--> ABSTRACT: Carbonate Platform Facies in the Karatau of S. Kazakstan: Outcrop Analogs for Carbonate Fields in the N. Caspian Basin, W. Kazakstan, by H. E. Cook, V. G. Zhemchuzhnikov, W. G. Zempolich, P. J. Lehmann, V. YA Zhaimina, V. M. Buvtyshkin, I. Golub, M. Bowman, N. Fretwell, P. A. Lapointe, A. Giovanneli, and M. Viaggi; #91021 (2010)

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Carbonate Platform Facies in the Karatau of S. Kazakstan: Outcrop Analogs for Carbonate Fields in the N. Caspian Basin, W. Kazakstan

COOK, H. E., V. G. ZHEMCHUZHNIKOV, W. G. ZEMPOLICH, P. J. LEHMANN, V. YA ZHAIMINA, V. M. BUVTYSHKIN, I. GOLUB, M. BOWMAN, N. FRETWELL, P. A. LAPOINTE, A. GIOVANNELI and M. VIAGGI

4,500 m-thick Devonian and Carboniferous carbonate platform facies in S. Kazakstan are analogs for coeval oil and gas fields in the N. Caspian Basin, W. Kazakstan. Relative sealevel fluctuations evidenced throughout the section were responsible for platform margin drowning and backstepping, karsting, multiple stacked sequence sets and paleosols.

1) Frasnian and Famennian platform margins are reef-rimmed algal-stromatoporoid-calcisponge boundstone and rudstone; platform interiors contain mud mounds, peritidal carbonate sands, cryptalgal laminites and evaporitic laminites. Basin margins contain megabreccia debris flow aprons. 2) Tournasian carbonates form ramps of brachiopod-crinoid biostromes; ramp interiors have mud mounds and abundant tidal flat facies; seaward ramp shelfings contain bioclastic turbidite aprons. 3) Visean and Serpukhovian carbonates have both reef and shoal-rimmed platform margins. Reef-rimmed margins and upper slopes are sponge-Tubiphytes-algae-mud boundstone and flanking facies are crinoid-bryozoan-coral -brachiopod- mud boundstone and cementstone. Deeper water parts of these slopes contain mud mounds and turbidite aprons. Platform interior facies consist of interbedded ooid and bioclastic sands and phylloid algae-rich sands. Shoal-rimmed platform margins are dominated by cross-bedded ooid-bioclastic sands and turbidite aprons. 4) Bashkirian carbonates are reef-rimmed platform margins comprised of algae-brachiopod boundstone and cementstone.

Thick stacks of dolomitized and karsted platform margin grainstone and platform interior facies form potential reservoirs whereas platform margin reefal boundstone and slope facies contain abundant marine cement and are relatively tight. These geometric and diagenetic patterns are analogous to some reservoirs in the N. Caspian Basin. 

AAPG Search and Discovery Article #91021©1997 AAPG Annual Convention, Dallas, Texas.