Exam practice Flashcards by Édouard Ungur

The process by which magmas cool and solidify to rock is termed … ?

Crystallization

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

Calcite

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Shales are distinguished from other mudrocks by their …?

Fissility

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

CaMg(CO3)2

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Which is not a requirement? To be a mineral it must be or have ________.

well-formed external crystal shap

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Which minerals that make up the Mohs scale are softer than your fingernail?

gypsum and talc

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Minerals like diamond and graphite exist because of ________.

the law of polymorphism

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Under the application of uniform, confining pressure, rocks will generally ________.

increase in density but retain primary bedding orientations

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What type of environment is typified by brittle deformation?

shallow, low temperature settings with high strain rates

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________ is a strong, parallel alignment of coarse mica flakes and/or of different mineral bands in a metamorphic rock

Foliation

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Chemically active fluids like ________ tend to transport ions and mineral components and their activity ________ with increasing temperature.

water, increases

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During metamorphism, what is the major effect of chemically active fluids? (2) (Diss. Ions + Silicates ; metam. mineral grains)

Aid in movement of dissolved ions and silicate constituents from parent minerals
Facilitate growth of new metamorphic mineral grains

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Metamorphic grade refers to ________.

metamorphic intensity as recorded by particular minerals which are sensitive to temperature and pressure

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How would you correctly refer to the metamorphic grade of a rock that contains abundant chlorite as its highest temperature mineral such as a greenschist or phyllite?

low grade < 200°C

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The ________ in California is the boundary between the North American and Pacific lithospheric plates.

San Andreas strike-slip fault

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An unconformity is ________.

an erosional (or non-depositional) surface with younger strata above and older rocks below

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The size, shape, and geometric arrangement of mineral grains in igneous rocks is called ________ and it indicates ________.

texture, the environmental conditions in which the rock formed

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The main factors which directly govern the development of texture in all igneous rocks are ________.

cooling rate
dissolved volatiles
silica content

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An________ texture would be most unlikely to occur in an extrusive igneous rock.

phaneritic

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Visible quartz and potassium feldspar grains are the main constituents in which igneous rock?

granite

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As ________ increases the surface area of a rock or mineral, this allows ________ to occur at a faster rate.

mechanical weathering, chemical weathering

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How does a sediment become transformed into a sedimentary rock?

by compaction and dewatering, followed by cementation

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Diagenesis occurs at temperatures below ________ in the outer few kilometres of Earth’s crust

100°

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

mud

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________ cement produces dark red and orange colours in some sandstone.

Iron oxide

Where and how does metamorphism occur?

wherever solid rocks are subjected to new conditions of temperature, pressure, stress, and a change in their constituent fluids

________ is an erosional contact between tilted, older strata below and horizontal, younger strata above.

An angular unconformity

Which of the following statements is true, concerning sedimentary strata separated by a disconformity?

All strata exhibit parallel bedding or stratification, but there is a hiatus (missing record).

What are the three types of differential stress in the Earth's lithosphere?

compression, shear, and tension

When measuring the orientation of a planar structure in rocks the dip direction is measured ________ to the strike

at 90 degrees

What kind of stress creates most fold belts?

compressional

New oceanic crust and lithosphere are formed at ________.

C) divergent boundaries by submarine eruptions and intrusions of mafic magma

Normal and reverse faults are characterized mainly by ________.

dip slip

________ are the products of horizontally directed, tensional stresses.

Normal faults

In a ________ fault, the hanging wall block moves up over the footwall block.

reverse or thrust

A thrust fault has ________.

a shallow inclination less than 45° and a hanging wall that rode up over the footwall

Most earthquakes form a new fault where one did not exist before?

FALSE

Which of the following is more likely to exhibit brittle behaviour?

granite

The ________ is the point of origination for an earthquake.

hypocenter

Which one of the following is true for anticlines but not for synclines?

Some may be asymmetric and some may have plunging axes.

_______ is the widely accepted explanation for the mechanism that generates earthquakes.

Reid's elastic rebound theory

What are the smaller magnitude quakes that follow a major earthquake?

aftershocks

Which one the following does not propagate through liquids?

S waves

Which of the following foundation materials is most stable during earthquake shaking?

bedrock

_______ refers to the tendency for a foundation material to lose its internal cohesion and fail mechanically during earthquake shaking.

Liquefaction

Which mass wasting process has the fastest rate of movement?

rockslide

Where does the majority of fresh groundwater reside?

in pores within soils and sediments or in fractures in rocks

________ is a measure of the connectedness of pore spaces, which controls the ease (or difficulty) of groundwater transmission through a porous material.

Permeability

Of the choices listed on flow characteristics alone, if the following aquifers became contaminated, which would remain contaminated for the longest time?

clay

What happens inside a rock as a wave front from a P wave passes through?

The rock moves toward and away from the earthquake as the volume of the material alternately expands and contracts, changing the rock's density while the compression-rarefaction wave passes through.

Which of the following is not a fundamental particle found in atoms?

selectron

Which of the following denotes the tiny, but very massive, central part of an atom?

nucleus

Silicate igneous rocks make up the ________.

bulk of the Earth's crust and mantle

Three processes contribute to the formation of every igneous rock: ________.

partial melting, buoyant rise, and crystallization

The most common non-ferromagnesian silicate minerals (>40%) in most igneous rocks are ________.

feldspar

Which of the following igneous rocks is composed mainly of ferromagnesian minerals with less than 20% feldspar?

peridotite

Which of the following is the dominant feldspar in basalt?

plagioclase

What weight percentage of silica (SiO2) typifies granites and rhyolites?

70%

When magma cools and consolidates without growth of mineral grains, it is

glassy

Clay minerals formed from gabbro or diorite bedrock illustrate which kind of weathering?

chemical

What percentage of the Earth's crust is composed of sedimentary rocks?

The type of diagenesis that occurs in the transformation of aragonite to calcite is ________.

re-crystallization

Hot regions having basins with limited input and restricted circulation tend to have ________ deposits.

evaporite

Which major component of detrital sedimentary rocks only rarely occurs as a primary mineral in igneous rocks?

clays

Broad upwarps in the basement rock may deform the overlying sedimentary cover strata to generate large elliptical to circular folds called ________.

domes

How wide is the San Andreas Fault Zone at its northern and southern ends?

>100 kilometres

The ________ of the Earth does not transmit S waves.

outer core

What force pushes groundwater from pore to pore below the water table?

hydraulic gradient

How are travertine or silica deposits formed from boiling geysers and related hydrothermal systems?

Boiling off steam forces the remaining hot solution to be saturated or supersaturated as the same mineral content is now concentrated in less water and it precipitates.

When water is quickly produced from a well, locally the water table and aquifer experience _____

drawdown

Which of the following describes the configuration of an unconfined water table around a pumping well?

cone of depression

An artesian well is one in which ________.

water has enough head to rise above the top of the aquifer without any pumping

Which of the following statements is false for an area subsiding because of excessive pumping of groundwater?

The aquifer is consolidated bedrock.

The mechanical removal or diminution of unwanted substances such as bacteria, viruses, or mineral turbidity from groundwater is termed ________.

filtration

What percentage of the Earth's water is in the form of groundwater?

0.6%

What proportion of the world's water for agriculture (irrigation, greenhouses, golf courses) is supplied by groundwater aquifers?

40%

After ice sheets and glaciers, ________ contains the next highest percentage of Earth's freshwater that is readily accessible to humans.

groundwater

What is the belt of soil moisture?

at shallow depth, a surface film of water retained on soil, sediment, or organic particles

Water moves through most aquifers ________.

at slow but variable rates generally less than a few meters per day

The porosity of typical unconsolidated sediments and sedimentary rocks is ________.

10-50%

For unconfined aquifers, what hydrologic factor is approximated by the slope of the water table?

hydraulic gradient

A perched water table develops when ________.

an aquifer above the regional water table is overlain by a horizontal aquitard

Which one of the following concerning artesian wells is false?

When the well penetrates the aquifer, the water rises to the bottom of the aquitard above the aquifer.

Which of the following geologic materials would have the highest groundwater velocities and be least effective in removing unwanted pollutants from the water?

limestone with numerous solution channels and fractures widened by dissolution

Frost wedging and thawing on vertical cliffs produces ________.

talus cones

During wet weather or times when snow is melting, what sometimes happens to the downhill toe of a slump?

It becomes an earthflow.

Which mass-wasting event involves movement on a zone of compressed air?

rockslide

What are the most serious mass wasting hazards in mountain valleys?

debris flows

How do freezing, thawing, wetting, and drying contribute to soil creep?

The soil expands and contracts, lifting particles then lowering them a slight distance downslope.

How does a seismograph detect vibrations from the passing wave front of an earthquake?

The instrument is anchored to the ground or buried in a vault so that it is stationary with respect to the earth. When the instrument moves, the suspended mass inside is relatively stationary due to inertia. The relative motion registers the quake.