Bathymetry Quiz

terrigenous

(land)(rocks/debris) (can be found on continental shelf)

biogenous

(living organisms)(come from the shell)

Guyot

-An underwater plateau that has sunk beneath the ocean's surface -Originally formed from volcanic activity -Flat top from erosion

Seamount

-An underwater volcanic mountain -Pointy top -Will eventually be guyots -Once it breaks the surface it is an island

AUVs

-Can also be used to map the sea floor -Underwater robot

Mid Ocean Ridge

-Chains of volcanic mountains that run though the middle of the oceans -Create crust

Continental Shelf

-Gently sloping edge of the continent -Ocean is shallow on the shelf

What are the 3 spheres?

-Inner core (iron and nickel) -Asthenosphere- lower mantle and outer core -Lithosphere (crust and upper mantle)

Continental Margin

-Made up of continental shelf, slope, and rise -This is where the continent drops off to meet the ocean crust -Filled with life, light can reach the bottom

What are tectonic plates made of?

-Plates are made of rigid lithosphere -The lithosphere is made up of the crust and the upper part of the mantle

Abyssal Plain

-Relative smooth plains on the ocean floor -Ocean level is deep in these areas

Echo Sounding Sonar

-Send sounds waves down to sea floor -Listen for them to bounce back -Use a formula to calculate water depth

Echo Sounding

-Shapes can be determined by measuring the time it takes for the sound to "bounce back" -Some marine life also uses this method Dolphins and Bats use this

what do bathymetric cross section maps tell you?

-Shows what it would be like if you walked along the sea floor on a specific line -Depth often exaggerated to make features more visible

trench

-The deepest places in the ocean -they form from one crustal plate plunging under another -Destroy crust with magma

Satellite Altimetry

-Use satellites to measure sea surface height -Sea surface height corresponds to sea floor height

Continental Rise

-Where sediments builds up at the bottom of the continental slope

four types of sediments

-terrigenous -biogenous -hydrogenous -cosmogenouse

The earth's crust is divided into ___ major plates which are moved in various directions

12

how deep is the ocean

12,200ft

how big is the ocean?

140 million square miles (71% of the earth's surface

Deepest point?

36,198 feet in the Mariana (Trench Challenger Deep)

how far down have we gone into the oceanic crust?

6km

Who came up with the theory of plate tectonics

Alfred Wegener

continent-oceanic

Called subduction □Oceanic lithosphere subducts underneath the continental lithosphere □ Oceanic lithosphere heats and dehydrates as it subsides □ The melt rises forming volcanism □ Example = Andes mountains **where this collision takes place you will have volcanic mountains

Rift Valley

Low valleys in the middle of mid ocean ridges where two ocean plates are pulled apart

Plates move from the flow of the earth's ___

Magma

What is bathymetry

The measurement of water depth.

Continental Slope

The steep drop off at the edge of the continent

Multi Beam Bathymetry

Use lots of sound beams at once

Side Scan Sonar

Very detailed images of small areas of sea floor

what are the 3 kinds of convergent boundaries

continent-continent continent-oceanic ocean-ocean

what are the two types of crust earth is made of?

continental and oceanic crust

what do contour maps tell you?

contour lines connect areas of similar height/depth

Name the maps of the ocean floor

contour map and bathymetric cross section

What are the 3 layers of the earth?

core, mantle, crust

Formula for depth

depth = 1/2 (1500) (time)

3 types of plate tectonic movement

divergent, convergent, transform

continent-continent

form mountains (ex: European alps, Himalayas)

How do we know what the earth is made of?

geophysical surveys, acquisition, geological

After it is a seamount it is a ___

guyot

How are the Plates of lithosphere moved?

hot mantle convection cells

define a hot spot

hot plume of magma (ex:galapagos, hawaii, yellowstone)

Highest Mountain?

mauna kea (only some is visible)

convergent

plates come together and hit each other

divergent

plates separating (crust is being formed, mid ocean ridge) ex:iceland

transform

plates sliding past each other

Hydrogenous

seafloor sediments formed whey they precipitate out of seawater itself

Cosmogenous

sediment from space

What level do humans live on?

the crust

What plate are we living on?

the north American plate

characteristics of continental crust

thick, buoyant, mostly old

characteristics of oceanic crust

thin, dense, young

Lead lines

weighted rope with depth markings

ocean-ocean

§ When 2 oceanic plates collide one runs over the other which causes it to sink into the mantle forming a subduction zone § The subducting plate is bend downward to form a very deep depression in the ocean floor called a trench The worlds deepest parts of the ocean are found along trenches (ex: marina trench)

Why do we map the sea floor?

• To learn about the deep parts of the ocean that are hard to observe • To gather information about plate tectonics • To find shipwrecks and other items of interest • To aid navigation