The carbonate platform of the Upper Permian Wegener HalvØ Formation in the Karstryggen area of central East Greenland is an example of a carbonate system with low production rates (2-3 cm kyr-1) and differs from most other carbonate platforms by the lack of well-developed highstand progradation. The platform consists of three depositional sequences that formed in response to Kazanian sea-level cycles. Pinning point curves for the subaerial exposure surfaces separating the depositional sequences quantify the amplitude of the relative sea-level fluctuations in the range of 70-140 m. The platform developed on the karstified surface of an older Permian carbonate platform with a topographic relief locally exceeding 70 m. The predepositional relief influenced deposition in all three sequences. Transgressive systems tracts are thin and commonly dominated by condensed siliciclastic deposits in off-platform areas and palaeo-lows. Over palaeotopographic highs they consist of aggrading cementstones. Highstand deposits are limited to palaeotopographic elevated areas and consist of cementstone build-ups along the basin margin, and shallow subtidal to intertidal carbonates and evaporites in the platform area. Elsewhere, carbonate deposition took place during falling sea-level, and thin laterally extensive units of shallow-marine grainstones rest directly on top of deeper marine shales in the two first sequences, whereas thick prograding units of oolitic grainstones form the forced regressive systems tract of the uppermost sequence.
|Status||Udgivet - feb. 2001|
- Programområde 3: Energiressourcer