PhD students:


Chris Conwell: Began Fall 2017. Sr and Nd isotope stratigraphy in the Ordovician of Nevada and Baltoscandia; weathering and climate


Datu Adiatma: Began Summer 2019. Lithium isotope stratigraphy in North American Ordovician, and radiogenic isotope weathering proxies

Datu Adiatma

Teresa Avila: Began Spring 2020.  Devonian conodont-apatite based Sr and Nd isotopes in European sections integrated with d18O paleotemperature

Teresa Avila


PhD graduates:

Cole T. Edwards, PhD, 2014, Assistant Professor at Appalachian State University “Carbon, sulfur, and strontium isotope stratigraphy of the Early-Middle Ordovician: implications for atmospheric oxygen and the Great Ordovician Biodiversification Event”

Alexa R.C. Sedlacek, PhD, 2013, Associate Professor at the University of Northern Iowa.  “Strontium Isotope Stratigraphy of the Permian-Triassic Boundary and Early Triassic”

Dr. Alexa R. C. Sedlacek

Kate E. Tierney-Cramer, PhD, 2010, Lecturer and Adjunct Professor at the University of Iowa“Permian climate, sea level and carbon cycling: An integrated bio-, sequence and chemostratigraphic study”

Image result for kate tierney iowa

Bradley D. Cramer, PhD, 2009, Associate Professor at the University of Iowa, “High-resolution Silurian astrochronology using sequence stratigraphy, biostratigraphy, and stable isotope studies”

Image result for kate tierney iowa

Seth A. Young, PhD, 2008, Associate Professor at Florida State University. “An integrated chemo-, bio-, and sequence stratigraphic investigation of the Late Ordovician Greenhouse-Icehouse transition”

Dr. Young Photo


MS students:




2003      Seth A. Young “A Late Middle Ordovician carbon isotope excursion in central and eastern North America: sequence stratigraphic, biostratigraphic, and K-bentonite event stratigraphic relations”

2004      Bradley D. Cramer “Glaciation, CO2, and organic carbon burial during the early Silurian: carbon isotope stratigraphy from the mid-continent of North America”

2004      Nathaneal Barta “Investigation of the correlation of the lower Chatfieldian (upper Middle Ordovician) strata of New York, Ontario and Pennsylvania using the Guttenberg carbon isotope excursion”

2004      Matthew J. Williams “Carbon isotope chemostratigraphy and ocean chemistry analysis within the Helderberg group: Silurian-Devonian, Appalachian Basin”

2005      Kate E. Tierney “Carbon isotopic response to oceanographic changes at Milankovitch scale periodicity in Pennsylvanian aged limestones from Arrow Canyon, Nevada”

2006      Lisa Fay, “Carbon cycling in the Devonian Onondaga Formation of New York: Paleogeographic implications”

2008      Jeremy Gouldey, “Strontium and carbon isotope stratigraphy of the Silurian: Implications for tectonics and weathering”

2014      Nicholas Umholtz: “Ordovician C isotope stratigraphy and the Knox Unconformity at East River Mountain, West Virginia”

2018     Datu Adiatma: “Did early land plants produce a step-change in atmospheric oxygen centered on the Late Ordovician Sandbian Age ~458 Ma?”

2019     Teresa Avila: Seafloor weathering and the Middle to Late Ordovician seawater 87Sr/86Sr inflection point preserved in conodont apatite