Improving the method of low-temperature anisotropy of magnetic susceptibility (LT-AMS) measurements in air

2016 ◽  
Vol 17 (7) ◽  
pp. 2940-2950 ◽  
Author(s):  
R. Issachar ◽  
T. Levi ◽  
V. Lyakhovsky ◽  
S. Marco ◽  
R. Weinberger
1991 ◽  
Vol 28 (11) ◽  
pp. 1827-1833
Author(s):  
Nan-Hai Zhang ◽  
Maurice-K. Seguin

Magnetic susceptibility (K) and anisotropy of magnetic susceptibility (AMS) were measured on 69 specimens from five sites in the Chazy Group of the St. Lawrence Lowlands in southern Quebec. The K values depict an isotropic to slightly anisotropic character. The AMS ellipsoid shapes range from oblate to prolate. The axes of minimum susceptibility (Kmin) are mainly perpendicular to the subhorizontal bedding, whereas the other two axes (Kmax) and (Kint) are subparallel to it and somewhat scattered. These observations suggest that the Chazy seafloor was a relatively stable sedimentary platform, with a rather flat bottom, and was a high-energy depositional environment. A cluster analysis indicates a predominant orientation of the Kmax axes in the north-northwest – south-southeast direction. Microscopic studies have shown that detrital magnetic minerals in some specimens align in that direction as well. It is thus inferred that this direction reflects the flow direction of paleocurrents. K was measured also at low temperature (in liquid nitrogen). The results show that the paramagnetic contribution to K is relatively well detected at very low temperature, but it is hampered by diamagnetic contributions to K at room temperature. The specimens contain very few primary ferromagnetic mineral carriers, and therefore the sedimentary rocks of the Chazy Group are not appropriate for standard paleomagnetic investigation.


1966 ◽  
Vol 141 (2) ◽  
pp. 637-640 ◽  
Author(s):  
S. de ◽  
S. Barros ◽  
S. A. Friedberg

1992 ◽  
Vol 275 ◽  
Author(s):  
H. Y. Tang ◽  
W. L. Chen ◽  
W. J. Wen ◽  
M. K. Wu ◽  
M. L. Norton

ABSTRACTCrystalline bismuthates Ba1−xKxBiO3 with x greater than 0.5 are obtained by a low temperature anodic electrocrystallization method in a potassium hydroxide molten flux. The x = 0.56 bismuthate crystal shows 8K superconductivity determined by AC magnetic susceptibility.


2021 ◽  
Author(s):  
Sandra B. Ramírez-García ◽  
Luis M. Alva-Valdivia

<p>Magnetite formation of serpentinized ultramafic rocks leads to variations in the magnetic properties of serpentinites; however, magnetite precipitation is still on debate.</p><p>In this work, we analyzed 60 cores of ultramafic rocks with a variety of serpentinization degrees. These rocks belong to the ultramafic-mafic San Juan de Otates complex in Guanajuato, Mexico. Geochemical studies have been previously conducted, enabling us to compare changes in the magnetic properties against the chemical variations generated by the serpentinization process. By studying the density and magnetic properties such as anisotropy of magnetic susceptibility, hysteresis curves as well as magnetic and temperature-dependent susceptibility and, we were able to identify the relationship between magnetic content and serpentinization degree, the predominant magnetic carrier, and to what extent the magnetite grain size depends on the serpentinization.  Variations in these parameters allowed us to better constrain the temperature at which serpentinization occurred, the generation of other Fe-rich phases such as Fe-brucite and/or Fe-rich serpentine as well as distinctive rock textures formed at different serpentinization degrees.</p>


1963 ◽  
Vol 68 (1) ◽  
pp. 279-291 ◽  
Author(s):  
S. Uyeda ◽  
M. D. Fuller ◽  
J. C. Belshé ◽  
R. W. Girdler

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