APES UNIT 4

Earth’s structure

core-mantle-asthenosphere-lithosphere-crust

core

dense mass of solid nickel, iron, and radioactive elements that release massive amount of heat.

mantle

liquid layer of magma surrounding core, kept liquified by intense heat from core

asthenosphere

solid, flexible outer layer of mantle, beneath the lithosphere

lithosphere

thin, brittle layer of rock floating on top of mantle (broken up into tectonic plates)

Crust

very outer layer of lithosphere, earth’s surface

Divergent plate boundary

plates move away from each other; rising magma from the mantle forces plates apart; and forms: mid-oceanic ridges, volcanoes, seafloor spreading, and rift valleys on land.

Convergent plate boundary

plates move towards each other; leads to subduction (one plate being forced beneath another); forms: mountains, island arcs, earthquakes, and volcanoes.

transform fault plate boundary

plates slide past each other in opposite direction; forms: earthquakes.

Magma with convection cycles (divergent)

Magma heated by earth's core rises towards lithosphere; rising magma cools and expands, forcing oceanic plates apart—creates mid ocean ridges, volcanoes, spreading zones or "seafloor spreading"; magma cools, and solidifies into new lithosphere; spreading magma forces oceanic plate into cont. subduction zone—sinking oceanic plate melts back into magma, and also forces magma up creating narrow coastal mountains (andes) and volcanoes on land

magma

a molten mixture of rock-forming substances, gases, and water from the mantle.

subduction zone

the region where oceanic plates sink down into the asthenosphere

convergent boundary=

subduction zone

trench

a deep, steep-sided canyon in the ocean floor

Oceanic-oceanic

One plate subducts underneath other; forces magma up to lithosphere surface, forming mid ocean volcanoes- island arcs; off-shore trench

Oceanic-continental

Dense oceanic plate subducts beneath continental plate and melts back into magma; forces magma up to lithosphere surface; coastal mountains (andes), volcanoes on land, trenches, tsunamis

Continental-continental

One plate subducts underneath other, forcing surface crust upward (mountains); ex: Himalayas

transform fault boundary

plates sliding past each other in opposite directions creates a fault (fracture in rock surface); earthquakes

earthquakes

Most common activity; occurs when rough edges of plates get stuck on each other—pressure builds as plates keep sliding, but edges stay stuck—when stress overcomes the locked fault, plates suddenly release, slide past each other and release energy

Tectonic map can predict:

ring of fire, transform faults, and hotspots

ring of fire

pattern of volcanoes all around pacific plate; offshore island arcs (Japan); convergent plates

hot spot

area of especially hot magma rising up to lithosphere; mid-oceanic island

Explain how subduction leads to volcanic activity.

one plate being pushed down and melted; molten material/magma rising to the surface near the zone

what is soil

mix of rocks and organic components: sand, silt, clay; humus, nutrients, water, and air, and living organisms

humus

main organic part of soil (broken down biomass like leaves, dead animals, waste, etc)

nutrients in soil

ammonium, phosphates, and nitrates

plants

anchors roots of plants and provides water, shelter, and nutrients for growth.

water in plants

Filters rainwater and runoff by trapping pollutants in pore spaces and plant roots. Clean water enters groundwater and aquifers

effects on soil form

parent material, topography, climate, and organisms

topography

steep slope= too much erosion; more level ground=soil deposition

climate in regards to soil

Warmer=faster breakdown of organic matter; more precipitation= more weathering erosion and deposition

erosion deposits

soil particles from other areas, adding to soil

o-horizon

layer of organic matter (plant roots, dead leaves, animal waste, etc) on top of soil; provides nutrients and limits H20 loss of evaporation

a-horizon (topsoil)

layer of humus and minerals from parent material; most biological activity (earthworms, soil microbes) breaking down organic matter to release nutrients

b-horizon (subsoil)

lighter layer below topsoil, mostly made of minerals with little to no organic matter; contains some nutrients.

c-horizon

least weathered soil that is closest to the parent material, sometimes called bedrock.

loss of topsoil

tiling (turning soil for agriculture) and loss of vegetation disturb soil and make it more easily eroded by wind and rain; loss of top soil dries out soil, removes nutrients and soil organisms that recycle nutrients.

soil degradation

the loss of the ability of soil to support plant growth.

types of soil degradation

loss of topsoil, compaction, nutrient depletion

compaction

Compression of soil by machines (tractors, bulldozers, etc.), grazing livestock, and humans reduces ability to hold moisture; dry soil erodes more easily, dry soil supports less plant growth, less root structure, leading to more erosion

soil texture

The percentage of sand, silt, and clay in a soil; because sand in bigger, it has bigger pores(empty spaces between particles); this allows air and water to enter sandy soil easily; clay has smallest pores, so it's harder for air and water to enter clay-heavy soils

porosity

amount of pore space a soil has; more sand sand in a soil= more porous/higher porosity (easier for water and air to enter); more clay in a soil= less porous/less porosity (harder for water to enter)

permeability

how easily water drains through a soil

More porous/higher porosity=

More permeable/higher permeability; positive relationship between porosity and permeability

Effects on soil fertility

Soil that is too sandy(too permeable) drains water too quickly for roots and dries out; clay heavy soil doesn't let H20 drain to roots or waterlogs (suffocating them); idea soil for most plant growth is loam, which balances porosity or drainage with H20 holding cap

Factors that increase soil nutrients

Organic matter(releases nutrients); humus(holds and releases nutrients), decomposer activity(recycles nutrients), clay (negative charge binds positive nutrients), bases(calcium carbonate- limestone)

Factors that decrease soil nutrients

Acids leach positive charge nutrients, excessive rain/irrigation leeches nutrients; excessive farming depletes nutrients; topsoil erosion

Factors that increase H20 holding cap

Aerated soil (biological activity); compost/humus/organic matter; clay content; root structure, especially natives

Factors that decrease H20 holding cap

Compacted soil (machines, cows); topsoil erosion; sand; root los

What pH of soil tells you

How acidic(low pH) or basic/alkaline(high pH) soil is. More acidic soil=less nutrient availability

Gases of earth's atmosphere

Nitrogen, oxygen, argon, water vapor, CO2