What you can do with superb rift basin-fill exposures: Recent lithostratigraphic, paleoclimatic, biostratigraphic, and structural studies of the Española Basin, New Mexico (USA)

Session Chairs:
Daniel Koning, Jeremy Rugenstein Garrett Williamson, Siânin Spaur

Española and its namesake basin, located ~40 km north of Santa Fe, lie at the heart of northern New Mexico, a geographic region dominated by deep-rooted Puebloan and Hispanic culture and beautiful scenery. Additionally, the Española Basin offers the most extensive exposure of the clastic sediment filling the Rio Grande rift, here mapped as the Tesuque and Chamita Formations of the Santa Fe Group. These exposures have also yielded a trove of mammalian fossils, and these fossils and abundant tephra layers provide age control for sed/strat studies. This field trip uses these exposures to summarize recent and on-going sed/strat, paleoclimatic, paleontologic, and structural studies in the Española Basin. At Stops 1 and 2, located east of Española, we will visit exposures illustrating key stratigraphic units (lithosomes) comprising the basin fill. We discuss how the sedimentologic characteristics and spatial distribution of two lithosomes, representing piedmont and basin-floor paleo-environments, are controlled by autogenic and extrinsic drivers, such as paleoclimate and tectonics.  We also show how tephra layers and detailed sampling of carbonates have resulted in a detailed paleoclimate reconstruction using stable isotopes. Stop 3, located northwest of Española, showcases the Ojo Caliente Sandstone eolinite. At Stop 4, we discuss paleoclimatic studies in the Chamita Formation stratotype. Exposures of intra-basinal faults and the Embudo fault system will spur discussion of the tectonic evolution of the Española Basin and the transfer fault linking it with the San Luis Basin to the north, in addition to how this evolution affected Miocene sedimentation.