1.a) Evidence for the continental drift

Question 1

What are the 4 aspects of geological evidence?

Answer 1

• continental fit
• Geological method
• Sea floor spreading
• Paelomagnetism

Question 2

Explain the continental fit evidence?

Answer 2

Fit of the continents such as south America and Africa on either side of Atlantic - Theory developed by Wegener

Question 3

Explain geological method evidence

Answer 3

Mountain chains and geology on either side of the Atlantic share similarities explained only if they were formed at the same time/in the same way e.g N Scotland / NeE Canada
→ evidencing that they were once together

Question 4

Geological method example

Answer 4

Appalecian Mountains - shows similar characteristics to what is in the british Isles → as seafloor spreading has pushed us apart

Question 5

Explain the sea floor spreading evidence

Answer 5

Surveys recorded very young ages for places on or near the ridges (indicating new land is being formed due to volcanic activity where magma is rising and cooling creating new land) e.g Iceland less than 1 mill yrs old

Older rock is found nearer the edges near the continental masses (200 mil yrs old) as the older crust is continuously pushed aside.

Question 6

Explain what is meant by Paeloagnetism?

Answer 6

Two british Geologist VIne and Matthews
* Discovered magnetic stripes or banding running parallel to the Mid atlantic ridge in the 60s

• These stripes correspond to times the earth’s magnetic field reversed from N to S and so on
• Iron particles in the erupting magma either side of the ridge align themselves with the earth’s polarity at the time → overtime creates the striping effect within the rock
• Earth’s polarity reverses approx every 400,000 years - the magnetic north and south pole switches

**As the rocks facing different ways creating pattern of striping evidising new rocks have been formed over time **

Question 7

Important note about paleomagnetism

Answer 7

BUT
There is no evidence of for the planet growing in size as all of this ocean crust accumulates
As there is crust destruction and crust subduction elsewhere (e.g trenches)

Question 8

What are the two aspects of cliatological evidence ?

Answer 8

• coal
• glaciation

Question 9

Explain coal evidence

Answer 9

Coal deposits that would have been formed in tropical conditions are found in places that do not have a tropical climate →So they must have drifted E.G found in Antarctica (as it is to cold so it must have moved)

Question 10

Where has coal be found showing it must have moved?

Answer 10

Antartica

Question 11

Explain glaciation as a form of evidence

Answer 11

• Glacial deposits are found in Antarctica and africa and south America from 300 million years ago suggesting these land masses were connected at some point
• More evidence of glacial striations - are found in areas not where glaciers are → showing movement of glaciers

Question 12

Identify the two biological evidence

Answer 12

• marsupials
• mesosaurus

Question 13

Explain the marsupials evidence

Answer 13

Marsupials only found in Australia → due to the fact that it drifted away fro supercontinent before the predator that wiped them out elsewhere had migrated there

Question 14

Explain the Mesosaurus

Answer 14

Mesosaurus remains were found in Southern Africa and Eastern South America → two far away places ( the freshwater animals could not have crossed the atlantic ocean) Thus suggesting that Africa and America were once joined