Synthesis of micropaleontological age constraints for the reconstruction of the Tethyan realm in the Lesser Caucasus (Armenia, Karabagh)

Abstract

We present new biostratigraphic results from two ophiolite outcrops in Armenia. The discovery of upper Tithonian–lower Berriasian diagnostic radiolarian species (Vallupus gracilis Li and Sashida) in the lower radiolarites of the Dali section allows to date more accurately submarine lava eruptions of transitional to alkaline composition. The radiolarian results also indicate that blocks of shallow-water carbonates slid into the basin during this time interval. At Vedi, upper Coniacian–Santonian calcareous nannofossils identified in marls of the post-obduction sedimentary cover refine previous age data. Synthesis of the existing bio-chronostratigraphic constraints in Armenia and Karabagh sheds light to the depositional and magmatic history of Tethys in the Lesser Caucasus and highlights the age constraints of fossils on the timing of ophiolite obduction in the region.