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Thought about a magnetic anomaly (Updated)

Posted: Wed Apr 27, 2016 3:28 pm
by nTesla
Hi. I would like to ask for some, probably, basic knowledge here.

I have done a small magnetic survey and spend an awful lot of time reading the literature regarding this one, but just canĀ“t figure this out..

The question is how the remanent magnetisation is aligned compared to the earth magnetic field. (Object is 100% remanent)

So the total magnetic field is the green line. And since total magnetic field is the sum of the remanent and induced field, the inclination (74) should not be considered here, right?
That would lead to the conclusion that the orientation of the object must be "Alt: 3", am I right?


Re: Thought about a magnetic anomaly (Updated)

Posted: Thu Apr 28, 2016 10:02 pm
by geophix
Remanent magnetization should be aligned with the earth magnetic field at the time when rocks/minerals were formed. Since earth magnetic field changes over time, their directions do not have to agree with current geomagnetic direction, unlike induced magnetization. So if you have a negative magnetic anomaly caused by remanent magnetization, the source magnet should have an opposite direction compared to the current earth magnet. So I guess its north end points to the north pole.