APES Unit 4 Test

Core

dense mass of solid nickel, iron, and radioactive elements that release massive amounts 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) (where tectonic plates move and things happen)

Crust

very outer layer of the lithosphere, Earth’s surface

Divergent Plate Boundary

plates move away from each other. Rising magma plume from mantle forces plates apart

What does a divergent plate boundary form?

mid-oceanic ridges, volcanoes, seafloor spreading, and rift valleys (on land)

Convergent Plate Boundary

plates move toward each other. Lead to subduction

Subduction

one plate being forced beneath another

What do convergent plate boundaries form?

mountains, island arcs, earthquakes, volcanoes

Transform Fault Plate Boundary

plates slide past each other in opposite directions

What do transform fault plate boundaries form?

earthquakes

What are the steps of divergent convection cycles?

• Magma heated by Earth’s core rises towards the lithosphere 

• Rising magma cools and expands, forcing oceanic plates apart

• Magma cools, and solidifies into new lithosphere

• Spreading magma forces oceanic plate into continental crust (subduction zone)

What happens when magma cools and expands, forcing plates apart?

It creates mid-ocean ridges, volcanoes, spreading zones or “seafloor spreading”

What happens when spreading magma forces oceanic plates into continental crust?

The sinking oceanic plate melts back into magma and it forces magma up, creating narrow, coastal mountains and volcanoes on land

Oceanic-Oceanic Convergent

one Oceanic plate subducts underneath another

What do Oceanic-Oceanic convergent boundaries cause?

Forces magma up to lithosphere surface, forming mid-ocean volcanoes (Island arcs) and off-shore trenches

Oceanic-Continental Convergent

dense oceanic plate subducts beneath continental plate and melts back into magma

What do Oceanic-Contiental convergent boundaries cause?

Forces magma up to lithosphere surface and forms coastal mountains (Andes), volcanoes on land, trenches, tsunamis

Continental-Continental Convergent

one plate subducts underneath the other, forcing surface crust upward (mountains)

What do Continental-Contiental convergent boundaries cause?

mountains

How does a transform fault boundary work?

Plates sliding past each other in opposite directions creates a fault (fracture in rock surface)

Why does a transform fault boundary occur?

when rough edges of plates get stuck on each other and pressure builds up as plates keep sliding, but edges stay stuck 

What happens when stress overcomes the locked fault in a transform plate boundary?

the plates suddenly release, slide past each other and release energy that shakes the lithosphere

Ring of Fire

pattern of volcanoes all around the Pacific plate

What is an example of a formation of the Ring of Fire?

Offshore island arcs (Japan)

Transform Faults

likely location of earthquakes

Hotspots

areas of especially hot magma rising up to lithosphere

What is an example of a hotspot formation?

Mid-ocean islands (Iceland, Hawaii)

What do convergent boundaries result in?

creation of mountains, island arcs, earthquakes, and volcanoes

What do divergent boundaries result in?

seafloor spreading ,rift valleys, volcanoes, and earthquakes

What can maps that show the global distribution of plate boundaries be used for?

to determine the location of volcanoes, island arcs, earthquakes, hot spots, and faults

What are continental plates usually made of?

granite (lighter, less dense)

What are oceanic plates usually made of?

Basalt (heavier, more dense)

What will happen when a continental plate hits an oceanic plate?

the oceanic plate is going to be pushed under the continental plate because it is more dense. As it goes further down, it begins to melt and form volcanoes

What do divergent continental crusts cause?

Rifts (ex. East African Rift)

What are convection currents?

molten rock with hot areas moving up and cool areas moving down. This drives the movement of tectonic plates

How is a hotspot formed?

when magma comes closer to the crust

Soil

a mix of geologic (rock) and organic (living) components

What are the three main components of soil?

sand, silt, clay

Humus

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

Nutrients

ammonium, phosphates, nitrates

What is soil composed of?

• sand, silt, clay

• Humus

• nutrients

• Water and air

• Living organisms

What role does soil play with plants?

anchors roots of plants and provides water, shelter, and nutrients (N, P, K, Mg) for growth

What role does soil play with water?

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

What role does soil play with nutrient recycling?

home to decomposers that break down dead organic matter and return nutrients to soil

What role does soil play with habitat?

provides habitat for organisms like earthworms, fungi, bacteria, moles, slugs

Weathering

Breakdown of rocks into smaller pieces

What are physical causes of weathering?

wind, rain, freezing/thawing of ice

What are chemical causes of weathering?

acid rain, acids from moss/lichen

What are biological causes of weathering?

roots of trees crack rocks

What does weathering of rocks contribute to?

soil formation

How does weathering contribute to soil formation?

Rocks get broken into smaller and smaller pieces and are carried away and deposited by erosion

Erosion

Transport of weathered rock fragments by wind and rain

Deposition

when eroded rock is transported to a new location and deposited

What is the difference between weathering and erosion?

weathering is the break-down and erosion is the movement

How does soil form from below the soil?

Weathering of parent material produces smaller and smaller fragments that make up geological/inorganic part of soil (Sand, silt, clay and minerals)

How does soil form from above the soil?

Breakdown of organic matter adds humus to soil, and erosion deposits soil particles from other areas, adding to soil

How does parent material affect soil formation?

soil pH, nutrient content

How does topography affect soil formation?

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

How does climate affect soil formation?

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

How do organisms affect soil formation?

soil organisms like bacteria, fungi, and worms breakdown organic matter

What are the five factors that affect soil formation?

parent material, topography, climate, organisms, time

O-Horizon

organic; layer of organic matter (plant roots, dead leaves, animal waste, etc) on top of soil

What does the O-Horizon do?

Provides nutrients and limits water loss to evaporation

A-Horizon

topsoil; layer of humus (decomposed organic matter) and minerals from parent material

What is special about the A-Horizon?

Has the 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

weathered rock; least weathered soil that is closest to the parent material, sometimes called bedrock (R-horizon)

Soil Degradation

the loss of the ability of soil to support plant growth

How is topsoil lost?

tilling (turning soil for agriculture) and loss of vegetation disturb soil and make it more easily eroded by wind and rain

What does loss of top soil lead to?

dries out soil, removes nutrients and soil organisms that recycle nutrients

Compaction

compression of soil by machines (tractors, bulldozers, etc), grazing livestock, and humans reduces the ability to hold moisture

What is bad about dry soil?

it erodes more easily and supports less plant growth, less root structure, which leads to more erosion

Nutrient Depletion

repeatedly growing crops on the same soil removes key nutrients (N, P, K, Na, Mg) over time. Reduces ability to grow future crops

What are the sizes of soil particles listed biggest to smallest?

Sand, silt, clay

Soil Texture

the % of sand, silt, and clay in a soil

Because sand is bigger, it has bigger _____

pores

What happens as a result of sand having larger pores?

allows air and water to enter sandy soil easily

What happens as a result of clay having small pores?

it’s harder for air and water to enter clay-heavy soils

Porosity

how much (volume of) water that a soil sample can hold; the amount of pore space a soil has

More sand in a soil means…

more porous/higher porosity (easier for water and air to enter)

More clay in a soil means…

less porous/lower porosity (harder for water and air to enter)

Permeability

the opposite of porosity, how easily water drains through the soil

What is the relationship between porosity and permeability?

Positive. If there is high porosity, there is high permeability

H₂0 Carrying Capacity

how well water is retained, or held by a soil

What is the relationship between porosity/permeability and H₂0 Carrying Capacity?

Inverse relationship. More porous/permeable = lower H₂0 holding capacity 

What happens if there is too much sand in a soil?

drains water too quickly for roots and dries out

What happens if there is too much clay in a soil?

doesn't let H₂O drain to roots, or waterlogs (suffocating them)

What is the ideal soil for most plant growth? Why?

loam, which balances porosity (drainage) with H₂O holding capacity

Soil Fertility

ability of soil to support plant growth

What are factors that increase soil nutrients?

• Organic matter

• Humus

• Decomposer activity

• Clay

• Bases

How does organic matter increase soil nutrients?

releases nutrients

How does humus increase soil nutrients?

holds and releases nutrients

How does decomposer activity increase soil nutrients?

recycles nutrients

How does clay increase soil nutrients?

negative charge binds positive nutrients

How do bases increase soil nutrients?

calcium carbonate-limestone

What are factors that decrease soil nutrients?

• Acids

• Excessive rain and irrigation

• Excessive farming 

• Topsoil erosion

How do acids decrease soil nutrients?

leach positive charge nutrients 

How do excessive rain and irrigation decrease soil nutrients?

leeches nutrients