MAGNETOSTRATIGRAPHY

 MAGNETOSTRATIGRAPHY

An important tool to date sedimentary and volcanic sequences.

• The polarity of earth's magnetic field is preserved in the sediments at the time when they were deposited.
• Magnetic material among the sediments orient themselves with existing earth's magnetic field while settling at the bottom of the basin.

Earth's magnetic north pole : Eastern Canada

Earth's magnetic south pole : Eastern Antarctica

∙Earth's magnetic north and south poles have switched their position periodically in the geological past.

Reversal of magnetic poles take places in two stages:

• AT FIRST : Intensity of Earth's magnetism that is apparently related to slowing down of the flow of electric currents of the earth's core is gradually reduced to a near zero level.                                 TIME: 10Ka

• AT SECOND STAGE : Reversal of the Earth's magnetic poles take place and Earth's magnetic intensity is gradually brought back to its original value.                                                                     TIME: 1 to 2 Ka

Thanks for reading.

                                                                                                                                                   -Ichbinaasif