Abstract

In Central Kazakhstan there are two main types of sections of marine Famenian deposits: the carbonate coral-brachiopod; and siliceous-clay-carbonate mollusc. Local zones of conodonts, foraminifers and ammonoids have been established for both types of sections. These two schemes have been compared with the standard conodont and ammonoid zonations (from crepida to praesulcatus). The zonal subdivision of the Famennian and the lithological data make it possible to trace the stages of geological evolution of the marine basin and to illustrate it on lithofacial maps. The above mentioned allow us to determine the exact age of the iron-manganese deposits: within the Famennian every ore-bearing region has its own prevailing age of mineralization, with subordinate mineralization of another age. The ore deposits belong to different lithofacies. The greatest of them are confined to relatively deep water, siliceous-clay, knot-bedded red limestones formed under conditions similar to those of the recent depressions of the Red Sea.