Plate tectonics

what is the evidence for plate tectonics

the fit of continents - south america firts nicely into west africa

far flung fossils - fossils matched across different continents, even though the creatures could not swim

paleoclimate - Current Geology did not conform to current climate

truncated geologic features - Fossils matched across different continents, even though the creatures could not swim

what is paleomagnetism

Paleomagnetism is the magnetic record preserved in rocks that shows the direction of Earth’s magnetic field when the rocks formed.

how does paleomagnetism prove tectonics

Palaeomagnetism proves plate tectonics because rocks on the ocean floor show symmetrical patterns of normal and reversed magnetic polarity on either side of mid-ocean ridges, proving new crust is formed, and plates move apart.

what are the different parts of the earth

crust
mantle
lithosphere
outer core
inner core

how do plates move

due to ridge push and slab pull

what are the 2 different crusts

oceanic and continental

how are the hawaiian islands formed

The Hawaiian Islands are formed by a hot spot beneath the Earth’s crust where magma rises from the mantle, creating volcanoes; as the Pacific Plate moves over the hot spot, a chain of volcanic islands forms.

what are hotspots

A hotspot in geography is defined as an area on Earth where volcanic activity occurs due to a plume of hot material rising from deep within the mantle. 

what happens at a constructive plate boundary

At a constructive plate boundary, the plates are moving apart from one another.
When this happens, magma from the mantle rises to form new crust. This can cause earthquakes. Rising magma can also create shield volcanoes.  

what is a rift valley

A rift valley is a long, narrow depression formed when the Earth’s crust is pulled apart and sinks between faults.

how is a rift valley formed

A rift valley is formed when tectonic plates move apart, causing the Earth’s crust to stretch, thin, and crack, and the land between the faults sinks down.
e.g like a muffin

what is the volcanic activity like on a constructive plate boundary

Volcanic activity at constructive margins is usually basaltic, producing runny, low-viscosity lava, and two of the world’s permanent lava lakes are found in East Africa.

what is an ocean ridge

An ocean ridge is an underwater mountain range formed at constructive plate boundaries where magma rises, creating new oceanic crust.

how is an ocean ridge formed

An ocean ridge is formed when tectonic plates move apart at a constructive boundary, allowing magma from the mantle to rise, cool, and create new oceanic crust, which builds up into an underwater mountain range.

what is a shield volcanoe

A shield volcano is a wide, gently sloping volcano formed by layers of low-viscosity (runny) lava that spreads over a large area

what happens at destructive plate margins

At destructive plate margins, plates collide, the denser one is subducted, causing earthquakes, volcanoes, and mountain formation.

what are the 3 types of destructive margins

subduction - oceanic vs continental
subduction - oceanic vs oceanic
collision - continental vs continental

what happens at subduction margins

earthquakes and volcanoes

what happens at collision margins

fold mountains

NO VOLCANOES - earthquakes only

an example of the oceanic vs continental

nazca plate subducting under south american plate
andes navada del ruiz colombia (volacanoe)

give an example of oceanic vs oceanic

give an example of continetal vs continental

creates fold mountains eg mountain everest where the indian and asian plates are colliding