Final Exam Tests 1-2 GEOL 1001
Which of the following best describes the way(s) in which limestone forms?
A combination of biological and inorganic processes
Silica
A compound containing only silicon and oxygen in a ratio of 1:2 (SiO2)
What is the difference between a joint and a fault?
A fault displaces the rocks on one side relative to another
Match the images depicting crystal shapes with the correct descriptions.Pink rock (A)White rock with other stuff (B)
A. >Crystals have well-defined shapes with terminations. >Crystals likely grew into a space filled with hot or cold water rather than solid rock. B. >Crystals are irregularly shaped masses. >Crystals grew into small areas that were impeded by the surrounding rock and mineral material.
Which of the following does NOT match a sedimentary rock with a possible metamorphic equivalent?
All of these are correct matches. (sandstone-quartzite, limestone-marble, shale-schist, shale-gneiss)
Which of the following is NOT a way to form layers in a sedimentary rock?
All of these are ways to form layers. (Occurrence of a discrete event like a flood. A change in the strength of the current. A change in the supply of sediment. A change in climate of the region.)
Which of the following rocks cannot be metamorphosed?
All of these can be metamorphosed. (shale, sandstone, limestone, granite)
Which of the following is NOT a problem addressed by geologists?
All of these choices are addressed by geologists (energy and mineral resources, volcanoes and other natural hazards, geometry of rock layers in the subsurface, flow of groundwater
Which are true of a hypothesis?
All of these choices are correct (It may be tentatively assumed, it may be scrapped or amended after testing, it can be tested for validity)
A key step in developing a new explanation is
All of these choices are correct (making observations about a place or process, asking questions about the observations, proposing an interpretation that can be tested, collecting new observations to test predictions)
Quantitative data may include
All of these choices are correct (specific temperature data, size measurements of sediments, chemistry of water in a stream, age of a rock)
The distribution of natural resources is influenced by the
All of these choices are correct (type of rock, age of the rocks, way in which the rocks formed)
Which of the following are tests we can quickly and easily perform (even in the field) to help us identify a mineral?
All of these choices are correct (magnetism, effervescence, streak, hardness)
Which of the following is true about rocks and minerals?
All of these choices are correct. (A rock can contain more than one mineral, A mineral is composed of chemical elements, A single rock can include more than one mineral)
Which of the following are characteristics typical of volcanic domes?
All of these choices are correct. (Steep-sided, rubble-covered surface, often occur in clusters)
Which of the following occurs in a lava tube?
All of these choices are correct. (The surface of the lava flow solidifies to form a roof over the moving lava; Lava tubes insulate a lava flow, allowing it to flow farther; If a lava tube drains, it becomes a tube-shaped cave.)
Which of the following is common in most calderas?
All of these choices are correct. (a large, circular depression with steep walls; thick sequences of volcanic ash; rounded mountains that are volcanic domes)
Flood basalts influence life on Earth because
All of these choices are correct. (large volumes of flood basalts are erupted during a short time; eruptions can release large amounts of gas that cool the atmosphere; eruptions can release large amounts of gas that warm the atmosphere.)
Which of the following is NOT a mineral?
All of these choices are correct. (liquid water, crystals grown in a laboratory, volcanic glass, piece of wood)
Important characteristics to observe in rocks include
All of these choices are correct. (types of minerals present, sizes and shapes of crystals, presence or absence of layers)
Which of the following are processes that can occur in large magma chambers?
All of these choices are correct. (Crystals that form may sink or rise in the chamber; A partially crystallized magma could be heated by a new, hotter magma entering the chamber; Magma may partially melt the chamber's rock walls, forming a new magma composition.)
Which of the following can we understand by studying sedimentary rocks?
All of these choices are correct. (How environments shifted in location through time. Past changes in climate. Past events, such as landslides and earthquakes. Migration of deserts and advances of the sea.)
Breccia and conglomerate are the coarsest types of clastic sedimentary rocks. Match the rock type to the shape of clast.
Breccia - Angular clasts; Conglomerate - Rounded clasts
Which of these ways in which lava flows destroy human-made structures?
Burning buildings, covering roads, crushing/bulldozing buildings
Match the nonsilicate mineral with its description. Gypsum
CaSO42H20; can be scratched with a fingernail; typically grey, white or clear; forms as an evaporite or a precipitate from hot or warm water underground
______ eruptions can erupt more than 1000 cubic kilometers of magma, resulting in the collapse of the overlying ground into a large crater
Caldera-forming
Mount St. Helens is a volcano in the ____ Range in the Pacific Northwest.
Cascade
How fast do plates move relative to one another?
Centimeters per year
Metallic bond
Electrons are shared widely by many atoms
Which of the following are true of the organization of rows and columns in the Periodic Table?
Elements in the first column have only one electron in their outer shell Elements in the last column are noble gases and have full outer shells.
Metals
Elements represented in this group include Na, K(alkali) and Fe, Cu (transition).
______ per unit area is ______.
Force; stress
Choose all those statements that correctly describe limestone.
Forms in water from various processes; Is known as a carbonate; Gray or yellowish in color; Commonly includes shells
Strike-slip zones _____.
May lie totally within a tectonic plate; Can separate two plates (either being continental or oceanic); May create large shear zones
Which of the following is not a common type of volcano?
Mesa (Common types of volcanoes: Composite cone, dome, shield)
________ rocks are formed by changing previously existing rocks through increases in temperature, increases in pressure, deformation, or chemical reaction
Metamorphic
Match the metamorphic rock on the left with its probable rock of origin.
Metarhyolite - Rhyolite; Deformed granite - Plutonic rock; Greenschist - Mafic volcanic rock; Marble - Limestone; Slate - Shale
Which of the following is NOT one of the main families of rocks?
Meteorites (Main families of rocks: Sedimentary, Metamorphic, Igneous)
What is the name of this metamorphic rock formed when temperatures get so high that the rock partially melts?
Migmatite
Match the nonsilicate mineral with its description. Halite.
NaCl; cubic cleavage, salty taste; generally forms from the evaporation of salty water
Which of the following factors helps magma rise toward Earth's surface?
None of these choices are correct. (NONE ARE CORRECT: Pressure decreases with increasing depth, Magma is more dense and therefore tougher than the surrounding solid rocks, Gas bubbles generally form at great depth and drive magma upward.)
Which of the following is true about tests we can perform on a mineral?
None of these choices are correct. (These choices are not correct: A softer mineral will scratch a harder mineral, Many common minerals react (effervesce) with dilute hydrochloric acid, A streak plate is used to determine how hard a mineral is, Many minerals are strongly magnetic.)
Which of the following factors influence the composition of a magma?
Partial crystallization, the type of source area, the completeness of the melting of the parent rock(s), assimilation of magma mixing
Match the nonsilicate mineral with its description. Galena
PbS; distinctive metallic-grey cubes with cubic cleavage; high specific gravity; mined for lead
A sandstone with a history that can be traced to beach deposits will likely include sans and ________.
Pebbles and larger clasts; pieces of shells
________ is a chemical process that can occur during metamorphism and deformation. (Choose all that apply.)
Recrystallization, Pressure solution, or Remobilization
Which of the following are common types of cleavage (and their associated minerals/mineral groups)?
Three non-perpendicular directions (calcite) Two perpendicular directions (pyroxene) Two non-perpendicular directions (amphibole) One direction (mica) Three perpendicular directions (halite)
Which of the following may be true of metamorphic rocks?
They have preserved structures from before the rock was metamorphosed; Most metamorphic rocks have folds; They display shear zones; They contain flattened or folded pebbles
Which of the following combinations would result in the highest regional elevations?
Thick, less dense crust
At which of the following scales would you be most successful in determining the mineral content of a rock?
Thin section
Which of the following would be evidence that a volcano has been inactive for a long period of time?
Well-developed soils on volcanic rocks
Select all the statements that are correct for cooling magma.
When magma reaches the surface of Earth, thermal energy is transferred to the atmosphere and land surfaces by conduction and radiation; Magma can lose heat when it releases gases either underground or above ground; At depth magma loses thermal energy to the surrounding rocks by conduction; And groundwater can receive heat from magma by conduction.
Geology can help us learn about Earth's past by studying
Why continents and oceans are different, why a landscape looks the way it does, how life in the past was different than today, how global climate has changed since the ice ages.
Which U.S. national park has an "supervolcano" evidenced by hydrothermal activity, frequent earthquakes, and historical ash beds that reach as far as Canada to Mexico?
Yellowstone
A hot spot is interpreted to have formed from
a rising plume of hot mantle material.
A formation is defined as
a rock unit that is distinct and laterally traceable.
The Pacific Ring of Fire is formed by
a string of volcanoes.
Which of the following factors indicates a high risk for volcanic mudflows or lahars?
a volcano with a thick covering of snow or ice
The main source of heat energy for the Earth's interior is a direct result of
alpha decay, which is an unstable atom losing 2 protons and 2 neutrons.
A magma chamber is ____.
an underground body of molten rock
The most common volcanic rock found in lava flows on composite volcanoes is
andesite
The volcanic rocks associated with domes are felsic to intermediate in composition, and hence are classified as rhyolite and
andesite
A fold in which rock layers warp up in the shape of an A is a(n)
anticline
The main difference between the lithosphere and the asthenosphere is the
asthenosphere is less rigid
Melting glaciers tend to deposit most of the sediment they carry and create
at their terminus (end).
The largest eruptions on Earth are floods of _____ magma.
basaltic
If bubbles cannot escape easily from a magma, the resulting eruption is likely to
be explosive
If bubbles cannot escape easily from a magma, the resulting eruption is likely to
be explosive.
A dry climate might impact how people live by increasing
both the risk of drought and other water shortages and irrigation needs.
Intense geologic activity occurs at plate
boundaries
Which of the following is most likely to occur at shallow crustal levels?
brittle deformation
Shield volcanoes, like Mauna Loa, have what kind of slopes?
broad, gentle
The mechanism(s) causing regional metamorphism is/are _____.
burial and heating
This very common carbonate mineral effervesces when it contacts dilute HCl. What mineral is it?
calcite
Limestone and other related sedimentary rocks are also called _____ rocks because they are composed of carbonate ions bonded to other elements.
carbonate
When a rock is buried deep in the Earth and experiences the same force from all sides, it is under
confining pressure
________ metamorphism occurs when rocks are heated locally and have little associated deformations, whereas _________ metamorphism involves heating and deformations over large areas.
contact; regional
The convergence of two continental masses is known as a
continental collision
A divergent boundary can form within a continent. If it does it is called a
continental rift
Some continents continue outward from the shoreline under shallow seawater, forming submerged benches called
continental shelves
Above which type of plate tectonic boundary is Mount Rainier located?
convergent
In which of the following types of bonding do atoms share one or more electrons, as shown in this figure?
covalent bonding
Over 90% of Earth's ____ is composed of silicate minerals.
crust
The main layers of the Earth in correct order, from the surface moving down, are
crust, mantle, outer core, inner core.
What are the two main ways that minerals are put together in rocks?
crystalline versus clastic
Which of the following is very common in oceanic crust?
dark-colored silicate minerals
In _________, magma cools at a slow rate, allowing the formation of _________.
deep magma chambers; coarse-grained rocks
In a rock subjected to heat and pressure, folding, faulting, and shearing may simply be called _____, but if mineralogical or rock texture changes take place, the process is called ______.
deformation; metamorphism
Which of the following is a characteristic of crystals and/or clasts that is not used in classifying a rock?
density
A sandstone with a pinkish or reddish color that is the result of oxidation of iron-bearing minerals indicates the sand was
deposited on land and exposed to air.
Which of the following is NOT a factor that affects the viscosity of magma?
depth
When a rock is subjected to tectonic forces and experiences stress that is not the same in all directions, it is under
differential stress
Mid-ocean ridges form where two ocean plates
diverge
When two plates are moving away from each other, they are said to be ____.
diverging
Continents differ in appearance from ocean basins because
each has its own geologic history
Scoria cones are composed primarily of ______.
ejected fragments of vesicular lava
The Periodic Table categorizes ___ based on their atomic number and chemical properties.
elements
Some volcanic ash rises vertically in an ______, cools before accumulating on the surface, and forms deposits that are _____.
eruption column; nonwelded
An igneous rock that solidifies on Earth's surface is called a(n)
extrusive rock
Compared to unfractured rocks, the rate of weathering in fractured rocks of the same composition is ______.
faster
Fractures along which rock has slipped relative to the other side are called ______, whereas fractures that are simple cracks where the rock has pulled apart by a small amount are _____.
faults; joints
What types of rocks would be most common in a composite volcano?
felsic and intermediate lava flows and tephra
The most common clastic sedimentary rocks are made of the clasts that are
fine grained (smaller than sand).
The magma that flows through a fracture in a rock forms a(n) ____ that becomes a(n) ____ when the magma solidifies.
fissure; dike
The adjective ______ refers to the processes and sediment of streams and rivers.
fluvial
What tectonic setting is interpreted to be the cause of volcanism at Yellowstone?
movement of North America over a mantle plume
The Earth's magnetic field is generated by
movement of iron and electrical currents within Earth's outer core.
Enormous mountain belts and high plateaus can be formed when two continental plates collide and
neither is subducted.
If a mineral fractures, how many directions of cleavage does it have?
no directions of cleavage
Minerals that do not contain silicon are classified as
nonsilicates
The actual age of a rock or event is its
numeric age
Cracks and steps that cross the sea floor and run at right angles to mid-ocean ridges are called
oceanic fracture zones
The rock cycle was conceived by James Hutton in an attempt to explain how
older rocks become new sediment
Lava is molten rock that cools ____.
on the surface
If a mineral cleaves into thin sheets, it probably has
one dominant direction of cleavage.
Shale is a common sedimentary rock because _______.
one of the places clay is deposited is very widespread (the seafloor)
Which environment is least likely to deposit sand?
open ocean away from land
A substance that has well-defined geometric crystals is likely to have a(n) ____ internal structure.
ordered
Which of the following processes is NOT considered physical weathering?
oxidation
Magma can partially crystallize at depth and then rise to shallow depths where the remaining magma solidifies. The early-formed crystals are _______ and the texture is _______.
phenocrysts; porphyritic
Carbon dioxide, hydrogen sulfide, and sulfuric acid are _____ associated with volcanic eruptions that are hazardous to humans, livestock, and crops.
gases
Continental rifts have a diverse suite of igneous rocks associated with them because melting occurs
in the mantle and in the crust
Minerals crystallize _____.
in the opposite order that they melt
Choose appropriate way(s) that steep cliffs might impact people living nearby.
increases landslide hazard
Choose the appropriate way that steep cliffs might impact people living nearby.
increases landslide hazard
Which of the following is NOT a way(s) that an oil field might impact people living nearby?
increasing likelihood of volcanic eruptions (Ways that an oil field might impact people living nearby: improving the local economy, increasing job opportunities,increasing likelihood of an oil spill)
Topographic maps often have some contour lines that are darker than other contour lines. These darker lines are called
index contours
An igneous rock that solidifies below the surface is a(n) ___ rock.
intrusive
An igneous rock that solidifies below the surface is called a(n)
intrusive rock
An igneous rock that solidifies below the surface is called a(n)
intrusive rock.
In which of the following types of bonding do atoms loan one or more electrons, as shown in this figure?
ionic
The two main processes by which sediment is produced are
physical and chemical weathering.
Proximity to certain types of _____ boundaries is the major factor making some places more prone to volcanic hazards than others.
plate
A magma chamber that is solidified is a(n)?
pluton
Choose appropriate way(s) that hot springs might impact people living nearby.
provides geothermal power
Which of the following rock types requires dissolved gas in the magma?
pumice
Which of the following is NOT a typical match between the type of eruption and resulting rock type?
pyroclastic flow-scoria
Some volcanic ash forms ______, that accumulate while hot and can become ______, to some extent.
pyroclastic flows; welded
Rocks rich in what mineral tend to have a poor solubility during weathering?
quartz
How much something changed, divided by the time required for the change to occur, is
rate
A(n) _____ occurs when the sea retreats because sea level drops and/or land is uplifted.
regression
Sedimentary facies shift toward the sea as the sea moves out during a
regression
Sedimentary facies shift toward the sea as the sea moves out during a
regression.
The age of a fossil, organism, rock, geologic feature, or event as defined relative to other geologic features or events is the
relative age
If the pressure and bond strength are sufficient to overcome vibrations due to an increase in temperature, a rock or mineral will _____.
remain solid
Basaltic magma forms the rock at mid-ocean _______
ridges
A mantle plume rises because
it is solid but less dense than material around it.
Fractures that are simple cracks where the rock has pulled apart by a small amount are
joints
A(n) ______ is formed by the sheltering of nearshore water from wave action by a reef or islands. The sheltered water is commonly shallow, quiet, and perhaps warm.
lagoon
Steep and unstable slopes can produce ______, forming _____.
landslides and mudflows; volcanic breccia
Which of the following igneous rocks has a texture consistent with a magma that cooled and solidified slowly at first, followed by more rapid cooling?
large, early formed crystals surrounded by smaller, late formed crystals
Magma erupted on the surface can form a ______ that cools quickly, resulting in ______.
lava flow; volcanic glass
Flood-basalt eruptions are fed by _____.
long fissures/dikes
Sedimentary clasts are ________.
loose fragments of rocks and minerals
Lithifies can be defined as
loose sediment hardens into sedimentary rock.
Felsic minerals melt before ___ minerals.
mafic
A hot spot is a site of intense ________ activity that cannot be explained easily by its plate tectonics.
magmatic
According to the fossil record, what events have coincided with the approximate times when flood basalts were erupting?
mass extinction
The formula to determine density is
mass/volume
If rock is exposed to enough heat after metamorphism it will eventually
melt into magma
What type of rock forms through solid-state alteration of a previously existing rock, by heating, pressure, and/or fluid chemistry?
metamorphic
Igneous rocks vary in their chemical composition and subsequently in their ___.
mineral content
Geologists and other scientists who study minerals are called ____. mineralogists
mineralogists
A geologist who is also a mineralogist would generally study
minerals, like quartz and halite.
Rocks are composed of ____, and minerals are composed of _____.
minerals; elements
As boulders are moved downstream and weathering breaks them into smaller clasts, they first become cobbles, then pebbles, and finally _____ or smaller particles.
sand
Sandstone is defined by being mostly or wholly composed of ________-sized grains.
sand
Sandstone is common because _________.
sand occurs in many environments
Which of the following materials is NOT produced by erupting volcanoes?
sandstone
The main way water gets into a subduction zone is by
seawater introduced into oceanic crust at the mid-ocean ridge, prior to subduction.
Clastic sedimentary rocks are classified primarily on the basis of ______.
sediment size
Loose sediment hardens, or lithifies, into _____ rock.
sedimentary
Petroleum, coal, and water are all resources found most frequently in _____ rocks.
sedimentary
Which of the following matches a sedimentary rock with a possible metamorphic equivalent?
shale-slate
Magma that cools in ________ has a relatively short time to cool and so forms _________, but not volcanic glass
shallow magma chambers; fine-grained rocks
The special geologic terms used to represent the direction of a horizontal line on an inclined surface (as in a fault) and the angle of that surface to the horizontal are
strike and dip
The special geologic terms used to represent the direction of a horizontal line on an inclined surface (such as in fault) and the angle of that surface to the horizontal are _____.
strike and dip
The magma feeding Mount Rainer and the other Cascade volcanoes results from melting associated within the Cascadia _______ zone, which is an ocean-continent ______ boundary
subduction; convergent
Atomic symbol
This is one or two letters representing the name of an element.
Atomic number
This is the number or protons in an atom
Periodic Table
This organizes all the chemical elements according to atomic number and electron orbitals
Loose debris on a rock-exposed landscape is known as ______.
talus
A continental rift occurs when _____.
tectonic forces split a continent apart
A large volcanic eruption in a populated region could kill ____ of people at a time. Choose the most likely, or common, answer.
tens of thousands
This is the one word geologists use to describe how grains and minerals are arranged in a rock.
texture
If a rock is subjected to differential stress, then it means that
the amount of stress is greater in some directions than in others
A region generally is higher than an adjacent region if ______ than in the adjacent region.
the crust is thicker
When a fracture cuts across several rock layers, we can interpret that
the fracture is younger than the layers it crosscuts
Mid-ocean ridges are higher than surrounding oceanic crust primarily because
the lithosphere is thinner and hotter.
A lava solidifies into nonvesicular basalt instead of vesicular basalt because
the magma has a low content of gas.
The higher the gas pressure builds in a magma, _______.
the more explosive an eruption it is likely to produce
Tectonics is the study of
the origin and arrangement of the broad structural features of Earth's surface.
What characteristic of water helps it cause a mineral, such as halite, to dissolve?
the polar nature of the water molecule
Fluvial refers to
the processes and sediment of streams and rivers.
Coarsely crystalline igneous textures indicate that
the rock cooled slowly
Sorting describes _______.
the size range of clasts in sediment
Sorting describes
the size range of clasts in sediment.
When magma plumes (hot spots) encounter the oceanic crust, they spread out along the boundary. Magma from melted lithosphere and plume can create large _______ on the seafloor, like those that form the Hawaiian islands.
volcanoes
The natural cements that hold clasts together precipitate in the empty pore spaces after compaction. Those precipitates come from
water containing dissolved materials.
In ________ very large crystals can grow, forming ______.
water-rich parts of the magma; pegmatite
The majority of transform boundaries are found
in conjunction with mid-ocean ridges.
Match the sedimentary rock name with the description that is the best fit.
- Conglomerate: rounded pebbles and cobbles with sand and finer particles between the larger clasts - Breccia: angular pebbles and cobbles with sand and finer particles between the larger clasts - Sandstone: sand-sized particles of varying mineral content - Siltstone: silt-sized particles, mostly containing quartz - Shale: very fine-grained clay minerals
Match the nearshore or ocean sedimentary environment to its description.
- Deep Seafloor: dominated by fine dust of windblown origin and the remains of single-celled organisms - Lagoons: mixed sand and mud of fluvial origin derived from land and coral and sand from reefs - Tidal Flats: low areas alternately covered by water and exposed to the air - Barrier Island: long, narrow accumulation of sand located parallel and near to the shoreline
Match the magma type with its gas bubble behavior.
- Felsic magma = gas bubbles cannot escape easily; high pressures build up in the magma; typically explosive eruptions; magma is high viscosity - Basaltic magma = gas bubbles escape easily; little pressure builds in the magma; typically nonexplosive eruptions; magma is low viscosity
Match the resource found in sedimentary rocks with its most common, current societal use.
- Groundwater: Fresh supplies essential to life - Petroleum: Transportation and energy - Coal: Electrical energy - Salt: Food, medicine, industry - Limestone (cement): Construction
Which of the following are true for domes and basins?
- In a dome, the rock layers dip away from the center in all directions. - In a basin, the rock layers dip toward the center in all directions - A basin is the structural opposite of a dome - Erosion of a dome exposes older rocks in the center
Match the type of material (mineral or nonmineral) with its diagnostic attributes.
- Mineral: > Ordered internal structure > Occurs naturally > Inorganic composition - Nonmineral: > Created in a laboratory > Randonmly arranged atoms > Organic composition (part of an animal or plant)
Rank the following in order of how a rock responds to progressively increasing stress. Start at the top with the behavior of rock with very little stress applied to it.
- Minerals present may change (e.g., mica may be created where clay existed). - Rock texture may change (e.g., quartz grains may grow together). - Crystals of minerals may become larger with higher-grade metamorphism.
Match the sedimentary environment to the description that best fits it.
- Mountain: steep gradients, vigorous erosion, and fluvial systems confined by bedrock - Dry climates: wind moving sand and fine particles and forming large sand dunes - Delta: formed by sediments piling up where a river enters a standing body of water - Wet environments: soil saturated by water with vegetation adding to the available sediment
Match the nonclastic sedimentary rock with the process by which it typically forms.
- Rock salt and gypsum: Evaporation - Dolostone: Chemical Replacement - Chert and iron-rich formations: Precipitation
Match the volcanic feature with the hazard.
- Scoria cone: > falling volcanic cinders and bombs > volcanic ash and gases - Lava flow: > burial of roads > bulldozing and crashing of houses and other structures
The potential hazards associated with a volcano can be assessed by studying various characteristics and the history of the volcano. Match the characteristics with what type of information it provides.
- Shape: steep slopes indicate high viscosity, explosive magma; gentle slopes indicate less explosive magma - Rock type: chemical analysis determines magma composition and potential for explosiveness - History: the sequence of layers and isotopic dating can indicate the timing and frequency of eruptions
Which of the following determine the outward shape of a crystal?
- The arrangement of atoms in the crystal - How the crystal's growth was affected by the material around it
Based on the image, showing the Mohs Hardness Scale and the hardnesses of some common objects, match the following situations relating to testing a sample mineral to the correct hardness for the sample.
- You can scratch it with your fingernail =Hardness is less than 2.5 - It scratches glass = Harness is greater than 5.5 - You can scratch it with a copper wire; it will not scratch glass = Hardness is between 3.5 and 5.5 - You cannot scratch it with your fingernail, but you can scratch it with copper wire = Hardness is between 2.5 and 3.5
Which of the following phenomena are monitored to predict volcanic eruptions?
- heat flow changes - changes in gas output - ground shaking - changes in topography
Which of the following are responsible for the huge size of flood basalts?
- large (long and wide) fissures from which the lava spews - multiple eruption events in the same area - low viscosity of the basaltic magma
Gas in basaltic magma is the major controlling factor that determines _____.
- what rock types it will form - what landforms it will create
Which of the following are erupted by volcanoes?
-Ash -Pumice -Lava
Which of the following are characteristics of actively erupting volcanoes?
-Billowing clouds of ash rising into the air -Glowing orange lava flowing downhill -Fragments of molten rock blasting into the air
Put the events of the 1980 Mount St. Helens eruption in order. Begin with the earliest event on top and proceed to the latest.
-Earthquake -Landslide -Lateral blast and eruption column
Which of the following best describe lineation?
-It may be due to elongated mineral crystals that grow in linear orientation -Stretched-out mineral crystals may show lineation -It can form under ductile shearing
Which of the following are properties characteristic of calderas?
-Large, basin-shaped volcanic depression -Form from collapse of overlying ground into emptied magma chambers -Bounded by steep escarpments
Which of these rock types are clastic sedimentary rocks?
-Sandstone -Conglomerate -Shale
Rank the following types of igneous rocks according to silica composition, with the highest percent of silica at the top
1) Felsic 2) Intermediate 3) Mafic 4) Ultramafic
Place the following minerals in order of their crystallization from a magma as it cools from high to low temperatures. The mineral that crystallizes at the highest temperature should be at the top.
1) olivine 2) pyroxene 3) biotite 4) muscovite 5) quartz
Order the steps involved in the formation of the Valles Caldera.
1. A huge volume of magma rose from deep within the crust and accumulated as a magma chamber several kilometers below Earth's surface. 2. Some magma reached the surface and erupted explosively. 3. The roof of the magma chamber collapsed and formed a roughly circular depression. 4. Small eruptions of magma piled up into dome-shaped mounds.
Contrast silicate and nonsilicate minerals. Silicate minerals
1. Account for over 90% of the minerals in Earth's crust. 2. Include quartz, feldspar, mica, olivine, and pyroxene. 3. Contain silicon-oxygen tetrahedra.
Rank the minerals according to their stability with increasing metamorphism (rank from low-grade on top to high-grade metamorphism)
1. Chlorite 2. Muscovite 3. Biotite 4. Garnet
Rank the following in order for the formation of a fault from a cylinder of rock in a lab. Place the first step on the top and the last step on the bottom.
1. Compressive stress is applied parallel to the axis of the cylinder. 2. Rock experiences internal strain and is shortened slightly. 3. Stress exceeds strength of the rock and a fracture forms. 4. Slip occurs along the fracture, creating a fault.
Contrast silicate and nonsilicate minerals. Nonsilicate minerals
1. Do not contain silicon. 2. Include the carbonates, oxides, sulfides, and halides. 3. Include calcite, hematite, pyrite, gypsum, and halite.
Rank the bond types in order of their strength, placing the weakest bond at the top and the strongest at the bottom.
1. Intermolecular force 2. Metallic bond 3. Ionic Bond 4. Covalent Bond
Rank the following eruption styles in order of increasing explosivity. Start with least explosive (on top) and proceed to the most explosive eruption style.
1. Lava flows 2. Lava fountains 3. Eruption columns
Rank the rock types in order from non-metamorphosed rock (at the top) to progressively higher metamorphic grades. The rock at the bottom should represent the one that partially melts due to such a high degree of metamorphism.
1. Shale 2. Slate 3. Phyllite 4. Schist 5. Gneiss 6. Migmatite
List the rocks typically found in calderas, from the top downward. Begin with the rocks at the surface and continue to the rocks the farthest below the surface.
1. Volcanic tuff 2. Hard, welded volcanic rock 3. Finely crystalline granite
Place the following events in chronological order based on how they contributed to the development of the Valley and Ridge Province. Put the oldest event on the bottom and the most recent event on the top.
1.) Folds and faults guide erosion, and distinctive valleys and ridges are created 2.) Central part of Appalachians is uplifted, forcing rocks over others to the west 3.) Continental collision occurs between Africa and eastern North America 4.) Paleozoic sedimentary rocks are deposited in the easter United States
Rank the following earth materials in order of their most likely occurrence, starting at Earth's surface. Think about moving from the crust to the mantle, and then to the outer and inner core.
1.) Granite and basalt 2.) Increasing amounts of olivine and pyroxene 3.) Minerals stable only at very high pressures; Fe-Mg silicates and oxides 4.) Molten iron with nickel and some other elements 5.) Crystalline iron and iron-nickel alloy
Rank the following in order to show the dissolution of halite in water. Place the first event at the top and the last event at the bottom.
1.) Halite crystals are immersed in water 2.) The positive end of a water molecule becomes attracted to Cl anions, whereas the negative end of a water molecule becomes attracted toNa cations 3.) When the attraction of the polar water molecule to various cations and anions is strong enough, it pulls the ions away from the halite crystal 4.) Na cations become surrounded by negative sides of water molecules and Cl anions become surrounded by positive sides of water molecules 5.) As this process is repeated, the halite crystals are eventually dissolved in water
Put the events leading to the formation of Crater Lake as we see it today. Put the first (earliest) event on top and proceed to the latest.
1.) Massive ash column eruption of composite volcano empties the magma chamber 2.) Overlying volcano collapses into the resulting void 3.) Scoria cone forms in the caldera 4.) Rain and snowmelt fill the caldera, producing a large and deep lake
Place in correct vertical order (as you would see them in a stratigraphic section) the sedimentary facies created during a sea regression.
1.) beach sandstone 2.) mud 3.) limestone
Rank the particle sizes from smallest (on the top of the list) to the largest.
1.) clay 2.) silt 3.) sand 4.) pebble 5.) cobble 6.) boulder
Silicone
A synthetic material (often used for grease or caulk) in which carbon is bonded to silicon atoms to keep the material in long chains
A silicon-oxygen tetrahedron ___.
>May join with other tetrahedron or cations to form different types of silicates and a wide variety of minerals. > has one silicon atom bonded with 4 oxygen atoms > forms a building block for the vast majority of minerals on earth.
Which of the following are true for horsts and grabens?
A horst is a block that is uplifted relative to blocks on either side, A graben is a block that is dropped down relative to blocks on either side, Horst and graben formation may be associated with multiple normal faults.
A formation is defined as ________.
A rock unit that is distinct and laterally traceable
Which of the following is a hazard but not a risk, according to the textbook?
A scoria cone that erupts hot molten fragments on an unpopulated Pacific island
How does an observation become valid?
A series of specific measurements is made, repeated, and recorded
Which of the following sites near a volcano might be relatively less dangerous?
A site on a ridge as opposed to a site in a valley.
Which of the following is characteristic of continental rifts?
All of these choices are correct. (Some magmas are felsic and intermediate, Heat from hot, mafic magma can melt continental crust, Solid asthenosphere undergoes decompression melting.)
Which of the following are true of felsic magmas?
All of these choices are correct. (They do not allow gas bubbles to escape easily, They tend to have high viscosities, High gas pressures commonly lead to highly explosive eruptions.)
What causes the stress that forms joints?
All of these choices are correct. (burial and tectonic forces, cooling and contraction, uplift and unloading of pressure)
Which of the following is a common metamorphic process?
All of these choices are correct. (deforming objects into new shapes, rotation of minerals into a common orientation, remobilization of chemical constituents into light and dark bands, dissolving some parts of the rock and carrying the material away)
Which of the following processes produce sedimentary clasts?
All of these choices are correct. (fracturing of bedrock that results in angular pieces, breaking of round cobbles as they are transported, scouring and abrasion of bedrock along rivers, decomposition of granite into quartz grains and clay)
Flood basalts influence life on Earth because
All of these choices are correct. (large volumes of flood basalts are erupted during a short time, eruptions can release large amounts of gas that cool the atmosphere, eruptions can release large amounts of gas that warm the atmosphere.)
Which of the following processes could result in a felsic magma?
All of these choices are correct. (partial melting of an intermediate-composition source, partial melting of continental crust, formation and settling of mafic crystals in an intermediate magma)
Identify the factor(s) that strongly influence the size, shape, and/or sorting of sedimentary clasts.
All of these choices are correct. (steepness of slope, sediment supply, strength of current, agents of transport)
Which are important ways that magma can rise through the crust?
All of these choices are correct. (through fractures that can form dikes, pieces of the wall rocks can break off, tectonic forces can help open pathways, magma is hotter and less dense than surrounding rocks)
Which of the following geologic hazards was NOT discussed for the area around St. George, Utah?
All of these choices were discussed. (Volcanic eruptions, earthquakes from a fault along the Hurricane cliffs, flooding from the main river, flash flooding from the mountains)
Rainfall in mountain ranges might impact people living nearby by:
All of these. (increasing flooding hazards, increasing erosion in mountains, increasing mudslide hazards, water flowing into streams and rivers, increasing water supply)
Choose appropriate way(s) that volcanoes might impact people living nearby.
All these might impact people living nearby volcanoes. (They release steam and noxious gases into the atmosphere, Ash ejected into the atmosphere blocks sunlight, Volcanic ash provides fertile sediment for growing crops, Projectiles thrown into the air can hit your house)
What is true of atoms, elements, minerals?
An atom is smallest unit of an element that retains the characteristics of that element, minerals are composed of chemically bonded elements, en element is a type of atom that has a specific number of protons
Overturned
Axial surface is inclined such that a limb has been rotated more than 90°.
Asymmetric
Axial surface is inclined to Earth's surface
Upright
Axial surface is vertical
Long, narrow islands composed mainly of sand that rise out of coastal waters are ______ islands.
Barrier
Match the magma type with the corresponding eruption type.
Basaltic magma - fluid lava flows from shield volcanoes; low viscosity Felsic magma - Explosive eruptions from composite volcanoes; high viscosity
Match the rock texture with the correct description: Clastic Crystalline
Clastic: forms in low-temperature environments, at or near Earth's surface Crystalline: Forms in high-temperature environments; minerals are interlocking
As sediment is buried by material above it, compaction starts to occur. Identify some of the effects of this compaction on the sediment.
Clasts get pushed together. Excess water is expelled. The sediment becomes more dense packed.
Which of the following produced significant amounts of heat during the early formation of Earth, which started approximately 4.5 billion years ago?
Collision and compression of materials by gravity; Sinking of the molten iron and nickel into Earth's interior; Impacts of meteors and asteroids
_______ begins after sediment is buried. Pressure pushes clasts together and forces out excess water.
Compaction
What strategy was described for inferring the environment in which a rock formed?
Comparing the characteristics of the rock to deposits from modern environment
What strategy was described for inferring the environment in which a rock formed?
Comparing the characteristics of the rock to deposits from modern environments
__________ volcanoes produced pyroclastic flows that killed tens of thousands of people at Pompeii and St. Pierre.
Composite
Which of the following are forms of differential stress?
Compression, Tension, Shear
Match the terms regarding heat transfer between objects to their correct definitions.
Conduction - Heat transfer by direct contact; Radiant heat transfer - Heat that radiates outward from a source; Convection - Heat transfer by moving material
Compare contact and regional metamorphism by placing the descriptors in the correct category.
Contact metamorphism - Metamorphosed rocks lack lineation and foliation, Occurs near the edge of magma bodies; Regional metamorphism - Deformation accompanies metamorphism, Associated with tectonics and burial; Both contact and regional metamorphism - Occurs deep within Earth, Results in the growth of new minerals
_______, which are colonial in nature, are the marine animals that help create the major portion of modern reefs.
Corals
What are three types of beds formed by sedimentary layers?
Cross, Graded, and Parallel
Select the factors that directly control the viscosity of magma.
Crystal content, composition, temperature.
Match the intrusion on the left with its definition on the right.
Dike - A sheetlike intrusion that cuts across layers in a hot rock; Sill - An intrusion that is parallel to the layers in the host rock; Laccolith - An intrusion that can eventually form a dome
The puzzle-like fit of the continents, similarity of rock types across continents, and glacial evidence all were pieces of evidence supporting Wegener's hypothesis of continental drift. What was another piece of supporting evidence?
Distribution of similar fossils across multiple continents
Which of the following best describes the temperature of materials typically erupted from volcanoes?
Extremely hot
True or false: A geologist must know all of the different types of minerals in order to correctly identify and classify most rocks.
False
True or false: The terms rock cleavage and foliation are always used interchangeably.
False
True or false: Molten rock can only reach Earth's surface by forming into igneous rocks underground and later being exposed by uplift and erosion.
False (Molten rock may also reach Earth's surface by erupting in a volcano.
True or false: All hills made of volcanic rocks are volcanoes
False (Some of these hills may be covered in lava flows.)
Match the nonsilicate mineral with its description. Pyrite
FeS2; pale bronze to brass-yellow; commonly forms cube-shaped crystals with striations; "fool's gold"
Non-plunging
Fold hinge is horizontal.
Plunging
Fold hinge is inclined from the horizontal; may be gentle, moderate, or steep.
_____ is a coarse-grained intrusive igneous rock composed predominantly of feldspar and quartz
Granite
Match the name of the igneous rock on the left with its compositional term on the right.
Granite - Felsic; Diorite - Intermediate; Basalt - Mafic; Peridotite - Ultramafic;
Match the metamorphic rock type with the igneous rock from which it is derived and its metamorphic grade.
Greenstone - Mafic or intermediate volcanic; low grade; Gneiss - Plutonic rock; high grade; Deformed granite - Plutonic rock; low grade; Greenschist - Mafic or intermediate volcanic; moderate grade; Metarhyolite - Felsic volcanic; low grade
Which of the following is a correct statement about resources in sedimentary rocks?
Groundwater mostly resides in the pore spaces between grains and in fractures.
Which of the following is NOT a typical environment in which a sedimentary rock forms?
Heating next to magma (typical enviornments: beside glaciers, shoreline of a lake, deep sea floor, river channels)
What can geologists learn by studying sequences of ancient sedimentary rocks?
How environments changed over time; How climate changed over time
Which of the following is not a required criterion for a substance to be classified as a mineral?
Human-made
Which of the following U.S. states were covered by parts of the large Columbia Plateau flood basalts?
Idaho, Washington, and Oregon
Which of the following does NOT describe continental rifting?
If rifting continues the continent will remain intact
If compressive stress is applied in the directions indicated by the arrows (consider that arrows directly oppose one another), what will likely happen to the rock layers?
If rocks deform in a ductile manner, they will fold in a direction perpendicular to the stresses.
Which of the following are tectonic settings where large magma chambers can form?
In the continental lithosphere within regions of hot spots and rifts; In the oceanic lithosphere above hotspots and within mid-ocean ridges; Above subduction zones; In areas of continental collisions
Which of the following are locations where flood basalts are known to have occurred?
India, Brazil, Siberia, oceanic plateaus
If a rock is metamorphosed but does not contain foliation or lineation, what has probably happened to the rock?
It has been metamorphosed but not deformed
Select the three ways in which magma can travel through Earth's crust.
Magma can travel through existing fractures in rock, forming fissures and dikes; Magma can travel in regions where tectonic forces have newly fractured solid rocks; Magma can travel upward as rocks above magma chambers collapse
Match a factor on the left that determines how far magma can rise toward Earth's surface with its definition.
Magma pressure - Pressure of the overlying rock is directed toward the magma from all sides; Density - Magma is less dense than surrounding solid rock and thus rises; Gas pressure - Carbon dioxide and sulfur oxide bubbles form in magma, decreasing density of the magma; Stress - Opening of fractures is induced by tectonic forces.
Which of the following Earth layers is the thickest?
Mantle
Most of the material contained within nonclastic sedimentary rocks consists of ______. (Choose all that apply.)
Minerals precipitated from solution as water evaporates; Materials formed through biological activity such as making shells or other hard parts
Identify the list that consists of ten common minerals ranked in order of increasing hardness, from 1 to 10.
Mohs Hardness Scale
Match the type of fault with its description.
Normal - Hanging wall moves down relative to footwall.; Reverse - Hanging wall moves up relative to footwall.; Strike-slip (general) - Fault motion is parallel to the strike; Left-lateral - This is a type of strike-slip; opposite side displaced to the left; Right-lateral - This is a type of strike-slip; opposite side displaced to the right;
Match the igneous rock example on the left with its description on the right.
Obsidian: shiny volcanic glass Pumice: contains vesicles and can float on water Scoria: contains many vesicles; usually dark to reddish in color Tuff: Ash, pumice, crystals, and rock fragments that may be welded. Volcanic breccia: Fragmented igneous rock Pegmatite: Contains very large crystals
Match the stage of rifting with the best descriptions of deformation and metamorphism.
Onset of seafloor spreading - continental margin rocks experience metamorphism because they are close to the new mid-ocean ridge; edges of continents drop below sea level; Continental rifting - normal faults form as continents begin to break apart; graben forms as continental crust thins; contact metamorphism occurs; Mid-ocean rifting -normal faulting forms a graben at the rift; contact metamorphism occurs due to rising magma; circulating seawater heats up and may also metamorphose rocks;
Ionic bond
Oppositely charged ions are attracted to one another (halite is the example given)
Why are silicate minerals the most abundant in Earth's crust and mantle?
Oxygen and silicon are the most common elements in the Earth's crust and are two of the most common elements in the Earth's mantle.
How does a cross bed form?
Piling of sediment down the front of a dune or ripple.
From the list below select the terms that are associated with igneous rocks that have crystals observable by the unaided eye.
Porphyritic, Phaneritic, Pegmatite
How does iron formation form?
Precipitation from seawater early in Earth's history.
The melting of rock to form magma is influenced mainly by which of the following three factors?
Pressure, Temperature, Water content
If a description of sediment states that it contains large, angular fragments that are mostly red in color, what type of data would this represent?
Qualitative
______ is a physical process that may occur during metamorphism.
Rotation, Shearing, or Grain and clast deformation
Volcanic vents can take which of the following forms?
Roughly circular craters; Narrow linear fissures
Match each type of metamorphic foliation to its description.
Schistosity - Parallel orientation of mica minerals; Gneissic - Alternating light and dark colored bands; Ductile shearing - Flattened and smeared mineral grains;
What type of map is used primarily to show the shape of the land by simulating light and dark shading on the hills and valleys?
Shaded relief map
Fine-grained rocks are the most common type of clastic rocks. Select all of the following rock types that are fine-grained clastic rocks.
Shale; Siltstone; Mudstone;
Match the particular rock behavior, mineral response, or effect of fluids with either shallow or deep depth.
Shallow - rock shows brittle behavior; fracture in the rock, minerals are stable and barely respond to conditions, and there is little effect; may from low-temperature mineral veins; Deep - ductile behavior occurs; flowing of the rock, mineral recrystallize into larger or smaller crystals, and high-temperature veins from; mobilization of chemical constituents;
Drag the name of each mineral into its correct order according to Mohs Hardness Scale, arranged from the softest mineral (#1) to the hardest mineral (#10).
Softest 1. Talc 2. Gypsum 3. Calcite 4. Fluorite 5. Apatite 6. . K-feldspar 7. Quartz 8. Topaz 9. Corundum 10. Diamond
Which of the following is NOT a typical environment in which a metamorphic rock forms?
Solidification of lava (typical enviornments in which a metamorphic rock forms: Squeezing by tectonic forces, heating adjacent to underground magma, burial to great depths)
Select the statement that best describes how the process of plate tectonics circulates materials between the asthenosphere and the lithosphere.
Some asthenosphere becomes lithosphere at mid-ocean spreading centers and reenters the asthenosphere at subduction zones.
Which of the following are tests we can quickly and easily perform (even in the field) to help us identify a mineral?
Streak Hardness Effervescence Magnetism
How is magma created in a subduction zone?
Subduction brings one plate to a depth hot enough for minerals to release water; this water causes melting in the overlying asthenosphere.
Continental ice sheets were more common 28,000 years ago than they are today because
The Earth was cooler then than now
Which of these best describes the location of the core within the Earth?
The core is located in the central zone of the Earth, beneath the mantle.
Silicon
The fourteenth element of the Periodic Table; term may also be used to describe a synthetic material used to make computer chips
If a mineral lacks planes along which it may cleave, what will occur?
The mineral will fracture in an irregular pattern.
What do these images show? (insert water molecule here)
The polarity of a water molecule with respect to its O and H "ends" Graphic representations of the water molecule That the atoms in a water molecule are covalently bonded
Which of the following is a characteristic of fine-grained clastic rocks?
The rocks tend to be easily eroded.
Which of the following was mentioned in the opening two-page spread of Chapter 1?
The scenery of Glacier National Park
How does the strength of the continental crust vary with increasing depth?
The strength of the continental crust first increases and then decreases with increasing depth
Nonmetals
These elements include O and Si and typically bond with types of metallic elements to form minerals.
Noble Gases
These include the elements Ar and He; these do not readily combine with other elements.
Which of the following is NOT true about shield volcanoes in the landscape?
They are large mountains with steep slopes. (True statements: They can construct some of the world's largest volcanoes)
Match the environmental depositional shift to its correct description.
Transgression - The sea moves inland, Facies shift toward land; Regression - Facies shift away from land, The sea moves out.
Sedimentary clasts (pieces of other rocks) are formed by ______.
Transport; weathering
True or false: A rock may undergo metamorphism without deformation.
True
True or false: Clastic sedimentary rocks are usually comprised of sediment that comes mainly from other locations.
True
True or false: The complete melting of a source area to form igneous rocks is rare.
True (Most magmas result from partial melting)
Covalent bond
Two atoms share an electron (a water molecule is the example given)
Match each metamorphic condition with its best description.
Typical metamorphism - metamorphism under these conditions can occur over large regions (regional); most metamorphic rocks form under these conditions; Low-P/high-T metamorphism - shallow levels in the crust are heated by magma; contact metamorphism occurs under these conditions; High P/low T metamorphism - when rocks are taken to depth faster than they can heat up, like in a subduction zone or accretionary prism, this metamorphism occurs;
Which of the following are ways that viscosity affects gases in magma?
Viscous magma prevents gas from escaping easily.
Intermolecular bond
Weak bonds attract a molecule to another molecule
An ion with a positive charge is called a(n) _____, whereas an ion with a negative charge is called a(n) _____
cation, anion
The yearly rate of tectonic plate movement is best measured in
centimeters
When halite dissolves in water the
chlorine and sodium atoms become separated by water molecules.
Rocks deformed under low to moderate temperatures (less than 300 degrees C) may develop a planar fabric along which they break called rock
cleavage
Which of the following mineral properties can be directly observed by the naked eye, without the need for testing supplies and equipment, and relate to the appearance of the mineral?
cleavage/fracture luster color crystal shape
Rocks that are more resistant to erosion are more likely to create
cliffs
The grain size of ___ igneous rocks is larger than 1 millimeter. More commonly, this grain size is described as being large enough to see with the unaided eye.
coarse-grained
A hand lens could be used to examine a(n) _____ -grained igneous rock, while a(n) _____ would be needed to examine the crystals in a fine-grained igneous rock.
coarse; microscope
Folds are most often created through what type of stress?
compression
What are the three main types of stress?
compression, tension, and shear
Shield volcanoes typically have ____ slopes than composite or scoria cone volcanoes.
gentler
The periods and subdivisions of Earth history, arranged in proper order, are called the
geologic timescale
The temperature increase with depth is called the geothermal _____.
gradient
Which of these minerals would you use to make wallboard for the interior walls of your house?
gypsum
Because shales and siltstones are easily eroded, the areas where they are exposed typically _______.
have soft slopes and soil cover.
The existence of a potentially dangerous situation or event is known as a(n) _____, whereas the likelihood and magnitude of its impact on society is known as its _____.
hazard; risk
_________ and ________ increase with depth into Earth.
heat; pressure
Gases more easily remain dissolved in liquids at _____ pressures.
high
Rock that has solidified from magma is a(n) _____ rock.
igneous
Which of the following volcanoes is generally the largest?
shield volcano
The most common chemical compound in igneous rocks, varying between 44% and 77%, is
silica.
The two elements most abundant in the Earth's crust are
silicon and oxygen
Sediment _______ is the primary characteristics used to classify clastic sedimentary rocks.
size
A force that is important in driving plate tectonics is
slab pull, ridge push, and upwelling mantle, such as in hot spots.
The higher a magma's viscosity is, the ___.
slower it will flow
In the formation of an ingenious rocks, melting needs to occur first, which happens in the ____ area.
source
The ratio of density of a mineral to that of freshwater is called the mineral's _____.
specific gravity
A composite cone has slopes that are ______ than those of a shield volcano.
steeper
Which of the following best describes the materials that cover Earth's surface?
there are many different materials, and they vary by location
Which of the following is NOT a characteristic of an actively erupting volcano?
totally covered in a fresh blanket of clean, white snow
The ______ of a sea across a region that was previously dry is caused by a rise in a sea level and/or the lowering of the land surface.
transgression
Which of the following is NOT a main type of silicate structure?
triple chains (Main types of silicate structures: single chains, frameworks, sheets, double chains)
There are more than 4,000 known minerals, most of which are
uncommon to rare
When stress fields orient themselves so that rock may be pulled apart in a horizontal direction, _______ joints form. If stress fields are oriented so that rock may be pulled apart in a vertical direction, ______ joints form.
vertical; horizontal
Steep-sided hills of viscous lava that pile up over volcanic vents are known as ________.
volcanic domes
Which of the following igneous rocks would be formed by the fastest cooling?
volcanic glass