Intro to Landforms Exam 2

What causes the process of exfoliation?

the removal of the weight of rocks and sediments as a result of exhumation

What is one of the techniques USGS scientists use to "see" how much groundwater enters or leaves the stream?

thermal imaging

Which feature can strengthen slopes?

vegetation

Igneous Rocks (Extrusive)

volcanic rock, forms on the crust, volcanoes and lava flows, forms fine-grained igneous rocks

Large amounts of which substance indicate that a landslide is a flow?

water

In what ways are some sedimentary rocks economically significant?

Oil and natural gas fossil fuels are often found in shale deposits Bituminous coal deposits are used for the generation of electricity.

Why are exfoliation domes rounded?

Pressure-release jointing forms parallel to the rock surface, rounding the rock into a dome shape.

silicate minerals

Rocks composed of this mineral class are structurally strong and relatively resistant to weathering and erosion. Feldspar and quartz belong to this class, and both are among the most abundant minerals found on Earth.

Which statement summarizes the relationship between the spatial distribution of sinkholes and climate types?

Sinkholes occur more in humid or wet, warm climate types than in dry or cold climate types.

carbonate minerals

These minerals form when carbon combines with other elements, particularly oxygen. Calcite is the most common mineral in this class and is the main mineral component in limestone.

halide minerals

These minerals form when halogen elements, such as chlorine and iodine, bond with metallic elements. The mineral sodium chloride belongs to this class and typically forms as salt water evaporates.

oxide minerals

These minerals form when other chemical elements combine with oxygen. When iron reacts with oxygen, the mineral hematite forms. Hematite gives many rocks a reddish color.

sulfide minerals

These minerals form when sulfur bonds with metallic elements such as copper, iron, zinc, or lead. Pyrite, or fool's gold, and gypsum belong to this mineral class.

How are slate, schist, and gneiss similar?

They all are foliated metamorphic rocks. They can all share the same protolith, depending on the degree of heating.

Can changes in groundwater levels affect streamflow?

Yes. Groundwater levels can affect streamflow in areas underlain by limestone bedrock.

What forms when the lowest level of a collapse sinkhole lies below the water table?

a cenote

The process of unequal weathering across a rock surface is called

differential weathering

This igneous rock cools slowly, deep in the crust. Its density is between 3 and 2.5 gm/cm3 and its silica content is between 50% and 70%.

diorite

What is the process of cave formation in which limestone is dissolved and carried away?

dissolution

Stalactites and stalagmites are both types of

dripstones

According to the rock cycle model, in what stage do rocks first begin?

igneous rocks

Volcanic eruptions often produce mass movement events called

lahars

In what kind of rock do karst caves form?

limestone

Most karst topography forms in

limestone

Which feature is not part of surface karst topography?

limestone columns ARE part of: cockpit karst, karst spires, limestone pavement

Through what process are sedimentary rocks formed?

lithification

Igneous Rocks (Intrusive)

magmatic rock, forms beneath Earth's surface, batholiths/plutons/ dikes, forms coarse-grained igneous rocks

What factors lead to differential weathering across rock surfaces?

mineral composition, exposed surfaces

What is the most stable type of regolith?

moist, vegetated regolith

What is the key to developing an early warning system for deadly landslides?

monitoring movement long before the slope fails

Karst Features: 1) Limestone Pavements (looks like cracked concrete, pretty flat) - exposed limestone bedrock dissolves in the absence of overlying soil and vegetation. 3) Karst Spires (these jagged peaks) - limestone bedrock weathers along weak vertical jointing

2) Cockpit Karsts (like there hills with vegetation on them) - limestone weathers at the surface in the presence of overlying vegetation 4) Tower Karsts (Avatar/ China rock towers) - karst processes lower the landscape's surface and weak vertical joints direct rock dissolution along vertical planes

How much damage do mass movement events cause each year in the United States?

2-4 billion $

The processes of physical weathering have their greatest effect at high elevations and high latitudes. Chemical weathering is dominant where temperatures are above freezing and there is ample moisture. Rocks in the lowland tropics are most susceptible to chemical weathering. Physical (exfoliation, salt weathering, frost and root wedging) Chemical (oxidation, hydrolysis, carbonation)

Both types of weathering can occur at the same time and affect each other's rates. --- Chemical weathering occurs mainly on the surfaces of rocks and physical weathering assists in the process of chemical weathering by breaking rocks into smaller pieces and increasing the surface area.

In what conditions do cave formations develop?

Cave formations develop when the cave is dry but water drips from the ceilings and walls.

Increase slope stability: friction between soil particles, electrical charges in soil particles, moderate soil moisture, plant roots

Decrease slope stability: geologic faults, joints in rocks, foliation planes in metamorphic rocks, layers of saturated clay or sand, layers of ice between layers of snow

Which of the following statements are true of dissolution?

Dissolution occurs most often where water flows through joints in the rock. Dissolution occurs most quickly in areas that are cool but not frozen. Dissolution is primarily due to formation of a weak carbonic acid solution.

Metamorphism is a process that changes existing rock under great pressure, high temperature, or both. Hot and chemically reactive fluids are sometimes present during the process. The temperature at which metamorphism occurs ranges from about 100 °C to 900 °C (200 °F to 1,600 °F). Why is there an upper limit to the thermal range of metamorphism?

If rock is heated too much it will melt, forming an igneous rock when crystalization occurs.

What happens to material on a hillslope when friction exceeds the downslope force?

The material does not move.

This igneous rock cools quickly near the surface. Its density is between 3 and 2.5 gm/cm3 and its silica content is between 50% and 70%.

andesite

The steepest slope that can be maintained while remaining stable is called the

angle of repose.

This igneous rock cools quickly near the surface. Its density is 3 gm/cm3 and its silica content is 50%.

basalt

Why is dissolution greatly slowed in Arctic regions?

because water is frozen and chemically non‐reactive for most of the year

What is the most important type of weathering in warm, humid environments?

chemical weathering

organic sedimentary rock

composed mostly of organic material derived from ancient organisms or their shells, fossiliferous limestone, chalk, coal

clastic sedimentary rock

composed of broken pieces of other rocks or minerals, shale, sandstone, conglomerate

The process where joints form parallel to the rock surface, creating sheet‐like slabs of rock, is called

exfoliation

chemical sedimentary rock

forms as dissolved minerals precipitate out of a solution, forms as water evaporates from sedimentary deposits, gypsum, limestone, rock salt

In high mountainous areas __________ is the most important type of weathering.

frost wedgin

Examine Figure 16.1 and consider the geographic setting of Mount Rushmore. Which type of weathering is most likely to break apart the monument?

frost wedging

Examine Figure 16.9 and notice the large blocks piled at the base of the monolith. Considering the geographic setting, which process produced these large blocks?

frost wedging

This igneous rock cools slowly, deep in the crust. Its density is 3 gm/cm3 and its silica content is 50%.

gabbro

This igneous rock cools slowly, deep in the crust. Its density is 2.5 gm/cm3 and its silica content is 70%.

granite

In which environment does talus form?

on steep unvegetated mountain slopes

What characteristics define a mineral?

ordered crystalline structure uniform chemical composition naturally occurring

In solifluction, soil slowly flows downslope in

overlapping sheets

Exfoliation domes are formed from

plutons

The sand in most beaches is composed of grains of

quartz

This igneous rock cools quickly near the surface. Its density is 2.5 gm/cm3 and its silica content is 70%.

rhyolite

Which process is a type of biophysical weathering?

root wedging

The process of moving rock fragments through moving water, ice, or air is called

sediment transport

In what type of rocks are fossils commonly found?

sedimentary rocks

A type of mass movement in which regolith detaches and slides downslope along a spoon‐shaped plane and comes to rest more or less as a unit is called

slumping

"Failure surface," "rotational slide," "head scarp," and "toe," are terms associated with what?

slumps

The imperceptible downslope movement of soil and regolith as they change volume in seasonal expansion‐contraction cycles is called

soil creep.

Choose the list that ranks mass movement events from slowest to fastest.

solifluction, slump, mudflow, rockfall

Which region has the best examples of tower karst?

southern China

What grows upward from a cavern floor?

stalagmites

Rounded pits or cavities on the surface of a rock that form through salt wedging are called

tafoni

Examine Figure 16.9. What is the name for the large blocks piled at the base of the monolith?

talus