Geology Test 2
At high pressures and elevated temperatures of regional metamorphism, silicate rocks are more resistant to flowage and deformation than at low temperatures and pressures.
False
Foliated metamorphic rocks are composed largely of equidimensional grains of minerals such as quartz and calcite.
False
________ is a strong, parallel alignment of coarse mica flakes and/or of different mineral bands in a metamorphic rock.
Foliation
________ is characterized by the segregation of light- and dark-colored minerals into thin layers or bands.
Granitic gneiss
________ forms from the metamorphism of limestone or dolostone.
Marble
Metamorphic rocks containing garnet are considered to be _______.
Medium grade
________ is thought to form by partial melting and in situ crystallization of the melted portion.
Migmatite
Which of the following best describes the conditions of contact metamorphism?
Pressures are fairly low, the rock is in the upper part of the crust, and heat is supplied from a nearby magma body.
________ is typically formed by metamorphism of a sandstone.
Quartzite
High-grade, regional metamorphism produces significant and recognizable changes in the textures and mineral compositions of rocks.
True
Muscovite, biotite, and chlorite are common minerals found in phyllites and schists.
True
Partial melting is an important process in the formation of migmatites.
True
Rock cleavage or slaty cleavage in slates is largely a consequence of abundant, parallel-aligned, very fine-grained mica flakes in the rock.
True
Three major factors involved in metamorphism are elevated temperature, elevated pressure, and the chemical action of hot fluids.
True
The altered rocks that form around a molten igneous body are called _____.
an aureole
In which setting would regional metamorphism be most likely?
at great depths in the crust where two continents are colliding
What term describes the zone of contact metamorphism surrounding an intrusive magma body?
aureole
A ________ forms at very high pressures but moderately low temperatures associated with subduction of oceanic crust and sediments.
blueschist
Amphibolite is a foliated metamorphic rock composed principally of hornblende and plagioclase. How does it form?
by regional metamorphism of volcanic rocks such as andesite and basalt
What major change occurs during metamorphism of limestone to marble?
calcite grains grow larger and increase in size
In confining pressure, forces are applied _______.
equally in all directions
Which of the following would exhibit sheared and mechanically fragmented rocks?
fault movements at shallow depths
Which texture best describes a metamorphic rock with a planar arrangement of mineral grains?
foliation
Which of the following statements concerning slate is not true?
has abundant, coarse-grained mica
What is the major source of heat for contact metamorphism?
heat from a nearby magma body
Tektites originate in what metamorphic environment?
high temperatures associated with meteorite impacts
Slate is a _____-grade metamorphic rock.
low
What two, metamorphic rocks are composed predominantly of single minerals?
marble and quartzite
What platy, parallel, mineral grains are the most visual aspect of foliated metamorphic rocks?
micas
Metamorphism can lead to changes in _____.
mineralogy, texture, chemical composition,
What foliated, metamorphic rock is texturally intermediate between slate and schist?
phyllite
Where does Earth's internal heat come from?
radioactive decay, energy from Earth's formation, magma
Which of the following forms at the highest grade of regional metamorphism?
schist
Slate's parent rock is _____.
shale
Which low-grade metamorphic rock, composed of extremely fine-sized mica and other mineral grains, typically exhibits well-developed rock cleavage?
slate
During metamorphic process, the rock essentially remains a _____.
solid
Calcite is the main mineral constituent of the sedimentary rock limestone and of the metamorphic rock marble.
true
Slate and schist are both derived by metamorphism of shales and mudstones.
true
