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.Meteoric iron differs from iron of terrestrial origin in its admixture of nickel, and it is thischaracteristic that makes it possible to differentiate iron tools of early ages, for instance of thepyramid age in Egypt, and to decide whether iron pieces were smelted from ore or were workedmeteorites."Nickel is a very rare element in most terrestrial rocks and continental sediments,and it is almost absent from the ocean waters.On the other hand, it is one of the maincomponents of meteorites." ^Thus it is assumed that the origin of the abysmal nickel was in meteoric dust or "the very heavyshowers of meteors in the remote past.The principal difficulty of this explanation is that itrequires a rate of accretion of meteoric dust several hundred times greater than that whichastronomers, who base their estimates on visual and telescopic counts of meteors, are presentlyprepared to admit." * In a later publication, a popularized account of the Albatross expedition, Pettersson writes:"Assuming the average nickel content of meteoric dust to be two per cent, an approximate valuefor the rate of accretion of cosmic dust to the whole Earth can be worked out from these data.The result is very high about 10,000 tons per day, or over a thousand times higher than thevalue computed from counting the shooting stars and estimating their mass." ^In other words at some time or times there was such a fall of meteoric dust that, apportionedthroughout the entire age of the ocean, it would increase a thousandfold the daily accumulationof meteoric dust since the birth of the ocean.The ash and lava on the bottom of the oceans indicate catastrophic occurrences in the past.Ironand nickel point to celestial showers of meteorites, and thus possibly also to the cause of thetectonic ruptures, of the collapse of the ocean floor and of the outbursts of lava under thesurface of great oceanic spaces.8 Pettersson, Westward Ho with the Albatross (1953), pp.149 50.4 Pettersson, Scientific American, August 1950.5 Pettersson, Westward Ho with the Albatross, p.150.Evidence of great upheavals has been brought forth from the islands of the Arctic Ocean and thetundras of Siberia; from the soil of Alaska; from Spitsbergen andGreenland; from the caves of England, the forest-bed of Norfolk, and the rock fissures of Walesand Cornwall; from the rocks of France, the Alps and Juras, and from Gibraltar and Sicily; fromthe Sahara and the Rift of Africa; from Arabia and its harras, the Kashmir slopes of theHimalayas, and the Siwalik Hills; from the Irrawaddy in Burma and from the Tientsin andChoukoutien deposits in China; from the Andes and the Altiplano; from the asphalt pits ofCalifornia; from the Rocky Mountains and the Columbia Plateau; from the Cumberland cave inMaryland and Agate Spring Quarry in Nebraska; from the hills of Michigan and Vermont withskeletons of whales on them; from the Carolina coast; from the submerged coasts and thebottom of the Atlantic with its Ridge, and the lava bottom of the Pacific.With many other places in various parts of the world we shall deal in some detail in the pagesthat follow; but we shall not exhaust the list, for there is not a meridian of longitude or a degreeof latitude that does not show scars of repeated upheavals.CHAPTER VIIIPOLES DISPLACEDThe Cause of the Ice AgesONE AFTER THE OTHER, scenes of upheaval and devastation have presented themselves toexplorers, and almost every new cave opened, mountain thrust explored, undersea canyoninvestigated, has consistently disclosed the same picture of violence and desolation.Under theweight of this evidence two great theories of the nineteenth century have become more andmore strained: the theory of uniformity and the theory of evolution built upon it.The otherfundamental teaching originating in the nineteenth century the theory of ice ages has beenloaded more and more heavily with the responsibility for the geological facts revealed; however,the cause of the ice ages remained a much-discussed and never-agreed-upon subject.The origin of the glacial periods was sought "on the earth below and in the heaven above." Thetheories that endeavored to explain what caused them fall under the following headings:astronomical, geological, and atmospherical. In the first group, some theories seek the cause of the ice ages in space, some in the sun, somein the relative positions of the sun and the earth.One idea was that the space through which thesolar system traveled was not always of equally low temperature, the variations beingdue to gases or dust present in some areas.This idea has been abandoned.Another theory wasthat the sun is a variable star emitting more heat at some periods and less at others.This theoryalso failed to be substantiated and was generally rejected; yet sporadically it finds newproponents.1 Still another theory would have the ice ages arrive when a hemisphere, theNorthern or the Southern, happens to have its winter while the globe is at the farthest end of itsellipse, as the Southern Hemisphere is at present.The winter would be a little longer and colder;however, the summer, though a bit shorter, would be hotter, and if the earth always traveled onits present orbit, the described variations would not bring about an ice age.It was also claimedthat the terrestrial orbit becomes alternately more and less stretched.Of the geological group of theories, one supposed a change in the activity of warm springs;another, a change in the direction of the Gulf Stream, which carries water warmed in theCaribbean Sea to the northern Atlantic; if there were no Isthmus of Panama, and North andSouth America were separated, a part of the stream from the Caribbean would flow into thePacific.Both these theories were shown to be inadequate, and the paleonto-logical survey ofsea fauna on both sides of the isthmus suggests that the dividing strip of land existed longbefore the advent of the Ice Age.Another geological theory, which still has some adherents,sees the origin of the glacial periods in the changing altitude of the continents, which would alsoinfluence the direction of winds and precipitation.But it is definitely opposed by such an authorityon glacial geology as A.P.Coleman, professor emeritus of geology at Toronto University:1 Barbara Bell, Science Newsletter, May 24, 1952."When one considers the distribution of ice sheets in the Pleistocene, covering 4,000,000 squaremiles of North America and half as much of Europe.[and the ice in] Greenland, Iceland,Spitsbergen.the southern island of New Zealand and Patagonia in South America, itbecomes evident that all parts of the world could not have been elevated at once.The theorybreaks down of its own weight
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Tematy
IndexHubbard, L Ron Mission Earth 04 An Alien Affair
Hubbard, L Ron Mission Earth 07 Voyage of Vengeance
Schmitt Eric Emmanuel Papugi
§ Baratte Emmanuel
Stone Katherine ZmiennoÂść uczuć
§ MiłoÂść bez końca Spencer Scott
Weiss, Richard Recipes for Immortality Healing Religion and Community in South India
Barton Beverly Griffin Powell 05 Cichy zabójca
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Christina A Burke [Queenie Ba On Assignment (epub)