Current Interests

I am involved in cooperative interdisciplinary studies with colleagues at the University of Ankara (Turkey) and Mashhad University (Iran) concerning the geological evaluation and hydrocarbon potentials of basins in central Turkey and in northeastern Iran. I also maintain interests in siliciclastic depositional systems recorded in Pennsylvanian strata in the Midcontinent, Middle-Upper Jurassic strata of the Western Interior of North America, and Cretaceous strata throughout the Western Hemisphere. A unifying thread in these projects is reservoir characterization of siliciclastic sandstones deposited in a variety of tectonic and depositional settings. My long-term interest has been relating tectonic and depositional processes to sandstone aquifer and petroleum reservoir characteristics.

During the past few years, my research efforts were centered on the stratigraphy, paleogeography and paleoclimatology of the "mid" Cretaceous (Albian-Turonian) of the Western Interior of North America. I had been working with Dr. Luis Gonzalez (now at the University of Kansas), Dr. Greg Ludvigson (Iowa Geological Survey Bureau), and Dr. Brian Witzke Ludvigson (Iowa Geological Survey Bureau). Our project objectives were to investigate paleoclimatic and paleogeographic conditions during this greenhouse period using an integrated approach combining biostratigraphy, sedimentology, sequence stratigraphy, and stable isotope geochemistry. Stratigraphic analyses were conducted on the outcrop belt that extends from central Kansas to Manitoba and Saskatchewan, Canada.

With support from the National Science Foundation, the American Chemical Society-Petroleum Research Fund, the Iowa Science Foundation, the Center for Global and Regional Research (University of Iowa), and the National Geographic Society, we collected and interpreting the stable isotopic paleoclimatic record of meteoric carbonates from Albian through Turonian strata along the eastern margin of the Western Interior Basin along a paleolatitudinal transect between Kansas and Manitoba. Our research has shown that meteoric phreatic cements along the cratonic margin of the basin yield 18O values that are characteristic of coastal lowland environments, and can serve as reasonable proxies for paleoclimates. Data obtained during preliminary studies show a secular decrease in 18O values between Late Albian and Middle Cenomanian meteoric phreatic sphaerosiderite, corresponding to an expected long-term cooling that would produce lighter 18O of atmospheric precipitation. The results from this project are presented in a series of published manuscripts, abstracts, Ph.D. dissertations, M.S. and senior undergraduate theses.