Dear Colleagues, The abstract submission deadline (15 January 2026, 13:00 CET) for EGU 2026 is approaching quickly. We invite contributions on the behavior of carbon and hydrogen throughout Earth's interior, from deep mantle to shallow crust. We particularly welcome studies employing geochemical, petrological, experimental, computational, and modeling approaches that address: Carbon and hydrogen from mantle to crust: speciation, transport, and resource formation (https://www.egu26.eu/session/57787 <https://www.egu26.eu/pg/GMPV#>) C and H speciation and fractionation in minerals, melts, and fluids under varying redox conditions Carbon and hydrogen budgets and cycling in the bulk silicate Earth The roles of C and H throughout Earth's history Implications for C-H-bearing mineral and energy resource formation Session Details: Convener: Huaiwei Ni Co-conveners: Bin Chen, Guanghui Yuan, Sylvie Demouchy, Zhijun Jin Solicited Speaker: Rajdeep Dasgupta This session provides an excellent forum to present research on volatile cycling, mantle-crust interactions, and the fundamental processes governing planetary evolution and resource formation. We look forward to your contributions and to stimulating discussions at the session. Best regards, Bin Chen On behalf of the convening team ---- Bin Chen, Ph.D. Hawaii Institute of Geophysics and Planetology School of Ocean and Earth Science and Technology University of Hawaii at Manoa 1680 East West Road, POST Bldg, Office 818A Honolulu, Hawaii 96822 Phone: (808) 956-6908 (office) Fax: (808) 956-3188 (shared) E-mail: binchen@hawaii.edu Homepage: https://www.soest.hawaii.edu/HIGP/Faculty/binchen/