Weathered ultrabasic rocks in the Lapaopao, an implication for development of nickel laterite

Abstract

The research conducted in the Lapaopao area focuses on analyzing the process of serpentinization in ultramafic rocks and its impact on the formation of nickel laterite. Ultrabasic rocks containing olivine and pyroxene minerals undergo hydrothermal metamorphism, resulting in the formation of serpentine minerals. The research purposed to understand effect of serpentinization process to development of nickel laterite. Various samples were taken on location to see the correlation in both the Lapaopao sub-block and Babarina sub-block. There are two (2) types of samples were taken, including fresh rock (bedrock samples) and laterite samples (limonite and saprolite material). All samples were analyzed using methods such as XRF, thin section, and XRD. Bedrock samples were analyzed using the thin section method, while laterite samples (limonite and saprolite) were analyzed using XRF and X-RD analyzing methods. The serpentinization process in the Babarina sub-block is generally medium to high level, while in the Lapaopao sub-block low to moderate level. The enrichment of nickel (Ni) in the supergene zone is dominantly influenced by Ni’s ability to replace magnesium (Mg) in weathered serpentine minerals.