience
higher pressures than those formed by contact metamorphism. The increased
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