OCEA SG 1

Identify the lithosphere and the asthenosphere

Lithosphere: Strong rigid layer on top

Asthenosphere: Weak layer, rocks near their melting temp

Oceanic crust

the uppermost layer of the oceanic portion of the tectonic plates

Continental Crust

the outermost layer of Earth's lithosphere that makes up the planet's continents and continental shelves

Why do tectonic plates move?

The transfer of heat in Earth’s interior causes convection to occur.

Describe the process of convection currents in the mantle

Convection currents in the mantle provide the energy for plate motion.

Who created the continental drift hypothesis?

Alfred Wegener

What is the continental drift hypothesis

all present continents once existed as a single supercontinent. (PANGEA)

what was the issue with the continental drift theory?

Wegener could not explain what causes the continents to drift.

What are convection currents?

It provides the energy for plate motion

What is seafloor spreading

Seafloor spreading is the production of new oceanic crust.

Where does seafloor spreading happen?

Divergent boundaries on the ocean floor

What kind of boundary is formed when two lithospheric plates slide past eachother?

Transform Boundaries also called Transform Faults.

What two types of crust make up the surface of the earth?

The continental and oceanic crust

Which two types of crust on the earth is denser?

land crust and lithosphere

What is the lithosphere?

the strong, upper 100 km of the Earth.

What is the asthenosphere?

The weak and easily deformed layer of the Earth that acts as a “lubricant” for the tectonic plates to slide over.

What are the three basic types of tectonic plate boundaries

Divergent, Convergent, Transform

Divergent motion

two plates move apart

Convergent motion

two plates move towards each other

Transform motion

two plates grind past each other

What are the seven major tectonic plates found on earth?

1. North American
2. South American
3. African
4. Eurasia
5. India - Australian
6. Antarctica
7. Pacific

What is one minor tectonic plate found earth?

Arabian plate, Cocos plate, Philippine plate. scotia plate, juan de fuca, caribbean plate

Why do tectonic plates move?

convection currents, in which the materials inside the mantle heat up and rise to the surface whilst the cooler liquid sinks; as it sinks it then heats up and rises again.

How are island arcs and volcanic arcs formed?

As the subducting oceanic slab descends deep into the hot asthenosphere, melting of the oceanic slab occurs deep below. This melt then rises up towards the surface

What is convection?

the process by which heat is transferred by movement of a heated fluid such as air or water.

What kind of plates have to converge to make each type?

Ocean and Land (continental) ?

What type of plate boundary movement causes rifts, rift valleys, and continental rift

Divergent boundaries

How does earth keep balance with new oceanic lithosphere being formed?

A balance is maintained because older, denser proportions of oceanic lithosphere descend into the mantle at a rate equal to seafloor production.

Where is earths balance with new oceanic lithosphere destroyed?

it is destroyed in subduction zones.

Where do you find the youngest's ocean floor?

Ocean floor nearest to the mid-ocean ridge are the youngest

where do you find the oldest ocean floor? (oceanic crust)

Near subduction zones

Why does subduction occur?

areas where old, dense plate subducts beneath a less dense plate.

What are the three types of convergent plate boundaries?

1. Oceanic - Continental Convergence
2. Oceanic - Oceanic Convergence
3. Continental - Continental Convergence

At ocean-ocean and ocean- continental convergent boundaries that you can have:

Earthquakes, tsunamis, volcanoes, trenches, and subduction zones.

Can you have all those things in continental-continental convergence too?

no?

Where are the most divergent boundaries found on earth

mid-ocean ridges.

Where do most volcanoes and earthquakes occur on earth?

Along plate boundaries

Hot temp makes solids

weak and more elastic

cold temp makes solids

strong and less elastic

How does the lithosphere deform?

Cracks

How does the asthenosphere deform

Bends

describe how the Universe originated.

In the big bant 13.7 million years ago due to a massive explosiob

summarize how our Solar System was formed within the milky Way galax

Debris from the explosion cooled down and condense into the first stars and galaxies making the milky way galaxy

What are the four inner planets mostly composed of

mostly metal + rock.

What are the four outer planets mostly composed of?

ice and gas.

What are the three layers of the Earth?

Crust, mantle, and core

What cause the formation of the three layers of earth?

Formed by collisions with asteroids in space.

Explain how the Moon originated.

Formed by collision of large object (planetesimal) with Earth. Debris from the collision came together to create the Moon. This all happened when the Earth was still forming

explain how the Ocean and Atmosphere originate

Ancient volcanic eruptions were releasing large quantities of gaseous material from the Earth’s interior. Gas released by volcanoes contained water, carbon dioxide, and other chemicals. Water vapor condensates to produce rain. Ocean was formed drop by drop.

what came first? the ocean or the atmosphere

The Ocean?

Where does the heat inside the Earth come from?

The core

Gradient formula

change in field value / distance

What do passive continental margins not have?

Trench

What do active continental margins have?

a trench (subducting plate)

fathom

a unit of length equal to 6 feet used for marine depth

1 Nautical Mile

1\.1507 miles (a nautical mile is slightly longer than a regular mile)

A contour line connects

points of the same elevation

Contour lines will make a ‘V’ when there is a

stream present

hash marks indicate a

depression

Index Contour

every 5th line is printed darker and has an elevation printed on it

change in field value formula

point 1 or 1 - point 2 or b

Rift

a linear zone where continental lithosphere is being pulled apart.

Rift valley

a long, steep valley formed when continental lithosphere have been pulled part and the land between them sinks.

Further pulling apart of continental lithosphere will lead to

Continental Rift

Continental rift

a linear zone along which continental lithosphere stretches, thins out, and pulls apart, which eventually widens to form a narrow sea, and then a new ocean basin.

When the land cracks it’s called a

Rift (small scale cracks)

Rift valley

Larger crack and can form a lake

Continental rift stage

The stage between Africa and South America. That is a continental rift. Two land masses separated

In order for continental to happen

The land masses have to be separated with a mid ocean rift

To create oceanic floor or crust is by

Thin lithosphere, magma, and cold water

Divergent forces on the sea means

Mid ocean ridge

Oceanic continental convergence

Continental lithosphere (land) will never subduct (go under). When the ocean floor goes under and melts, it rises and creates a volcano on the coastline. It has a trench

Ocean ocean convergence

Both ocean floors don’t subduct because they don’t have the same density so the heavier one subducts. It creates seismic waves under water.

Continental continental convergence

Creates cracks and earthquakes activity. Mountains are created without volcanic activity.

Continental volcanic arc is only made by

Oceanic continental convergence

Oceanic lithosphere is

Denser

Volcanic island arc

Created by ocean ocean convergence

Land will never

Subduct

Transform plate boundaries

Found on the ocean floor in between w mid ocean ridge. It displaces the mid ocean ridge. Gives it a zig zag formation

Transform boundaries are called

Transform faults

Inside a plate will there ever be a subduction

No, they are passive continental margins where the ocean is fused with the land