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p Continuing our attempt to solve the riddles of Easter Island, we must now take a look at the floor of the Pacific, where scientists have discovered a vast submarine land, with mountains and abysses. And to explain the origin of this submarine land we shall have to look into another abyss, not oceanic but geological—the abyss of time that has passed since our planet was formed.

p Geophysics has shown that there are two types of crust, the oceanic type and the continental type. Was there always this division? Or did the whole earth originally have an oceanic type? Or did it have a continental type? Which came first?

The answers to these questions will resolve the’ problem of the origin of the Pacific basin, a basin that covers almost half the globe. Below, we reproduce the table of hypotheses of the origin of oceanic basins drawn up by the prominent American oceanographer Professor H. W. Menard. 45 The tabio clearly sols forth all Hie possible variants of a solulion lo the problem, so thai we have only to find the “correcl” section of the table.

Hypotheses of the Origin of Ocean Basins Modification Meteorite Original crust impact 1 OCEANIC Meteorites arc continents Ejection 3 Differentiation 5 Mantle yields continents and water 6 Continents “basaltified” to oceanic basins CONTI- 2 NENTAL 4 Scar is Pacific Basin ocean basins

p According to the hypothesis in the section numbered 1, the oceanic crust came first, after which continents grew as meteorite matter accumulated on the surface of the earth. The hypothesis in section 2, on the contrary, assumes that the continental crust came first, after which basins were blasted in the crust by impact of meteorites. Neither hypothesis is popular today.

p The section numbered 3 is empty. No one will assume that the gigantic Pacific basin could have been formed because land became separated from the surface of the earth and was ejected into outer space. But hypothesis 4 is intriguing and has won many supporters. They believe that the Pacific basin is the space left by the Moon after it became detached from the Earth!

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p The hypothesis, however, is rejected by most scientists today because it, explains too little, and too many facts contradict it. Efforts are still being made to resurrect it, although not very successfully. Analyses of moon rock show that our satellite is composed of non-terrestrial matter.

p Today the overwhelming majority of oceanographers and geologists share the last two hypotheses. According to one (section 5 of the table), the oceanic crust came first, and the continents and water were formed from the mantle. (Professor Menard supports this assumption.) Soviet geologist A. P. Vinogradov is the scientist who has most thoroughly substantiated it.

p The opposite hypothesis (sec section G) assumes that the oceanic basins, including the largest, the Pacific, were formed as a result of gradual fragmentation of the continents. Blocks of continental crust were “dissolved” in the basalt rising out of the bowels of the earth, and this crust turned into oceanic crust. However, as F. Shephard, one of the founders of marine geology, has correctly noted, our present knowledge of the structure of the earth’s crust is only sufficient to reject some of the older and more obviously erroneous assumptions but insufficient to construct promising new hypotheses.

p Geophysicists have proposed an impressive project of deep sea drilling through the thick layer of sediment that has accumulated on the floor for millions of years, and then farther down through the oceanic crust to the mantle itself. Evidently, only this can tell us which is primary, the oceanic crust or the continental crust.

But even before scientists drill through the crust we may confidently state that the Pacific Ocean 47 was once different from what it is today although, says Professor Menard, "almost all of the geology of the Pacific Basin may well have originated during the last 200 million years”.