[S-IT17] Mass and energy transport in the crust and mantle: from properties to processes

[SIT17-P02] Serpentinization and carbonation of pre-Tertiary ultramafic rocks in Eastern Luzon Metamorphic Belt

*Juan Miguel Ramirez Guotana¹、Celine D Tatco¹、Jenielyn Tuando Padrones²、Decibel Villarisco Faustino-Eslava¹ (1.UPLB-SESAM、2.UPLB)

キーワード：carbonation, ophiolite, Philippines, ultramafic

The mantle section of ophiolitic sequences typically undergoes fluid-rock interaction when exposed at crustal depth. Mg silicates and other ultramafic mineral phases interact with fluids from varying sources. Carbonation of ultramafic rocks leads to mineral replacement during the reaction of silicates with CO₂-rich fluids. Fluid-rock interaction in ultramafic rocks has also been a focus in carbon capture and storage strategies through mineral carbonation. Secondary carbonates are present in the serpentinized peridotites of the ophiolite in Camarines Norte, Philippines, which forms part of the Eastern Luzon Metamorphic Belt. The least altered sections of the ultramafic bodies are composed mainly of harzburgites and dunites. Samples from exposures distant from and adjacent to the granodiorite intrusive body reveal varying degrees of serpentinization and metasomatic assemblage.
This study correlates degrees of serpentinization, carbonation, and metasomatic effects on ultramafic rocks with geochemical and physical characteristics (density and magnetic susceptibility). The Philippines preserves extensive belts of ophiolites of varying ages and preserved lithologic assemblages. This correlation highlights how chemical and physical properties of ultramafic rocks can be used in prospecting ultramafic bodies with high carbonation potential.