Dr. Duke's research has included work on granites and pegmatites, carbon migration and graphite deposits, geochemistry of metamorphic rocks, and mineral reactions in concrete. He has been Principal Investigator or Project Director on roughly $15 million in grants and contracts. Much this funding is related to NASA Space Grant and NASA EPSCoR activities, but it also includes competitive research and equipment awards from NSF, DOE, NASA, ACS-Petroleum Research Fund, mining companies, South Dakota DOT, the SD Governor's Office of Economic Development, and EROS Data Center.

Recent research focuses on applications of field-based infrared spectroscopy and remote sensing to characterize processes in metamorphic rocks. Field sites for this work include the Black Hills, South Dakota; the Belt Supergroup, western Montana and northern Idaho; Death Valley National Park, California; the Damara Orogenic Belt, Namibia; and the Tavsanli Zone, northwest Turkey. Some of these sites have supporting hyperspectral remote sensing coverage from NASA's AVIRIS spectrometer or HyVista's HyMap system. Relevant SDSM&T equipment includes two field-portable Vis/NIR (350-2500 nm) spectrometers: an Analytical Spectral Devices (ASD), Inc., FieldSpec FR Pro and a new (2014) PANalytical Boulder (formerly ASD) TerraSpec Halo. Spectral processing software includes: ENVI, Unscrambler, and GRAMS/IQ. Additional SDSM&T analytical facilities include: a Zeiss Supra 40 variable-pressure field-emission SEM with an Oxford X-Max 80 mm² silicon-drift detector and Oxford AZtecEnergy and AZtecHKL advanced systems for X-ray microanalysis and electron backscattered diffraction; a Rigaku Ultima-Plus X-ray diffractometer; high-resolution TEM (JEOL JEM-2100 LaB6), X-ray MicroCT (Xradia MicroXCT 400), AFM, Micro-Raman, AA, ICP-MS, portable XRF, and petrographic microscopes.