Diagenesis of mid-triassic ghail formation, Wadi bih, Ras Al Khaimah

This study focuses on the Early to middle Triassic carbonates of the Ghail Formation outcropping in Ras Al Khaimah (UAE). A range of different methods, which includes outcrop logging, sampling, petrographic descriptions, fluid inclusion and isotopic analyses has been used to describe the main stratigraphic and diagenetic features of the outcropping sedimentary series. Optical microscopy, Scanning Electron Microscopy (SEM) and Backscattered Electron image (BSE) with Energy-dispersive X-ray spectroscopy (EDS) were used to assess the timing of different diagenetic events (paragenesis), which included dolomitization, physical/chemical compaction, iron oxide formation and late calcite cementation. Isotope analysis showed two different generations of dolomites, i.e. a low temperature dolostone and a high temperature dolomite cement, which could result from evaporation in a sabkha environment and from burial diagenesis, respectively. Fluid inclusion microthermometry in cements filling vugs proved useful to confirm the mesogenetic (burial origin) of the drusy dolomite cements.