Earliest Triassic microbialites in Çürük Dag, southern Turkey: composition, sequences and controls on formation

摘要: The Permian–Triassic Boundary sequence at Curuk Dag, near Antalya, Turkey, begins with a major erosion surface interpreted as being the Late Permian lowstand, on which lies ca 0·4 m of grainstone/packstone composed ooids, peloids and bioclasts. Most ooids are superficial coats fragments calcite crystals presumed to be eroded from crystal fans no longer present. is smooth shows evidence dissolution; contains intraclasts underlying wackestone, proving erosion. Next 15 m microbialite comprised interbedded stromatolites, thrombolites, plus beds planar limestones small-scale latter comprise complex interlayering stromatolitic, thrombolitic peloidal fabrics precipitated fans, form hybrid inorganic carbonate, together bioclastic debris micrite. Dag repetitious; lower part more complex, abundant stromatolites microbialites. Some themselves hybrids fans. In upper missing rock mostly recrystallized thrombolites that develop upwards tabular domal form. domes directly below small breaks in growth where very thin shelly micrites grainstones/packstones deposited. Repetition facies may controlled by sea-level change; deepening-up model consistent evidence. Stromatolites (with fans) dominate shallower water, deepening through interlayered sediments thrombolite, probably than few tens metres deep, followed renewal growth. An interpretation open marine fully oxygenated waters for ongoing parallel work has identified Bairdioid ostracods microbialite, group known marine. However, other researchers have proposed low oxygen conditions boundary globally, so continues confirm whether grew dysoxic or normally conditions. principal stimulus post-extinction microbialites likely carbonate supersaturation oceans. overlain further 25 m (without microbialite), Early Triassic shales. Overall, aggradational during an overall relative rise, global eustatic rise following lowstand.