Collaborative Research: Linking crustal and surface processes to their impacts on the biosphere, western Anatolia

Idaho State University, Pocatello ID

Investigators

Abstract

Anatolia is an important epicenter for documenting the timing of major faunal dispersion on Earth following establishment of the “Gomphotherium landbridge” that occurred millions of years ago. Faunal migration included emigration of hominoids from Africa to Eurasia. However, there is a delay of at least 2 Million Years (Myr) and possibly up to 6 Myr between establishment of the landbridge and dispersal of hominoids to central Anatolia. High elevations in western Anatolia may explain this delay in faunal dispersion, as mountain ranges, like the oceanic passages that precede landbridges, pose formidable barriers to faunal dispersion. In this study, scientists will combine datasets of Earth's crust (structural analysis, thermochronology, crustal thickness) with surface expression (basin evolution and surface elevation) to document how the formation of mountains may have potentially impacted faunal migration. This project endeavors to establish and strengthen international partnerships among four institutions in the USA, Canada, and Türkiye where field work will be conducted. The project will collectively contribute to the academic growth and training of several graduate and undergraduate students including through engagement in workshops and joint field trips that combine expertise from each institution. Results from this multidisciplinary research will cover a wide range of spatial and temporal scales necessary to link crustal and basin processes to their surficial, environmental, and biological impacts. Western Anatolia is considered to have been at low elevations since the Eocene. However, previous research places the pre-extensional crustal thickness at 55–60 km predicting elevations of 3.5–4.1 km (if in isostatic equilibrium). This has direct implications for the timing and location of faunal migration corridors. Tectonic reconstruction of this region is hampered by multiple factors: (1) basins are characterized by widely dispersed and incomplete stratigraphic sections and lack detailed chronostratigraphic control, (2) existing structural reconstructions are in conflict on the geometry of Oligocene–early Miocene extension, (3) paleo-crustal thickness estimates are limited, and (4) no proxy-based paleoelevation estimates exist. This project will investigate the Oligocene–Pleistocene evolution of sedimentary basins, extensional structures, crustal thickness, and paleoelevation in this highly extended region. Refined age control and stratigraphic correlations, as well as new crustal thickness estimates from whole-rock and detrital zircon geochemistry and proxy-based paleoaltimetry, will provide context to test models explaining single- or doubly-vergent extension using thermochronometric analysis and thermokinematic modeling. Collectively, this project will assess general models of crustal evolution during subduction to determine whether Airy isostasy was the primary control on elevation or if alternative models such as Pratt isostasy or dynamic, mantle support are permissible. 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.