unit 2 vocab

crust and upper mantle

d=2.7g/cm²

older

thicker (25-70 km)

granite

d=2.9g/cm²

younger

thinner (5 km)

basalt

in the mantle, magma closer to the core is heated, which then rises due to density, which then cools, so it falls and is heated again. explains plate tectonic theory; as currents move magma, plates collide, separate, and slide past each other.

formed by convergent boundaries; denser plate gets subducted under less dense plate

two plates collide

forms trenches, mountains, earthquakes, tsunamis

plates dont move and pressure builds, burst of energy when there is finally movement, releasing siesmic waves

caused by a sudden release of energy on the seafloor such as an earthquake or volcanic eruption

the separation of two plates

magma gets pushed through the crust and forms new crust (seafloor spreading)

causes mid-ocean ridges, volcanoes, and hydrothermal vents

underwater mountain ranges found along divergent plate boundaries. magma can move through the new cracks and form new rock. the most major is in the atlantic. supports plate tectonic theory

crack in the crust caused by slabs of ocean crust seperating at ridges

when to plates slide past each other. does not create or destroy lithosphere

causes earthquakes

found along mid-ocean ridges

cracks in the crust along boundaries. water gets heated by mantle and dissolves surrounding rock. pressure then forces the water back up, water cools, resolidifying minerals, creating structure

large, flat, featureless expanses of seafloor

results from sea floor spreading or transform boundaries

becomes thick with a layer of sediment, making it smooth and flat

causes the movement of plates

old, cold, dense plates lithosphere sinks into the mantle and pulls the rest of the plate along with it

the breaking down of materials overtime into sediments

the removal and transportation of material from its original location over time

the chemical composition of a material over time due to oxygen or water exposure. this process may occur more easily if rain is more acidic

when material is broken into smaller pieces without any change to the substance’s chemical composition

when living organisms break down rock. lichen may be present in this process

the delivery of sediments which occurs after weathering and erosion. defined as the deposition of particles into a new location. particles are often deposited at deltas where water slows and particles settle. rates of this process are determined by water speed and particle size

the mouth of a river which forms a fan-like shape

the intertidal region between the high and low water mark. categorized by:

shore’s morphology (shape)

waveaction and erosion

shoreline substrate (surface which organisms live)

organisms living there

land’s geology

weathering

erosion

sedimentation

high levels of erosion (smaller particles get carried away quickly leaving larger particles such as pebbles and boulders behind

little sedimentation

usually granite or igneous rock

formed along coastlines where rock type alternates between rock more and less resistant. the stronger rock remains and juts out more

rate of erosion<rate of sedimentation (small particles are carried from elsewhere to here)

loose deposits of sand, coral, gravel, and seashells

in constant motion and change

mud flats (murky areas in intertidal region formed by sedimentation) occur in protected/enclosed areas due to low levels of erosion and waveaction

usually murky or highly turbid (cloudy and opaque due to particles) because silt is quick to stir up and slow to settle

pattern of the rise and fall of the oceans surface

the distance between the high and low water mark, and varies due to:

the alignment of the earth, sun, and moon

features and shape of coastlines

size of the body of water

wind and air pressure

the highest point that a tide rises in a day

the lowest point that a tide rises in a day

when a rising tide is moving towards the shore

when the water is rushing back towards the sea

the period between flood and ebb tide

a type of wave which travels very fast, moves very far, and are very high. most commonly occur in shallow estuaries and river mouths with large tidal amplitudes

occurs during new and full moons (earth, moon, and sun are in a straight line, amplifying the effect of the moon and sun’s pull)

largest tidal range of the month

occurs during 1st and 3rd quarter moons. sun moon and earth form a 90 degree angle, so earth feels tidal pull in both directions

smallest tidal range of the month

high and low tides of equal heights occur twice a day

one high and one low tide per day

two high and two low tides per day of different heights

a continous flow of water in a particular direction. driven by:

wind

density differences (vertical currents)

coriolis effect

caused by the rotation of the earth, giving currents a spiral pattern (why planes usually can’t fly in a straight line even if the path is mapped out straight on a globe)

currents are deflected clockwise in the N hemisphere and
counterclockwise in the S hemisphere

winds blowing east to west that occur near the equator

winds blowing west to east that occur between the equator and the polar regions

winds blowing east to west around the poles

heat energy from the sun

the layer of the water column that wind can effect

describes how the ekman layer overall moves 90 degrees from the wind direction.

describes how wind and the coriolis effect work together to create a spiral effect in the water column (note: the effects of wind decreases with depth)

equatorial waters are driven westward by tradewinds then curved pole-ward by the coriolis effect

maintains heat balance by transferring warm water from equator to polar and back

creates a cycle

occurs in major ocean basins

ocean water moves up or down throughout layers as opposed to primarily horizontally

the rising of deep ocean water occuring when a low pressure area is formed. can also occur when ridges or seamounts push water upward

brings cold, nutrient-rich water to the surface. water becomes fertilized and increases plankton productivity and strengthens food webs

caused by wind and coriolis effect

the sinking of surface waters. denser (colder, saltier) water sinks. forms the north atlantic deep water current, carrying oxygen rich water to the deep atlantic

a network of slow currents beginning with downwelling in the nadwc and travelling through all oceans

also called thermohaline circulation

driven by density differences (salinity and temp)

– Strong tradewinds blow west across the equatorial Pacific
– Warm water piles up in the western Pacific → evaporation
• results in moisture / precipitation in the western Pacific
– Upwelling is strong along coast of South America
• Driven by strong winds coming off the continent
• It is cold and nutrient-rich (excellent fishing grounds)
• Cold surface water → little evaporation → dry
atmosphere

occurs every 3-7 years• Phenomenon that occurs
Results in major shifts in:
-Trade winds weaken
– Eastern Pacific becomes warmer because:
• warm waters aren’t pushed as far west anymore
• weaker upwelling along S. America
– More evaporation/moisture/precipitation occurs in E Pacific
• Dry regions get drought relief (California)
– Food webs collapse with less nutrients from upwelling
• seabirds and marine mammals starve from lack of fish

opposite reaction of opposing phenomenon– Opposite of El Nino
– Tradewinds are STRONGER
• Warm water is pushed further west
across the Pacific
• Upwelling off South America is STRONGER
- colder waters
– Western coast of N and S America even drier than normal