Characteristics, origin, and application potential of Diatomite at Lam Ha ward, Lam Dong province

Abstract

Diatomite in the Lam Ha area, Lam Dong province, primarily belongs to the upper part of the Di Linh Formation (Miocene – Lower Pliocene), where sedimentation was influenced by active tectonics along the Song Ba Fault and intermittent basaltic volcanism. The grain size distribution of diatomite sediments ranges from very fine sand to clay, with a sorting range from poorly sorted to moderately sorted. The skewness of the grain size is predominantly fine - skewed, and the kurtosis varies from platykurtic to highly leptokurtic. The CM pattern, based on the C (1%mm) and M (50%mm) percentiles, indicates sediment deposition in this area is associated with a continental lacustrine or distal floodplain environment with the main channel, characterized by slow - flowing and fluctuating water turbulence. Scanning electron microscopy (SEM) analysis revealed the dominance of Aulacoseira granulata species in the diatomite sediments, with particle sizes ranging from 10μm to 30μm. This indicates a similarity in age and paleoenvironmental conditions with the diatomite - bearing sediment in Kostenets, southern Bulgaria. X - ray diffraction (XRD) analysis identified mineral components in the diatomite, including quartz, cristobalite, smectite/montmorillonite, illite and kaolinite, reflecting the combined effects of volcanic input and weathering. Geochemical results show approximately 57.42% SiO₂, 3.96% Fe₂O₃, and various alkali oxides, while the density of diatomite ranges from 1.2 to 2.4 g/cm³. These findings confirm the need for post - depositional processing to meet industrial quality standards. Despite its moderate silica content, targeted acid leaching and thermal treatment can raise SiO₂ purity above 90%, making the processed material suitable for beer filtration and other industrial applications. Beyond economic utility, the abundance of Aulacoseira granulata offers insights into Neogene – Pliocene paleoenvironmental conditions. Overall, the Dan Phuong diatomite deposit not only holds promise for local resource development but also contributes to understanding the tectonic and environmental evolution of the region.