Geology Midterm

What is the chemical formula for dolomite, the major mineral in dolostones?

CaMg(CO3)2

Which carbonate mineral reacts readily with cool, dilute hydrochloric acid to produce visible bubbles of carbon dioxide gas?

Calcite

________, a popular natural philosophy of the 17th and early 18th centuries, was based on a firm belief in a very short geologic history for Earth.

Catastrophism

A ________ system is one in which energy moves freely in and out, but no matter enters or leaves the system.

Closed

All of the following provide evidence or clues to the composition of Earth's interior except for ________.

Comets

The ________ is the thinnest layer of the Earth.

Crust

________ has the same mineral composition as andesite

Diorite

A scientific theory is a tentative or untested explanation that is proposed to explain scientific observations.

False

Aa flows are generally thinner and have smoother surfaces than pahoehoe flows.

False

Aristotle and other prominent Greek philosophers were the first ones to promote the doctrine of uniformitarianism.

False

At high pressures and elevated temperatures of regional metamorphism, silicate rocks are more resistant to flowage and deformation than at low temperatures and pressures.

False

Calcite and halite react with dilute acids to release carbon dioxide.

False

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

False

Mineral luster is broadly classified as either being metallic or opaque.

False

Olivine and quartz commonly crystallize together from mafic or basaltic magmas.

False

Orthoclase and plagioclase feldspars have quite different forms of cleavage.

False

Positive ions are atoms that have gained electrons during a chemical reaction.

False

Quartzites and metaconglomerates are formed along faults by intensive fracturing and fragmentation of conglomerate beds and quartz veins.

False

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

False

________ is characterized by the segregation of light- and dark-colored minerals into thin layers or bands.

Granitic gneiss

What are the basic differences between the disciplines of physical and historical geology?

Historical geology involves the study of rock strata, fossils, and geologic events, utilizing the geologic time scale as a reference; physical geology includes the study of how rocks form and of how erosion shapes the land surface.

________ rocks form by crystallization and consolidation of molten magma.

Igneous

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

Outer Core

The ________ division of the geologic time scale is an era of the Phanerozoic eon.

Paleozoic

________ is characterized by very coarse mineral grains?

Pegmatite

Which of the following best describes the conditions of contact metamorphism?

Pressures are fairly low, the rock is in the upper part of the crust, and heat is supplied from a nearby magma body.

________, a common mineral found in igneous rocks, is the most abundant mineral in detrital sedimentary rocks.

Quartz

Earth's interior

Study it

Which of the following is correct for isotopes of the same element?

The atoms have different numbers of neutrons and the same number of protons.

A ________ is a well-tested and widely accepted view that best explains certain scientific observations.

Theory

Compared to the age of Earth accepted as correct today, how did 17th and 18th century proponents of catastrophism envision the Earth's age?

They believed Earth to be much younger than current estimates.

Which one of the following is not true for minerals?

They can be a liquid, solid, or gas.

How do the electrons behave in a mineral with metallic bonding?

They can move relatively easily from atom to atom inside the mineral.

According to the rock cycle, any type of rock (igneous, sedimentary, or metamorphic) may be transformed into another type of rock, given enough time.

True

Calcite is the main mineral constituent of the sedimentary rock limestone and of the metamorphic rock marble.

True

Continental shields and stable platforms are part of the interior region known as a craton.

True

Electrically neutral atoms have equal numbers of electrons and protons.

True

Ferromagnesian silicate minerals contain some magnesium and/or iron.

True

Internally, the Earth consists of spherical shells with different compositions and densities.

True

Magma generation at depth almost always involves partial melting, not complete melting of the source rock.

True

Metamorphic rocks formed during episodes of mountain building typically show textural characteristics indicative of shearing stress and deformation.

True

Much of our modeling of Earth's interior comes from the study of seismic or earthquake waves.

True

Mud cracks in a shale or mudstone indicate that the mud or clay was deposited in deep waters of an offshore marine environment.

True

Peat is thought to be the original material from which coals are formed.

True

Plutonic rocks are intrusive and generally consist of mineral grains coarse enough to be readily visible in a hand sample.

True

Quartz is quite resistant to weathering and is an important component of sands in riverbeds and on beaches.

True

Rock-forming silicate minerals have higher specific gravities than water.

True

Rocks are aggregates of one or more minerals.

True

Talc and graphite are very soft minerals found in some schists.

True

The distinctive layers or bands of different minerals in gneisses may be complexly folded.

True

The doctrine of uniformitarianism implies that the current forces and processes shaping the Earth have been operating for a very long time.

True

The lithosphere and asthenosphere are both layers of Earth defined by their composition.

True

The micas, biotite and muscovite, both exhibit one direction of cleavage.

True

________ is often paraphrased as "the present is the key to the past."

Uniformitarianism

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

Weathering

Rock Cycle

Weathering, Erosion, Sediments, Lithification, Sedimentary Rocks, Metamorphism, Metamorphic Rocks, Melting, Magma, Crystalization of Minerals, Igneous Rocks, Uplift

In which area are pedocal soils most likely to be found?

a tropical rainforest in the Amazon Basin of Brazil

Which type of basaltic lava flow has its surface covered with sharp-edged, angular blocks and rubble?

aa

The average composition of rocks comprising a large composite cone or stratovolcano is similar to a (an) ________ magma.

andesitic

Volcanic bombs originate ________.

as erupted magma blobs that partly congeal before falling to the ground

Chrysotile, crocidolite, and amosite are different mineralogical forms of what industrial commodity?

asbestos

The ________ is not a part of the Earth's physical environment.

astrosphere

The ________ refers to the sum total of all life on Earth.

biosphere

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

Which of the following will react readily with acids such as hydrochloric?

calcite

Which one of the following is a typical product of weathering?

clays

Ruby and sapphire are red and blue forms of the mineral ________.

corundum

In which type of chemical bonding are electrons shared between adjacent atoms?

covalent

All of the following are factors that affect the generation of magma except for ________.

crystal size

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

texture

________ destroyed the city of St. Pierre, Martinique in 1902.

A nueé ardente

Compaction is a very important part of the lithification process for which of the following sediments?

mud

The most prominent features on the ocean floor are the ________.

oceanic ridges

What element is the most abundant in the Earth's crust by weight?

oxygen

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

phaneritic

Which of the following best describes seamounts and islands of the deep ocean basins?

piles of basaltic lava flows built up from the ocean floor by multiple, summit and flank eruptions

Which mineral is composed of silicon dioxide (Si02)?

quartz

Which group of minerals are the most abundant in the Earth's crust?

silicates

All silicate minerals contain which two elements?

silicon, oxygen

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

slate, phyllite, schist

The currently accepted age of Earth is ________ years.

4.6 billion

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

Basalt

In 1980, ________ was the first Cascade Range volcano to erupt since Mt. Lassen, California, in 1915-16.

Mt. St. Helens

What are the lightest or least massive of the basic atomic particles?

electrons

Which of the following would exhibit sheared and mechanically fragmented rocks?

fault movements at shallow depths

The last minerals to crystallize on Bowen's Reaction Series result in igneous rocks with a ________ composition.

felsic

Which of the following has the highest specific gravity?

gold

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

Detrital sedimentary rocks are classified (named) based on the ________.

grain sizes of the detrital particles

Which of the following minerals is a ferromagnesian silicate?

hornblende

Which of the following statements concerning humus is not true?

is readily leached from the B horizon in weakly acidic, soil solutions

Which of the following best describe the A soil horizon?

leaching zone

The ________ forms the relatively cool, brittle plates of plate tectonics.

lithosphere

Which of the following diseases has been linked directly to prolonged inhalation of asbestos dust?

lung cancer