by Acad. Mikhail KUZMIN, Vinogradov Institute of Geochemistry, RAS Siberian Branch (Irkutsk); Acad. Vladimir YARMOLYUK, Institute of the Geology of Ore Deposits, Petrography, Mineralogy and Geochemistry, Russian Academy of Sciences, Moscow; Professor Vadim KRAVCHINSKY, University of Alberta (Edmonton, Canada)
The last fifty years have seen great changes in geological knowledge. Owing to achievements of seismic tomography, two vast regions of hot matter have been detected in the bowels of the earth reaching as far down as the central core. Remarkably, their projections to the planet's surface actually concur with hot fields of the mantle identified by Soviet geologists thirty years ago by indirect evidence. These and related discoveries underlie the global geodynamics theory that has made it possible to link plutonic processes within the mantle to global surface geology.
Internal structure of the earth. Upper/lower mantle interface, 660 km. Partly molten matter contained in the upper mantle often contacts the asthenosphere.
INTERNAL STRUCTURE OF THE EARTH
First, some background information. In his major work on fundamentals of geology (published in 1830-1833 in three volumes) the British geologist Charles Lyell formulated the principles of what he termed actualism (contemporary observations make it possible to postulate geological processes of the past) and uniformism (all natural changes notwithstanding, the laws responsible for them remain immutable). Later on two American geologists, James Hall and James Dana (in 1858 elected honorary member of the St. Petersburg Academy of Sciences) came up with the concept of geosynclines (with respect to mobile zones of the earth) explaining the origins of folded mountain masses. And the Russian earth scientist Acad. Alexander Karpinsky identified stable regions on earth, the platforms (1887, 1894). The works of these eminent scientists became a groundwork for the geological pa ... Читать далее