Marine Acquatics Test 3

what evidence suggested that present day continents originated in the single landmass Pangaea?

the mountain ranges from different continents, fossil records, continental fit

what have scientists found about the age of the ocean floor?

they are the youngest at divergent plate boundaries and mid ocean ridges. It gets older the more it moves away from the divergent plate boundaries

these plates slide past each other separate ways

transform

lithosphere

A rigid layer made up of the uppermost part of the mantle and the crust.

Glomar Challenger

Drilling ship 1968-1983, took crust samples from the ocean's bottom Found that crust was thinnest and rock was youngest at the area of oceanic ridges This was consistent with hypothesis that new crust is being formed in these areas

the deepest trench is, and is how many miles deep

Mariana's Trench, 7 miles

subduction zone

The region where oceanic plates sink down into the asthenosphere. TRENCH both happen at convergent

lithospheric plates

a series of rigid plates that are going to move around Separated by trenches, ridges, and faults

mantle

asthenosphere and lithosphere

describe the underwater landscape of the ocean

be able to label an ocean landscape

what types of particles in the sediments make up the composition of the seafloor? are sediments important? why?

clay, mud, sand, biogenious sediments

what does trench also mean?

conduction zone

what bathygraphic feature contains the most sediment?

continental shelf

this feature is found at the boundary of the shelf and includes a abrupt change in slope

continental slope

at what type of plate boundary will a subduction zone form?

convergent

Francis Wegner

created name Pangea

plates move apart at this type of plate boundary

divergent

where does seafloor spreading start?

divergent plate boundary

what plats a factor in the formation of a continental shelf?

erosion from waves

abyssal plain

flat expanse of the deep ocean basin, formed by turbidity currents and sediment falling from above, they cover as much as 50% of Atlantic seafloor and 80% of pacific and Indian seafloors Abyssal hills are usually grouped together

continental rise

found are the base of a steep continental slope, these are found in the Atlantic and Indian ocean usually

continental slope

found at the boundary of the continental shelf, this is where we see an abrupt change, less sediment due to the angle

continental shelf

found at the edge of continents, generally flat area, slope towards the bottom of the ocean, goes out 68 kilometers in width and 130 meters in depth

what usually determines the width of a continental shelf?

if the land is really flat, the continental shelf will go out for longer

where is magma located and how does it move throughout the earth?

in the mantle, it moves up a volcano and in divergent plate boundaries

inner core

in the very center, pressure on it so it is solid, very dense and hot, rich in iron and nickel

what are the layers of the earth?

inner core (a solid), outer core, mantle (thickest), crust

seafloor spreading is

lateral movement of the Earth's crust (moving side to side) Magma rises from the deep mantle and is turned back by the rigid lithosphere. Moves toward subduction zoners

define latitude and longitude and give their primary line names. what are they used for?

latitude-north or south of the equator longitude-east and west of the prime meridian

these form at divergent plate boundaries

midocean ridges

outer core

more of a liquid/sludge material, transitions between dense inner core and the mantle

trenches

most common in pacific ocean, see more convergent plates there so this is where they'll happen, famous one is Mariana's trench,

mid ocean ridges

moving magma breaks through the crust of the ocean floor, ling mountain ranges from over time, origins of Seafloor Spreading

Bathygraphic features

physical features of the ocean bottom

where do most earthquake zones correspond closely too? what area of the world do most earthquakes occur?

plate boundaries. Pacific Ocean

explain how a continental shelf can form?

plates apart. they were formed during glacier periods.

subduction zones

region where the removal of old crust takes place, happens at a certain plate boundary Ocean trenches Old crust sinks down and eventually reaches the mantle and is recycled into the Earth's core

what activity produces a lateral movement of crust?

seafloor spreading

seamounts

sharp sided formations that rise sharply from the seafloor, formed from underwater volcanoes, most prevalent in the Pacific ocean, some show evidence of coral reefs and surface erosion, this suggests they were above the surface at one time

in the 1600s, what Englishman proposed that the continents may have once been connected?

sir Francis bacon

another term for a trench

subduction zone

where is the crust the oldest?

subduction zone, bottom of the trench

lithosphere....

tectonic plates causing earthquakes are found in this area

explain how seafloor spreading takes place

the formation of new areas of oceanic crust, which occurs through the upwelling of magma at midocean ridges and its subsequent outward movement on either side