by Rudolf BALAN DIN, geologist
Ocean studies are a challenging task. When onshore, a geologist is able to explore the area in detail and drill a more or less close well net, including deep wells, while vast water areas are still an aqua incognita in this respect. Such definition can be applied to the Pacific Ocean-the largest (its area, including seas, is 178.6 mln km2) and the most mysterious structure of our planet, though much has been learnt for the last decades by scientists, including national specialists, on its structures and rocks of its bottom. They have been described and classified in the fundamental work by Boris Vasilyev, Dr. Sc. (Geol. & Min.), The Geological Structure and Origin of the Pacific Ocean (Vladivostok: Dalnauka, 2009).
First research works on the bottom of the Pacific Ocean were carried out about a hundred years ago. The first observation report was made on the basis of materials gathered in the course of round-the-world expedition onboard the research boat Challenger. It was published in the late 19th century by a Scotch oceanologist John Murray (Foreign Corresponding Member of St. Petersburg AS from 1897), who summarized all available data. In particular, he singled out the tectonosphere (analog of the modern asthenosphere, a layer of reduced hardness and viscosity in the upper part of the Earth mantle), pointed out availability of huge plates on the bottom separated by "lines of faults and ruptures along which volcanic activity and gas emissions are observed".
Murray came to the following conclusion: continental migration or separation of the Moon from the Earth is more credible than "a theory that the whole continents allegedly disappeared under the present-day ocean beds". A little bit later (1912) German geophy-sicist Alfred Wegener proposed the continental drift theory.
Numerous foreign and national expeditions continued studying the bottom of the World Ocean and its remote areas (the m ... Читать далее