scholarly journals Magma flow pattern in dykes of the Azores revealed by anisotropy of magnetic susceptibility

2015 ◽  
Vol 120 (2) ◽  
pp. 662-690 ◽  
Author(s):  
M. A. Moreira ◽  
L. Geoffroy ◽  
J. P. Pozzi
Keyword(s):  
Magnetic Susceptibility ◽  
Flow Pattern ◽  
Anisotropy Of Magnetic Susceptibility ◽  
Magma Flow

scholarly journals ANISOTROPY OF MAGNETIC SUSCEPTIBILITY (AMS) IN VOLCANIC FORMATIONS: THEORY AND PRELIMINARY RESULTS FROM RECENT VOLCANICS OF BROADER AEGEAN.

2004 ◽  
Vol 36 (3) ◽  
pp. 1308 ◽  
Author(s):  
I. Zananiri ◽  
D. Kondopoulou
Keyword(s):  
Magnetic Susceptibility ◽  
Flow Direction ◽  
Source Region ◽  
Physical Property ◽  
Anisotropy Of Magnetic Susceptibility ◽  
Magnetic Fabric ◽  
Local Flow ◽  
Magma Flow ◽  
Preliminary Results ◽  
Scalar Properties

The anisotropy of magnetic susceptibility (AMS) is a physical property of rocks widely used in petrofabric studies and other applications. It is based on the measurement of low-field magnetic susceptibility in different directions along a sample. From this process several scalar properties arise, defining the magnitude and symmetry of the AMS ellipsoid, along with the magnetic foliation, namely the magnetic fabric. Imaging the sense of magma flow in dykes is an important task for volcanology; the magnetic fabric provides a fast and accurate way to infer this flow direction. Moreover, the AMS technique can be used in order to distinguish sills and dykes, a task that is almost impossible by using only field observations. Finally in the case of lava flows, the method can be applied to define the local flow conditions and to indicate the position of the "paleo" source region. However, this technique is quite new in Greece. Some preliminary results from volcanic formations of continental Greece and Southern Aegean are presented (Aegina, Almopia, Elatia, Gavra, Kos, Patmos, Samos, Samothraki and Santorini).

Variations in magnetic properties of Mexican serpentinites and related micro-textures 

2021 ◽  
Author(s):  
Sandra B. Ramírez-García ◽  
Luis M. Alva-Valdivia
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Anisotropy Of Magnetic Susceptibility ◽  
Ultramafic Rocks ◽  
Magnetic Carrier ◽  
Temperature Dependent ◽  
Geochemical Studies ◽  
The Relationship ◽  
Magnetite Formation

<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>

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