Role of single-domain magnetic particles in creation of inverse magnetic fabrics in volcanic rocks: A mathematical model study

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• 作者：František Hrouda ; Josef Ježek
• 关键词：AMS of SD magnetic particles ; inverse magnetic fabric ; volcanic rocks
• 刊名：Studia Geophysica et Geodaetica
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：61
• 期：1
• 页码：145-161
• 全文大小：
• 刊物类别：Earth and Environmental Science
• 刊物主题：Geophysics/Geodesy; Structural Geology; Atmospheric Sciences;
• 出版者：Springer Netherlands
• ISSN：1573-1626
• 卷排序：61

文摘

The role of single-domain (SD) magnetic particles in creation of inverse magnetic fabrics is investigated on simple mathematical models using a realistic estimate for SD intrinsic susceptibility. In contrast to the fraction created by multi-domain (MD) particles, in which the anisotropy of magnetic susceptibility (AMS) is controlled by both the grain AMS and intensity of the preferred orientation of the particles, the AMS of the SD fraction is controlled solely by the intensity of the preferred orientation. The degree of AMS of ensemble of SD grains with a preferred orientation is therefore much higher than that of the same ensemble of MD particles implying the existence of frequent inverse magnetic fabrics. However, the occurrence of inverse magnetic fabrics due to SD particles is more the exception than the rule. Consequently, the amounts of SD particles is probably in general low. Nevertheless, the presence of SD particles in amounts insufficient to create inverse magnetic fabrics may diminish the whole rock AMS substantially. This can be one of the reasons for relatively low AMS in volcanic rocks whose magnetic particles may be really small obeying the conditions for the existence of SD particles.