L. Maulida, S. Zulaikah, F.A. Zahroh, R. Pujiastuti, E.Y. Agustin, A. Juliansyah
The aim of this study was to determine the magnetic properties of weathered and unweathered rocks of basalt and basaltic andesite by measuring magnetic susceptibility and analysis of magnetic domain distribution. The identification of magnetic rock properties by magnetic susceptibility has been done on rock weathering of rip rap in Lahor Dam, Malang regency. Samples were tested using Bartington Magnetic Susceptibility Meter (MS2B) to determine the value of magnetic susceptibility. The result of susceptibility test shows that low-frequency susceptibility (?lf) of the outer part of the potentially weathered rock has values ranged from (314-2,744) × 10-8m3kg-1 for basalt with average 1,470.38 × 10-8m3kg-1, and the inner part (296-2,681) × 10-8m3kg-1, with average 828.85 × 10-8m3kg-1. The average of dependent frequency susceptibility (?fd) for this rock is about 0.767%. Meanwhile for the outer part of basaltic andesite has low-frequency susceptibility (?lf) ranged from (529-3,974) × 10-8m3kg-1, with average 2,241.23 × 10-8m3kg-1, and the inner part ranged from (540-3,754) × 10-8m3kg-1, with average 2,336.11 × 10-8m3kg-1. The average of dependent frequency susceptibility (?fd) for this rock is about 1.018%. Thus, it can be concluded that the magnetic susceptibility of the outer part of the rock is higher than that of the inner part. There are no differences in magnetic domain distribution between the inner and outer parts of rock during the weathering process, and all the samples have a tendency to multi-domain magnetic grains (MD). © 2020 Author(s).
Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang, Jl. Semarang No. 5, Malang, 65145, Indonesia; Advance Material and Mineral Laboratory, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang, Jl. Semarang No. 5, Malang, 65145, Indonesia
