2.2: Earth Systems and Resources- Introduction to ecosystems

Geology

study of the processes that occur on the surface and interior of the Earth

Core

inner zone, solid inner part surrounded by semi-liquid molten part

Mantle

thick zone of rock just below the surface

where is the Asthenosphere? what is it’s property?

in the mantle, partially melted and able to flow

where is the crust? How much is continental, how much is oceanic?

thinnest and outer most layer

30% continental crust

70% oceanic crust

describe Earth’s convection cells, and movement of rock

Earth’s mantle moves massive volumes of rock. warm rock goes up, cooler rock goes down

what do the convection cells in the mantle cause?

tectonic plates on the asthenosphere shift slowly

lithosphere

the tectonic plates and the outer most part of the mantle

where does most geologic activity occur

at the boundaries of the plates as they rub against each other

divergent boundaries

plates pull apart, usually under the ocean

convergent boundaries

plates come together

transform boundaries

plates slide past each other

on a map, what are divergent boundaries marked by?

red lines

on a map, what are convergent boundaries marked by?

arrows

on a map, what are transform boundaries marked by?

blue lines

what typically happens after divergent movements?

oceanic plates pull apart forming oceanic ridges, some form higher peaks than what is found on land

do divergent movements happen more on land or in the ocean?

on land

examples of divergent movement

mid Atlantic ridge, great rift valley

what happens during convergent movement between a continental and oceanic plate?

oceanic plate collides and slides under the continental plate

oceanic plate melts and flows back up as magma

what happens after convergent movement between two continental plates?

non volcanic mountain ranges form along the collision boundary

subduction, subduction zone during convergent movement

continental plate slides over the heavier oceanic plate, pushing it down into the mantle

what forms as a result of subduction?

trenches and volcanoes

where do most transform faults occur? What happens there?

along oceanic plates earthquakes occur

what do volcanoes release?

molten rock from the Earth’s interior

describe the process and terms linked to an active volcano

magma reaches the surface through a central vent, becoming lava

what is the difference between magma and lava?

magma is molten rock beneath the surface, lava is molten rock once it reaches the surface

Where do most volcanoes form?

where one plate slides under another, or when two plates are pulled apart

list all the things that volcanoes (besides lava)

lava rocks, hot ash, liquid lava, water, carbon dioxide, sulfur dioxide

explain pyroclastic flow, and why it is the biggest threat to people

mixture of hot, fragmented solids and expanding, high density gases
quick moving, unlike lava

examples of deadly volcano eruptions

mount Pinatubo, Mount St. Helens

After volcanoes erupt, how does nature recover?

secondary succession

how can risks from volcanoes be avoided?

identifying high risk areas and using monitoring devices to signal an impending eruption

what is the benefit of volcanoes? (aside from scenery)

highly fertile soil once lava has weathered

Earthquakes

forces in the mantle and surface push, deform, and stress rocks

what do earthquakes cause rocks to do

shift, bend, or break

what will a break of a rock result in?

fracture in the earth’s surface

seismic waves

vibrations caused when a fault forms a movement across a line

what do seismic waves produce? where is it usually found?

earthquakes, along fault zones

what is the focus of an earthquake?

where the earthquake begins below the surface

what is the epicenter of an earthquake

area on the surface directly above the focus

what determines the strength of an earthquake?

how much energy is released at once and how close the focus is to the epicenter

liquifaction

surrounding rock begins to act like liquid

what is the severity of an earthquake measured be?

magnitude of seismic waves

what is magnitude indicated by

amplitude (size of seismic waves)

what effects can earthquakes have on the surface

shaking and vertical displacement of the ground

how can we reduce the risk of damage and death?

look at historical records and make geological measurements to locate active fault zones

enforcement of building codes

list the world earthquake zones

ring of fire, Himalayan mountains, Arabian plate

what causes tsunamis?

part of the ocean floor has risen or dropped

why do tsunamis generally occur?

earthquakes along a subduction zone or when a landslide occurs because of an underwater volcano

describe the movement and growth of tsunamis

start with faster moving smaller waves in the deep and slow down and grow in the shallows

Mass wasting

pull of gravity causes loosened rock, soil, or mud to slide down steep slopes

what activities cause increased damage from Mass wasting?

deforestation and building along hillsides

What does the crust consist of?

minerals and rock

Minerals

naturally occurring solid elements in the crust with a regular internal crystalline structure

pure minerals examples

gold and silver

compound minerals examples

salt and quartzite

what is rock?

solid combination of one or more minerals in the crust

Geologic cycle

interaction of the chemical and physical processes that change one type of rock into another

the Geologic cycle is the ____ cycle on earth

slowest

What is a benefit of Geologic cycling for non-renewable mineral resources

can concentrate the resources into amounts that are usable

What processes are used in the geologic cycle?

crushed and broken, weathered and eroded, heated and pressurized, cooled and recrystallized in the mantle and crust

Sedimentary rock

made of inorganic and organic sediments, formed through pressure

Sedimentary rock examples

shale and sandstone, limestone, coal

Igneous rock

forms from magma below or on the surface

form most of the earth’s crust

Igneous rock examples

granite (cooled underground) lava rock (cooled above ground)

Metamorphic Rock

preexisting rock is exposed to high temp or pressure or chemically active fluids

forces change internal structure and physical properties

Internal geological processes

help form the oceanic and continental plates from intense heat

External geological forces

wear down the surface and more matter from one place to another

what are external geological forces indirectly caused by

the sun

Weathering

external geological process that breaks down rocks into smaller pieces, which helps to build soil

What are the different types of weathering?

physical, chemical and biological

Biological weathering examples

tree roots and lichens eat at rocks

Chemical Weathering examples

acid rain and gases

Physical Weathering

wind, rain, thermal expansion and contraction, water freezing

what type of process is erosion

external geological process

Erosion

dissolving, loosening, or wearing away of a material from the Earth’s surface and depositing it somewhere else

Erosion causes examples

flowing rivers, rain, wind, glaciers picking up rocks and moving them

What is soil composed of?

rock, mineral nutrients, decaying organic matter, water, air, organisms

What type of organisms are in soil?

microscopic decomposers

What natural services does soil provide?

purify and store water, stores CO2, plant growth

How does soil formation begin?

weathering of rock

briefly explain soil development

goes through stages as it builds up until it is considered mature, takes hundreds of years

Topsoil

a renewable resources, but can be depleted

What are the layers of mature soil called?

horizons

List the horizons of the soil from top to bottom

o, a, b, c, bedrock

O horizon

leaf litter

A horizon

topsoil

Describe characteristics of the O and A horizons

full of bacteria, fungi, earthworms, and insects near the plant roots

what is humus, and where is it found?

partially decomposed plant and animal matter in the O and A horizons

as long as the O and A horizons are____, it does what?

anchored by vegetation; acts as a sponge, storing and slowly releasing water

B and C horizons

subsoil and parent material; contain most of the inorganic matter

describe percolation in the soil

broken down rock, sand, silt, clay, and gravel transported by water through the A horizon, pores between solid organic and inorganic contain air

what gases are found in the pores between organic matter in the soil? What is the second one used for?

nitrogen and oxygen, oxygen is used by plant roots for cellular respiration

Sand

largest particle size, better drainage and large pores

doesn’t bind to nutrients, doesn’t support root growth

Clay

smallest particle size, retains water, excludes O2, killing off bacteria and fungi

large surface area, chemically active, binds to nutrients and organic material

silt

medium particle size

Soil texture

percentage amounts of sand, silt, and clay

Soil porosity

amount of empty space between the particles that make up the soil

how is soil porosity measured?

a percentage of the soil that is the “empty space”

What type of soil has high porosity?

clay, because it has a lot of micropores