PLATE tectoinic SG

What is the difference between oceanic and continental crust?

Oceanic crust is composed of basalt, and continental crust includes a variety of rocks. Also oceanic crust is young and continental crust is old. Oceanic crust also forms at mid-ocean ridges and continental crust is not.

continental lithosphere is

thicker and found at higher elevations

oceanic lithosphere is

thinner and found at lower elevations

A tectonic plate can have both

continental and oceanic lithosphere

Continental Crust + upper most part mantle gives you

continental lithosphere

Oceanic crust + upper most part mantle gives you

Oceanic Crust

True or false, earth only has 7 tectonic plates?

FALSE, we have medium and small plates and micro plates

Why do tectonic plates move? (convection currents in the mantle)

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

Who created the continental drift hypothesis?

Alfred Wegener

What was the issue with the continental drift hypothesis?

He could not explain what causes the continents to drift.

What was the continental drift theory?

All present continents once existed as a single supercontinent

what is the four evidences to the continental drift hypothesis

1. Continents fit together like puzzle pieces
2. Geology matches up (Outer margin rocks match to matching puzzle pieces)
3. Fossils of identical organisms match up (at the other end of the puzzle pieces)
4. Paleo Climates match up (scratches of glacial ice on land, swamps that are only able to be at the equator)

What are convection currents? and how do they move the lithosphere?

The currents in the mantle control the direction the lithospheric plates move.

What is a mid ocean ridge?

The crack and lithosphere where the plates are being dragged apart. where oceanic crust is created! (It is essentially a volcano)

deep open trenches are where

Two tectonic plates are colliding

What is seafloor spreading?

Seafloor spreading is the production of new oceanic crust.Two tectonic platesare being pulled apart, and the wound is being sealed by magma undernearth

Where does seafloor spreading occur?

Divergent boundaries on the ocean floor

What kind of boundary is formed when two lithospheric plates SLIDE past each other?

Transform. two plates slide past eachother

What two types of crust make up the surface of the earth? Which one is denser

The continental crust and the oceanic crust. The continental crust is THICKER and LESS DENSE. Oceanic crust is THINNER and DENSER.

What is the lithosphere?

The strong upper 100km of the earth that is rigid.

What is the asthenosphere

The weak and easily deformed layer of the earth that is melting temperature.

Describe the differences in characteristics between the lithosphere and the asthenosphere. Make sure to mention things like rigidity and differences in temperatures

Lithosphere: Strong, upper 100km of the earth that is rigid.

Asthenosphere: Weak layer, rocks near their melting temperature. Acts as a lubricant for the plates to slide over.

List the three basic types of tectonic plate boundaries. Briefly describe the motion that occurs between two plates at each boundary.

Transform: Slide past each other

Convergent: Two plates move towards each other

Divergent: Two plates move apart

List all seven major tectonic plates found on Earth.

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

give an example of one minor tectonic plate found on Earth

Juan de Fuca

continental - continental convergence

has no subduction and will never subduct but will have mountain building and no volcanic activity, but there is earthquake activity.

How are continental volcanic arcs formed? What plate must converge to make it

are only created by OCEANIC-CONTINENTAL convergence. They are formed where subduction occurs and the melting underground creates a volcano. Two tectonic plates collide with an oceanic lithospheric plate and a continental plate.

How are island arcs formed? What plate must converge to make it

Created by ocean-ocean convergence as slippage happens and the melt/magma creates island on the surface or volcanic islands underwater.

oceanic crust is heavier and goes

under continental crust

Rifts, rift valleys, and continental rift. These are caused by what type of plate boundary movement?

Divergent boundaries

what are the stages for rifts?

1. Rifts
2. Rift valleys
3. Continental drift

what is a rift?

A small scale crack moving apart

What is continental rift?

Where the mid-ocean ridge is actively creates new mid-ocean floor and land is separated into 2

What is a rift valley?

A large scale rift that is dented and can form lakes

what is the goal of rifting?

To thin out the land, fill it up with water and create a mid-ocean ridge

Youngest oceanic crust is closest to the?

Mid-ocean ridge

Know where to find youngest ocean floor and where to find oldest ocean floor

Youngest ocean floor: Mid ocean ridge

Oldest ocean floor: Subduction zone

Where does subduction occur?

Where one plate moves towards the right and one to the left, creating a convergent boundary where one plate is subducting under another plate creates a subduction zone.

The three types of convergent plate boundaries.

1. Oceanic - Continental convergence
2. Oceanic - Oceanic convergence
3. Continental - Continental convergence

What possible things can happen in ocean-continental that you can have… Can you have all those things in continental-continental convergence too?

you can have earthquakes, tsunamis, volcanoes, trenches, and subduction zones. CANNOT HAVE volcanoes or subduction zones in continental-continetal

oceanic - continental convergence

Ocean lithosphere is being dragged under the continental lithosphere.

Know where most divergent boundaries are found on Earth

At mid-ocean ridges

Where do most volcanoes and earthquakes occur on Earth?

\

the outer margins of tectonic plates. (RING OF FIRE)

W**hat does heat to do elasticity of solids?**

elasticity decreases at high temperatures.

where are most transform boundaries found?

on the ocean floorwwwwwwwwwwwwww

active continental margin

Volcanic and tsuanmi zones, dealing with plates diving. Destruction of ocean floor

passive continental margins

no subduction nor trench, Has a continental rise, shelf, and slope

Why do tectonic plates move? Describe the process of convection

Convection currents are **patterns of circulation** that are produced by this movement in the Earth's mantle, oceans, and atmosphere. Plates move in the direction of one another where convection currents converge

Why is the pacific ocean getting smaller

because the pacific plate is subducting along the subduction zones.

What does colder temperatures do to the elasticity of solids?

Colder temperatures generally decrease the elasticity of solids. which reduces their ability to move and deform when a force is applied. (COLD SNICKER)

How does the lithosphere deform? Does it bend or crack?

the lithosphere deforms by cracking because it has a low temperature

How does the asthenosphere deform? Does it bend or crack?

The asthenosphere deforms by bending because it has a high temp and is weak

where does ocean floor get destroyed?

At the subduction zone