please gotta help me (science question)?

Question

can you explain how the processes of sea floor spreading and magnetic reversal produce bands of oceanic crust that have different magnetic polarities?

short answers please?

i didnt ask u this because i didnt pay attention at class i wasnt there and i didnt even had the book!!so please help me and just explain what is it and how please :((

Answer 1

The polarity of the magnetic field changes every few hundred thousand years, give or take a bit.

When magma cools, the orientation of the magnetic field is "frozen" into the rock.

It was discovered that the rocks to either side of mid-ocean ridges displayed alternating bands of normal and reversed polarity. The bands on each side of the mid-ocean ridge were mirror images.

This discovery was fundamental in demonstrating plate tectonics. The mirror banding indicated that material was being added at the ridges over time as the crust on either side moved in opposite directions.

In reverse, if you take out the middle band, the two next bands on either side fit together. Take them out and the next two fit together, and so forth.

I tried to keep it really simple. You need to understand because this discovery was extremely important.

Answer 2

The iron in iron bearing minerals align themselves with the magnetic north, whichever direction it happens to be.

As the seafloor spreads, it creates new rock, the iron in which aligns itself to the current pole configuration as it cools. As the sea floor continues to spread it pushes the old rocks out. New rocks form and iron continues to align itself and if the poles change the iron will too. After a while you have symmetrical bands of rocks with alternately aligning iron.

This symmetrical banding is one of the bits of evidence for sea floor spreading.

This would be a lot easier if you paid attention in class.

**Then it would be A LOT easier if you went to class and bought the book.

This is as short as I can get it.