Reports: B8 45737-B8: Detailed Provenance Analysis of the Hornbrook Formation, Oregon and California: Testing Paleogeographic Models of the Cretaceous Cordillera in the Western United States

Kathleen DeGraaff Surpless, Trinity University

During this third and final year of my ACS-PRF Grant, I focused research on geochemical analysis of the Ochoco basin, Hornbrook Formation, and Great Valley Group, three now-separated systems that may have been connected during Cretaceous time. Previous results from year 2 of this grant suggest a combined Hornbrook-Ochoco basin during the Late Cretaceous, and I have collected bulk-rock neodymium isotopic data from both basins, as well as beginning hafnium isotopic analysis of detrital zircon to corroborate these early results. I presented the preliminary results from these studies at the Annual GSA conference in fall 2009. Much of my current work is now supported through an NSF CAREER Grant, which directly resulted from the research I was able to complete in these regions with ACS-PRF funding. My continuing research in the region will focus on substantiating possible trends in geochemical data and strengthening correlation between basins to better guide paleogeographic reconstructions.

The budget for this third year of the grant was restricted to partial PI summer salary, minimal funding for additional analyses, and meeting travel.  During this third year of the project, I completed field work with two Trinity undergraduate students in the northern Great Valley Group of California to sample mudstone for geochemical analysis, as well as the Lower Cretaceous plutons of the northern Sierra Nevada Mountains and the Klamath Mountains to collect samples for zircon hafnium analysis.  My students traveled to the University of Wisconsin – Eau Claire to complete sample preparation and begin XRF major- and trace-element analysis at the UWEC Materials Science Center. Finally, neodymium isotopic analysis of sixteen Ochoco basin samples was completed at Dr. Jeff Vervoort’s Lab at Washington State University. Thus, despite the limited third year budget, this PRF Grant has partially supported the research of two undergraduate students (one male, one female) during spring and summer 2010, as these students began their Senior Honors and Directed Studies research that they will continue this academic year. The ACS-PRF grant paid for some of the Neodymium analytical costs, student travel to and in the field, and my travel to the Annual GSA meeting in October 2009.

All of my research students indicated that their research experiences have confirmed and intensified their interest in pursuing an advanced degree and meaningful employment in the geosciences. Of the four students whose undergraduate research was fully supported by this grant, three are working towards or have completed their Masters degrees in geosciences, and the fourth is taking a year to work in Alaska before continuing with graduate studies. My two current research students, who are only partially supported by this grant, both intend to pursue graduate study. The impact of this research on my own career has also been substantial. My research results raise important new questions about paleogeography and Cordilleran tectonics, and will guide my future research in these areas. Results to date formed the basis of an NSF CAREER grant that will support my continuing research in these areas through 2014.

Moving Mountains; Dr. Surpless
Desert Sea Fossils; Dr. Olszewski
Lighting Up Metals; Dr. Assefa
Ecological Polymers; Dr. Miller