From the history of discovery of overthrust structure of the Urals

In the early 1950-s the state program for mapping the territory of the Soviet Un- ion at a scale of 1:200,000 was adopted. At that time the fixist paradigm prevailed in Soviet science, which was associated with the struggle against "bourgeois pseudo-ideas in science" of the 1930-s, with mobilism originated in the West.In 1938 such outstanding geologists as G.N.Fredericks, the first Ural supporter of overthrusts, D.I.Mushketov, supporter of the overthrust-nappes structure of the Central Asia, and others were shot as public enemies. Many scientists were sent to labor camps and exile, and the rest were morally broken.Work on the implementation of the state program in the Urals was started in the Karatau ridge - one of the key structures in the tectonics of this folded re- gion, located in the Western part of the Bashkirian anticlinorium. Here in 1954, M.A.Kamaletdinov mapped a large overthrust, which was the first evidence of allochthonous structure of the Ural orogen after many years of denial. In 1956 data on the overthrust folding structure of the Karatau ridge were fixed in the state geological map of the USSR, sheet N-40-X, scale 1:200 000.In subsequent years, M.A.Kamaletdinov carried out mapping of other areas of the southern Urals and the role of thrust was confirmed everywhere. In the 1960s the geological survey within the Ufa amphitheatre allowed him for the first time to map klippes - tectonic outcrops, previously known only within young mountain structures in the Alps, Pyrenees, Carpathians. Soviet Geology denied the existence of klippes along with the thrusts. Such outcrops of ancient rocks within younger deposits in the Urals were related to the vaults of the an- ticlinal structures or raised small blocks. The discovery of the klippes also confirmed the overthrust-nappes structure of the Urals. An important practical conclusion of the new scientific results was the prospectivity of the folded Urals for oil and gas, as hydrocarbon deposits were already discovered in the platform sediments of the PreUral trough, these sediments were assumed to be under the Ural allochthon. The establishment of overthrust tectonics of the Urals played an important role in adoption of the concept of mobilism in Geology.