In this region Palaeogene volcanic rocks increase in alkalinity from east to west. Among the alkaline effusive rocks there are leucite tephrites, leucite basalts, limburgites and analcime trachytes. Fuller information seems not to be available.
You are here
The Caucasus is an Alpine orogenic structure generated by collision between the Eurasian and Afro-Arabian plates, the area of contact being marked by the Lesser Caucasus ophiolite zone and intense volcanic activity. The Alpine alkaline volcanism in the Caucasus occurs in two distinct structural settings the first of which is palaeoceanic and characterised by volcano-sedimentary sequences which are closely associated with the ophiolites. In the second setting the alkaline rocks are associated with an intra-arc extensional regime and were emplaced immediately after the main stage of continental collision. The alkaline magmatism is essentially Eocene to Miocene in age and is principally developed in the countries of Armenia, Azerbai'an and Georgia (Fig. 2_50). The greatest contributions to our knowledge of the Caucasian alkaline rocks were made by Adamyan (1955), Aslanyan (1958), Bagdasaryan (1966), Gevorkyan (1965), Kotlyar (1939), Meliksetyan (1963a and 1963b) and Azizbekov et al. (1979).