2025-26 Frederick L. Hovde Distinguished Lecturer

Doug Schmitt

Professor and Stephen and Karen Brand Endowed Chair of Unconventional Energy

A Story About the Kentland Impact Crater and What It Taught Me About Indiana Geology

Abstract

Jay Melosh informed me when I arrived at Purdue in 2018 that we had our own nearby impact structure, and shortly thereafter the Department went there on a field trip! This excited me greatly as I had been lucky to work on a number of other impact structures (Bowsumtwi, Sudbury, Chicxulub, and Bow City); and having another one to 'play' with so close to home was exciting. The superb exposures within the Newton County Quarry of a central peak of a complex crater leave no doubt that Kentland is an impact structure. But despite that fact that its anomalous geology has been studied for nearly 150 years, no one really knew how large the structure is due to the thick glacial sediment cover in the area. With this goal in mind, MSc Brian Robitaile organized modern seismic reflection profile using the Purdue seismic vibe leading south from the central peak to 'hunt' for a complex crater's rim faults - these would unambiguously define its radius. Luckily, we managed to obtain a sufficiently long profile (before the vibrator truck broke down!) and we caught the faults. The interpretation of the seismic data required that we learn much more about the subsurface of Indiana, a problem exacerbated by the lack of borehole data. The interpretation of the profile even required us to go back to some of the earliest work in the 1890's where geologists noted the existence of coals far from where they should have been, and to digitize the excellent gravity survey of Tudor from the late 1970's. You must come to the talk to find out how large it is and for the details of why it is an anomalous impact structure. Just as importantly, however, Kentland introduced me to regional geology; and this information has been key in helping me convey to stakeholders the scientific issues associated with the geological sequestration of greenhouse gases. We have made good connections with the Indiana Geological and Water Survey and are collaborating with them on interpreting old core materials through X-ray computed tomography and laboratory measurements. There remains a lot to do with projects particularly for undergraduate students.

Bio 

Douglas R. Schmitt is currently the Stephen and Karen Brand Professor of Unconventional Energy in the Department of Earth, Atmospheric, and Planetary Sciences at Purdue University. He arrived at Purdue in 2018 after 29 years at the University of Alberta, Edmonton. Prior to that he carried out Postdoctoral Research on crustal stress determination and rock physics at Stanford and completed his PhD at Caltech in experimental high pressure shock waves and holographic interferometry. He is a Geophysicist whose team carries out a mix of field and laboratory based investigations with a focus on the physics and mechanics of rock. He has been involved with projects related to geothermal and hydrocarbon energy extraction, base metal and potash mining, crustal stress determination and induced seismicity, and greenhouse gas sequestration. He has been involved and continues active with more than 15 scientific drilling investigations globally on nearly all the continents. Notable past projects include the Alpine Fault (New Zealand), the Chicxulub Impact Structure (Mexico), and the ANDRILL project (Antarctica). Currently, he is on the science teams of the REEDRILL project to map a carbonatite deposit in Malawai and a deep drilling project into a zone of seismicity near Koyna, India. He is serving as the Deputy Editor-In-Chief of the Journal of Geophysical Research - Solid Earth and a member of the Independent Advisory Group of the Canadian Nuclear Safety Commission with oversight duties on the construction of Canada's nuclear waste repository in a granitic pluton.