Magnetic susceptibility as parameters of rock weathering

Abstract

Magnetic susceptibility is a magnetic vulnerability that is often measured in rocks for various purposes. In this study, magnetic susceptibility was applied to distinguish weathering in rocks in different environments i.e., beaches and mountains. The rocks used are igneous rocks originating from Sikambe mount and rocks on the Prigi Coast in Trenggalek Regency. The samples were taken in three categories, i.e., are Fresh, semi weathered, and perfectly weathered rocks. All the rock was crushed to form like gravel, then tested magnetic susceptibility (?lf and ?hf). It is shown that the magnetic susceptibility value of the mount Sikambe area in fresh rocks is higher than that of perfectly weathered rocks, while in the coastal area, Prigi has the magnetic susceptibility value of weathered rocks is greater than fresh rocks. The values of ?lf and ?hf can be calculated the value of frequency-dependent susceptibility (?fd). The average value of ?fd in Sikambe mount is indicating that magnetic mineral grains are in the range of multi-domains (MD), and on the coast of Prigi is indicating that magnetic mineral grains are in the range of pseudo-single domains (PSD). In this case, ?fd, can be useful to knowing the level of rock weathering.