Abstract:
Tengiz field is an isolated carbonate buildup in the southeastern Precaspian Basin, containing a succession of shallow-water platforms ranging in age from late Famennian to early Bashkirian. Platform backstepping from Tournaisian through late Visean resulted in approximately 800 m (2625 ft) of bathy-metric relief above the Famennian platform. This was followed by as much as 2 km (1.2 mi) of Serpukhovian progradation, which formed a depositional wedge around the older platforms referred to as the Serpukhovian rim and flank. Rim and flank facies include lower slope mudstone, volcanic ash, and platform-derived skeletal packstone to grainstone interbedded with boundstone breccia; middle-slope poorly bedded to massive boundstone breccia with subtypes based on clast composition, size, and packing; upper-slope in-situ microbial boundstone; and outer-platform to shallow-platform skeletal, coated-grain, and ooid packstone to grainstone. The upper-slope microbial boundstone represents the
