Geological Characteristics and Preliminary Study to Genesis of Danao Nickel Deposit in Bohol, Philippine

Danao nickel deposit is located near the Western Bicol-Eastern Leyte ophiolite belt. Ore-bearing limonite and saprolite layers above ultramafic rocks consisted with red-brown soil where garnierite ores developed well. Chemical analysis showed that the mineralization source is ultramafic rocks; further analysis and study on the ultramafic rock, climate, geography, and degree of rocks fragmentation suggested the genesis type of deposit is weathering crust-eluvial type. According to the crust uplift, the ultramafic rocks weathered to release Ni²⁺ which was captured by the serpentines when infiltrated to the limonite and saprolite layers with surface water, isomorphied and then released Mg²⁺. Due to the high permeability, Mg²⁺ were enriched near the basement rocks, while Ni²⁺ serpentine was into the limonite and saprolite layers, precipitated down, and concentrated to mineralize.