Figure 2 |
Figure 3 |
[39] Comparing R_{t} and R_{c}, it is easy to show that, with increasing H_{c max}, the parameter R_{c} reaches an ultimate value at greater values of B than the parameter R_{t} does. This is due to the fact that the chemical and thermoremanent magnetizations are mainly due to, respectively, low- and high- coercivity grains. Note also that, in the experimentally observed range of interaction fields ( B 3-30 Oe) [Ivanov et al., 1981; Ivanov and Sholpo, 1982], the maximum value of R_{c} is R_{c} 1, whereas R_{t} depends on coercivity.
[40] Knowing the response of each particle to an external effect (variations in H_{c} and I_{s} and the corresponding displacements of representative points in a diagram), we can easily calculate all of the aforementioned types of remanent magnetization and establish the relations between them.
[41] The function g(|H|) can also be applied for the estimation of detrital magnetization in a system of large particles whose orientation is modified by a magnetic interaction field rather than temperature. This estimate is directly related to the so-called cluster model of depositional magnetization developed in [Shashkanov et al., 1989, 2003
].[42] Using the distribution density given by (4), one can show [Belokon and Nefedev, 2001] that, before the decrease in the tilt angle of a certain portion P of elongated or flattened particles, the detrital magnetization is given by the formula
(26) |
where
(27) |
(28) |
Here (p2- _{0}) is the inclination of I_{r0} and _{0}-_{0} is its error.
[43] In conclusion, we can note the following.
[44] (1) Knowledge of values of R_{t} and R_{c} is insufficient for the identification of thermoremanent and chemical magnetizations in an ensemble of single-domain particles. This identification requires additional information on the coercivity and the intensity of magnetostatic grain interaction that can be obtained from laboratory experiments.
[45] (2) Spontaneous magnetization can change with time due to diffusion processes [Afremov and Belokon, 1972]. This can lead to stabilization of the vector I_{s} and a rise in the magnetic moment of the system (diffusion-induced viscous magnetization).
[46] (3) The formation of chemical magnetization can be interpreted in terms of a mechanism [Belokon et al., 1995] that is an analogue of the thermoremanent magnetization formation mechanism and differs from the crystallization mechanism proposed by Haig [1962].
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