ESC midterm 2

Minerals are all naturally occurring solid substances with a definable chemical composition. They must also possess an ability to be synthesized in the laboratory as well as be found in nature. metallic elements, such as iron, calcium, or magnesium. a nonmetallic, vitreous luster. a fixed crystalline structure (spatial arrangement of atoms and ions).

a fixed crystalline structure (spatial arrangement of atoms and ions).

Cleavage in minerals refers to a tendency to break in an irregular pattern. a tendency to break along planes of weakness. the sharpness of edges between crystal faces. the development of well-formed crystal faces.

a tendency to break along planes of weakness.

Felsic igneous rocks typically__________. contain more iron and magnesium than intermediate rocks are lighter in color than mafic rocks are darker in color than mafic rocks are found in oceanic crust

are lighter in color than mafic rocks

Which of the following minerals is more commonly known as table salt? gypsum feldspar halite quartz

halite

What type of rock forms by the solidification of a melt? igneous metamorphic sedimentary biologic

igneous

All other factors being equal, if a body of magma becomes more felsic, its viscosity will __________. increase decrease stay the same Chemical composition has no effect on viscosity.

increase

Diamonds are usually found in (Hint: Igneous rock in which diamonds are usually embedded with) pegmatite. kimberlite. sandstone. granite.

kimberlite.

A batholith is a(n) __________. large body of sedimentary rock large body of metamorphic rock large compound igneous intrusion small tabular igneous intrusion

large compound igneous intrusion

Granite, a course-grained, felsic intrusive igneous rock is most similar in mineral composition to __________, which is a fine-grained, felsic extrusive equivalent. andesite basalt gabbro rhyolite

rhyolite

Which of the following forms either by the cementing together of grains broken off preexisting rocks or by the precipitation of mineral crystals out of water solutions at or near the Earth's surface? igneous rocks sedimentary rocks metamorphic rocks meteorites

sedimentary rocks

Which type of volcano forms from layers of mafic lava erupted in primarily effusive eruptions? cinder cone stratovolcano shield volcano fissure volcano

shield volcano

The mineral class that makes up more than 95% of rocks in the continental crust is termed the silicates. carbonates. halides. oxides.

silicates

n the figure provided below, what type of igneous intrusion is the horizontal rock unit indicated by the arrow? dike sill pluton laccolith

sill

Which of the following is a mineral? petroleum (oil), a liquid coal snowflakes (water in the solid state) obsidian (volcanic glass)

snowflakes (water in the solid state)

Compared with mafic igneous rocks, all felsic igneous rocks __________. cool and solidify more quickly cool and solidify more slowly solidify at higher temperatures solidify at lower temperatures

solidify at lower temperatures

A mineral property defined by the density of the mineral sample divided by the density of water (1.0 g/cm3) is mass. specific gravity. luster. streak.

specific gravity

The color of a mineral in powdered form is termed color. specific gravity. luster. streak.

streak.

Pyrite (FeS2) is in which mineral class? silicates carbonates oxides sulfides

sulfides

A sill is a(n) __________. tabular intrusion that lies parallel to surrounding layers of sedimentary rock cooled layer of an ancient lava flow intrusion formed within the magma chamber of a volcano tabular intrusion that cuts across preexisting layers

tabular intrusion that lies parallel to surrounding layers of sedimentary rock

Which of the following common minerals is softest? quartz calcite talc fluorite

talc

The mantle is composed entirely of __________. felsic rock ultramafic rock You Answered mafic rock intermediate rock

ultramafic rock

Bubbles trapped in lava after the molten material are cooled are called __________. phenocrysts vesicles porphyroblasts pyroclasts

vesicles

Viscosity of a magma does NOT depend on __________. temperature volatile content silica content volume of the magma

volume of the magma

Important volatiles in magmas include __________. mafic minerals, such as olivine potassium and aluminum water and carbon dioxide silicon and iron

water and carbon dioxide

Which of the following is most typical of what you would find in a lahar? rock fragments ash and gas water and mud lava

water and mud

Volcanoes are able to cool global climate in which of the following ways? They release heat during eruptions. Gas emissions reduce the amount of moisture in the atmosphere Aerosols and ash reflect sunlight, causing cooling. There is no evidence that volcanoes can affect climate.

Aerosols and ash reflect sunlight, causing cooling

Which of the following is NOT true about minerals? All minerals are compounds of more than one element. All minerals are naturally made. Some minerals are precipitated by organisms. All minerals can be expressed as chemical formulas.

All minerals are compounds of more than one element.

_________ form from piles of pyroclastic debris (mainly lapilli) that fountain out of a vent during an effusive eruption. Cinder cones Stratovolcanoes Shield volcanoes Fissure volcanoes

Cinder cones

Columnar jointing forms primarily because of __________ Contraction and cracking of rock during the cooling process Changes in density of the material as it cools Partial remelting of lava on the surface Fragmentation of the rock due to volatile escape

Contraction and cracking of rock during the cooling process

__________ melting occurs at subduction zones because the down-going plate __________. Heat transfer; is extremely hot Heat transfer; creates abundant friction Flux; contains abundant water Decompression; rises toward the surface

Flux; contains abundant water

The May 18, 1980, eruption of Mount St. Helens was unique in which way? Lava flows erupted from the base of the volcano. The explosion was initially directed sideways. Large amounts of gases were emitted. The explosion was directed vertically only.

The explosion was initially directed sideways.

Despite the fact that the temperatures within Earth are hot enough to melt rock, Earth is mostly solid (Outer core is an exception). Why do the rocks within Earth NOT melt? The pressure is too high. The pressure is too low. There is not enough water. They are not in contact with air.

The pressure is too high.

Why is the outer core the only layer in Earth that is molten? The pressure decreases within Earth, thus allowing iron to melt. The pressure increases within Earth, thus allowing iron to melt. The temperature is high enough but pressure low enough to melt iron. The temperature is high enough but pressure low enough to melt olivine.

The temperature is high enough but pressure low enough to melt iron.

With regard to minerals, hardness refers to the ability to resist melting. being scratched. reactivity to acid. malleability.

being scratched.

Which of the following is NOT a way for minerals to crystallize? solidification of a melt (lava or magma) bonding carbon to oxygen atoms to form organic compounds solid-state diffusion Biomineralization

bonding carbon to oxygen atoms to form organic compounds

The image below shows a mineral with hydrochloric acid applied to it. What mineral is this? quartz halite calcite fluorite

calcite

Which of the following is a mineral? granite lab-grown quartz crystal salt dissolved in water calcite

calcite

Calcite (CaCO3) is in which mineral class? silicates carbonates oxides sulfides

carbonates

Trace amounts of impurity in a mineral can commonly produce significant differences in __________ among individual crystals of this mineral. color cleavage luster streak

color

Synthetically made glass and natural quartz crystals both exhibit a fracture pattern termed glassy fracture. conchoidal fracture. one-directional cleavage. obtuse fracture.

conchoidal fracture

The image below shows a mineral specimen of quartz. What is the term for the smoothly curving, clamshell-shaped surface on the sample below? conchoidal fracture facet cleavage plane striation

conchoidal fracture

Volcanic arcs form along __________ boundaries. transform hot spot convergent divergent

convergent

Compared with coarse-grained igneous rocks, fine-grained igneous rocks __________ cool and solidify more quickly cool and solidify more slowly solidify at higher temperatures solidify at lower temperatures

cool and solidify more quickly

If the volatile content of magma is increased, its viscosity will __________. increase decrease stay the same Volatile content has no effect on viscosity.

decrease

All other factors being equal (i.e., depth, volume, temperature, etc.), which type of igneous intrusion would cool fastest? pluton dike batholith All intrusions cool at the same rate.

dike

The diamonds typically seen in engagement rings today do not display their natural crystal faces but rather __________, which are made by grinding the gem on a spinning lap. striations facets cleavage planes facades

facets

Viscosity controls how __________. hot the fluid is fast a rock will melt quickly the fluid cools fast a fluid flows

fast a fluid flows

Which type of magma has the greatest silica content? felsic intermediate mafic ultramafic

felsic

A __________ is a mineral-lined cavity in a rock. crystal geode Mohs cavity precipitate

geode

Ore minerals, such as galena, tend to be different from typical minerals (such as quartz) in that they have a very dark color. diamond-like crystal habit. large specific gravity. vitreous luster.

large specific gravity.

All things equal, a magma will have __________ viscosity than a lava. the same fractional lower higher

lower

The difference between magma and lava is that __________. magma cools more rapidly than lava magma is found at the surface, whereas lava is found below the surface magma is found beneath the surface, whereas lava is found at the surface There is no difference; the two terms mean the same thing.

magma is found beneath the surface, whereas lava is found at the surface

What type of rock forms when preexisting rocks undergo changes in response to a modification of their environment, without first melting? igneous rocks sedimentary rocks metamorphic rocks meteorites

metamorphic rocks

In general, if a body of igneous (source) rock is subjected to partial melting, the magma that is produced is expected to be __________. identical in chemical composition to the source rock more mafic than the source rock more felsic than the source rock The melt composition is not predictable.

more felsic than the source rock

Magma tends to __________. move upward, away from where it formed move downward, away from where it formed move laterally stay in one place

move upward, away from where it formed

Which of the following minerals is a silicate? galena olivine calcite halite

olivine

For most minerals, the streak color obtained when the mineral is scratched against a porcelain plate is only useful if the mineral is softer than porcelain. more variable than the color in a hand sample among crystals. not useful because the porcelain will often chemically react with the mineral. always dark brown or black.

only useful if the mineral is softer than porcelain

Geologists refer to an exposure of bedrock on the surface as a(n) bed. foliation. outcrop. pegmatite.

outcrop.

Which layer of Earth does NOT contain silicate minerals? oceanic crust upper mantle outer core continental crust

outer core

The tetrahedral structure that forms the backbone of all silicate minerals is composed of silicon and what other element? magnesium oxygen iron carbon

oxygen

Which of the following is not considered a type of pyroclastic debris? lapilli blocks ash pahoehoe

pahoehoe

Which of the following is NOT a mineral? quartz diamond petroleum gold

petroleum

An irregular-shaped and bloblike igneous rock body that cooled beneath the surface of Earth is a __________. dike pluton sill laccolith

pluton

A facet is a __________ on a gem. polished surface cleavage plane small impurity crystal face

polished surface

When a solution becomes oversaturated, new solid particles are said to (Hint: process that leads to the formation of thick layers of salt along the banks of Dead Sea) precipitate from the solution. dissolve into the solution. react with the solution and produce heat. rapidly expand, causing an explosion.

precipitate from the solution.

Minerals that grow around volcanic vents MOST likely form by solidification from a melt. diffusion in a solid. biomineralization. precipitation from a gas.

precipitation from a gas.

The extremely high __________ within Earth prevents rock from melting. temperature pressure silica content water content

pressure

Ash, and larger fragments of pumice are all examples of __________. intrusive igneous rocks hot spots volatiles pyroclastic debris

pyroclastic debris