Volcanos And Geo Time

Front 1

which of the following types of magma has the highest vicosity?

Back 1

rhyolitic

Front 2

which of the following parameters has an influence on whether a volcanic eruption will be effusive or violient

Back 2

amount of gas in the magma

Front 3

which of the following types of lava will most likely lead to a volcanic eruption of a effusive nature

Back 3

basalic

Front 4

the seduction of oceanic crust under the continental crust predominately produces which of the following types of volcanic eruption?

Back 4

violent and explosive

Front 5

A hot spot that occurs in oceanic crust is likely to produce which of the following types of eruptions?

Back 5

quiet and effusive

Front 6

Volcanism at the edges of continents occurs at convergent plate boundaries where subduction of denser ocean crust under continental plates results in deep mantle melting. The molten magma moves upward to the surface to form volcanoes on the edge of the continental plate. The volcanoes that surround the Pacific Ocean, known as the Ring of Fire, are volcanoes of this type—these are often explosive. Mt. Vesuvius is another volcano that is known to be explosive

Back 6

Mt. St. Helens, Crater Lake, Mt. Etna

Front 7

Volcanism in the ocean often occurs at divergent plate boundaries, where the oceanic lithosphere is pulling apart through seafloor spreading. Volcanoes form on the seafloor where there is eruption of magma. These include the numerous small volcanoes along the mid-Atlantic ridge. Volcanism can also occur in instances where the continental lithosphere is pulled apart, such as the East African Rift Valley.

Back 7

East African Rift Valley

Front 8

Volcanism in the middle of a plate (intraplate volcanism) is more variable in terms of the type of lava. Volcanism can occur at the center of continental lithosphere, like the Deccan Plateau, or at the center of an oceanic plate like the Hawaiian Islands, created by hot spots within the mantle.

Back 8

Deccan Plateau, Kilauea

Front 9

explosive eruption

Back 9

volcano fed by silica-rich magma, water rich magma

Front 10

non explosive

Back 10

volcano fed by mafic (basaltic) magma, volcano fed by magma with low amounts of dissolved gases, volcano fed by high temperature (1000*C) magma

Front 11

Asthenosphere

Back 11

magma with the highest temperature

Front 12

lithosphere

Back 12

magma undergoing partial crystalization of high-density mineral, Magma with desnity lower than the lithospheric mantle, but higher than the crust

Front 13

crust

Back 13

magma undergoing degassing of water and other volatiles during an eruption. Magma with highest silica content, magma with desnity lower than the crust

Front 14

in which of the following lava types would you expect to see the development of pahoehoe

Back 14

basaltic

Front 15

in which of the following lava types would you expect to find the greatest percentage of gases

Back 15

rhyolitc

Front 16

in which of the following types of lavas would you expect to find the greatest production of pyroclastic materials

Back 16

rhyolitic

Front 17

What do we call pyroclastic material, ejected during a volcanic eruption, composed of incandescent lava that is greater than 64 millimeters (2.5 inches) in diameter?

Back 17

bombs

Front 18

which of the following gases is most abundant in basaltic lavas

Back 18

water vapor

Front 19

At which of the following tectonic settings would you expect to find volcanoes producing the highest volumes of pyroclastic material?

Back 19

subduction of an oceanic plate under a continental plate

Front 20

at which of the following tectonic settings would you expect to find volcanoes producing significant amounts of very fluid, high-temperature lavas?

Back 20

mantle plumes

Front 21

Basalts are mafic lavas with low silica contents (~50%) and high eruption temperatures, causing them to flow easily and have a low viscosity. Basalts flow far from volcanic vents and form broad, sheet-like lava flows.

Back 21

fast lava flow, glows in sheets, 90% of lava on earth

Front 22

Rhyolites are felsic lavas with high silica contents (~70%) and low eruption temperatures, giving them high viscosities. Rhyolitic lavas mound up and stay near the volcanic vent because of their resistance to flow.

Back 22

1% of lava on Earth, Silica-rich lava, slow lava flow

Front 23

aa flow

Back 23

lava landform with rough, broken surface caused by rapidly moving basalt that cools quickley

Front 24

pahoehoe flow

Back 24

lava landform with smooth, billowy surface caused by slowly moving basalt that are still hot

Front 25

lava tube

Back 25

lava landform which results from a relatively fluid lava cooling and forming an outer shell through which the flow continues to flow

Front 26

block lava

Back 26

lava landform with rough surface of smooth-sided fragments formed by vicous lava cooling quickley

Front 27

pillow lava

Back 27

lava landform of solid, bubble like masses caused by lava quenching extremely quickley

Front 28

bombs

Back 28

smoother particles erupted as liquids are greater than 64 millimeters (2.5 inches) in size

Front 29

blocks

Back 29

rougher particles erupted as solidsare greater than 64 millimeters (2.5 inches) in size

Front 30

lapilli

Back 30

walnut-sized

Front 31

ash

Back 31

a fine dust or powder.

Front 32

scoria

Back 32

Darker (mafic) vesicular rocks

Front 33

pumice

Back 33

while lighter (felsic) vesicular rocks

Front 34

which of the following are types of volcanoes

Back 34

shield volcano, composite volcano, cinder cone

Front 35

what information do geologist use to classify volcanoes?

Back 35

shape and type of depsoits

Front 36

cinder cones are made of ________

Back 36

pyroclastic deposites

Front 37

in general, how often do most cinder cones erupt

Back 37

once

Front 38

what are shield volcanoes generally made of?

Back 38

basalt flows. known for long lava flows and lava tubes, broad steep slops and a caldera. Mauna loa, hawaii

Front 39

what is the range of shield volcano height

Back 39

300 to 10,000 meters

Front 40

what are composite volcanoes made of?

Back 40

pyroclastic deposites

Front 41

why are shield volcanoes wider than composite volcanoes

Back 41

the lava that flows out of shield volcanoes is more fluid than the lava that flows out of composite volcanoes

Front 42

what type of magma erups out of dome complexes

Back 42

felsic magma

Front 43

what type of volcanoes are the tallest

Back 43

shield volcanoes

Front 44

what is the range of dome complex height

Back 44

500 to 2,000 meters high

Front 45

what geologic process is related to caldera formation

Back 45

volcanism

Front 46

how do calderas form

Back 46

when the summit of a volcano collapses

Front 47

in addition to rock deposits, what evidence do we have that the eruption that preceded the formation of Crater Lake was very large?

Back 47

The eruption was so large that the magma chamber under Crater Lake partially emptied, causing the volcano to become unstable and collapse.

Front 48

why does crater lake have an island in it

Back 48

the volcano is still active, and a new volcanic peak has formed

Front 49

volcanic ash is best described as which of the following?

Back 49

microscopic pieces of rock ejected by a volcano

Front 50

which of the following is the volcanic feature in which magma rises through before it is released at the surface?

Back 50

conduit

Front 51

composite volcano

Back 51

is steep and primarily due to the eruption of a mixture of volcanic material, containg less fluid material that travel shorter distances

Front 52

sheild volcano

Back 52

a wide volcano that produces mainly basaltic lava flows

Front 53

cinder cone

Back 53

a very steep-sided volcano build from ejected lava fragments. reddish-brown lapilli, and steep sides and a crater at the peak. San francisco peaks, paricutin mexico

Front 54

basaltic

Back 54

brod sheets of fluid lava travel long distances and give shield volcanoes their distinctive shape

Front 55

moderately viscous and gas-rich lavas can erupt as lava flows or pyroclastic materials, leading to the steepening slope of composite volcanoes.

Back 55

andesitic

Front 56

rhyolitic

Back 56

explosive eruptions of highly viscous lavas creat steep-sided cinder cone volcanoes

Front 57

composite cone

Back 57

erupting lava and pyroclastic material, steep summit and broad flanks. Fujiyama, japan, mount st. helens, mount augustine, alaska

Front 58

which of the following features at yellowstone national park is evidence for a magma chamber beneath the park?

Back 58

welded tuff, rising (or bowing upward) ground near Yellowstone river, geysers and hot springs (steam)

Front 59

which of the following pieces of evidence for a pst volcanic eruption are present at yellowstone national park

Back 59

lava flows, pyroclastic material, a caldera rim

Front 60

yellowstone is best described as

Back 60

an active volcano that has erupted in the last 1 million years

Front 61

Which of the following was a stage in the formation of Yellowstone caldera?

Back 61

crust bows upward above a magma chamber

Front 62

dike

Back 62

tabular igneous pluton that occurs in an orientation that is discordant with the bedding surfaces of adjacent sedimentary rocks

Front 63

sill

Back 63

tabular igneous pluton that occurs in an orientation that is concordant with the bedding surfaces of adjacent sedimentary rocks. Formed when magma intrudes between existing sedimentary layers

Front 64

batholith

Back 64

massive pluton

Front 65

Batholiths are known to form the cores of mountain ranges such as the Sierra Nevada. What is the implication of this observation?

Back 65

Because batholiths form deep within Earth, the occurrence of one at the surface implies that it has since been uplifted and/or the rocks above have been removed.

Front 66

While working in the field, you find a dike cutting across some sedimentary rocks. What grain size would you expect to find in this pluton?

Back 66

fine-grained

Front 67

what lies underneath volcanic features at earth's surface

Back 67

magma chambers and volcanic conduits

Front 68

What is the difference between a dike and a sill?

Back 68

A dike intrudes across sedimentary layers, and a sill intrudes between sedimentary layers.

Front 69

What is a volcanic conduit called after the conduit has solidified and been exposed by erosion?

Back 69

a volcanic neck

Front 70

Why are volcanic rocks often exposed at Earth's surface as hills, ridges, and mountains surrounded by areas of lower elevation?

Back 70

Volcanic rocks are often more resistant to erosion than surrounding rock.

Front 71

What is a magma chamber called after it and the conduit have solidified and been exposed by erosion?

Back 71

batholith

Front 72

when will magma rise to earth's surface

Back 72

when the magma is less dense than adjacent rock

Front 73

In general, when will melted rock in the mantle rise?

Back 73

almost always

Front 74

How are felsic magmas formed?

Back 74

Heat from the mantle melts part of the lower crust.

Front 75

In general, why does Earth's crust sit on top of the mantle?

Back 75

In general, why does Earth's crust sit on top of the mantle?

Front 76

How do mafic volcanic rocks get to Earth's surface?

Back 76

Pressure from overlying crust forces mantle magmas through cracks to Earth's surface. These magmas erupt out of volcanoes, cool, and solidify into rock

Front 77

What type of volcanism characterizes the ring of fire?

Back 77

volcanism caused by convergent oceanic-oceanic, Oceanic-contenental boundaries

Front 78

What type of boundary is present along the eastern boundary of the North American plate?

Back 78

divergent oceanic-oceanic

Front 79

At what tectonic setting is Hawaii located?

Back 79

oceanic hot spot

Front 80

What drives melting at divergent boundaries?

Back 80

decompression melting

Front 81

Which of the following tectonic settings does NOT produce volcanism?

Back 81

transform boundary

Front 82

Which of the following would best describe the shape and composition of a volcano in the Cascade Range?

Back 82

Cone-shaped volcano with alternating layers of lava and pyroclastic material

Front 83

Which of the following statements describe a part of the process of the formation of the Cascade Mountain Range?

Back 83

Partial melting due to the presence of water, Eruption of material at the surface, Rising of magma to the surface

Front 84

which mountain is associated in the ring of fire

Back 84

Mt. pinatubo

Front 85

What is the relationship between the crust and the lithosphere?

Back 85

All of the crust is contained within a larger layer called the lithosphere.

Front 86

What is the relationship between the mantle and the lithosphere?

Back 86

Some of the mantle is contained within a smaller layer called the lithosphere.

Front 87

What is the relationship between the mantle and the asthenosphere?

Back 87

All of the asthenosphere is contained within a larger layer called the mantle.

Front 88

What surface feature provides evidence for the location of hot spots?

Back 88

volcanoes within tectonic plates

Front 89

When will a hot spot volcano become extinct?

Back 89

when the volcano is carried away from the hot spot by the tectonic plate

Front 90

What surface feature would you expect to form if both a hot spot and a tectonic plate are stationary?

Back 90

a single volcano

Front 91

Which of the following are common tectonic settings associated with volcanic activity?

Back 91

mantle plumes, continental rifts, island arcs, continental arcs

Front 92

Which of the following is a present-day example of a continental rift?

Back 92

the East African rift valley

Front 93

Which of the following often forms after continental rifting?

Back 93

a new ocean basin

Front 94

Where are continental volcanic arcs found?

Back 94

on the overriding plate near a subduction zone

Front 95

How are continental rift magmas and continental arc magmas different?

Back 95

Continental arc magmas are more viscous than continental rift magmas.

Front 96

How are island arc and continental arc magmas similar?

Back 96

Both are formed near subduction zones.

Front 97

What is a mantle plume?

Back 97

a circular column of magma that rises from deep within Earth

Front 98

Which of the following is an example of modern-day mantle plume volcanism?

Back 98

hawaian islands

Front 99

Which of the following results from a mantle plume as the source of the lava?

Back 99

the deccan plateau, kilauea

Front 100

Which of the following is characteristic of a continental volcanic arc along an oceanic–continental subduction zone, such as the western margin of South America? Choose all that apply.

Back 100

an explosive eruption, Pyroclastic material such as volcanic ash

Front 101

Which principle or law of geology states that in a sequence of undeformed sedimentary rocks, each bed is older than the one above?

Back 101

superposition

Front 102

What term describes an erosional surface bounded above by flat-lying sedimentary rocks and below by igneous or metamorphic rocks?

Back 102

nonconformity

Front 103

The fact that sedimentary rocks are almost always deposited in a horizontal position reflects which law or principle of geology?

Back 103

original horizontality

Front 104

While working in the field, you encounter an outcrop in which sandstone, shale, and limestone have been intruded by a basaltic dike. You know that the basaltic dike is younger than the sedimentary rock by applying which law or principle?

Back 104

the principle of cross-cutting relationships

Front 105

In the field you encounter a sequence of sedimentary rocks that has a dike running through them. A normal fault crosses the entire sequence, cutting off part of the dike near the surface. Which scenario best describes your observations? (All scenarios list events from oldest to youngest.)

Back 105

The relative ages of the sequence are as follows: sedimentary rocks > dike > normal fault.

Front 106

due to unconformity, the ____ period is missing from the rock record

Back 106

jurassic

Front 107

the trassic and cretaceous rocks are separated by this type of unconformity

Back 107

angular unconformity

Front 108

the quaternary and tetiary rocks are separated by this type of unconformity. exhibits sedimentary layers that are parallel to each other above and below the erosive surface

Back 108

disconformity

Front 109

the trassic rocks must have been most likely tilted during or after the _____ period

Back 109

triassic

Front 110

the dike dates at least to the

Back 110

quaternary

Front 111

If a limestone, a shale, and a sandstone are deposited in that order without interruption, which of the following is true?

Back 111

The limestone is the oldest and the succession is conformable

Front 112

What scenario requires a geologist to use the principle of cross-cutting relationships?

Back 112

A dike truncates layers in a sedimentary succession.

Front 113

Which of the following is associated with an erosive surface?

Back 113

a stream running across an irregular surface

Front 114

An igneous dike cuts across existing sedimentary layers and erupts at the surface, creating a layer of basalt. The basalt, as well as all the layers below, are then cut by a fault. Which statement is true?

Back 114

The fault is the youngest because it cuts through all the sedimentary layers and basalt.

Front 115

A sandstone contains inclusions of metamorphic rock. An igneous dike cuts both the sandstone and inclusions. List the rocks from youngest to oldest.

Back 115

igneous dike, sandstone, metamorphic rock

Front 116

If a sequence of sedimentary units is cut by a fault, what does the principle of cross-cutting relationships tell a geologist?

Back 116

All of the sedimentary units must have been deposited and lithified before being cut by the fault.

Front 117

Which of the following describes the principle of original horizontality?

Back 117

Folded sedimentary layers were originally laid down flat and later deformed.

Front 118

An undeformed sequence of sedimentary rocks is exposed in a large river canyon. Which two principles would be demonstrated by the rocks?

Back 118

principles of superposition and lateral continuity

Front 119

An igneous dike cuts through limestone, but not through the overlying sandstone. Which of the following statements is most accurate?

Back 119

First, the limestone was laid down, then intruded by the igneous dike, and lastly the sandstone was deposited.

Front 120

Following the deposition of a sequence of sedimentary rocks, which event is the first to occur to produce an angular unconformity?

Back 120

deformation

Front 121

Which of the following is an accurate description of a nonconformity?

Back 121

younger sedimentary strata overlie uplifted and weathered igneous or metamorphic rocks

Front 122

The sedimentary layers above an erosive surface are __________ relative to all rocks present below the surface.

Back 122

younger

Front 123

Which of the following is a common feature that all unconformities exhibit?

Back 123

erosive surface

Front 124

What does the termunconformity mean?

Back 124

a missing rock layer in a sequence that represents a period of erosion or nondeposition

Front 125

What characteristic most directly DISTINGUISHES an angular unconformity from a nonconformity?

Back 125

Angular unconformities separate rock layers along nonparallel surfaces.

Front 126

Which of the following statements about relative and absolute age dating is correct?

Back 126

Relative age dating places rocks and events in chronological order, but does not provide information about absolute age.

Front 127

What is the Principle of Original Horizontality?

Back 127

Sedimentary rocks are close to horizontal when deposited.

Front 128

What is the Principle of Superposition?

Back 128

Within a sequence of rock layers formed at Earth's surface, rock layers lower in the sequence are older.

Front 129

What is the Principle of Cross-Cutting Relationships?

Back 129

Geologic features that cut through rocks must form after the rocks that they cut through.

Front 130

Five layers of rock are cut by two faults. Both faults cut through all five layers of rock. Fault A breaks through to the surface, while Fault B does not. Which of the following statements about Faults A and B is correct?

Back 130

Faults A and B are about the same age, and both are younger than the five layers of rock.

Front 131

Which principle of relative age dating is important for determining the relative age of igneous rock that has intruded into overlying rock?

Back 131

the Principle of Cross-Cutting Relationships

Front 132

A fault (F) breaks three layers of sedimentary rock (S). An igneous intrusion (I1) has broken through the bottommost layer of rock. A second igneous intrusion (I2) has moved up the fault and pooled on top of the uppermost layer of rock. Which event would be considered the youngest?

Back 132

The intrusion of I1 or I2 is the youngest event. Without more information, we cannot know which igneous rock is youngest.

Front 133

What is the best definition of fossil range?

Back 133

The period of time when an organism first and last appears in the sedimentary record.

Front 134

Which of the following characteristics is the most desirable for constraining the relative age of rocks?

Back 134

organisms with overlapping ranges and geologically short lifespans

Front 135

Which organism from the video is the least useful for relative dating?

Back 135

scallop

Front 136

If a rock contains ten different kinds of fossils, which of the following must be true?

Back 136

All of the organisms had to be alive when the rock was deposited.

Front 137

How is the geologic time scale related to the fossil record?

Back 137

The periods of the time scale were constructed based on ranges of fossil organisms.

Front 138

How is the atomic number of an atom determined?

Back 138

counting the number of protons in the nucleus

Front 139

Which process is not a common form of natural radioactive decay?

Back 139

nuclear fission

Front 140

Which material, principle, or process enables a method of numerical dating?

Back 140

radioactivity

Front 141

Which is an example of radioactivity that occurs when a neutron is converted to a proton and an electron is emitted from the nucleus?

Back 141

emission of a beta particle

Front 142

After four half-lives of decay, what is the ratio of radioactive parent isotope to stable daughter isotope?

Back 142

1:15

Front 143

A radioactive element undergoes decay via the loss of two alpha particles to form a stable daughter isotope. Following the decay, what would the atomic number of this newly created stable isotope be?

Back 143

The atomic number of the daughter isotope would be four units less than the original parent isotope.

Front 144

You attend a geology lab where you are asked to estimate the age of a fossil. The ratio of parent to daughter elements in the fossil sample is 1:7. You know that fossils are the remains of living organisms, which have some amount of C-14 isotope. The C-14 isotope, which has a half-life of 5730 years, begins to decay as the organism dies.What would be your estimation of the fossil's age?

Back 144

17,190

Front 145

C-14 dating:

Back 145

This process is often known as radiocarbon dating. It is used to determine both historical and recent events of archeological artifacts of biological origin such as bone, cloth, wood, and plant fibers.

Front 146

U-235 dating:

Back 146

This is used to determine the age of inorganic substances such as ancient rocks and minerals.

Front 147

What happens during radioactive decay?

Back 147

Parent isotopes turn into daughter isotopes.

Front 148

What is the scientific definition of half-life?

Back 148

the amount of time over which the number of parent isotopes decreases by half

Front 149

Two containers hold the same radioactive isotope. Container A contains 1000 atoms, and container B contains 500 atoms. Which of the following statements about containers A and B is true?

Back 149

The rate of decay of atoms in container A is greater than the rate of decay of atoms in container B.

Front 150

A container holds 100 atoms of an isotope. This isotope has a half-life of 1.5 months. How many total atoms will be in the container after 3 months?

Back 150

100 atoms

Front 151

A container holds 100 atoms of an isotope. This isotope has a half-life of 1.5 months. How many atoms of the radioactive isotope will be in the container after 3 months?

Back 151

25 atoms

Front 152

A rock sample contains 75 atoms of a parent isotope and 25 atoms of a daughter isotope. The half-life of the parent isotope is 100 years. How old is this rock?

Back 152

50 years old

Front 153

Which represents the correct sequence from oldest to most recent or current eras on the Geologic Time Scale?

Back 153

Paleozoic, Mesozoic, Cenozoic

Front 154

Which eon translates to “visible life” from the Greek?

Back 154

Phanerozoic

Front 155

Which is the shortest interval of geologic time?

Back 155

epoch

Front 156

The subdivisions of the Geologic Time Scale were based on which criteria or characteristics?

Back 156

types of fossils within the units

Front 157

Which event is generally used to indicate the beginning of the Phanerozoic eon?

Back 157

widespread occurrence of hard parts

Front 158

While working in the field, you find some sedimentary rocks that include hundreds of fossils of crinoids, numerous brachiopods, and a few trilobites. Realizing that these ancient organisms are some of the first with hard parts, and (when taken as a group) are not very similar to animal communities living today, in which unit of geologic time would you place these rocks?

Back 158

the Paleozoic