GEO Exam 4

The carbon dioxide levels today are around...

400 ppm

Aquifer

A rock or sediment that has good permeability and porosity, and allows water to move easily, making it possible to get water for human use.

Rain shadow deserts form from...

Air flowing over mountains must rise, where it cools, condenses and rains abundantly. Dry air descends on the other side and as it warms, it absorbs all available atmospheric moisture

If a stream reaches base level of a valley floor, it forms a...

Alluvial fan

Glacial Deposition

Almost all deposition occurs as glaciers stagnate or recede

What is the base level of a stream

Base level is the level below which a stream cannot erode

Streams are...

Bodies of water confined to a channel that flow from higher to lower elevations

Which type of stream is characterized by multiple small channels that split and recombine downstream?

Braided

What is the primary contributor of anthropogenic CO2 emissions since the Industrial Revolution?

Burning of Fossil fuels

The global atmospheric circulation is responsible for...

Climatic belts

Coastal deserts form from...

Cold ocean currents where cold ocean water cools the overlying air by absorbing heat

Hydrologic Cycle

Constant circulation of water from one place to another

What feature is more characteristic of dunes

Cross-bedding

If a stream reaches base level of an ocean or lake, it forms a...

Delta

Slower stream flow velocities favor __________.

Deposition

The size of a stream is measured in terms of...

Discharge

Solution

Dissolving soluble rocks from stream bed

What is the hydrologic cycle driven by

Energy from the sun

Glacial Transportation

Eroded material ends up within, on top of, or in the front of the glacier and moves downhill with it like a conveyor belt

Faster stream flow velocities favor __________ and __________

Erosion and transportation

Why does it become a problem if we pump it out water than it recharges

Finite groundwater supply

Floodpain

Flat area around a river channel that is filled with water during flooding events.

Earth's Energy Budget

Flow of incoming and outgoing energy

Continental deserts form from...

Form in the interior of continents because air moving across large landmasses loses moisture even without coastal mountains

Melting ice tends to drop everything in a mass of unsorted debris know as

Glacial till

Subtropical deserts form from...

Global atmospheric circulation patterns

The slope of a stream channel, expressed in either meters per kilometer (m/km) or feet per mile (ft/mi) is the...

Gradient

The part of the global atmospheric circulation system that rises at the equator and descends at the subtropics (30 degrees north/south latitude) are called...

Hadley cells

Coarser grains =

Higher permeability

Primary Factors Affecting Earth's Climate

How much energy we receive from the sun How that energy is distributed How much of the sun's energy is retained by earth

What does the hydrologic cycle explain?

How water changes phases and locations

Karst topography

Landscape formed by dissolution of limestone (or evaporites) to create caves, sinkholes, etc

The faster a stream is flowing, the ______________the sediment it can carry.

Larger

What can overpumping of groundwater cause

Leads to subsidence or the downward movement of ground either slowly or catastrophically

Why is the rate of weathering and erosion slower in desert regions

Less water

What types of rocks are most commonly affected by dissolution and the formation of karst topography, caves, and sinkholes?

Limestones

What is the thalweg in a stream?

Location of deepest water

Which type of stream sweeps side to side in wide turns or bends?

Meandering

What causes sea-level rise?

Melting of glacial ice and thermal expansion of warmer water

What is the cause of short-timescale climate change in the Quaternary (Pliocene-Pleistocene) Ice Age where 20-30 glacial advances occurred over the last ~2.5 million years?

Milankovitch cycles

Depositional glacial landforms

Moraines are accumulations of sediment at the margins (base, sides, ends) of glaciers

What are proxy data?

Natural recorders of climate variability

What is a long-term (millions to 100's of millions of years) cause of climate change from Earth's history?

Plate tectonics

Glacial Erosion

Rocks embedded at base of glacial scape the underlying bedrock surface to form glacial striations and rock flour can act as fine grit to smooth hard bedrock to form glacial polish

The bedload in deserts is transported by

Saltation and creep

Sediment that is carried as bed load in a stream moves downstream by...

Saltation and traction

Which of the following rocks would make a good aquifer because they commonly have high porosity and permeability?

Sandstones

Parabolic dune shape

Similar to barchan but usually reversed

Abrasion

Smoothing down grains by collision between 2 rocks or between rocks and stream bed

Tributaries are...

Subsidiary streams that flow into larger streams or rivers

Locations of deserts?

Subtropical (15-30 degrees) latitudes Rain shadows or mountains Along coasts Across Large Continents

Most deserts around the world are...

Subtropical deserts

Silt and clay are transported downstream as...

Suspended load

The greenhouse effect

The ability for the atmosphere to absorb heat that is emitted by a planet's surface.

Watershed or drainage basin is...

The area a stream and its tributaries drain

Where is the water table

The interface between the capillary fringe and the saturated zone

What happens during stream flooding

The rate at which streams erode, transport, and deposit sediments greatly increases

Discharge is...

The total volume of water flowing per unit time

Glacial sediment can range from...

Tiny clay particles (rock flour) to massive boulders (glacial erratics)

Hydraulic Action

Turbulent flow of water "plucks" rocks or grains off the side or floor of stream

#1 source of contaminants

Underground storage tanks

Vadose Zone

Unsaturated zone; place where pores are filled with some water and some air above the water table

The water table separates the _________, above, that is unsaturated with respect to water from the _________, below, that is saturated with respect to water.

Vadose zone/phreatic zone

Recipe to form a desert

Warm air rises and cool air falls in Hadley Cells Warm air absorbs more moisture than cool air

Transverse dune form...

When moderate sand supply and no vegetation to stabilize

Barchan dunes form...

When sand supply is limited and there is a fairly constant wind direction

Longitudinal dunes form...

Where sand supply is greater and the wind blows around a dominant direction, in a back and forth manner.

The recharge area

Where surface water enters an aquifer through the process of infiltration

Parabolic dunes form...

Where vegetation anchors part of the sand and unanchored parts blowout.

Climate is...

a longer term view of atmospheric patterns and processes over many years to millennia

Gradient

change in elevation / horizontal distance

Condensation

cooling of water vapor to form liquid water

Transpiration

plants release this water vapor in photosynthesis

Deserts are...

regions with less than 25 cm of rain/year that support vegetation on less than 15% of its surface

What is porosity

the amount of empty space within a rock or sediment

Eolian processes

the erosion, transportation, and deposition of sediments by wind; the shaping of landforms by wind

What is permeability

the interconnectedness of pores within in a rock or sediment

Evaporation

warming of water to form water vapor (gas)

Runoff

water flows over surface

Precipitation

water released from clouds

Infiltration

water seeps into soild

zone of saturation (phreatic zone)

where the pores are completely saturated and the fluid in the pores is at or above atmospheric pressure