About the Faculty

Dr. Gabriel Theophilus V. Valera, D.Sc. is an igneous and metamorphic petrologist and geochemist whose work focuses on understanding the evolution of collision zones and subduction-related systems through integrated field geology, petrography, and geochemical analysis. His research interests include: field geology in relation to petrology; igneous and metamorphic rocks linked to ancient and active collision zones; and pressure–temperature–deformation–time (P–T–D–t) paths of metamorphic rocks.  

Education

• Kyoto University, Kyoto, Japan — D.Sc. Earth and Planetary Sciences, 2022  
• University of the Philippines Diliman, Quezon City — M.Sc. Geology, 2018  
• University of the Philippines Diliman, Quezon City — B.S. Geology, 2014

Field of Specialization

Igneous and Metamorphic Petrology and Geochemistry 

Publications (as of Feb 2026)

Yang, Y., Huang, X-L., Payot, B., Liu, H-Q., Jiang, Y-D., Wang, Y., Dimalanta, C.B., Ou, X-F., Valera, G.T.V., Yang, F., Yumul Jr., G.P., Xu, Y-G., Tang, X-H. (2026). Ba isotope unmasks recycling processes of fluid mobile elements in subduction zones. Geochimica et Cosmochimica Acta. In Press. https://doi.org/10.1016/j.gca.2026.01.038  

Valera, G.T.V., Payot, B.D., Kawakami, T., Sakata, S., Niki, S., Hirata, T. (2026). From spreading to subduction: Timelines of induced subduction zones recorded in the Central Palawan Ophiolite. Lithos, 522–523, 108346.  

Soberano, N.P., Payot, B.D., Valera, G.T.V., Olfindo, V.S.O. (2024). Metasomatic enrichment of the sub-arc mantle: Evidence from the petrography and geochemistry of the xenolith-bearing andesites from Dinem Island, Batanes, Philippines. Journal of Asian Earth Sciences, 262, 105999.  

Austria, R.S., Armada, L.T., Parcutela, N.E., Dimalanta, C.B., Payot, B.D., Valera, G.T.V., Reyes, E.M.L., Yumul Jr., G.P. (2023). The Macolod Corridor (Philippines) – A passive rift compensated by ponded magmas? Tectonophysics, 862, 229965.  

Pasco, J.A., Payot, B.D., Valera, G.T.V., Dycoco, J.M.A., Labis, F.A.C., Tamura, A., Morishita, T. (2023). From rifting to emplacement: Variable mantle melting preserved in the central Palawan Ophiolite peridotites, Philippines. International Geology Reviews. https://doi.org/10.1080/00206814.2023.2191347  

Parcutela, N.E., Austria, R.S., Dimalanta, C.B., Valera, G.T.V., Gabo-Ratio, J.A.S., Payot, B.D., Armada, L.T., Sangalang, K.J.F., Yumul Jr., G.P. (2023). Enhanced arc magmatic productivity of the Western Pacific island arcs deduced from gravity-derived arc crustal growth rates. Frontiers in Earth Science, 11:1107833.  

Valera, G.T.V., Kawakami, T., Payot, B.D. (2022). Mixing, fluid infiltration, leaching, and deformation (MILD) processes on the slab–mantle wedge interface at high T and P conditions: Records from the Dalrymple Amphibolite, Philippines. Chemical Geology, 120941. https://doi.org/10.1016/j.chemgeo.2022.120941  

Valera, G.T.V., Kawakami, T., Payot, B.D. (2022). The slab–mantle wedge interface of an incipient subduction zone: Insights from the P–T–D evolution and petrological characteristics of the Dalrymple Amphibolite, Palawan Ophiolite, Philippines. Journal of Metamorphic Geology, 40, 717–749.  

Dycoco, J.M.A.D., Payot, B.D., Valera, G.T.V., Labis, F.A.C., Pasco, J.A., Perez, A.D.C., Tani, K. (2021).Juxtaposition of Cenozoic and Mesozoic ophiolites in Palawan island, Philippines: New insights on the evolution of the Proto–South China Sea. Tectonophysics, 819, 1–19.  

Midea, W.P., Hattori, K., Valera, G.T.V. (2021). Igneous rocks related to porphyry Cu–Au mineralization at the Dizon mine, Philippines. Resource Geology, 71, 392–408.  

Labis, F.A.C., Payot, B.D., Valera, G.T.V., Pasco, J.A., Dycoco, J.M.A., Tamura, A., Morishita, T., Arai, S. (2020).Melt–rock interaction in the subarc mantle: records from the plagioclase peridotites of the southern Palawan Ophiolite, Philippines. International Geology Review, 63, 1067–1089.  

Olfindo, V.S.O., Payot, B.D., Valera, G.T.V., Arai, S. (2020). Petrogenesis of heterogeneous mantle peridotites with Ni-rich olivine from the Pujada Ophiolite, Philippines. Journal of Asian Earth Sciences: X, 4, 1–16.  

Valera, G.T.V., Payot, B.D., Arai, S., Takeuchi, M., Ishimaru, S., Tamura, A. (2019). Petrologic nature of the active subarc crust–mantle boundary: Mixed magmatic–metasomatic processes recorded in xenoliths from Sabtang island, Luzon arc. Journal of Volcanology and Geothermal Research, 34, 80–99.  

Pasco, J.A., Dycoco, J.M.A., Valera, G.T.V., Payot, B.D., Pillejera, J.D.B., Uy, F.A.A.E., Armada, L.T., Dimalanta, C.B. (2019). Petrogenesis of ultramafic–mafic clasts in the Dos Hermanos Mélange, Ilocos Norte: Insights to the evolution of western Luzon, Philippines. Journal of Asian Earth Sciences, 184, 104004. https://doi.org/10.1016/j.jseaes.2019.104004  

Olfindo, V.S.V., Payot, B.D., Valera, G.T.V., Gadot Jr., E.G., Villaplaza, B.R., Tani, K., Dimalanta, C.B., Yumul Jr., G.P. (2019). Petrographic and geochemical characterization of the crustal section of the Pujada Ophiolite, southeastern Mindanao, Philippines: Insights to the tectonic evolution of the northern Molucca Sea Collision Complex. Journal of Asian Earth Sciences, 184, 103994. https://doi.org/10.1016/j.jseaes.2019.103994  

Awards

• DOST Balik Scientist (Sept 2023 – present), DOST–PCIEERD  
• UP Balik PhD Grantee (Sept 2022 – present), UP OVPAA  
• Academic Scholar (Apr 2019 – Mar 2022), MEXT  
• Outstanding Student Poster Presentation Award, 14th NIGS Research Symposium (2017)  
• Outstanding Student Paper Presentation Award (Oral Presentation), 13th NIGS Research Symposium (2016)  
• Academic Scholar (Nov 2012 – Apr 2014), Gold Fields Philippines Corporation