Penecontemporaneous diagenesis of the carbonate rocks in a sequence stratigraphic framework:An example from the Lower and Middle Ordovician carbonate rocks in the Lunnan palaeouplift, Xinjian

There is a correlation between the depositional systems tracts based on the eustatic fluctuations and penecontemporaneous diagenesis in the marine carbonate rocks. This correlation, in turn, can be incarnated by the diagenesis developed in the systems tracts.Exemplified by the Middle and Lower Ordovician carbonate rocks in the Lunnan palaeouplift, Tarim Basin, Xinjiang, the types and characteristics of the diagenesis developed in individual systems tracts are summarized in a sequence stratigraphic framework. The calcite cementation and dolomitization mainly occur in the transgressive systems tract (TST), and calcite cementation and meteoric dissolution dominantly appear in the highstand systems tract (HST). The comparative study of the diagenesis in a sequence stratigraphic framework shows that the HST deposits and their underlying deposits are believed to be the favourable intervals reworked by diagenesis and potential reservoirs, as proved by statistic physical data for the strata in the study area.