Earth 101 Exam 2

If you equate all Earth history to one calendar year, our species (Homo sapiens) would appear on

11 P.M. on New Year's Eve.

The most recent interval of Quaternary glaciation gave way to warmer, interglacial conditions __________ years ago.

11,000

About ____ of Earth's freshwater is groundwater.

30%

Earth is approximately how old?

4.54 billion years

Why does adding a small amount of water to a substance increase its cohesion but adding a lot of water decrease its cohesion?

A small amount of water increases surface tension and holds the grains together. Too much water between the grains will eliminate surface tension.

Which of the following would increase the risk of a landslide?

Allowing water to infiltrate the slope

What type of unconformity is illustrated by the sequence?

Angular unconformity

Some researchers have suggested the use of the term __________ to denote the most recent part of the geologic record, which has been characterized by rapid changes in the atmosphere, landscape, and biodiversity as a result of human actions.

Anthropocene

Which eon saw the first single-celled organism?

Archean

The evolution of life is tied to the geologic column, with the first life appearing in the _________, the ________ referred to as the Age of Mammals, and the _________ referred to as the Age of Dinosaurs.

Archean Eon, Cenozoic Era, Mesozoic Era

In the cross-section, identify the oldest feature in the sequence.

Bed 1

The __________ occurred possibly because of the creation of many new ecological niches that formed as a result of the breakup of Pannotia.

Cambrian explosion

What mass-wasting process most likely explains the tilting of gravestones in a hillside cemetery?

Creep

What drainage network is produced when bedrock is relatively uniform and unfractured?

Dendritic

Which of the following accurately ranks the subdivisions of geologic time in order from largest to smallest?

Eon, era, period, epoch

In the cross-section, identify youngest event in the sequence.

Erosion of the land surface

Where is the majority of the Earth's freshwater (liquid or solid) stored?

Glaciers, ice caps, snow

Which of the following is a surface feature that indicates a slump is beginning to develop?

Hummocky ridges

The Himalayas were produced during the Cenozoic by the collision of southern Asia with

India.

The age of beds exposed in one location is related to the age of beds exposed in another location based on similarities in rock type between the two locations. What is this process called?

Lithologic Correlation

What type of unconformity is illustrated by the sequence?

Nonconformity

This figure shows the progressive development of a meander in a river system. What feature is created in the fourth panel?

Oxbow lake (Thin to big C shape)

The eon represented by abundant deposits of strata with shelly fossils is the

Phanerozoic.

The first supercontinent, Rodinia, formed at the end of the

Precambrian.

Which principle states that in an undisturbed sedimentary sequence, the oldest layer lies at the bottom and the youngest layer at the top?

Principle of superposition

Which of the following correctly lists the time divisions shown from oldest to youngest?

Proterozoic Eon, Paleozoic Era, Mesozoic Era, Cenozoic Era

Which of the following is a tectonic process?

Rifting

The two images show a change in course of a river system. What process is represented in this sequence of images?

Stream piracy (Water Gap over time)

Which of the following is a suitable method of managing mass wasting?

Targeted, controlled explosions

Which of the following regions has the highest relief?

The Himalayan mountain belt

Why were mammals able to become the dominant species at the beginning of the Cenozoic?

The dinosaurs died off and the small rodentlike mammals of the Mesozoic evolved to fill the niche.

Lakes are bodies of standing water, but not all lakes contain freshwater. Why are some lakes fated to become salt lakes?

They have only inlets but no outlets.

The first mammals appeared during the __________ Period.

Triassic

The image shows water flowing around rocks and boulders, resulting in inconsistent direction and velocity of water flow. What feature of fluid motion describes this type of flow?

Turbulent flow (Spinny water)

The image shows a stratigraphic section of the Grand Canyon. Between which two groups is there an angular unconformity?

Unkar Group and Tapeats Sandstone

This picture shows a coastline that is rising relative to sea level. Which process may be responsible for the terrace features shown here?

Uplift

Which of the following is a typically weak surface that geologists recognize as a potential failure surface?

Wet clay layer

Did the dinosaurs walk on Pangea?

Yes, some of them did, because Pangea did not break up until the Jurassic Period.

Streams that flow down steep mountains onto much flatter land will spread out and lose velocity, and drop material in triangular-shaped structures called

alluvial fans.

A channel is

an elongated depression or trough of running water.

For a well to function properly, it must be drilled below the water table and into a(n)

aquifer.

The total load that a stream can carry is called its

capacity.

Which of the following is NOT a likely reason for global sea level change in the Proterozoic?

changes in the volume of water in the Earth system

Braided streams

consist of a series of intertwined channels that are overloaded with sediment.

Stromatolites are layered structures produced by the activity of

cyanobacteria.

If a dam is built on a river, what effects might be felt downstream?

decrease in sediment supply

Weathering is a failure trigger because it __________ of the material.

decreases the cohesion

Mass movement

depends on the difference between the downslope force and the resistance force.

The rate of groundwater flow

depends on the permeability of the material it flows through and on the slope of the water table.

The presence of inland seas results in

deposition of strata.

An organism is most likely to be fossilized if it

dies in an oxygen-poor environment.

Land subsidence is likely when

discharge lowers the water table.

The Basin and Range Province contains an alternating series of fault-block mountains and basins created by __________ of the continent.

extension

Which of the following is NOT an example of a cyclic change in the Earth system?

faunal succession cycle

Which of the following would be considered evidence for an orogeny?

folded strata

Uniformitarianism means

geologic processes that operate today operated in the past at about the same speed.

Ephemeral streams

have flowing water either episodically or during only a portion of the year.

The competence of a mountain river is __________ than that of a river on a floodplain because __________.

higher; the gradient is greater

If a sandstone contains pieces of basalt, then the sandstone is younger than the basalt according to the principle of

inclusions.

The Great Oxygenation Event occurred ~2.4 Ga and forced large amounts of __________ to precipitate out of the ocean.

iron minerals

Solifluction

is a kind of creep found on slopes that are underlain by permafrost.

Geologists estimate that the Earth is 4.54 billion years old, based on

isotopic dating of meteorites from the first differentiated bodies of the Solar System.

Features that are created when water dissolves surface and subsurface limestone, like sinkholes, troughs, caverns, natural bridges, and towers, are collectively called

karst landscapes.

Mudflows that are triggered by volcanic eruptions, such as the mass-wasting events associated with the eruption of Mt. Pinatubo, are called

lahars.

Groundwater contaminants

like methane, arsenic, and salt may occur naturally in groundwater.

The discharge of a stream is

likely to decrease downstream in arid regions and increase downstream in temperate regions.

Pumping vast quantities of water locally

lowers the local water table, forming a cone-shaped depression.

The earliest continental crust likely had a __________ composition.

mafic

Deltas

may form where a stream empties into the slower waters of a lake or the ocean.

The elevation of the water table

may rise during rainy periods and sink during droughts.

The heavy bombardment was a time in which Earth was struck by many

meteorites.

During the Hadean Eon, Earth's surface was mostly

molten.

Stream-eroded landscapes that are early in their evolutionary progression have

narrow, deep valleys.

Within a meander, where is sediment most likely to be deposited?

on the inner banks of the meander

Banded iron formations (BIFs) show evidence of an

oxygen-rich atmosphere that forced the oceans to become oxidizing and precipitate iron-oxide minerals.

Petrified wood is an example of a

permineralized fossil.

Oxygen in Earth's atmosphere is derived from

photosynthesis.

The evolution of shells was important for the diversification of life because shells

protect organisms from predators and environmental conditions.

The concept that times of relative stability in the number and identity of species alternate with times of rapid change is called

punctuated equilibrium.

The figure below shows an example of a __________ drainage network.

radial

The determination that one feature is older or younger than another feature, without calculating their actual ages, is known as

relative dating.

Which of the following consist(s) of large boulders placed at the base of slopes?

riprap

An area of slightly dipping sedimentary rock layers has large inclusions and is intruded by an igneous dike. Using the basic principles for determining relative ages you can infer that the

sedimentary rock "baked" by the igneous intrusion is older than the intrusion.

The interaction of groundwater with limestone bedrock can create a geologic hazard called a

sinkhole.

Slides with a spoon-shaped (concave upward) underlying surface are called

slumps.

The distinction between a valley and a canyon is

that the sides of a canyon are more steep than those of a valley.

One reason the landscapes on the Moon do not change as fast as Earth's landscapes is because

the Moon does not have mass wasting.

Landslides are likely to happen when

the downslope force becomes greater than the resistance force.

The largest reservoir of water on Earth, whether saltwater or freshwater, is

the oceans and seas.

Footprints, feeding traces, burrows, and dung are considered to be

trace fossils.

Groundwater

typically moves slowly within the ground through porous rock layers like sandstone.

Continental crust was only able to form once Earth's temperature had cooled enough for partial melting of the mantle to occur and produce basalt that was buoyant enough to stay afloat. Before this point, small rafts of thin crust formed and remelted in a continuous cycle. What was the composition of these rafts?

ultramafic

Which of the following is NOT an example of a landform?

water

Porosity increases

when rocks develop joints or fractures.