Geog 1 Final Exam

Wavelength

the distance between two wave crests (tops)

Wave height

the vertical distance from the trough to the crest

Wave trough

the lowest point of a wave

Wave velocity

how fast the wave moves through the water

Swash

water rushing up the beach after a wave breaks

Backwash

water flowing back down the beach toward the sea

Tides

the rise and fall of sea level caused by the Moon's gravitational pull

Rip currents

fast, narrow channels of water flowing away from shore (dangerous for swimmers)

Sea-level change

rising seas erode coastlines and can drown beaches; falling seas expose new land

Erosional vs. Depositional Features:

• Waves erode cliffs and headlands, carving sea caves, arches, and stacks

• Waves deposit sediment to form beaches, sandbars, and spits

Divide

a ridge or high area separating two drainage basins

Drainage basin

all the land that drains into a particular river

Source

where a river begins (usually in mountains)

Tributary

a smaller stream that flows into a larger river

Confluence

where two rivers meet and join

Estuary

where a river meets the sea (mix of fresh and salt water)

Sediment Transport Methods:

• Suspension

• Saltation

• Traction

Suspension

fine particles (like silt) float and are carried along in the water

Saltation

sand-sized particles bounce along the riverbed

Traction

large rocks and boulders are rolled or dragged along the bottom

Point bar

deposit of sediment on the inside of a river bend (slow water)

Cut bank

erosion on the outside of a river bend (fast water)

Porosity

how much empty space (pores) a rock or soil has to store water

Permeability

how easily water can flow through a material

Water table

the upper surface of the underground saturated zone

Aquifer

an underground layer of rock that holds and transmits groundwater

Excessive depletion effects

land subsidence (sinking), wells drying up, saltwater intrusion near coasts

Types of Sand Dunes:

• Barchan

• Transverse

• Parabolic

• Blowout

• Star

Barchan

Crescent shaped, horns point down, consistant one direction

Transverse

Long ridges perpendicular to wind, consistant, abundant sand

Parabolic

U shaped, horns point up, vegitation anchors the edges

Blowout

Bowl shaped depression, wind scoops out loose sand

Sand

Multiple arms radiating out, variable/ Multiple wind directions

Plateau

large, flat elevated landform

Mesa

smaller flat-topped hill with steep sides

Butte

even smaller than a mesa, narrow flat-topped tower

Yardangs

wind-sculpted ridges of rock, streamlined like an upside-down boat

Erg

a vast sea of sand dunes (like the Sahara's sandy parts)

Arroyo

a dry creek bed that fills suddenly with water during rain

Playa

a flat, dry lake bed in a desert basin

Exotic stream

a river that originates in a wet region and flows through a desert (e.g., the Nile, Colorado River)

Two Main Types of glaciers:

• Continental glaciers (ice sheets)

• Alpine (mountain) glaciers

Continental glaciers (ice sheets)

massive, cover entire continents (like Antarctica & Greenland); flow outward in all directions

Alpine (mountain) glaciers

confined to mountain valleys; flow downhill due to gravity

Earth has had multiple glaciation periods

• the most recent major one ended about 10,000–12,000 years ago

• These are linked to Milankovitch cycles

Zone of accumulation

upper area where snowfall adds to the glacier

Zone of ablation

lower area where ice melts or evaporates

Alpine Glacier Features:

• Crevasses

• Arête

• Col

• U-shaped valley

• Hanging valley

• Truncated spurs

Crevasses

deep cracks in the glacier's surface caused by stress

Arête

a sharp, knife-like ridge between two glacial valleys

Col

a low pass between two peaks formed by two glaciers eroding back-to-back

Horn

a sharp, pyramid-shaped peak carved by glaciers on multiple sides (e.g., the Matterhorn)

U-shaped valley

a valley carved by a glacier into a wide, flat-bottomed "U" shape (unlike river valleys which are V-shaped)

Hanging valley

a smaller tributary glacial valley that ends abruptly high above the main valley floor, often creating a waterfall

Truncated spurs

ridges that were cut off and flattened by a passing glacier

Proxy Data

indirect evidence used to reconstruct past climates before instruments existed

Ice cores

trapped air bubbles reveal ancient atmospheric composition and temperature

Sea-floor sediments

contain fossils of organisms sensitive to temperature

Fossilized pollen

tells scientists what plants (and therefore climates) existed in the past

Tree-ring analysis (dendrochronology)

wide rings = good growing year; narrow rings = drought/cold

Corals

their growth rings record ocean temperature changes

Water contains two forms of oxygen:

light (¹⁶O) and heavy (¹⁸O)

During cold periods what gets locked into ice ?

more ¹⁸O gets locked in ice, leaving ocean water enriched in ¹⁸O

What did scientists analyze

ice cores and sea-floor sediments to measure these ratios, which tells them how warm or cold past climates were

Plate tectonics

moving continents change ocean circulation and atmospheric patterns over millions of years

Volcanic activity

eruptions release ash and SO₂, which can cool the Earth by blocking sunlight

Milankovitch cycles

natural changes in Earth's orbit and tilt that affect how much solar energy Earth receives (cycles of ~100,000, 41,000, and 26,000 years)

Variations in the Sun's output

the Sun's energy isn't perfectly constant; changes affect Earth's temperature

Greenhouse Gases

• Water vapor

• Carbon dioxide

• Methane

• Nitrous oxide

• Ozone (O₃) and others

Water vapor

the most abundant natural greenhouse gas

Carbon dioxide

released by burning fossil fuels and deforestation

Methane

from livestock, landfills, and natural gas

Nitrous oxide

from agriculture and fertilizers

The IPCC (Intergovernmental Panel on Climate Change)

states with greater than 95% certainty that human activity is the dominant cause of the warming observed since the mid-20th century. This is considered a scientific consensus.