Stratigraphy of the Silurian type areas in East Siberia

Three stratigraphic type areas (the Moiero River vicinity, Turukhansk and N oril'sk districts), where clayey-carbonate sedimentary facies are widesprea d, characterize the Silurian of East Siberia. The Moiero River neighborhood is a type area of the Moierokan, Khaastyr, Agidy (representing together th e Llandovery), and Khakoma (an equivalent of the Wenlock) horizons, whereas the Tukal (Gorstian Stage) and Postnichnyi horizons (Ludfordian-Pridoli in terval) are distinguished in the Turukhansk and Noril'sk districts, respect ively. The type areas exhibit stratotypes of all Silurian horizons, which a re simultaneously the stratotypes of synonymous formations of East Siberia. The formations are subdivided into subformations, inside which the local c hronozones are recognized. The chronozones are described on the basis of el ementary geological bodies ("geothemes"), whose sequences are shown in the respective profiles. Structural and facies variations are exemplified for 6 formations, 13 subformations, and 54 local chronozones.