tectonics 1.3

Question 1

what is the geographic north?

Answer 1

( North pole )

Question 2

what is the geographic south

Answer 2

( south pole )

Question 3

what is magnetic north

Answer 3

direction the needle of a compass points to , direction of earth’s magnetic north pole where earth acts as a magnet itself

Question 4

what is magnetic south

Answer 4

direction the needle of a compass points to, direction of earth’s magnetic south pole.

Question 5

what is normal polarity

Answer 5

where earth’s magnetic north points towards geographic north and magnetic south points towards geographic south

Question 6

what is reverse polarity

Answer 6

when earth’s magnetic north points towards geographic south and magnetic south points towards geographic north

Question 7

what is magnetic striping

Answer 7

zebra like pattern where there are strips of normal polarity rocks alongside strips of reversed polarity rocks on seafloor
They are symmetrical on both sides of the mid-oceanic ridge.

Question 8

why does magnetic striping occur?

Answer 8

basaltic rocks from the oceanic crust are formed from iron rich lava
They contain magnetic material
When the iron rich lava erupts cools and solidifies
Its magnetic materials point towards earth’s magnetic north, recording evidence of earth’s polarity of that time

Question 9

why does evidence of magnetic striping support the plate tectonic theory?

Answer 9

The zebra like pattern is symmetrical on both sides of mid oceanic ridge, proving that it is not a random occurrence

oceanic plates move away from each other
iron rich lava erupts from the centre of the ridge
lava cools and solidifies to form new oceanic crust
crust is then pushed away from the ridge when more lava erupts and solidifies when plates move
when earth’s polarity reverses, rocks record reversals.
a symmetrical zebra like pattern is formed when more lava erupts and solidifies over time