Facies Analysis of the Svidol Formation (Lower Triassic) of the Teteven Anticlinorium (Central Fore-Balkan)

On the basis of studies of structures, textures, composition and fossil remains of the rocks from the Svidol formation, three main facies were determined, namely: (a) transitional low-relief coastal silty mud plain; (b)supratidal evaporite clayey-carbonate flat, and (c) intertidal shallow subtidal carbonate flat. It is assumed that the Buntsandstein sediments were formed in an arid alluvial plain. The Svidol formation was formed in an epicontinental tidal flat which was characterized by cyclic development. The established facies types are analogous to the corresponding supratidal, intertidal and subtidal facies in the Andros Island, the Persian Gulf and Florida. 
   The yellow supratidal carbonates show highest dolomite content. Chlorite is typical also of the supratidal facies. 
   The Triassic marine transgression advanced slowly through tidal mud flats, mainly in the direction east-west.