456 RUSSIA RUSSIA A S Yakubchuk, The Natural History Museum, London, UK A M Nikishin, Lomonosov Moscow State University, Moscow, Russia Copyright 2005, Natural History Museum All Rights Reserved Introduction The Russian Federation is the world’s largest country, spread across 10 time zones from west to east and from the Arctic to Subtropical climates from north to south Her territory is mostly plains in the lowlands of Eastern Europe and western Siberia and highlands in eastern Siberia The country’s mountain ranges are the Urals, Verkhoyansk, Koryak, Sikhote-Alin, Altai, Sayan, and Caucasus Geological exploration of this vast area started in the sixteenth century, when Russia began its advance to the east However, it became systematic only in the eighteenth century when Russia invited European scientists and many Russian people received education in Europe, many in mining centres This stimulated development of base metal and silver deposits in the Urals, Altai, and Transbaikalia provinces Gold and platinum were discovered only in the late eighteenth to early nineteenth century in the Urals This boosted exploration, and many prospectors moved to Siberia and the Russian Far East, where they found many rich gold placers before the Golden Rushes of the nineteenth century in the West These discoveries required systematisation, and the Russian government established the Geological Committee in 1882 After the 1917 Revolutions, these works expanded across the Soviet Union, and its first geological map at a scale of 1:5 000 000 was compiled by 1937 In the 1940–1970s, regional tectonic maps were compiled and many world-class deposits of Ni, Au, diamonds, and oil were discovered During this period, Russian geology evolved in isolation, but under the significant influence of the German geological school As a result, the fixistic approach dominated in geology and many local names were proposed for orogenic events, such as Baikalides, Salairides, etc As a result, Russia has its own system of Proterozoic subdivisions, such as Riphean (1600–680 Ma), that incorporates the Middle and Upper Proterozoic in the International Scale, and Vendian (650–540 Ma), roughly corresponding to the Eocambrian Phanerozoic subdivisions generally correspond to the International Scale After the introduction of plate tectonics, Russian geologists remained mostly non-mobilistic in their thinking Its regional geology was revised in line with plate tectonic theory only in the 1980s, which was also a period of active study of the Russian shelves and participation of many geologists in international projects During these years, Russian geological knowledge advanced significantly, with superdeep drilling in the Kola Peninsula, Urals, Central Asia, and western Siberia After the breakup of the Soviet Union in 1991, there has been a significant reduction of geological work However, interesting compilations were produced, as well as detailed petrological studies The country is now an area of international exploration activity General Geology Russian territory consists of Precambrian cratons and Neoproterozoic to Cenozoic orogenic collages, overlapped by the Mesozoic-Cenozoic sedimentary basins (Figure 1) The East European and Siberian cratons are the oldest structures in continental Russia On the Arctic shelf, west of the Gakkel Ridge in the Arctic Ocean, there are the Svalbard and Kara blocks The Hyperborean Craton is prominent in the Arctic shelf east of the Gakkel Ridge and north of Chukotka The cratons are bordered by the Neoproterozoic orogens of the Baikalides and Timanides, which probably continue on to the Arctic shelf Between these cratons is the Palaeozoic orogenic collage of the Altaids, mostly hidden under the West Siberian Mesozoic-Cenozoic sedimentary basin The Altaids extend to Transbaikalia (Figure 2) To the south of the Siberian Craton is the Mongolide orogenic collage Between the Siberian and Hyperborean cratons and along the Far East coast are the Mesozoic-Cenozoic Circum-Pacific orogens The Alpine orogenic belt borders the East European Craton in the south East European Craton The East European Craton consists of shields, basement rises, and sedimentary basins The Baltic Shield outcrops in the Kola Peninsula and Karelia In the south, the crystalline basement occurs in the so-called Voronezh Rise There are several sedimentary basins – Baltic, Moscow, Mezen, Volga-Ural, Pachelma, Ulianovsk-Saratov, Peri-Caspian – and the Peri-Urals foredeep The craton formed prior to 1.6 Ga (Figure 3) In the Baltic Shield, there are the Karelia, Central