Laboratory of Magnetic Anisotropies and Rock Magnetism


Profa. Dra. Maria Irene Bartolomeu Raposo
Prof. Dr. Carlos José Archanjo


+55 (11) 3091-3913 or 3091-3911


The Laboratory of Magnetic Anisotropies and Rock Magnetism from São Paulo University (LAMs-IGc-USP), was created in 1997, due to a special program from FAPESP Support to Young Research in the Emerging Research Centers whose the researcher contemplated in the Program was the current Professor from Institute of Geoscience (IGc-USP), coordinator and responsible of the LAMs M. Irene B. Raposo ( The creation of this laboratory introduced a new line of research at the Institute of Geosciences of the USP.

The magnetic anisotropies are physical properties of rocks and arise due to the preferred orientation of the minerals present in them and can be of two types: Anisotropy of Magnetic Susceptibility (AMS) and Anisotropy of Magnetic Remanence (ARM). The creation of the LAMs aimed to deploy the ARM technique hitherto nonexistent in Brazil, this technique is now in routine in the laboratory.

The Magnetic Anisotropies can be determined in all rock types and are powerful tools that help Structural Geology and Geotectonics, since they provide the fabric or petrofabric of the rocks and can be applied to numerous geological situations such as: deformation studies in rocks, emplacement of the igneous bodies, magmatic flow in fracture filling, among others.

The Magnetic Anisotropies are also used to correct Paleomagnetic poles whose determination is also done in LAMs and represents another line of research of the Laboratory. These data are used in Paleogeographic Reconstructions and Magnetoestratigrafia Sedimentary Sequence. The LAMs is equipped with modern instruments such as:


1- Agico KLY4-S Magnetic Susceptibility Bridge, CS-3 Furnance (in argon atmosphere) and CS3-L Cryostat.

2- Agico MFK1-FA Magnetic Susceptibility Bridge with 3 frequencies and variable field, CS-4 Furnance (in argon atmosphere) and CS4-L Cryostat.

3- Alternating field demagnetizer from Molspin (maximum field 100 mT).

4- ARM and pARM system linked with AF demagnetizer from Moslpin.

5- D-Tech D-2000, Alternating field demagnetizer from ASC Scientific (maximum field 200 mT) with ARM and pARM system, computer controlled.

6- ASC TD48 Thermal demagnetizer separate heating and cooling chambers, with vacuum chamber, allows the heating and cooling are performed in argon atmosphere.

7- Agico JR-5A spinner magnetometer.

8- Agico JR-6A Dual speed spinner magnetometer.

9- Vibrating Sample Magnetometer (VSM) from Molspin for generation of hysteresis curves and determination of Hcr.

10- Magnetic Measurements Pulse Magnetometer MMPM9, with two coils (1 and 0.5) inches.

11- ASC Magnetic Shielding (Mu-metal) for storage the samples.

12- Precision Scale.

13- Material for the field work: drill, drills and orientation system of the samples.

14- Sample preparation systems, machines for cutting and marking system of the samples.