CAREER: Dynamic rebound basins: Surface fingerprints of a dynamic lower lithosphere

Dense, gravitationally unstable parts of Earth’s outer shell can sink into the deeper Earth. This hidden process cannot be observed directly. When this happens, the land above them may subside, and later rebound. The basins that form as a result may then be preserved in the rock record. Unlike many sedimentary basins that form when Earth’s crust is pulled apart or pushed together, basins that form from upward or downward motion may look distinct. However, scientists currently lack clear criteria for distinguishing these basins from more familiar tectonic basins. This project will study a potential example in central Tibet. It will be compared to other nearby basins and other proposed examples globally. These strata could help us understand how deep Earth processes shape surface landscapes. A integrated plan will train the next generation of field geologists across educational levels and institutions. Immersive virtual reality modules will teach spatial reasoning, observational uncertainty, and the process of scientific interpretation will bridge research and teaching, bringing remote research localities into classrooms. This project will test and refine a structural-stratigraphic model for dynamic rebound basins by evaluating competing hypotheses for the origin of several Eocene basins in central Tibet, including 1) localized dynamic subsidence and rebound caused by lithospheric removal, 2) flexural loading from thrust systems, or 3) a hybrid mechanism. The study will integrate structural and sedimentologic fieldwork, geochronology and thermochronology, and coupled geodynamic-landscape evolution-stratigraphic modeling. These approaches will document basin geometry, deformation timing, subsidence history, proximal magmatism, uplift and exhumation, and sediment routing. The project will develop testable criteria for identifying sedimentary basins formed by relatively localized, small-scale dynamic topography and clarify the tectonic evolution of the central Tibetan Plateau. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria. NSF Award ID: 2543033 | Program: 01003031DB NSF RESEARCH & RELATED ACTIVIT,01002930DB NSF RESEARCH & RELATED ACTIVIT,01002627DB NSF RESEARCH & RELATED ACTIVIT | Principal Investigator: John He | Institution: University of California-Los Angeles, LOS ANGELES, CA | Award Amount: $326,896 View on NSF Award Search: https://www.nsf.gov/awardsearch/show-award/?AWD_ID=2543033 View on Research.gov: https://www.research.gov/awardapi-service/v1/awards/2543033.html