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 most valuable results were obtained onboard the research ship Vityaz, a flagship of the Soviet research fleet in 1949-1968). This issue was studied by famous national scientists-geologists Academicians Pyotr Kropotkin, Yuri Pushcharovsky, Mikhail Muratov (Corresponding Member of the USSR AS), Lev Krasny and Gleb Udintsev (RAS corresponding members), Ivar Murdmaa, Dr. Se. (Geol. & Min.), etc. A detailed report on the geological structure of the Pacific Ocean was made in 1964 by the American scientist Henry Menard. At that time geophysical research methods were used for the most part.

Based on the data gathered in the second half of the 20th century, a new theory--global tectonics of lithosphère plates--was developed*. It assumes displacement of giant plates of the crust in the asthenosphere, some of which "dive" under the continents in separate areas. For the last forty years this theory has become a leading one in geotectonics.

As you know, practice in natural sciences is a criterion of truth. But was this theory of any help in solving two crucial practical tasks--development of a system of scientific prediction of earthquakes and efficient mineral exploration methods? Alas, all attempts were in vain.

Certainly, the said theory played a positive role in geosciences. Assessing it in 1969, Academician Yuri Kosygin proposed to treat the theory as any other scientific hypothesis--"be careful and perceive it as an instrument of cognition, not as a fetish..." Twenty years later his colleague Vladimir Belousov, Corresponding Member of the USSR AS, wrote: "Here we face a well-known scientific paradox, when a wrong idea stimulates scientific progress attracting numerous scientists from related fields of knowledge and promoting enhancement of research methods."

If global tectonics of lithosphère plates is basically correct and is still in the process of formation, there is one thing we have to do--to develop a model that would be more precise in describing reality. However, we cannot be sure that this theory has no fundamental defects**.

A substantiated answer to this question could be made after analysis of the newest data on the geological struc-

* See: V. Trubitsyn, " Global Plate Tectonics: New Turn?", Science in Russia, No. 2, 2003.--Ed.

** See: N. Pavlenkova, "Impregnable Ramparts of Continents", Science in Russia, No. 1, 2005.--Ed.

ture of the Pacific Ocean and adjacent water bodies (after the drilling of the (12,262 m) Kola superdeep well in 1970-1990, interpretation of the section on the basis of geological data is not always proved by drilling results). If we analyze the largest planetary structures in the context of formation of the lithosphere, rock case of the Earth, this giant cavity filled with water will "be in opposition" to the continents.

That is why the fundamental work by Boris Vasilyev, chief researcher of the Regional Geology and Tectonophysics Laboratory of the Pacific Ocean Institute of Oceanology named after V. Ilyichev (RAS Far Eastern Branch), The Geological Structure and Origin of the Pacific Ocean is of high interest. As explained in the foreword to this book by Vladimir Sakhno, RAS Corresponding Member, (Institute of Geology of the RAS Far Eastern Branch): "This work is based on the results obtained by the author in the course of active research of the Pacific Ocean. From the 1960s to the first years of the second millennium B. Vasilyev headed studies carried out on scientific vessels of the RAS Far Eastern Branch... Materials presented in the monograph are unique."

It is worth adding: this scientific work has many references to papers of national and foreign scientists--the list of used literature is vast. Unfortunately, there are no references to the Dutch scientist Rein van Bemmelen, a researcher of geological structure of the Indonesian region. It would be interesting to assess his ideas on the gravitational relations of the ocean floor and continents (big islands) proposed more than fifty years ago in the context of new facts.

But, in any case, the monograph written by Boris Vasilyev is an up-to-date geological encyclopedia of the Pacific Ocean. The author also analyzes existing tectonic concepts and advances his own hypotheses on the origin and evolution of the global structure under consideration.

The first part of the book is dedicated to the general characteristics of the whole depression of the Pacific Ocean. The author points out: given significant individual differences of its specific areas, as a whole it was quite stable as compared with the surrounding dynamic belt with its numerous earthquake centers and the "fire ring" of active volcanoes.

The second part of the monograph describes the edge zone of this part of our planet where an active interaction in the "continent-ocean" system is going on. The third part contains hypotheses of the endogenic origin of the ocean depression, a problem of hydrosphere evolution and ideas on the formation of the Earth-Moon system.

According to the conclusions made by the scientist, "the megadepression of the Pacific Ocean... formed about 4.5 bin years ago as a result of a rare event of cosmic nature, most probably, due to formation of the Earth-Moon system or after separation of the Moon from the proto-Earth as stated in Darwin's theory (George Howard Darwin, English astronomer and mathematician, Foreign Corresponding Member of St. Petersburg AS from 1907.--R. B.), or as a consequence of collision with another big planet."

In this respect it is necessary to recollect the words of Academician Vladimir Vernadsky, founder of modern complex of geosciences (The Chemical Structure of the Earth's Biosphere and its Environment, M.: Nauka, 1965): "The reason for the absence of the granite case under the Pacific Ocean lies not in the indepth life of our planet, not in tectonic... movements of the bottom of the Pacific Ocean, not in the history of the Moon... as once a component part of the Earth in place of the Pacific Ocean, as astronomers assume, but in the geological history of the continents."

Science in Russia, No.3, 2011

We can interpret statements made by competent scientists in different ways. But there is one thing we must always keep in mind: the ocean floor is covered with a thick layer of water protecting it from solar energy, which is an engine of geochemical cycles in the biosphere transforming the surface of the continents. Originally, the giant area of the Pacific Ocean was more inert in the geological sense (if we omit underwater vul-canism) compared with the continents.

According to Vasilyev, "available data are unanimously evidencing that in the Jura* and early Cretaceous** there were subaerial conditions (i.e. dry land--R. B.). Sinkings began in the Jura due to a planetary oceanization process (changes in the continental crust as a result of its enrichment by iron and manganese and impoverishment by silicon.--R.B.) that marked a new phase in the development of the Earth that is still going on nowadays."

One important remark: is it absolutely indisputable that 150-200 mln years ago there were subaerial conditions in the whole territory of the megastructure?

The physical geography reference book says: "Subaerial processes on dry land take place under the influence of atmospheric phenomena without participation of rivers." In this case it is strange that no rivers formed on such a vast territory. Or perhaps other specific conditions are implied? It remains unclear for readers.

The Jurassic (Jura)--the second system of the Mesozoic; started 185±5 mln years ago, duration--53 mln years.--Ed.

** The Cretaceous-the third system of the Mesozoic, started 132-137 mln years ago, duration--66 mln years.--Ed.

When we refer to a new phase in the development of the Earth, it is useful to mention reconstructions of paleogeographers. Do they mention such significant event in the history of biosphere? As you know, living forms, ecosystems and biogeocenoses are very sensitive to global changes.

Let us turn to the monograph The Climate in the Period of Major Biospheric Transformations (2004)* prepared by leading national specialists in historical geology and paleontology Nikolai Chumakov, Mikhail Akhmetyev, Alexei Herman, Drs Sc. (Geol. & Min.). According to them, there are no reasons to presuppose major climatic changes, flora and fauna in the Jura and early Cretaceous. In particular, the book says: "In the early Cretaceous the Pacific Ocean looked like a vast deep-water basin somewhat bigger than the existing one."

Well, what was there in the early Cretaceous: subaerial conditions in a vast territory or a spacious deep-water basin? Both opinions are substantiated and contradictory at the same time. Which one to prefer?

The answer to this question is determined by the attitude of this or that specialist. On the one hand, the probability of transformation of the continental crust into the oceanic one that is denser and contains less silicates is presupposed. On the other hand, there is the concept of movement of continents or lithosphere plates (that is crucially different).

In my opinion, it is clear that the continents, in the course of geological history, did not stay in one state,

* See: R. Balandin, "Structural Changes in the Biosphere and Earth Climate", Science in Russia, No. 3, 2005.--Ed.

occasionally joining in Pangaea (this was demonstrated, in particular, by the authors of the said monograph). At the same time, there are weighty arguments in favor of oceanization of the continental crust--they are laid out in Vasilyev's book. He refers to "indisputable evidence of existence of shallow water and dry land areas in place of present-day ocean depressions". The scale of such areas is unknown. With a comparatively rare network of observation points (which is typical for most regions of the Pacific Ocean), local phenomena may seem as widely spread.

The global tectonics of plates was most criticized by the author, who presented weighty proofs against this theory. For example, viscosity in the lower mantle is so high "that it excludes the possibility of convection as in case of tectonics of plates". Structure and geological characteristics of deepwater gutters presented by the scientist turn down the hypothesis on the submergence of ocean plates under the continents, presupposed by the aforementioned tectonics.

Vasilyev reasonably notices: "This mechanical theory based on the predominance of geophysical research methods in marine geology... is forcibly introduced into geological surveying and exploration works, which is particularly dangerous as it could be an obstacle for development of mineral and raw material base of the country."

Moreover, this theory is widely promoted. It affects not only mass conciousness, but also young and experienced specialists. In science and philosophy the dominance of one specific theory sooner or later leads to stagnation and decline of theoretical thought.

Nevertheless, advocates of global tectonics of plates are presenting it as the only true geological doctrine. I recoil my conversation with an expert in petroleum geology Nikolai Vassoyevich, Corresponding Member of the USSR AS, which took place 33 years ago: he lost his temper when students and postgraduates of Lomonosov Moscow State University heckled Vladimir Belousov, a prominent national geologist and Corresponding Member of the USSR AS, when he stumbled at this theory.

Turning back to the problem of geological structure, origin and evolution of the Pacific Ocean, we can say: the existing theories are more or less correct for separate zones of this giant water area and adjacent territories, including islands. If we speak of the drift of continents, i.e. Alfred Wegener's theory, we could combine the theory of oceanization of the crust and the mobilism concept. We should also keep in mind the hypothesis of lithosphère cycles (it was advanced in the second half of the last century by American and Soviet geologists King and Bonchakovsky) on the active contacts of the continental and oceanic crust observed in the remote areas of the Pacific Ocean*.

Finally, it would be very interesting to know Vasilyev's attitude towards ideas presupposing changes in the form of our planet, geoid and hydrosphere under the effect of rotation powers and astronomic factors (for example, these issues were discussed in the book On the Fundamentals of the Modern Theory of the Earth, 1965, by Boris Lichkov, Dr. Sc. (Geol. & Min.).

However, we evaluate existing hypotheses and theories, which remain in science as a kind of architectural structures based on collected, analyzed and summarized facts. Let me cite words of the outstanding biologist Charles Darwin (Foreign Correspondent Member of St. Petersburg AS from 1867): "Science is a grouping of facts that makes it possible to make general conclusions and elaborate laws." The great factual material, collected by Vasilyev in his monograph, deals not only with one main scientific approach, but gives full play to scientific imagination, new methods of research and discoveries.

* See: R. Balandin, "Cycles of the Lithosphere", Science in Russia, No. 5, 2004.--Ed.