Exp359. JOIDES.Magnetic susceptibility: simply great !!

Magnetic susceptibility: the name could seem weird !

The process used now in sedimentology  is smart.

2 points to know:

– Magnetic susceptibility measures the answer of a sample in response to an applied magnetic field. A kind of degree of magnetization of the material.

– In sedimentology, the magnetic susceptibility changes due to the minerals in the sample and some minerals are especially interesting .

Some parameters can influence the magnetic susceptibility:

  • nature of these minerals in the sample
  • quantity 
  • size

So what ?DSCF2106

The parameter’s variations can be due to:

– Variations of the climate, if rains are increasing –> more sediments drifting –>minerals quantity increases: magnetic susceptibility increases.

– If sea level lowers –> weathering increases and sediments drift increases: magnetic susceptibility  increases.

(opposite if the sea level increases)

– Relief creation (orogeny): it  will be a source of erosion and in this way a source of sediments drifting: magnetic  susceptibility will increase

So, for the sedimentologists, since the 1990’s, magnetic susceptibility allowed :

– to relate sections comparing the magnetic susceptibility curves

– to identify climates changes

– to reconstruct sea level variations

and finally to rebuild  past climates.