Petrologic and geochemical attributes of dolomite recrystallization: An example from the Mississippian Pekisko Formation, west-central Alberta.

摘要

Carbonates of the Pekisko Formation are important reservoir rocks in west-central Alberta, especially in fields along the Pekisko subcrop edge. They represent a transgressive-regressive carbonate ramp sequence comprised of upward shallowing facies, which subsequently underwent extreme erosion leading to the development of karst topography. Lithofacies include grainstones, wackestones/packstones, mudstones, intraclast breccia mudstones and dolostones. Several generations of calcite cementation and dolomitization are the result of very complex diagenetic changes. Calcite cements include: isopachous, drusy mosaic, pendant/meniscus, blocky, syntaxial, fibrous and equant/prismatic. Five dolomite types have been identified: pervasive, dissolution seam-associated, planar void-filling, selective and saddle. Consequently, diagenetic alteration mainly by dolomitization has affected most of the carbonate facies.