UNIT FOUR APES

plate tectonics

scientific theory that Earth's rigid outer shell (the lithosphere) is divided into giant slabs (tectonic plates) that float and slowly move over the semi-fluid asthenosphere due to mantle convection currents

lithosphere

solid, rigid outer layer of Earth composed of the crust and the uppermost portion of the mantle that is broken into tectonic plates

convergent boundary

a region where two tectonic plates move toward and collide with each other

what do convergent boundaries result in

subduction zones, deep ocean trenches, volcanic island arcs, and mountain ranges

divergent boundary

a tectonic boundary where two plates move away from each other, allowing magma to rise from the mantle to fill the gap and cool, which forms new lithospheric crust

transform boundary

two plates slide past each other horizontally, building up mechanical stress that is suddenly released to cause earthquakes

earthquake

the sudden release of stored energy along a fault line in Earth's crust, which sends out seismic waves that vibrate the ground

volcano

a vent or opening in Earth's crust through which magma, toxic gases, and ash erupt onto the surface

hot spot

an area in Earth's mantle where plumes of hot magma rise up and break through the lithosphere, creating volcanic activity independent of tectonic plate boundaries

tsunami

series of massive ocean waves triggered by the sudden vertical displacement of the ocean floor, typically caused by an underwater earthquake at a subduction zone

subduction zone

a specific type of convergent boundary where a denser tectonic plate slides underneath a less dense plate and sinks down into the mantle

island arc

a chain of volcanic islands formed on the overriding plate at an oceanic-oceanic convergent boundary where a denser oceanic plate subducts beneath another

seafloor spreading

the process where new oceanic lithosphere (crust) is created at divergent plate boundaries as tectonic plates pull apart and magma rises from the mantle to fill the gap

rift valley

deep, long lowland region formed at a continental divergent boundary where a continental tectonic plate is actively pulling apart

parent material

the underlying geological or organic base material (such as bedrock or loose sediment) from which a soil develops through weathering

soil horizons

the distinct, horizontal layers of a soil profile that develop from the surface downward, each differing in chemical, physical, and biological composition

weathering

the physical or chemical breakdown of rocks and minerals at or near Earth's surface into smaller particles

first step in soil formation and rock cycle

weathering

erosion

the physical process by which weathered rock and soil particles are moved and transported from one location to another by natural forces like water, wind, ice, or gravity

water holding capacity

the total amount of water a soil can retain against the downward pull of gravity -

what does water holding capacity directly influence

plant growth and agricultural productivity

porosity

a measure of the volume of open pore spaces or voids within a given sample of soil or rock - typically expressed as a percentage of the total soil volume

permeability

the rate at which water and air can move downward through a soil or rock layer

soil texture triangle

a triangular chart used to classify a soil's texture class based on its relative percentages of sand, silt, and clay

sand

largest of the three primary soil mineral particles, measuring between 0.05 mm and 2.0 mm in diameter

what is formed by weathering or rocks

sand

silt

medium-sized soil mineral particle, measuring between 0.002 mm and 0.05 mm in diameter

clay

smallest of the three primary soil mineral particles, measuring less than 0.002 mm in diameter

compaction

process where physical pressure packs soil particles tightly together, reducing the volume of empty pore spaces between them

atmospheric gases

the specific blend of gases that wrap around Earth to form our atmosphere

nitrogen (N2)

78% - most abundant gas in the atmosphere; chemically inert until converted by bacteria via nitrogen fixation

oxygen (O2)

21% - produced via photosynthesis; essential for aerobic respiration

argon (Ar)

0.93% - chemically unreactive noble gas

water (H2O)

0.04% - highly variable depending on location and climate; acts as a powerful, natural greenhouse gas

carbon dioxide (CO2)

0.04 - trace gas but a critically important greenhouse gas driven upward by anthropogenic fossil fuel combustion

troposphere

the innermost layer of Earth's atmosphere, extending from the surface up to about 0–17 km (10 miles) high

stratosphere

second layer of Earth's atmosphere, extending from about 17 km to 50 km (10 to 31 miles) above Earth's surface

mesosphere

the third layer of Earth's atmosphere, extending from about 50 km to 85 km (31 to 53 miles) above Earth's surface

thermosphere

ourth and uppermost major layer of Earth's atmosphere, extending from about 85 km to 600 km (53 to 372 miles) above Earth's surface

exosphere

the outermost layer of Earth's atmosphere, extending from the top of the thermosphere (around 600 km) out into the vacuum of space

hadley cell

large-scale atmospheric convection cell located between the equator and 30 degrees North and South latitudes that drives global wind and climate patterns

coriolis effect

the apparent deflection of moving air and water currents caused by the rotation of Earth on its axis

tradewinds

the prevailing pattern of easterly surface winds found in the tropics, blowing from 30 degrees latitude toward the equator (0 degrees) in both hemispheres

westerlies

prevailing surface winds that blow from the west to the east in the mid-latitudes between 30° and 60° latitude in both hemispheres

watershed

an area of land where all precipitation, surface runoff, and underground water drain into a common outlet, such as a stream, river, lake, or the ocean

divide

a high geographical ridge, hill, or mountain range that separates one watershed from another

tributary

a smaller freshwater stream or river that flows into a larger parent river or lake rather than draining directly into the ocean

river delta

a low-lying, typically triangular or fan-shaped wetland landform created by the deposition of sediment at the mouth of a river where it enters a slower-moving body of water (such as an ocean, sea, or lake)

floodplain

flat, low-lying area of land adjacent to a river channel that is naturally susceptible to flooding when the river overflows its banks

riparian barrier

a managed strip of native vegetation (trees, shrubs, and grasses) located along the banks of a river, stream, or wetland

sediment pollution

an ecosystem-disrupting physical pollutant defined as the introduction of excessive particles of sand, silt, and clay into a body of water

insolation (incoming solar radiation)

the measure of the amount of solar radiation (sunlight) energy received on a given surface area over a specific period of time

winter solstice

the exact day of the year when a hemisphere experiences its lowest angle of insolation (incoming solar radiation) and its shortest period of daylight, marking the official astronomical beginning of winter

summer solstice

the exact day of the year when a hemisphere experiences its highest angle of insolation (incoming solar radiation) and its longest period of daylight, marking the official astronomical beginning of summer

equinox

one of two days in the year when neither hemisphere is tilted toward or away from the Sun, resulting in approximately 12 hours of daylight and 12 hours of darkness everywhere on Earth

polar night

natural phenomenon where a polar region experiences 24 consecutive hours of complete darkness due to the hemisphere being tilted entirely away from the sun

midnight sun

natural phenomenon where a polar region experiences 24 consecutive hours of daylight due to the hemisphere being tilted directly toward the sun

latitude

latitude is the geographic measurement of a location's distance north or south of the equator, expressed in degrees from 0 degrees (the Equator) to 90 degrees (the Poles).

equator

the imaginary line of 0 degrees latitude that circles Earth exactly halfway between the North and South poles, dividing the planet into the Northern and Southern Hemispheres

tropic of cancer

the parallel line of latitude located at 23.5° North of the equator - marks the northernmost boundary of Earth's tropics (the region between the equator and 23.5° N)

tropic of capricorn

the parallel line of latitude located at 23.5° South of the equator - marks the southernmost boundary of Earth's tropics (the region between the equator and 23.5° S)

climate

the long-term average pattern of weather conditions (such as temperature, precipitation, humidity, and wind) in a specific region, typically measured over a period of 30 years or more

rain shadow effect

a regional microclimate phenomenon where a mountain range forces air to rise, cool, and drop its moisture on one side, leaving the other side arid and dry

albedo

the measure of the reflectivity of a surface, expressed as a fraction or percentage of incoming solar radiation that is bounced back into space without being absorbed

urban heat island

phenomenon where urban or metropolitan areas experience significantly higher temperatures than their surrounding rural or suburban areas

ENSO (El Nino-Southern Oscillation0

disruptive climate variations caused by changes in water temperatures and atmospheric pressure patterns across the tropical Pacific Ocean - cycle constantly shifts back and forth every 2 to 7 years between three distinct phases

three distinct phases of ENSO

Normal Conditions, El Niño, and La Niña

el nino

a periodic climate event that occurs every 2 to 7 years when the equatorial Trade Winds weaken or reverse direction, causing a massive shift in water temperatures and global weather patterns - warm phase of the ENSO

la nina

periodic climate event characterized by the extreme strengthening of the equatorial Trade Winds, which intensifies normal global weather and ocean patterns - cold phase of the ENSO

upwelling

the oceanographic process where deep, cold, and nutrient-rich water rises toward the surface, replacing warmer, nutrient-depleted surface water that has been pushed away by wind