Test bench and method for estimating remanent magnetisations on sediment cores

A method for estimating the remanent magnetisations of portions of a sediment core extending along a main direction, the method comprising at least the following steps:

• i. Defining a succession of N elementary volumes and the dimensions thereof, each elementary volume corresponding to a portion of sediment core, the elementary volumes being adjacent and successively arranged along said main direction of the sediment core;
• ii. Translating the sediment core relative to a fluxgate probe so as to make each elementary volume pass opposite the fluxgate probe;
• iii. Measuring, by the fluxgate probe, the magnetic field produced by each elementary volume;
• iv. By using the magnetic field measurements of the fluxgate probe:
• determining a remanent magnetisation M−x specific to each elementary volume (101), this step comprising at least one from among the following steps;
• “directly” identifying a plurality of possible values of remanent magnetisation M−x, this first identification comprising:
• Calculating values of magnetic field B−x from a plurality of values of remanent magnetisation M−x selected arbitrarily;
• identifying, among said plurality of values of remanent magnetisations M−x selected arbitrarily, one or more values of remanent magnetisation M−x for which the magnetic field B−x calculated is between 0.7 and 1.3 times, preferably between 0.8 and 1.2 times, and preferably between 0.9 and 1.1 times, the magnetic field B−x measured by the fluxgate probe;
• “inversely” identifying one or more values of remanent magnetisation M−x, this second identification comprising:
• calculating a value M−x of remanent magnetisation according to the measurement of the magnetic field measured by the fluxgate probe.