Norilsk Ore Region

an area in the northern part of Krasnoiarsk Krai, RSFSR; includes sulfide cupronickel deposits (Noril’sk-1, Talnakh, and Oktiabr’skoe) and deposits of coal, petroleum, gas, and nonmetallic minerals.

The first data on the geology and minerals of the Noril’sk Ore Region were collected in 1840–43 by the Russian naturalist A. F. Middendorf, who noted the presence of coal there. In 1865–66 the Russian explorer F. B. Shmidt gave a short geological description of the coal deposits and secondary cuprous ores in the zone of oxidation on the northern segment of the present-day Noril’sk-1 deposit. In 1919, 1920, and 1922 a prospecting party led by the Soviet geologist N. N. Urvantsev established the great promise of the Noril’sk deposit for further exploration; chemical analysis of ore samples showed that they contained platinum metals. Through detailed geological study of the Noril’sk Ore Region significant reserves of cupronickel ore, coal, and nonmetallic minerals were discovered and prospected, and on this basis construction of the Noril’sk Mining and Metallurgical Combine was begun in 1935.

The Noril’sk Ore Region is confined to the northwestern edge of the Siberian platform. The tectonic structure is characterized by smooth, gently rolling bedding of a sedimentary-effusive rock series, from Cambrian to the Anthropogenic inclusive (thickness of more than 6,000 m), and also by the presence of rampart-like structures, brachysynclines, and abyssal fractures along which magmatic melt was introduced into the upper stories of the cross section, leading to the formation of traps. The entire rock series is permeated by intrusions of diabases and gabbro-diabases of various ages and compositions.

The main commercial deposits are located along the deep Noril’sk-Khatanga fault, forming the Noril’sk and Talnakh ore centers. The sulfide copper-nickel ores belong to the class of liquation deposits; they are localized in the bottom parts of stratiform, gently pitching intrusions of gabbro-diabases or the underlying rock, from the Upper Silurian to the Lower Triassic. The ore bodies are large, wavy layerlike beds, veins, and streaks of rich, continuous sulfide ores located primarily in the rock underlying the intrusion, and also in beds of inset ores in the bottom parts of the intrusions and the enclosing rock. The main ore minerals are pentlandite, magnetic pyrite, chalcopyrite, and cubanite. The chief components that determine the commercial value of the ores are nickel, copper, cobalt, and metals of the platinum group. Ore manifestations of lead, zinc, and mercury have been identified in the Noril’sk Ore Region, and there are deposits of iron ores, power and coking coals, natural gas (favorable signs for the identification of multilayer gas-petroleum deposits in the Taimyr depression), and nonmetallic minerals.