Analysis, occurrence, and reactions of dawsonite in AMSO well CH-1

•The paper compares three independent methods for dawsonite analysis in oil shale.•Results are presented as a function of depth in a region of the Green River Formation where little nahcolite is present.•The decomposition reactions of dawsonite are very sensitive to pressure during pyrolysis.

The abundance of dawsonite in an exploration well in the Green River Formation oil shale has been characterized by well logging, FTIR, DSC, and wet chemistry. The four methods agree qualitatively but not quantitatively. Thermal analysis was then used to characterize changes in the dawsonite decomposition endotherm as a function of pressure. The peak temperature of the endotherm increased with pressure and the size decreased with pressure. The total endotherm at high temperature that includes dolomite and calcite reactions decreased with increased pressure, presumably due to formation of more stable silicates.