TRIASSIC STRATIGRAPHY OF THE NORTHERN CAUCASUS BASED ON AMMONOIDS

Abstract

Field investigations and bed-by-bed sampling of ammonoids provide the basis for a more detailed and better constrained biostratigraphic scheme of Triassic deposits in the northern Caucasus. For the first time, these deposits are subdivided into ten ammonoid beds comprising the Triassic interval from the middle Scythian to the upper Rhaetian. The beds are correlated with the standard ammonoid zones. The Anisian deposits, which are especially rich in ammonoids, are correlated with synchronous sedimentary sections in Turkey, Iran, China, and the USA. New data elucidate that in the studied, region there is a considerable stratigraphic hiatus spanning the upper Anisian and the lower Ladinian.