Science Test 12/05/2023 Flashcards
Who developed the theory of Plate Continental drift?
Alfred Wegner
When was the idea of Continental drift first proposed?
1912
What pieces of evidence did Alfred Wegener use to support his theory? ( Hint 3 answers )
- Fit of the Continents
- Past Climate Belts and Distribution of Fossils
- Matching Rock Types
What happens to continents/ plates over millions of years as we know them?
They separated over millions of from their original state
What major criticism existed for Wegener’s theory?
He couldn’t explain how it actually moved
Why is the theory of Plate Tectonics like all theories?
When new evidence is revealed, theories can change with he available evidence.
When plates collide what is the most common outcome?
Usually, one of the converging plates will move beneath the other, a process known as subduction.
How does a Volcano form, and what kind of plates are involved?
When two plates (either oceanic plate descends below another oceanic plate or an oceanic plate descends below a continental plate) converge, subducting the less dense plate, magma then rise creating Volcanos
How deep is continental crust (minimum to maximum)?
Continental (land) plates 30-50 km thick
How deep is oceanic crust?
Oceanic plates 5-10 km thick, found mainly under the oceans.
How does an Earthquake occur?
When Plates, slide, slip, sub duct, colliding or spreading this is because they get stuck and pressure builds up
What does convergent boundaries look like?
When plates move together creating mountain ranges, volcanos etc
What do divergent boundaries look like?
When plates move apart, creating rift valleys and mid-ocean ridges
What do transform boundaries look like?
When the move parallel causing earthquakes
Why do some countries experience little or no Plate tectonic activity?
Some countries are on borders of tectonic plates, others like Australia, are in the middle.
What relationship does sea floor spreading have to plate tectonics?
Seafloor spreading occurs at divergent plate boundaries.
What are convection currents?
These plates move due to convection currents in the mantle . Heat from the core makes magma in the mantle rise towards the crust. As the hot current nears the crust, it begins to cool and sink back towards the core. As the magma sinks, it drags the plates across the surface of the Earth.
How does cooling affect the movements of plates?
shortening and deformation of the plates due to the cooling
How does heating affect the movements of plates?
The heat from radioactive processes within the planet’s interior causes the plates to move, sometimes toward and sometimes away from each other.
How is the lithosphere influenced by convection currents?
Convection currents carry heat from the lower mantle and core to the lithosphere
What is the approx temperature of the inner core compared to the mantle?
The temperature is around 1000°C at the base of the crust, around 3500°C at the base of the mantle, and around 5,000°C at Earth’s centre.
What is the average speed plate of plate movement?
Earth’s land masses move toward and away from each other at an average rate of about 1.5 centimetres.
What are the are seven major plates:
African, Antarctic, Eurasian, Indo-Australian, North American, Pacific and South American.
Name a plate the is entirely oceanic
Pacific Plate
Identify two plates that are moving apart
Indian plate and Asia plate
Locate where is Australia situated in regards to plate boundaries?
Australia is located centrally on the Australian plate
Locate where is Australia situated in regards to plate boundaries?
Australia is located centrally on the Australian plate
Locate where will Australia be in 100 million years
Up north
