Multiple fluid flow events and the formation of saddle dolomite: examples from Middle Devonian carbonates of the Western Canada Sedimentary Basin

Abstract

Saddle dolomite has been described from numerous Devonian carbonate reservoirs in Alberta and British Columbia. Its presence has been used as an indicator of the interaction of high-temperature hydrothermal fluids with host carbonates due to tectonic influences in the Western Canada Sedimentary Basin. The timing of the fluid flow events that precipitated the saddle dolomite and the chemistry of these fluids have been the basis of many arguments. Some researchers believe that the saddle dolomite was precipitated during the Late Devonian to Carboniferous while others contend that the fluid flow event was during the Late Cretaceous to Early Tertiary. In this study, we conducted a geochemical comparison between the Middle Devonian Sulphur Point and Slave Point carbonates from northwestern Alberta. The results demonstrate the presence of both an early fluid flow events associated with the Late Devonian to Mississippian Antler Orogeny as well as a later event coincident with the Late Cretaceous to Early Tertiary Laramide Orogeny.