Partial anhysteretic remanence and its anisotropy: Applications and grainsize‐dependence

Geophysical Research Letters - Tập 15 Số 5 - Trang 440-443 - 1988
Mike Jackson1, William Gruber1, Jim Marvin1, Subir K. Banerjee1
1Department of Geology and Geophysics, University of Minnesota

Tóm tắt

The distribution of remanence coercivities in a rock sample can be obtained by differentiating alternating field (AF) demagnetization curves of anhysteretic remanent magnetization (ARM); however, significant errors can be introduced by grain interactions and by the noise inherent in differentiation. We have found that 1) this error can be significantly reduced by measuring partial ARM's (pARM's) and 2) pARM patterns show a strong empirical correlation with grain‐size. pARM's are imparted by exposing a sample to a small direct magnetic field in the presence of a large, decreasing AF; the direct field is switched on over a specified range of AF's, thus magnetizing a fraction of the magnetite grains in the corresponding coercivity range. We have further found in both synthetic and natural sediments that measurement of the anisotropy of pARM enables us to detect the preferred orientations of distinct subpopulations of magnetite particles, related to the size and shape of the grains.

Từ khóa


Tài liệu tham khảo

10.1029/JZ070i018p04663

10.1111/j.1365-246X.1981.tb02676.x

10.1029/JB087iB08p07126

10.1111/j.1365-246X.1972.tb02346.x

10.1016/0031-9201(81)90093-5

10.1016/0012-821X(86)90068-3

10.1080/14786436108238365

Girdler R. W., 1961, The measurement and computation of anisotropy of magnetic susceptibility in rocks, Geophys. J. R. Astr. Soc., 5, 34, 10.1111/j.1365-246X.1961.tb00427.x

10.1063/1.1660627

10.1016/0012-821X(82)90142-X

10.1029/JZ071i002p00561

10.1111/j.1365-246X.1980.tb02601.x

Leach E. K., 1981, The archeological geology of the Archaic Morrisroe site, Tennessee River, Kentucky

10.1016/0012-821X(76)90042-X

Marvin J., 1986, Parm: A rock magnetic method for recognition of mixed grainsize magnetic materials [abstr.], EOS, 67, 927

10.1029/GL012i006p00333

10.1111/j.1365-246X.1986.tb04365.x

10.1111/j.1365-246X.1961.tb00431.x

10.1007/BF00875588

10.1111/j.1365-246X.1980.tb02614.x

10.1016/0031-9201(87)90174-9

Thông tin
Thông tin xuất bản

Geophysical Research Letters

Tập 15 Số 5

440-443

Thông tin tác giả