Vladimir Vladimirovich Belousov (or Beloussov) (Russian: Влади́мир Влади́мирович Белоу́сов) (30 October [O.S. 17 October] 1907 in Moscow – December 25, 1990) was an Earth scientist in the Soviet Union, and a prominent advocate of alternatives to the theories of plate tectonics and seafloor spreading during the period of the 20th century in which debate on these subjects was most intense.Beloussov was head of the Geodynamics Department of the Institute of the Physics of the Earth in Moscow (from 1944), a corresponding member of the Soviet Academy of Sciences (from 1953), and a professor at both the Moscow Geological Surveyance Institute (from 1943) and Moscow State University (from 1953). From 1960 to 1963, Beloussov was President of the International Union of Geodesy and Geophysics (IUGG). He was also a Foreign Member of Geological Society of London. In 1942 he advanced theory that the Earth's material has gradually differentiated according to its density to produce the present internal structure of the Earth and that this gradual movement is the basic cause of movements of the Earth's crust. During the 1960s he led three expeditions to the East African Rift to study continental structure and the Earth's mantle. These trips fuelled his idea that continental crust was transformed to oceanic crust by widespread processes involving basic magmas. Although his theories were ultimately rejected by the scientific community, he was an important figure in the development of the Earth sciences within the Soviet union following the Second World War.