Mineralogy and Provenance of Iron Sand Deposits from Cipatujah and Cikalong, Tasikmalaya, West Java, Indonesia

Abstract

Provenance, paleoweathering, and tectonic environment were studied on the iron sand samples taken from Cipatujah and Cikalong areas in Tasikmalaya, West Java, Indonesia using their mineralogical and geochemical data. These data were obtained from mineralogy grain analysis, X-ray fluorescence, dan ICP MS. From this study, iron sand deposits in both areas vary in grain sizes from very coarse to fine sand. Various minerals, such as magnetite, ilmenite, hematite, pyroxene, amphibole, garnet, quartz, ankerite, plagioclase, and zircon were identified. In addition, rock fragments, fossils, and clay are also found. In term of grain size, the placer deposit is geochemically classified as Fe shale (clay-silt grain size). The provenance shows that the basic rocks act as the source rock based on REE values, heavy mineral assemblage, and elemental ratios. Based on the provenance characteristics, regional geological framework, and catchment area pattern, the Jampang Formation and Young Formation of Mount Cikuray are the most possible sources of iron sand. The chemical index of alteration calculated from major oxide values indicates that the source area had intense chemical weathering. Heavy minerals contained in iron sand deposits reveal a low maturity based on compositional variability (16.58–36.55). Both iron sand deposits from Cipatujah and Cikalong originated in a continental arc setting, which coincides with the current tectonic setting of western Java.