PRINCIPAL GEOLOGIC AND METALLOGENIC FEATURES OF THE MOUNTAINOUS TAYMYR

Within the mountainous Taymry the oldest formations are highly metamorphosed sedimentary and extrusive rocks of Proterozoic age, overlain by less altered rocks of the Sinian complex. These in turn are overlain with angular unconformity by Lower Cambrian deposits, whose age has been determined on the basis of fossils. Paleozoic rocks are widespread, and all systems of the era are represented. Proterozoic rocks occur on the northern coast of the peninsula. The younger Sinian and Paleozoic formations are south and southeast of these. Mesozoic rocks constitute small areas in depressions. Quaternary sediments, consolidated by permafrost, are widely distributed throughout the area. Magmatic activity is well developed. The lower Proterozoic magmatic cycles began with intrusion and extrusion of basic rocks, and ended with granitoid injections accompanied by formation of pegmatitic zones. In the upper Proterozoic, magmatic activity is again characterized in early stages by extrusion and intrusion of basic rocks, and later by the formation of granitic intrusions and their facies, as well as by extrusion of felsite porphyry towards the end of the era. Intrusions of granitoids appeared in the middle Paleozoic. The upper Paleozoic was marked by the formation of traprock and sulfide mineralization. In the early Mesozoic, the occurrence of small subalkaline intrusions resulted in the formation of ores of various types.