Chapter 21: Earth's Changing Surface

Landslides

________ or rockslides also can produce distinct scars on slopes.

Crop Rotation

________ helps prevent erosion and reduces the risk of plant diseases and attack by pests.

Spits

________ are sand bars that project into the water from land and curve back toward land in a hook shape.

Mudflows

________ move rapidly and are as dense and damaging as fluid cement.

Erosion

________: the removal of surface mate- rial through the processes of weathering.

Pollution

________ can enter groundwater through infiltration.

Eskers

________ are composed of finer soil and rock material that was sorted and deposited by running water within the glacier.

Unconformities

________: gaps in the rock record during which erosion occurred or deposition was absent.

Physical forces

________ exerted on rocks cause mechanical weathering to occur.

Uniformitarianism

________: states that the laws of nature operate today as they have in the past.

Frost Wedging

________ occurs when water collects in the cracks in a rock and then freezes.

Infiltration

________: the process by which water enters Earth and becomes groundwater below the surface.

Raw Materials

The ________ for soil continuously form through the weathering of bedrock below and the addition of organic matter from above.

Broadens

Lateral cutting ________ river valleys and allows for floodplains to develop.

sandbar

A(n) ________ that seals off a bay from the open ocean is called a baymouth bar.

Groundwater

________ is stored in porous rock called aquifers.

Fossils

________ can be direct remains, such as an actual bone or shell.

Mechanical weathering

________ occurs when rocks are broken into smaller pieces without changing their chemical composition.

Shorelines

________ commonly lack erosional landforms when they have a thick sediment cover.

velocity

As wind ________ decreases, the load of sediment is dropped.

Pollutants

________ that are spilled or dumped on the ground and even air ________, washed from the air by precipitation, enter groundwater through infiltration.

Deposition

________: When a transporting agent drops its load of eroded material.

Porosity

________: the percentage of the materials total volume that is pore space.

valley glaciers

When ________ melt they deposit sediment in characteristic landforms.

Geologic Time Scale

The ________ is based on the appearance and disappearance of certain types of fossils.

Soil

________: a mixture of weathered rock, organic matter, water, and air that is capable of supporting plant life.

Geologic Maps

________ are two- dimensional models of Earths crust for a given region.

Aquifer

________: A rock unit that can transmit water through its pore space.

Soil Depletion

________ is most often corrected by the addition of fertilizers containing nitrogen, phosphorous, or potassium.

Ice

________ moves away in all directions from the highest areas of the ________ sheet.

Relative Dating

________ and absolute dating techniques can be combined to help determine the ages of some fossils.

C horizon

The ________ is partially crumbled and weathered bedrock.

Mass

________ wasting takes place where slopes are overly steep or lacking vegetation.

soluble elements

The process of dissolving ________ and transporting them deeper into the soil is called leaching.

Freshwater

________ moves between the atmosphere, land, and oceans in the water cycle.

Longshore Current

________: The resulting movement of water parallel to the shoreline.

stops infiltration

A rock that slows or ________ is an aquitard.

Absolute Dating

________: the process of assigning a precise numerical age to an organism, object, or event.

Natural Flow Path of Groundwater

The ________ has both horizontal and vertical components.

Soil

a mixture of weathered rock, organic matter, water, and air that is capable of supporting plant life

Sediment Transport

the movement of eroded materials from one place to another by water, wind, and/or glaciers

Deposition

When a transporting agent drops its load of eroded material

Drainage Basin

All of the land area that gathers water for a major river

Longshore Current

The resulting movement of water parallel to the shoreline

Infiltration

the process by which water enters Earth and becomes groundwater below the surface

Water Table

the boundary separating the saturated and unsaturated boundaries

Aquifer

A rock unit that can transmit water through its pore space

Porosity

the percentage of the materials total volume that is pore space

Absolute Dating

the process of assigning a precise numerical age to an organism, object, or event

Relative Dating

The process of placing objects or events in their proper sequence in time

Uniformitarianism

states that the laws of nature operate today as they have in the past

Principle of Superposition

in an undisturbed sequence of rock layers, the oldest rocks will be at the bottom of the sequence and the youngest rocks will be at the top

Unconformities

gaps in the rock record during which erosion occurred or deposition was absent

Fossils

The remains or traces of organisms found in the geologic rock record