Dear colleagues, With the Goldschmidt 2026 abstract deadline fast approaching which is today (*26 February 2026*), we warmly invite you to submit a contribution to our session: *Session 12h – Seawater Chemistry Through Time: Reconstructions, Mechanisms, and Feedbacks* The session will take place in *Montreal, Canada (12–17 July 2026)* under the theme: *Oceans and Atmosphere: Chemical and Physical Evolution and Modern Processes.* This session focuses on reconstructing and understanding long-term variations in seawater chemistry and the mechanisms and feedbacks that link ocean composition to processes operating across Earth’s spheres. We welcome work that address the evolution and controls of seawater chemistry in the geological record across various timescales through the development and application of marine geochemical proxies and archives (e.g., Li, Sr, Mg, Ca, SO4, Cl, B, C, P, REEs; redox and pH indicators, etc.), as well as studies employing experimental simulations, data integration, numerical modeling, and big data analysis. Our goal is to foster a comprehensive understanding of secular variations in seawater chemistry and links to key geological processes across Earth's spheres, biogeochemical cycling, and climate change. Our *keynote speaker* will be *Gaojun Li (*Institute of Mountain Hazards and Environment, Chinese Academy of Science Nanjing University). *Session conveners:* Mebrahtu F. Weldeghebriel (Princeton University) Pan Zhang (Northwest University) Kang-Jun Huang (Northwest University) Weiqiang Li (Nanjing University) Tim K. Lowenstein (Binghamton University) *Submission link:* Session 12h <https://conf.goldschmidt.info/goldschmidt/2026/cfp.cgi> Best Regards, Mebrahtu (on behalf of the conveners) ------------ Mebrahtu F. Weldeghebriel, Ph.D. Postdoctoral Research Fellow Department of Geosciences C461 Briger Hall, Princeton University Princeton, NJ 08544