Two generations of dolomite cements postdate replacement dolomites: a coarse and planar-e(s) cement (Dolomite-C1), and a later coarser nonplanar cement (Dolomite-C2). Dolomite-C1 has oxygen (mean d¹⁸O = -4.73 PDB) and strontium (mean ⁸⁷Sr/⁸⁶Sr = 0.70855) isotopic compositions similar to replacement dolomites. These similarities, combined with the local association of Dolomite-C1 with stylolites, suggest that some Dolomite-C1 precipitated from fluids whose composition reflects pressure solution of the preexisting replacement dolomites. The composition of fluid inclusions in Dolomite-C1 (mean T_h = 117°C; mean salinity = 19 wt % aCl equivalent) indicates that most Dolomite-C1 precipitated from warm hydrothermal brines. Little variation in fluid-inclusion homogenization temperatures occur with burial depth, suggesting that Dolomite-C1 precipitated prior to basin tilting, and may be related to Antler orogenic events. Dolomite-C2 postdates Dolomite-C1, is relatively more depleted in ¹⁸O (mean d¹⁸O = -9.06 PDB), and has a more radiogenic ⁸⁷Sr/⁸⁶Sr ratio (0.71087). Preliminary fluid-inclusion data from the Crimson Field suggest precipitation temperatures of about 150°C. Thus, Dolomite-C2 originated from fluids of higher temperatures and different composition than Do omite-C1.

The petrographic, paragenetic, and geochemical characteristics of replacement dolomites in this study are similar to those of other Leduc buildups along the reef trend and of other Devonian dolostones of western Canada, supporting a model of large-scale basinwide fluid flow. The pervasive distribution of replacement dolomites along the Rimbey-Meadowbrook reef trend, and the similar petrographic and geochemical character of dolomites from both the Leduc and Cooking Lake Formations, is consistent with the hypothesis that the underlying Cooking Lake platform acted as a subsurface conduit system for the dolomitizing fluids. A potential regional fluid source may have been formation fluids (including residual evaporite brines) expelled tectonically during the Antler orogeny.