final exam dalman geol 1403 pt. 2

________ is a volcanic rock that is extremely vesicular and glassy.

Pumice

________ is characterized by very coarse mineral grains?

Pegmatite

Which of the following igneous rocks has a pyroclastic texture?

rhyolitic tuff

A ________ is an open cavity in a volcanic rock that was filled by a gas bubble when the lava was still mainly liquid.

vesicle

A(n) ________ texture represents a single, long period of cooling and crystallization.

phaneritic

Visible quartz and potassium feldspar grains are the main constituents in a ________.

granite

________ is the dominant lava erupted from volcanoes on Hawaii and Iceland.

Basalt

The sizes, shapes, and arrangements of mineral grains in an igneous rock are known as ________.

texture

What do pumice and obsidian have in common?

glassy texture

In a porphyritic volcanic rock, which mineral grains are the last to crystallize?

matrix or groundmass

Which one of the following best describes volcanism in the Cascade Range, northwestern United States?

related to plate subduction

________ are usually the most abundant gases emitted during basaltic volcanism.

Water and carbon dioxide

Which one of the following statements is not true?

When magma reaches the surface, its dissolved gas content increases.

Mount St. Helens is ________.

an explosive stratovolcano

Pockets of magmas can be formed by the melting of deep continental crust heated by the intrusion of other magmas. Which of the following correctly describes this process?

Intrusion of basaltic magma causes deep crustal rocks to melt, producing andesitic or rhyolitic magmas.

Which of the following is associated with deep mantle hot spots?

the volcanoes of Hawaii and Quaternary activity in Yellowstone National Park

Which one of the following shows the correct order (left to right) of decreasing magma viscosity?

rhyolite, andesite, basalt

Which kind of volcanism is typical of mid-oceanic ridge systems?

submarine; basaltic lava flows

Which type of basaltic lava flow has a fairly smooth, unfragmented, ropy surface?

pahoehoe

Which one of the following statements concerning volcanic blocks and bombs is true?

Bombs are ejected as magma lumps; blocks are ejected as solid fragments.

The ________ is an example of an active, continent-continent collision.

northward movement of India into Eurasia

________ was never proposed as evidence supporting the existence of Pangaea.

Islands of Precambrian rocks along the Mid-Atlantic Ridge

Which of the following energy sources is thought to drive the lateral motions of Earth's lithospheric plates?

export of heat from deep in the mantle to the top of the asthenosphere

A typical rate of seafloor spreading in the Atlantic Ocean is ________.

2 centimeters per year

The former late Paleozoic super continent is known as ________.

Pangaea

In the early part of the twentieth century, ________ argued forcefully for continental drift.

Alfred Wegener

The Himalayan Mountains are the tectonic product of a collision between India and Eurasia that began in Eocene time and still continues.

True

Which one of the following is an important fundamental assumption underlying the plate tectonic theory?

Earth's diameter has been essentially constant over time.

Deep ocean trenches are surficial evidence for ________.

sinking of oceanic lithosphere into the mantle at a subduction zone

All of the following are evidence supporting the theory of plate tectonics except for ________.

changes in the Moon's orbit due to shifting plates

The ________ is thought to be a liquid, metallic region in the Earth's interior.

outer core

The lithosphere, asthenosphere, and mesosphere are all layers of Earth defined by their composition.

False

The asthenosphere is a relatively cool and rigid shell that overlies the lithosphere.

False

________ rocks always originate at the surface of the solid Earth.

Sedimentary

The composition of the core of Earth is thought to be ________.

solid iron-nickel alloy

________ is the process by which rocks breakdown in place to produce soils and sediments.

Weathering

The Geologic Time Scale divisions are based on ________.

equal divisions of 1 million (era), 50,000 (period), and 5,000 (epoch) intervals

The ________ is the thinnest layer of the Earth.

Crust

Igneous rocks are produced largely by the deposition and consolidation of surface materials like sand and mud.

False

The ________ proposes that the bodies of our solar system formed at essentially the same time from a rotating cloud of gases and dust.

Nebular Hypothesis

Which one of the following describes a mineral's response to mechanical impact?

Cleavage

A cubic centimeter of quartz, olivine, and gold weigh 2.5, 3.0, and 19.8 grams respectively. This indicates that ________.

gold has a higher density and specific gravity than quartz and olivine

What in the name given to an atom that gains or loses electrons in a chemical reaction?

Ion

All silicate minerals contain which two elements?

silicon, oxygen

The ion at the center of a silicate tetrahedron is surrounded by ________.

4 oxygen ions

The strong tendency of certain minerals to break along smooth, parallel planes is known as ________.

Cleavage

Which of the following minerals is in the mineral group known as mica?

Muscovite

Which of the following best characterizes ferromagnesian silicates?

They are black to dark-green silicate minerals containing iron and magnesium.

Hornblende and the other amphiboles have what type of silicate structure?

double chains

Which of the following best defines a mineral and a rock?

In a mineral the constituent atoms are bonded in a regular, repetitive, internal structure; a rock is a lithified or consolidated aggregate of different mineral grains.

Overall, this type of seismic wave is the most destructive.

Surface Wave

Which of the following sedimentary features can each be used to determine paleocurrent directions?

ripple marks and cross stratification

Which of the following lists the rocks in the order of increasing grain size and increasing grade of metamorphism?

Slate, Phyllite, Schist

Which of the following do feldspars weather to form?

Clay minerals

The continental rise is located ________.

between an abyssal plain and continental slope

________ proposed a hypothesis (that later became a theory) on the creation of atolls.

Charles Darwin

On a typical seismogram, ________ will show the highest amplitudes.

Surface Waves

________ forms from the metamorphism of limestone or dolostone.

Marble

________ are NOT associated with a mid-ocean ridge.

Deep Ocean Trenches

________ is formed when carbon dioxide is dissolved in water.

Carbonic Acid

The ________ lies at the base of the continental slope.

Continental Rise

The ________ is an example of the earliest stage in the formation of a new ocean basin.

East African Rift

________ is another name commonly used by scientists to denote seismic sea waves induced by earthquakes.

Tsunami

An echo sounder operates by measuring the time required for a ________.

sound pulse to travel from a ship to the seafloor and back

Sedimentary rocks account for about what percentage of the Earth's outermost 10 kilometers of rock (first percentage). Also, what percentage of the Earth's continental area is covered by sedimentary rocks (second percentage)?

5% and 75%

What is the major source of heat for contact metamorphism?

heat from a nearby magma body

When strata are displaced so that a dipping reservoir rock abuts an impermeable bed, a ________ is formed.

fault trap

Which of the following places these coral reefs in order from youngest to oldest?

fringing reef, barrier reef, atoll

Which of the following is not one of the agents of metamorphism?

calcium-rich liquids

What is the main difference between a conglomerate and a sedimentary breccia?

Breccia clasts are angular; conglomerate clasts are rounded.

________ is the most common type of chemical sedimentary rock.

Limestone

The primary basis for distinguishing among detrital sedimentary rocks is ________.

Particle Size

This rock's texture resulted from pressure that was applied ________.

from top to bottom

Which metamorphic rock, widely used for monuments and buildings, would deteriorate significantly in contact with acid rain?

marble

What process does the diagram below illustrate?

sheeting

________ have the highest velocities.

Primary waves

The two basic categories of weathering are ________.

mechanical and chemical

________ can provide good indication of the metamorphic environment in which a rock formed.

Index minerals

Which of the following is/are most susceptible to chemical weathering by dissolution?

calcite

The metamorphic grade refers to ________.

the degree to which the parent rock changes during metamorphism

The gently sloping submerged surface extending from the shoreline toward the ocean is termed the ________.

continental shelf

________ is the principle ore of aluminum.

Bauxite

From the land surface downward to the unweathered bedrock, which of the following is the correct order of the different soil horizons?

O, A, E, B, C, bedrock

The layer of rock and mineral fragments, produced by weathering, that cover most of Earth's land surface, is called ________.

regolith

Which type of metamorphism alters the basaltic rocks of the seafloor?

hydrothermal

________ is the layer of warm rock below the crust and uppermost mantle that readily deforms and flows plastically.

The asthenosphere

Seamounts ________.

are volcanoes that form on the ocean floor

Major earthquakes are often followed by somewhat smaller events known as ________.

aftershocks

Sedimentary rocks formed from the accumulation of material that is transported as solid particles derived from both mechanical and chemical weathering are known as ________ sedimentary rocks.

detrital

Oceans cover approximately ________ of Earth's surface area?

70%

Which of the following components of granite are more resistant to chemical weathering?

Quartz

Which of the following sedimentary features would typically be found in shales but not in sandstones?

Mud Cracks

The position on Earth's surface directly above the earthquake source is called the ________.

epicenter

________ is a nonfoliated rock formed by contact metamorphism of a shale or mudstone.

Hornfels

Which of the following sedimentary rocks would you expect to have originally been deposited by fast-moving streams?

conglomerate

The mechanism by which rocks store and eventually release energy in the form of an earthquake is termed ________.

elastic rebound

The instrument that records earthquake events is termed a ________.

seismograph

Oxidation plays an important role in the weathering of ________.

ferromagnesian minerals

Which of the following mass movements is most likely to occur in a geologic setting where the rock strata are inclined?

Rockslide

A drainage pattern comprised of streams that diverge from a central area like spokes is called ________.

Radial