Record details

Title
    Limitations of tensor subtraction in isolating diamagnetic fabrics by magnetic anisotropy
Statement of responsibility
    František Hrouda, Bernard Henry, Graham Borradaile
Author
    Borradaile, Graham
    Henry, Bernard
    Hrouda, František
Language
    anglicky
Source title - serial
    Tectonophysics
Vol./nr.
    Vol. 322
Pages
    p. 303-310
Year
    2000
Notes
    4 obr., 22 bibl.
    il.
    Zkr. název ser.: Tectonophysics
Subject group
    anizotropie
    čistecko-jesenický pluton
    granodiorit
    kalcit
    křemen
    kvarcit
    magnetická susceptibilita
    magnetit
    magnetizace remanentní
    orientace přednostní
Geographical name
    Čistá (Rakovník)
    ČR-Čechy
Keyword
    Anisotropy
    Diamagnetic
    Fabrics
    Isolating
    Limitations
    Magnetic
    Subtraction
    Tensor
Abstract (in english)
   The anisotropy of low field susceptibility (AMS) represents the orientation distribution of all minerals in a rock, whereas the anisotropy of magnetic remanence (AMR, preferably anhysteretic) isolates that of the accessory remanence-bearing minerals. The subtraction of normalized AMR from AMS, in theory and under limited practical circumstances, may isolate the paramagnetic + diamagnetic anisotropy contribution and thus the orientation distribution of the matrix minerals (Borradaile et al., 1999. Geol. Soc. Lond., Sp. Publ. 151, 139-145). Limitations include the great sensitivity of the subtraction process to the precision of the definition of the respective (AMS, AMR) tensors, and a requirement that single-domain and superparamagnetic grains are absent. The latter is particularly important for superparamagnetic minerals because iron oxides may be part of the orientation distribution of the main group of remanence-bearing minerals, although they would be excluded from the AMR fabric.
   Low ratios of saturation isothermal remanence to induced susceptibility characterize those rare rocks in which superparamagnetic behavior is a significant contribution
Contributor
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
    U
Entered date
    24. 10. 2007
Import date
    8. 8. 2012