THERMAL-TECTONIC RECORD OF WILSON CYCLES DOCUMENTED BY DETRITAL RUTILE AND ZIRCON GEOCHRONOLOGY AND GEOCHEMISTRY IN THE PYRENEES, SPAIN

Sedimentary basins provide a deep time archive of tectonic and surface processes that can be leveraged by detrital mineral U-Pb dating and geochemistry to track paleogeography, magmatism, and crustal evolution. Zircon has been shown to record the long term (Ga) record of supercontinent cycles but has a bias toward preserving the record of the generation of felsic crust. Rutile has the potential to complement the detrital zircon record by providing additional constraints on the time and temperature for mafic magmatism, metamorphism, exhumation of middle and lower crustal levels, and amagmatic orogenesis and rifting. Permian to Eocene siliciclastic rocks in the Southern Pyrenees of Spain were sampled and analyzed for detrital zircon U-Pb and detrital rutile U-Pb along with trace and rare earth element (TREE) analysis. Detrital rutile age spectra show peaks at ~100 Ma associated with hyperextension in the Pyrenean realm, 200 Ma associated with the Central Atlantic Magmatic Province, and 330 Ma, 375 Ma, and 400 Ma associated with subduction and closing of the Rheic Ocean. Zr-in-rutile thermometry and Cr–Nb systematics discrimination from rutile provide further insight into the source rocks evolution including metamorphic grades and protoliths. Detrital zircon age spectra have peaks at ~300 Ma, 450 Ma, and 600 Ma and are associated with major orogenic events and felsic magmatism, and Th/U ratios provide information on zircon formation temperatures. Comparison of these independent records show that detrital rutile records rifting, magma-poor orogenesis, and oceanic lithospheric processes while detrital zircon records continental lithospheric processes. Integration of detrital zircon and rutile captures the holistic record of past geological events across multiple Wilson cycles.