Fri. May 29, 2026 9:00 AM - 10:30 AM Exhibition Hall Special Setting (8) (Exhibition Hall 7&8, Makuhari Messe)

Chairperson:Wallis Richard Simon(The University of Tokyo), Wu Jonny(University of Arizona), Yamaoka Ken(National Institute of Advanced Industrial Science and Technology), Wang Walter Jordan(University of California, Los Angeles)

Connections between plate motions and geological features (deformation, sedimentary records, metamorphism, and volcanism) are central in tectonics. Periods of non-steady-state e.g., just after subduction starts or when a spreading ridge is being subducted, offer special insight. Understanding these intervals is key to tracing how plate tectonics has shaped Earth from its beginnings through today and into the future. The circum-Pacific region provides an excellent natural laboratory: E. Asia and the W. U.S. have well-documented geological domains arising from long-lived plate convergence, and lack continental collision, simplifying interpretations; and the Pacific Oceanic domain preserves multiple transform faults, magnetic anomalies, and hotspot tracks essential for plate reconstruction. Nevertheless, significant disagreements persist: which oceanic plates bordered Japan during the Cretaceous-Paleogene; the direction and timing of spreading; the identity and behavior of subducted slabs etc. Studies of mantle tomography, geochronology, and petrology are helping resolve such disputes. We invite contributions that address geodynamic models or geological evidence in the circum-Pacific realm. Possible topics are: tomographic imaging of subducted slabs and implications for reconstructing past plate motions; new stratigraphic, sedimentary, structural data linked to subduction geometry, ridge-subduction, etc.; metamorphic and magmatic records from both steady- and non-steady-state tectonic regime; paleomagnetic, hotspot, or magnetic anomaly data that help constrain plate kinematics; and numerical or forward geodynamic models of mantle flow, slab geometry, ridge-trench interaction, or transient tectonic phases. By bringing these together, we aim to clarify how episodic tectonic events (such as ridge subduction or subduction initiation) shape the geology of convergent margins including its thermal structure, and metamorphic and magmatic architecture.