scholarly journals Late-stage magma flow in a shallow felsic reservoir: Merging the anisotropy of magnetic susceptibility record with numerical simulations in La Gloria Pluton, central Chile

2013 ◽  
Vol 118 (5) ◽  
pp. 1984-1998 ◽  
Author(s):  
F. Gutiérrez ◽  
I. Payacán ◽  
S. E. Gelman ◽  
O. Bachmann ◽  
M. A. Parada
Keyword(s):  
Magnetic Susceptibility ◽  
Numerical Simulations ◽  
Late Stage ◽  
Anisotropy Of Magnetic Susceptibility ◽  
Magma Flow ◽  
Central Chile

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).

Detection of a weak late-stage deformation event in granitic gneiss through anisotropy of magnetic susceptibility: implications for tectonic evolution of the Bomdila Gneiss in the Arunachal Lesser Himalaya, Northeast India

2016 ◽  
Vol 154 (3) ◽  
pp. 476-490 ◽  
Author(s):  
R. K. BIKRAMADITYA SINGH ◽  
A. KRISHNAKANTA SINGH ◽  
KOUSHIK SEN ◽  
S. J. SANGODE
Keyword(s):  
Magnetic Susceptibility ◽  
Late Stage ◽  
Tectonic Evolution ◽  
Northeast India ◽  
Anisotropy Of Magnetic Susceptibility ◽  
Magnetic Fabric ◽  
Second Phase ◽  
Lesser Himalaya ◽  
Deformation History ◽  
Metasedimentary Rocks

AbstractOutcrop-scale structures and magnetic fabric anisotropy of the Bomdila Gneiss (BG) that intruded the Lesser Himalayan Crystallines (LHC) of the Arunachal Lesser Himalaya are studied to understand the BG deformation history and tectonic evolution. Detailed analysis of structures reveals that the LHC have undergone three phases of deformation, D1, D2and D3. The S2foliation developed during the second phase of deformation (D2) is the most penetrative planar fabric in the studied rock, which shows a general ENE–WSW strike with moderate NW dip. Mesoscopic evidence of a later phase of deformation (D3) in the BG is lacking. Evidence of D3deformation in the form of F3folds is only observed in the adjacent metasedimentary rocks of the LHC. The magnetic foliations recorded from anisotropy of magnetic susceptibility (AMS) analysis of the BG are mostly striking NW–SE with a moderate dip towards the NE or SW, and magnetic lineation is mostly sub-horizontal and dominantly plunging towards the SE. Our study shows that the magnetic fabric of the BG does not correspond to any visible outcrop-scale mesoscale foliation. However, the magnetic foliation of the BG is parallel to the axial plane of the F3folds of the adjacent metasedimentary rocks of the LHC. Integration of AMS and outcrop-scale structural analysis helps us envisage the superposed deformation history of the BG. Our study emphasizes the importance of AMS to detect late-stage or feeble deformation events that leave no visible outcrop-scale imprint and are difficult to discern through conventional geological means.

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