1-31-13
Harry Hess
Seafloor spreading was accredited to Harry Hess. The seafloor is getting bigger. This is what is implied by seafloor spreading. Harry looked at rock age, magnetic stripes, and drilling samples and came up with seafloor spreading. He found the mid-atlantic ridge and started collecting rock samples. He took rock samples from the ridge and away from the ridge. The one next to the ridge was younger so it was produced recently compared to the one away from the ridge. Magma would rise up from the crust and create new rock when mixed with the water. Harry Hess thought that the magma rising was pushing the mountain apart. However, it was really convection currents of the magma that was pushing the mountain ranges away.
Magnetic stripes were also used. Rock that was formed from the magma will have magnetite. The magnetite will align differently if the north pole is in a different position. Old rock will have magnetite that is facing a different direction than the newer rock. And all the magnetite will face the exact opposite direction oft the other rock.
Rocks closer the to the ridge are younger while rocks farther away are older. Harry also physically saw the magma rise, cool down, and harden to form rock that would then push the plates away.
Magnetic stripes were also used. Rock that was formed from the magma will have magnetite. The magnetite will align differently if the north pole is in a different position. Old rock will have magnetite that is facing a different direction than the newer rock. And all the magnetite will face the exact opposite direction oft the other rock.
Rocks closer the to the ridge are younger while rocks farther away are older. Harry also physically saw the magma rise, cool down, and harden to form rock that would then push the plates away.