Chapter 12

Rainwater is slightly ____ because it contains dissolved carbon dioxide and sulfur oxide and will dissolve limestone if the two are in contact.

Acidic

Limestone is easily dissolved by weak acids because it is composed primarily of the mineral _______.

Calcite

Limestone of primarily composed of ____

Calcium carbonate

Rainwater is slightly acidic because of the dissolved ____ and sulfur oxide.

Carbon dioxide

How a mineral weathers depends on time of exposure, the surrounding climate, and the mineral's ____

Chemical composition Atomic structure

The decomposition of rock resulting from exposure to water and atmospheric gases is referred to as ______

Chemical weathering

The Slumgullion landslide is located in the San Juan Mountains of ___; it originates in high-elevation, steep peaks dominated by ___ rocks.

Colorado, igneous

Identify the examples of biotic weathering listed below.

A bear digs into the soil and loosens rocks A species of lichen living on a rock secretes a chemical that slowly dissolves the rock.

The very slow yet continuous movement of earth materials downslope is classified as _____

Creep

A very rapidly moving , turbulent mass of debris, air and water is known as a _____

Debris avalanche

____ such as fractures and bedding planes provide a pathway of water into the rock body and promote weathering processes.

Discontinuities

Slope failure, or mass wasting, is movement in which bedrock, rock debris, or soil moves ______ in response to the pull of ______

Downslope, gravity

An _____ is the downslope movement of earth as a viscous fluid.

Earth

The Slumgullion slope failure is typically called a landslide, but it could be categorized as an ____ flow because it is composed mostly of fine-grained materials.

Earth

Slope failures can be triggered by different types of specific events, including _____

Earthquakes Precipitation Slope modification

As rocks are uplifted to the surface, ____ May form as the rock cools and pressure released.

Expansion joints

Since time is variable in the rates of both physical and chemical weathering, time can be canceled out as a factor in weathering.

False

Chemical weathering occurs ____ in warm, humid areas then it does in cold, dry settings.

Faster

The process of ____ occurs when minerals react with oxygen at or near Earths surface.

Oxidation

What is the general term used for the rocks and minerals acted upon by physical and chemical weathering?

Parent Material

What features are indicators of rock dissolution?

Pits and Cavities

Which of the following are surface features that may indicate caves at depth?

Presence of limestone Sinkholes Disappearing streams

The work geologists do in studying recent and prehistoric slope failures helps to mitigate the loss of life and ____ from future slope failures.

Property

Match the rock type with the correct descriptions of its solubility and how it most commonly weathers.

Quartzite- weathers physically, very low solubility Limestone- prone to chemical weathering, very soluble

The outer zone of a rock that has been weathered is called the weathering ____

Rind

Which of the following human modifications might cause slope failure?

Road Construction

A weathered landscape would likely have which of the following features?

Rounded sediments Thick soils in areas with extensive weathering

Which of the following would decreases the angle of repose for a given sediment deposit?

Rounding the grains

The salt content of water is referred to as its ___

Salinity

Because they are so resistant to weathering, quartz grains that are eroded from granite typically become quartz ______

Sand

Chemical weathering is generally more intense on the corners and edges of a block of rock, resulting in the rock becoming rounded. This weathering feature is known as _____ weathering.

Spherodial

A ______ hangs from the ceiling of a cave, and a _____ grows upward from the floor.

Stalactite, stalagmite

What key factor is Florida lacking that results in a low overall risk for landslides?

Steep slopes

Which of the following indicates an area might have high potential for slope failure?

Steep slopes or recent changes in slopes Evidence of past slope failures in an area with known problems Loose material that is relatively weak Potential triggers on the area such as possible earthquakes and volcanic eruptions

As physical weathering occurs, the amount of __ area of a rock outcrop increases, and this allows more ___ weathering to occur.

Surface, chemical

The angular blocks of rock beat the bottom of a hill or mountain are called ____

Talus

Minerals formed at depth within earth may be unstable at the surface due to very different ____ conditions.

Temperature Moisture Pressure

The flow of material downhill would occur if _____

The slope is steep The material is poorly attached to the hillside The material is internally weak

Numerous factors control mass wasting; choose all of the primary factors from below.

Vegetation Geology Slope angle Climate

Slope failures are common secondary hazards of ____ eruptions that causes shaking, tilting, and fracturing of the ground.

Volcanic

Caved and caverns can be formed by the dissolution of limestone by flowing ______

Water

Flow stone or draperies are formed in caves when travertine precipitates out of ____ that is flowing down cave walls or along the cave floors.

Water

In a sequence of rocks that is susceptible to rock slide failure, detachment commonly occurs along the base of a __ rock, such as shale or salt.

Weak

Plant growth

Widening of cracks by expanding tree roots

Frost Wedging

Widening of cracks in rock by water expanding as it freezes ice

Studies show that the rate of movement in the Slumgullion landslide decreases in the _____

Winter

Secondary minerals that form from the chemical weathering of other minerals ______

Are more stable than the original minerals

Although debris and rock ____ vary in the size and types of materials that compose each, both can move very quickly and are extremely hazardous.

Avalanches

A site in an earthquake-prone area that is located on a steep slope composed of weak materials should be _____

Avoided, as its slope failure potential is high

What types of evidence are geologists looking for when trying to locate prehistoric slope failures?

Bedding and structures that are at a different tilt or orientation than surrounding outcrops Hummocky topography Debris pile rocks that are different in toe from the immediate landscape

Weathering that is caused by the activity of living organisms is _____ weathering.

Biotic

What type of material dominates the downslope movement of a debris flow?

Boulders and gravel in mud

Select the areas in the United States where karst typography is common.

Florida Along belts of folded rocks in and near the Appalachian Mountains

Unloading

Formation of joints due to the removal of overlying rock and subsequent expansion

Thermal expansion

Heating and cooling that causes minerals to expand and contract differently

Minerals that crystallize at ____ temperature inside earth are unstable at earths surface and weather easily.

High

Which of the factors listed below make the Pacific Northwest particularly vulnerable to damage from debris flows?

High elevation, steep slopes Volcanic activity Heavy annual precipitation

Limestone is composed of calcite, a mineral that dissolves easily in ____ climates.

Humid

What process occurs when a mineral reacts and combines with water to form a new mineral?

Hydrolysis

Excessive water increases the susceptibility of a slope to failure by adding weight and by ____

Increasing pore pressure and pursuing the grains farther apart.

This type of fracture, which is small and has no significant offset, promotes weathering by allowing water and plant roots to penetrate the rock.

Joint

Sinkholes, disappearing streams, and limestone pillars are characteristics of ____ topography.

Karst

Significant deposits of clay minerals typically accumulate in what types of environments?

Lake bottoms Floodplains Deltas

What is the general term commonly applied to the slow to very rapid movement of rock or soil downslope?

Landslide

______ cause 25 to 50 annual fatalities in the United States.

Landslides

Caves, travertine, and karst typography are formed when groundwater interacts with _____

Limestone

Which of the following are characteristics of karst topography?

Limestone pillars Disappearing streams Caves Sinkholes

Select that statement below that accurately describes the relationship between mass wasting and erosion.

Mass wasting is one of the many ways in which earth materials can be eroded.

Specific rock properties that influence weathering include the grain size and ____ composition, as well as the types and number of discontinuities, such as fractures and bedding planes.

Mineral

Data collected from the Slugullion landslide were used to create a computer _____ to better understand the movement of the materials.

Model

A debris slide occurs as unconsolidated materials move downhill in a semicoherent mass, leaving behind a low ___ in the hillside.

Scarp

After weak acids form in water and start to dissolve rocks and minerals, _____ minerals are often formed.

Secondary

Which of the following are possible causes for submarine slope failure?

Sediment overloading Earthquakes Volcanic eruptions

Soil on slopes resists downslope movement due to the ______ component of gravity.

Shear

Collapse of the roof of a cave can produce

Sinkhole

The Gros Ventre slope failure that occurred in Wyoming in 1925 is one of the largest rock ____ ever in the USA 1.5 km long slab of limestone was involved.

Slides

The lack of vegetation on this hillside is a scar indicating an area of ____

Slope failure

Slope failures can be triggered by different types of specific events, including ____

Slope modification Precipitation Earthquakes

Although earth flows and debris flows both are dominated by fine-grained materials such as mud and soil, an earth flow typically moves ____ than a debris flow.

Slower

Another name for a rotational slide is a

Slump

When ocean water evaporates,

The dissolved salts remain in the sea

Slope failure classification is based upon which of the three following characteristics?

The type of material involved How the material is moving The rate of movement

How do joints influence the development of a landscape?

They decrease a rocks resistance to weathering They decrease a rocks resistance to erosion They affect the strength of the rocks

The development of joints in rocks changes how a landscape develops because ___

They increase the rate at which weathering and erosion occurs.

Why are geomorphologists often some of the first people to arrive at the location of a recent, large slope failure?

They want to collect data in order to understand how the event happened. They are involved in assessing the potential for future danger from the same type of event

The leading downhill edge, or front of a rock is called the _____

Toe

When groundwater is carrying dissolved limestone and that groundwater flows onto the surface, ____ is formed.

Travertine

A rock outcrop may form alternating ledges and slopes because some sections are more susceptible to weathering than others.

True

Plants can be agents of physical weathering, breaking rocks apart.

True

Chemical and physical ____ causes the breakdown of surface materials. This process increases slope instability, thus increasing the likelihood of gravity causing mass ______.

Weathering, wasting