Carbonate minerals are common around the world and are often used as paleoclimate indicators because they record the changes in the isotopic composition of the waters in which they formed.  After carbonate sediments are deposited, they are altered through diagenesis. My project is focused on the diagenetic process of dolomitization, which occurs through a series of intermediate Ca-Mg-carbonate phases, including high Mg-calcite, disordered dolomite and ordered dolomite. Whereas calcite is routinely used as a paleoclimate indicator, attempts to use dolomite in the same fashion have been unsuccessful because isotope fractionation in these various Ca-Mg-carbonate phases is unclear. This renders dolomite a less effective paleoclimate record.

 

My research is focused on the hypothesis that the variation in O18/O16 ratios observed in the dolomite rock record may be explained by the cation ordering state of the various Ca-Mg-carbonate phases present during dolomitization. Essentially, we will attempt to answer the question: do the Ca-Mg-carbonate phases fractionate oxygen isotopes differently?

 

My project is funded by a collaborative grant from the U.S. National Science Foundation (NSF). WMU is the lead institution, but I will be working in close collaboration with researchers the University of Michigan and Grand Valley State University.