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Sunken Continents versus Continental Drift

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Carolyn Silver
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« on: July 28, 2008, 11:02:08 pm »

Sunken Continents versus Continental Drift



David Pratt



Contents

Introduction

Plate tectonics -- a failed revolution
        Plates in motion?
        Continental drift
        Seafloor spreading and subduction

Emergence and submergence
        Vertical tectonics
        The continents
        The oceans

Conclusion

References

Select bibliography



NB: For a more detailed critique of plate tectonics, see: Plate Tectonics: A Paradigm Under Threat, Journal of Scientific Exploration, vol. 14, no. 3, 2000, http://ourworld.compuserve.com/homepages/dp5/tecto.htm

______________________________________



Introduction

That worlds (also Races) are periodically destroyed by fire (volcanoes and earthquakes) and water, in turn, and renewed, is a doctrine as old as man. . . . Twice already has the face of the globe been changed by fire, and twice by water, since man appeared on it. As land needs rest and renovation, new forces, and a change for its soil, so does water. Thence arises a periodical redistribution of land and water, change of climates, etc., all brought on by geological revolution, and ending in a final change in the axis. (H.P. Blavatsky, The Secret Doctrine, 2:725-6)
In the latter half of the 19th century, when the above passage was written, the idea of submerged continents was accepted by many prominent geologists. This continued to be the case well into the 20th century, though the idea gradually began to go out of fashion. In the mid-1960s came the plate-tectonics 'revolution' in the earth sciences. Plate tectonics firmly denies that large landmasses can be elevated from the ocean floor or submerged to oceanic depths.    According to plate tectonics, the earth's outer shell, or lithosphere, is divided into a number of large, rigid, moving plates that interact at their boundaries, where they converge, diverge, or slide past one another. Such interactions are believed to be responsible for most of the seismic and volcanic activity of the earth. Plates cause mountains to rise where they push together, and continents to fracture and oceans to form where they rift apart. The continents, sitting passively on the backs of the plates, drift with them, at the rate of a few centimeters a year. At the end of the Permian, some 250 million years ago,* all the present continents are said to have been gathered together in a single supercontinent, Pangaea, consisting of two major landmasses: Laurasia in the north, and Gondwanaland in the south. Pangaea is believed to have started fragmenting in the Early Jurassic -- though some 'authorities' place the event earlier, in the Triassic, or even as late as the Cretaceous -- leading to the configuration of oceans and continents observed today.


*All dates given in this article are official 'scientific' dates. For the corresponding theosophical dates, see: Geochronology: theosophy and science, http://ourworld.compuserve.com/homepages/dp5/geochron.htm.
    It has been said that 'A hypothesis that is appealing for its unity or simplicity acts as a filter, accepting reinforcement with ease but tending to reject evidence that does not seem to fit.' Some proponents of plate tectonics have admitted that in the late 1960s a bandwagon atmosphere developed, and that data that did not fit into the new plate-tectonics model were not given sufficient consideration, resulting in a disturbing dogmatism. In the words of one critic, geology has become 'a bland mixture of descriptive research and interpretive papers in which the interpretation is a facile cookbook application of plate-tectonics concepts . . . used as confidently as trigonometric functions' [1]. A modern geological textbook acknowledges that 'Geologists, like other people, are susceptible to fads' [2].
    V.A. Saull pointed out that no global tectonic model should ever be considered definitive, since geological and geophysical observations are nearly always open to alternative explanations. He also stated that even if plate tectonics were false, it would be difficult to refute and replace, for the following reasons: the processes supposed to be responsible for plate dynamics are rooted in regions of the earth so poorly known that it is hard to prove or disprove any particular model of them; the hard core of belief in plate tectonics is protected from direct assault by auxiliary hypotheses that are still being generated; and the plate model is so widely believed to be correct that it is difficult to get alternative interpretations published in the scientific literature [3].
    The plate-tectonics hypothesis has faced growing criticism as the number of observational anomalies has increased. It will shown below that plate tectonics faces some fundamental -- and in fact fatal -- problems.

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« Reply #1 on: July 28, 2008, 11:04:35 pm »

Plate tectonics -- a failed revolution

Plates in motion?

According to the classical model of plate tectonics, lithospheric plates move over a relatively plastic layer of partly molten rock known as the asthenosphere (or low-velocity zone). The lithosphere, which comprises the earth's crust and uppermost mantle, is said to average about 70 km thick beneath oceans and to be 100 to 250 km thick beneath continents. A powerful challenge to this model is posed by seismic tomography, which produces three-dimensional images of the earth's interior. It shows that the oldest parts of the continents have deep roots extending to depths of 400 to 600 km, and that the asthenosphere is essentially absent beneath them. Seismic research shows that even under the oceans there is no continuous asthenosphere, only disconnected asthenospheric lenses.
    The crust and uppermost mantle have a highly complex, irregular structure; they are divided by faults into a mosaic of separate, jostling blocks of different shapes and sizes, and of varying internal structure and strength. N.I. Pavlenkova concludes: 'This means that the movement of lithospheric plates over long distances, as single rigid bodies, is hardly possible. Moreover, if we take into account the absence of the asthenosphere as a single continuous zone, then this movement seems utterly impossible' [1]. Although the concept of thin lithospheric plates moving thousands of kilometers over a global asthenosphere is untenable, most geological textbooks continue to propagate this simplistic model, and fail to give the slightest indication that it faces any problems.


Figure 1. Seismotomographic cross-section showing velocity structure across the North American craton and North Atlantic Ocean. High-velocity (colder) lithosphere, shown in dark tones, underlies the Canadian shield to depths of 250 to 500 km. (Reprinted with permission from Grand [2]. Copyright by the American Geophysical Union.)

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« Reply #2 on: July 28, 2008, 11:05:47 pm »

The driving force of plate movements was initially claimed to be mantle-deep convection currents welling up beneath midocean ridges, with downwelling occurring beneath ocean trenches. Plate tectonicists expected seismotomography to provide clear evidence of a well-organized convection-cell pattern, but it has actually provided strong evidence against the existence of large, plate-propelling convection cells in the mantle. The favored plate-driving mechanisms at present are 'ridge-push' and 'slab-pull', but their adequacy is very much in doubt.
    Thirteen major plates are currently recognized, ranging in size from about 400 by 2500 km to 10,000 by 10,000 km, together with a proliferating number of microplates (over 100 so far). Plate boundaries are identified and defined mainly on the basis of earthquake and volcanic activity. The close correspondence between plate edges and belts of earthquakes and volcanoes is therefore to be expected and can hardly be regarded as one of the 'successes' of plate tectonics! A major problem is that several 'plate boundaries' are purely theoretical and appear to be nonexistent, including the northwest Pacific boundary of the Pacific, North American, and Eurasian plates, the southern boundary of the Philippine plate, part of the southern boundary of the Pacific plate, and most of the northern and southern boundaries of the South American plate.




Continental drift

Geological field mapping provides evidence for horizontal crustal movements of up to several hundred kilometers. Plate tectonics, however, claims that continents have moved up to 7000 km or more since the alleged breakup of Pangaea. Satellite measurements of crustal movements have been hailed by some geologists as having proved plate tectonics. Such measurements provide a guide to crustal strains, but do not provide evidence for plate motions of the kind predicted by plate tectonics unless the relative motions predicted among all plates are observed. However, many of the results have shown no definite pattern, and have been confusing and contradictory, giving rise to a variety of ad-hoc hypotheses. For instance, distances from the Central South American Andes to Japan or Hawaii are more or less constant, whereas plate tectonics predicts significant separation. The practise of extrapolating present crustal movements tens or hundreds of millions of years into the past or future is clearly a hazardous exercise.
    A 'compelling' piece of evidence that all the continents were once united in one large landmass is said to be the fact that they can be fitted together like pieces of a jigsaw puzzle. However, although many reconstructions have been attempted, none are entirely acceptable. In the Bullard et al. computer-generated fit, for example, there are a number of glaring omissions. The whole of Central America and much of southern Mexico -- a region of some 2,100,000 km² -- has been left out because it overlaps South America. The entire West Indian archipelago has also been omitted. In fact, much of the Caribbean is underlain by ancient continental crust, and the total area involved, 300,000 km², overlaps Africa. The Cape Verde Islands-Senegal basin, too, is underlain by ancient continental crust, creating an additional overlap of 800,000 km². Several major submarine structures that appear to be of continental origin are also ignored, including the Faeroe-Iceland-Greenland Ridge, Jan Mayen Ridge, Walvis Ridge, Rio Grande Rise, and the Falkland Plateau.


Figure 2. The Bullard fit. Overlaps and gaps between continents are shown in black. (Reprinted with permission from Bullard et al. [3]. Copyright by The Royal Society.)
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« Reply #3 on: July 28, 2008, 11:06:19 pm »

Like the Bullard fit, the Smith & Hallam reconstruction of the Gondwanaland continents tries to fit the continents along the 500-fathom (1-km) depth contour on the continental shelves. The South Orkneys and South Georgia are omitted, as is Kerguelen Island in the Indian Ocean, and there is a large gap west of Australia. Fitting India against Australia, as in other fits, leaves a corresponding gap in the western Indian Ocean. Dietz & Holden based their fit on the 2-km depth contour, but they still have to omit the Florida-Bahamas platform, ignoring the evidence that it predates the alleged commencement of drift. In many regions the boundary between continental and oceanic crust appears to occur beneath oceanic depths of 2-4 km or more, and in some places the ocean-continent transition zone is several hundred kilometers wide. This means that any reconstructions based on arbitrarily selected depth contours are flawed. Given the liberties that drifters have had to take to obtain the desired continental matches, their computer-generated fits may well be a case of 'garbage in, garbage out'.
    The curvature of continental contours is often so similar that many shorelines can be fitted together quite well even though they can never have been in juxtaposition. For instance, eastern Australia fits well with eastern North America, and there are also remarkable geological and paleontological similarities, probably due to the similar tectonic backgrounds of the two regions. The geological resemblances of opposing Atlantic coastlines may be due to the areas having belonged to the same tectonic belt, but the differences -- which are rarely mentioned -- are sufficient to show that the areas were situated in distant parts of the belt. H.P. Blavatsky regarded the similarities in the geological structure, fossils, and marine life of the opposite coasts of the Atlantic in certain periods as evidence that 'there has been, in distant pre-historic ages, a continent which extended from the coast of Venezuela, across the Atlantic Ocean, to the Canarese Islands and North Africa, and from Newfoundland nearly to the coast of France' [4].
    One of the main props of continental drift is paleomagnetism -- the study of the magnetism of ancient rocks and sediments. For each continent a 'polar wander path' can be constructed, and these are interpreted to mean that the continents have moved vast distances over the earth's surface. However, paleomagnetism is very unreliable and frequently produces inconsistent and contradictory results. For instance, paleomagnetic data imply that during the mid-Cretaceous Azerbaijan and Japan were in the same place! When individual paleomagnetic pole positions, rather than averaged curves, are plotted on world maps, the scatter is huge, often wider than the Atlantic.
    One of the basic assumptions of paleomagnetism is that rocks retain the magnetization they acquire at the time they formed. In reality, rock magnetism is subject to modification by later magnetism, weathering, metamorphism, tectonic deformation, and chemical changes. Horizontal and vertical rotations of crustal blocks further complicate the picture. Another questionable assumption is that over long periods of time the geomagnetic field approximates a simple dipole (N-S) field oriented along the earth's rotation axis. If, in the past, there were stable magnetic anomalies of the same intensity as the present-day East Asian anomaly (or slightly more intensive), this would render the geocentric axial dipole hypothesis invalid.
    The opening of the Atlantic Ocean allegedly began in the Cretaceous by the rifting apart of the Eurasian and American plates. However, on the other side of the globe, northeastern Eurasia is joined to North America by the Bering-Chukotsk shelf, which is underlain by Precambrian continental crust that is continuous and unbroken from Alaska to Siberia. Geologically these regions constitute a single unit, and it is unrealistic to suppose that they were formerly divided by an ocean several thousand kilometers wide, which closed to compensate for the opening of the Atlantic. If a suture is absent there, one ought to be found in Eurasia or North America, but no such suture appears to exist. Similarly, geology indicates that there has been a direct tectonic connection between Europe and Africa across the zones of Gibraltar and Rif on the one hand, and Calabria and Sicily on the other, at least since the end of the Paleozoic, contradicting plate-tectonic claims of significant displacement between Europe and Africa during this period.
    India supposedly detached itself from Antarctica sometime during the Mesozoic, and then drifted northeastward up to 9000 km, over a period of up to 200 million years, until it finally collided with Asia in the mid-Tertiary, pushing up the Himalayas and the Tibetan Plateau. That Asia happened to have an indentation of approximately the correct shape and size and in exactly the right place for India to 'dock' into would amount to a remarkable coincidence. There is, however, overwhelming geological and paleontological evidence that India has been an integral part of Asia since Precambrian time. If the long journey of India had actually happened, it would have been an isolated island-continent for millions of years -- sufficient time to have evolved a highly distinct endemic fauna. However, the Mesozoic and Tertiary faunas show no such endemism, but indicate instead that India lay very close to Asia throughout this period, and not to Australia and Antarctica. It would appear that the supposed 'flight of India' is no more than a flight of fancy!
    It is often claimed that plate-tectonic reassemblies of the continents can help to explain climatic changes and the distribution of plants and animals in the past. However, detailed studies have shown that shifting the continents succeeds at best in explaining local or regional climatic features for a particular period, and invariably fails to explain the global climate for the same period. A.A. Meyerhoff et al. showed in a detailed study that most major biogeographical boundaries, based on floral and faunal distributions, do not coincide with the partly computer-generated plate boundaries postulated by plate tectonics. The authors comment: 'What is puzzling is that such major inconsistencies between plate tectonic postulates and field data, involving as they do boundaries that extend for thousands of kilometers, are permitted to stand unnoticed, unacknowledged, and unstudied.' Before their study was published by the Geological Society of America, a group of earth-science graduates was invited to study the manuscript. They became deeply disturbed by what they read, and commented: 'If this global study of biodiversity through time is correct, and it is very convincingly presented, then a lot of what we are being taught about plate tectonics should more aptly be called "Globaloney" ' [5].
    It is unscientific to select a few faunal identities and ignore the vastly greater number of faunal dissimilarities from different continents which were supposedly once joined [6]. The known distributions of fossil organisms are more consistent with an earth model like that of today than with continental-drift models. Some of the paleontological evidence appears to require the alternate emergence and submergence of land dispersal routes only after the supposed breakup of Pangaea. For example, mammal distribution indicates that there were no direct physical connections between Europe and North America during Late Cretaceous and Paleocene times, but suggests a temporary connection with Europe during the Eocene. A few drifters have recognized the need for intermittent land bridges after the supposed separation of the continents. Various oceanic ridges, rises, and plateaus could have served as land bridges, as many are known to have been partly above water at various times in the past. There is growing evidence that these land bridges formed part of larger former landmasses in the present oceans (see below).
    The present distribution of land and water is characterized by a number of notable regularities. First, the continents tend to be triangular, with their pointed ends to the south. Second, the northern polar ocean is almost entirely ringed by land, from which three continents project southward, while the continental landmass at the south pole is surrounded by water, with three oceans projecting northward. Third, the oceans and continents are arranged antipodally -- i.e. if there is land in one area of the globe, there tends to be water in the corresponding area on the opposite side of the globe.
    The Arctic Ocean is precisely antipodal to Antarctica; North America is exactly antipodal to the Indian Ocean; Europe and Africa are antipodal to the central area of the Pacific Ocean; Australia is antipodal to the North Atlantic; and the South Atlantic corresponds -- though less exactly -- to the eastern half of Asia.* Only 7% of the earth's surface does not obey the antipodal rule. If the continents had slowly drifted thousands of kilometers to their present positions, the antipodal arrangement of land and water would have to be regarded as purely coincidental. The antipodal arrangement of land and seas reflects the tetrahedral plan of the earth. If one corner of the tetrahedron is placed in Antarctica, at the south pole, the other three lie in three vast blocks of very ancient, Archean rocks in the northern hemisphere: the Canadian shield, the Scandinavian shield, and the Siberian shield, and the three edges correspond to the three roughly meridional lines running through the three pairs of continents: North and South America, Europe and Africa, Asia and Australia.**



*Rupert Sheldrake likens the earth to a developing organism, and says that the existence of an ocean at the north pole and a continent at the south pole may be the culmination of a morphogenetic process: 'Such a morphological polarization of a spherical body is very familiar in the realm of biology; for example, in the formation of poles in fertilized eggs' (The Rebirth of Nature, Bantam, 1991, p. 161).
**J.W. Gregory suggested that in the Upper Paleozoic the tetrahedron was the other way up, with one corner at the north pole. Instead of a continuous southern ocean-belt separating triangular points of land, there was then a southern land-belt, supported by three great equidistant cornerstones: the Archean blocks of South America, South Africa, and Australia.
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« Reply #4 on: July 28, 2008, 11:06:48 pm »


Figure 3. The antipodal arrangement of land and sea. (Reprinted with permission from Gregory [7]. Copyright by the Royal Geographical Society.)

    Another significant fact is that the triple points formed where 'plate boundaries' (i.e. seismic belts) meet coincide very closely with the vertices of an icosahedron, which, like the tetrahedron, is one of the five regular polyhedra or Platonic solids. This, too, would be a remarkable coincidence if 'plates' had really changed their shape and size to the extent postulated in plate tectonics.

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« Reply #5 on: July 28, 2008, 11:07:38 pm »



Figure 4. Major seismotectonic belts/'plate boundaries' (broken lines) compared with an icosahedron. (Reprinted with permission from Spilhaus [8]. Copyright by the American Geophysical Union.)



Seafloor spreading and subduction

According to the seafloor-spreading hypothesis, new oceanic crust is generated at midocean ridges by the upwelling of molten material from the earth's mantle, and as the magma cools it spreads away from the flanks of the ridges. The horizontally moving plates are said to plunge back into the mantle at ocean trenches or 'subduction zones'.
    The ocean floor is far from having the uniform characteristics that conveyor-type spreading would imply. The mantle is asymmetrical in relation to the midocean ridges and has a complicated mosaic structure independent of the strike of the ridge. N.C. Smoot and A.A. Meyerhoff showed that nearly all published charts of the world's ocean floors have been drawn deliberately to reflect the predictions of the plate-tectonics hypothesis, and the most accurate charts now available are widely ignored because they do not conform to plate-tectonic preconceptions [9]. Side-scanning radar images show that the midocean ridges are cut by thousands of long, linear, ridge-parallel fissures, fractures, and faults. This strongly suggests that the ridges are underlain at shallow depth by interconnected magma channels, in which semi-fluid lava moves horizontally and parallel with the ridges rather than at right-angles to them.
    The oldest known rocks from the continents are just under 4 billion years old, whereas -- according to plate tectonics -- none of the ocean crust is older than 200 million years (Jurassic). This is cited as conclusive evidence that oceanic crust is constantly being created at midocean ridges and consumed in subduction zones. There is in fact abundant evidence against the alleged youth of the ocean floor, though geological textbooks tend to pass over it in silence.
    Scientists involved in the Deep Sea Drilling Project were apparently motivated by a strong desire to confirm seafloor spreading. They have given the impression that the basalt (layer 2) found beneath the sedimentary sequences (layer 1) at the bottom of many deep-sea drillholes is basement, with no further, older sediments below it. Yet in some cases there is clear evidence that the basalt is a later intrusion into existing sediments. The ocean floor needs to be drilled to much greater depths -- up to 5 km -- to see whether there are Triassic, Paleozoic, or Precambrian sediments below the so-called basement.
    Plate tectonics predicts that the age of the oceanic crust should increase systematically with distance from the midocean ridge crests. However, the dates exhibit a very large scatter. On one seamount just west of the crest of the East Pacific Rise, the radiometric dates range from 2.4 to 96 million years. Although a general trend is discernible from younger sediments at ridge crests to older sediments away from them, this is in fact to be expected, since the crest is the highest and most active part of the ridge; older sediments are likely to be buried beneath younger volcanic rocks. The basalt layer in the ocean crust suggests that magma flooding was once ocean-wide, but volcanism was subsequently restricted to an increasingly narrow zone centered on the ridge crests. Such magma floods were accompanied by progressive crustal subsidence in large sectors of the present oceans, beginning in the Jurassic.




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« Reply #6 on: July 28, 2008, 11:11:29 pm »


Figure 5. A plot of rock age vs. distance from the crest of the Mid-Atlantic Ridge. (Reprinted with permission from Meyerhoff et al., 1996a, fig. 2.35. Copyright by Kluwer Academic Publishers.)

    The numerous finds in the Atlantic, Pacific, and Indian Oceans of rocks far older than 200 million years, many of them continental in nature, provide strong evidence against the alleged youth of the underlying crust. In the equatorial segment of the Mid-Atlantic Ridge numerous shallow-water and continental rocks, with ages up to 3.74 billion years have been found. A study of St. Peter and Paul's Rocks at the crest of the Mid-Atlantic Ridge just north of the equator, turned up an 835-million-year rock associated with other rocks giving 350-, 450-, and 2000-million-year ages, whereas according to the seafloor-spreading model the rock should have been 35 million years.
    Rocks dredged from the Bald Mountain region just west of the Mid-Atlantic Ridge crest at 45°N were found to be between 1690 to 1550 million years old. 75% of the rock samples consisted of continental-type rocks, and the scientists involved commented that this was a 'remarkable phenomenon' -- so remarkable, in fact, that they decided to classify these rocks as 'glacial erratics' and to give them no further consideration. Another way of dealing with 'anomalous' rock finds is to dismiss them as ship ballast. However, the Bald Mountain locality has an estimated volume of 80 km³, so it is hardly likely to have been rafted out to sea on an iceberg or dumped by a ship! In another attempt to explain away anomalously old rocks and anomalously shallow or emergent crust in certain parts of the ridges, some plate tectonicists have put forward the contrived notion that 'nonspreading blocks' can be left behind during rifting, and that the spreading axis and related transform faults can jump from place to place.
    Strong support for seafloor spreading is said to be provided by marine magnetic anomalies -- approximately parallel stripes of alternating high and low magnetic intensity that characterize some 70% of the world's midocean ridges. According to the plate-tectonic hypothesis, as the fluid basalt welling up along the midocean ridges spreads horizontally and cools, it is magnetized by the earth's magnetic field. Bands of high intensity are believed to have formed during periods of normal magnetic polarity, and bands of low intensity during periods of reversed polarity. However, ocean drilling has seriously undermined this simplistic model.
    Correlations have been made between linear magnetic anomalies on either side of a ridge, in different parts of the oceans, and with radiometrically-dated magnetic events on land. The results have been used to produce maps showing how the age of the ocean floor increases steadily with increasing distance from the ridge axis. As indicated above, this simple picture can be sustained only by dismissing the possibility of older sediments beneath the basalt 'basement' and by ignoring numerous 'anomalously' old rock ages. The claimed correlations have been largely qualitative and subjective, and are therefore highly suspect. More detailed, quantitative analyses have shown that the alleged correlations are very poor. A more likely explanation of the magnetic stripes is that they are caused by fault-related bands of rock of different magnetic properties, and have nothing to do with seafloor spreading.

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« Reply #7 on: July 28, 2008, 11:12:05 pm »


Figure 6. Two views of marine magnetic anomalies. Top: a textbook cartoon. (Reprinted with permission from McGeary & Plummer [2]. Copyright by The McGraw-Hill Companies.). Bottom: magnetic anomaly patterns of the North Atlantic (Reprinted with permission from Meyerhoff & Meyerhoff, 1972. Copyright by the American Geophysical Union.)

    A remarkable fact concerning oceanic magnetic anomalies is that they are approximately concentric with respect to Archean continental shields (i.e. continental nuclei more than 2.5 billion years old). This implies that instead of being a 'taped record' of seafloor spreading and geomagnetic field reversals during the past 200 million years, most oceanic magnetic anomalies are the sites of ancient fractures, which partly formed during the Proterozoic and have been rejuvenated since. The evidence also suggests that Archean continental nuclei have held approximately the same positions with respect to one another since their formation -- which is utterly at variance with continental drift.
    Benioff zones are distinct earthquake zones that begin at an ocean trench and slope landward and downward into the earth. In plate tectonics, these deep-rooted fault zones are interpreted as 'subduction zones' where plates descend into the mantle. They are generally depicted as 100-km-thick slabs descending into the earth either at a constant angle, or at a shallow angle near the earth's surface and gradually curving round to an angle of between 60° and 75°. Neither representation is correct. Benioff zones often consist of two separate sections: an upper zone with an average dip of 33° extending to a depth of 70-400 km, and a lower zone with an average dip of 60° extending to a depth of up to 700 km. The upper and lower segments are sometimes offset by 100-200 km, and in one case by 350 km. Furthermore, deep earthquakes are disconnected from shallow ones; very few intermediate earthquakes exist. Many studies have found transverse as well as vertical discontinuities and segmentation in Benioff zones. The evidence therefore does not favor the notion of a continuous, downgoing slab.




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« Reply #8 on: July 28, 2008, 11:12:44 pm »


Figure 7. Cross-sections across the Peru-Chile trench (left) and Bonin-Honshu arc (right), showing earthquake centers. (Reprinted with permission from Benioff [10]. Copyright by the Geological Society of America.)

    Plate tectonicists insist that the volume of crust generated at midocean ridges is equaled by the volume subducted. But whereas 80,000 km of midocean ridges are supposedly producing new crust, only 30,500 km of trenches exist. Even if we add the 9000 km of 'collision zones', the figure is still only half that of the 'spreading centers'. With two minor exceptions, Benioff zones are absent from the margins of the Atlantic, Indian, Arctic, and Southern Oceans. Africa is allegedly being converged on by plates spreading from the east, south, and west, yet it exhibits no evidence whatsoever for the existence of subduction zones or newly forming mountains belts. Antarctica, too, is almost entirely surrounded by alleged 'spreading' ridges without any corresponding subduction zones, but fails to show any signs of being crushed. It has been suggested that Africa and Antarctica may remain stationary while the surrounding ridge system migrates away from them, but this would require the ridge marking the 'plate boundary' between Africa and Antarctica to move in opposite directions simultaneously!
    If up to 13,000 kilometers of lithosphere had really been subducted in circum-Pacific deep-sea trenches, vast amounts of oceanic sediments should have been scraped off the ocean floor and piled up against the landward margin of the trenches. However, sediments in the trenches are generally not present in the volumes required, nor do they display the expected degree of deformation. Scholl & Marlow, who support plate tectonics, admitted to being 'genuinely perplexed as to why evidence for subduction or offscraping of trench deposits is not glaringly apparent' [11]. Plate tectonicists have had to resort to the highly dubious notion that unconsolidated deep-ocean sediments can slide smoothly into a Benioff zone without leaving any significant trace. Subduction along Pacific trenches is also refuted by the fact that the Benioff zone often lies 80 to 150 km landward from the trench; by the evidence that Precambrian continental structures continue into the ocean floor; and by the evidence for submerged continental crust under the northwestern and southeastern Pacific, where there are now deep abyssal plains and trenches.
    An alternative view of Benioff zones is that they are very ancient contraction fractures produced by the cooling of the earth. The fact that the upper part of the Benioff zones dips at less than 45° and the lower part at more than 45° suggests that the lithosphere is under compression and the lower mantle under tension. Since a contracting sphere tends to fracture along great circles, this would account for the fact that both the circum-Pacific seismotectonic belt and the Alpine-Himalayan (Tethyan) belt* lie on approximate circles.


*The Alpine-Himalayan belt stretches from the Mediterranean to the Pacific, and is also visible in Central America. Some earth scientists believe it was once global in extent. Blavatsky says that the Himalayan belt does indeed encircle the globe, either under the water or above (The Secret Doctrine, 2:401fn).



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« Reply #9 on: July 28, 2008, 11:13:28 pm »

Emergence and submergence

Vertical tectonics

The theosophical tradition teaches that the earth's crust is constantly rising or sinking, usually slowly but at times with cataclysmic intensity. There is a constant alternation of land and water: as one portion of the dry land is submerged, new land emerges elsewhere. Blavatsky writes:


Elevation and subsidence of continents is always in progress. The whole coast of South America has been raised up 10 to 15 feet and settled down again in an hour. Huxley has shown that the British islands have been four times depressed beneath the ocean and subsequently raised again and peopled. The Alps, Himalayas and Cordilleras were all the result of depositions drifted on to sea-bottoms and upheaved by Titanic forces to their present elevation. The Sahara was the basin of a Miocene sea. Within the last five or six thousand years the shores of Sweden, Denmark and Norway have risen from 200 to 600 feet; in Scotland there are raised beaches with outlying stacks and skerries surmounting the shore now eroded by the hungry wave. The North of Europe is still rising from the sea and South America presents the phenomenon of raised beaches over 1,000 miles in length, now at a height varying from 100 to 1,300 feet above the sea-level. On the other hand, the coast of Greenland is sinking fast, so much so that the Greenlander will not build by the shore. All these phenomena are certain. Why may not a gradual change have given place to a violent cataclysm in remote epochs? -- such cataclysms occurring on a minor scale even now (e.g., the case of Sunda island with 80,000 Malays*).[1]
*A reference to the massive eruption in 1883 of the volcano on the island of Krakatoa in the Sunda Strait. It created a tsunami, or giant sea wave, that swept away more than 30,000 people on the islands of Java and Sumatra.

Blavatsky also quotes the following from a contemporary scientist:


forces are unceasingly acting, and there is no reason why an elevating force once set in action in the centre of an ocean should cease to act until a continent is formed. They have acted and lifted out from the sea, in comparatively recent geological times, the loftiest mountains on earth. . . . Sea-beds have been elevated 1,000 fathoms and islands have risen up from the depths of 3,000 fathoms . . . [2]
The existence of former continental landmasses in the present oceans may be at odds with plate-tectonic dogma but, as shown below, it is supported by mounting evidence.
    Classical plate tectonics seeks to explain all geologic structures primarily in terms of simple horizontal movements of lithospheric plates -- their rifting, extension, collision, and subduction. But random plate interactions are unable to explain the periodic character of geological processes, i.e. the geotectonic cycle, which sometimes operates on a global scale. Nor can they explain the large-scale uplifts and subsidences that have characterized the evolution of the earth's crust, especially those occurring far from 'plate boundaries' such as in continental interiors, and vertical oscillatory motions involving vast regions. The presence of marine strata thousands of meters above sea level (e.g. near the summit of Mount Everest) and the great thicknesses of shallow-water sediment in some old basins indicate that vertical crustal movements of at least 9 km above sea level and 10-15 km below sea level have taken place.
    Major vertical movements have also occurred along continental margins. For example, the Atlantic continental margin of North America has subsided by up to 12 km since the Jurassic. In Barbados, Tertiary coals representing a shallow-water, tropical environment occur beneath deep-sea oozes, indicating that during the last 12 million years, the crust sank to over 4-5 km depth for the deposition of the ooze and was then raised again. A similar situation occurs in Indonesia, where deep-sea oozes occur above sea level, sandwiched between shallow-water Tertiary sediments.
    The primary mountain-building mechanism in plate tectonics is lateral compression caused by collisions -- of continents, island arcs, oceanic plateaus, seamounts, and ridges. In this model, subduction proceeds without mountain building until collision occurs, whereas in the noncollision model subduction alone is supposed to cause mountain building. As well as being mutually contradictory, both models are inadequate, as several supporters of plate tectonics have admitted. The noncollision model fails to explain how continuous subduction can give rise to discontinuous mountain building, while the collision model is challenged by occurrences of mountain building where no continental collision can be assumed, and it fails to explain contemporary mountain-building activity along such chains as the Andes and around much of the rest of the Pacific rim.
    Asia supposedly collided with Europe in the late Paleozoic, producing the Ural mountains, but abundant geological field data demonstrate that the Siberian and East European (Russian) platforms have formed a single continent since Precambrian times. One geological textbook admits that the plate-tectonic reconstruction of the formation of the Appalachian mountains in terms of three successive collisions of North America seems 'too implausible even for a science fiction plot'. C.D. Ollier states that fanciful plate-tectonic explanations ignore all the geomorphology and much of the known geological history of the Appalachians. He also says that of all the possible mechanisms that might account for the Alps, the collision of the African and European plates is the most naive [3].
    The Himalayas and the Tibetan Plateau were supposedly uplifted by the collision of the Indian plate with the Asian plate. However, this fails to explain why the beds on either side of the supposed collision zone remain comparatively undisturbed and low-dipping, whereas the Himalayas have been uplifted, supposedly as a consequence, some 100 km away, along with the Kunlun mountains to the north of the Tibetan Plateau. River terraces in various parts of the Himalayas are almost perfectly horizontal and untilted, suggesting that the Himalayas were uplifted vertically, rather than as the result of horizontal compression.
    There is ample evidence that mantle heat flow and material transport can cause significant changes in crustal thickness, composition, and density, resulting in substantial uplifts and subsidences. This is emphasized in many of the alternative hypotheses to plate tectonics. Plate tectonicists, too, increasingly invoke mantle diapirism and related upwelling processes as a mechanism for vertical crustal movements.
    Plate tectonics predicts simple heat-flow patterns around the earth. There should be a broad band of high heat flow beneath the full length of the midocean rift system, and parallel bands of high and low heat flow along the Benioff zones. Intraplate regions are predicted to have low heat flow. The pattern actually observed is quite different. There are criss-crossing bands of high heat flow covering the entire surface of the earth. Intra-plate volcanism is usually attributed to 'mantle plumes' -- upwellings of hot material from deep in the mantle. The movement of plates over the plumes is said to give rise to hotspot trails (chains of volcanic islands and seamounts). Such trails should therefore show an age progression from one end to the other, but good age progressions are very rare, and a large majority show little or no age progression. H.C. Sheth has argued that the plume hypothesis is ill-founded, artificial, and invalid, and has led earth scientists up a blind alley [4].
    A major new hypothesis of geodynamics is surge tectonics, which rejects both seafloor spreading and continental drift [5]. Surge tectonics postulates that all the major features of the earth's surface, including rifts, foldbelts, metamorphic belts, and strike-slip zones, are underlain by shallow (less than 80 km) magma chambers and channels (known as 'surge channels'). Seismotomographic data suggest that surge channels form an interconnected worldwide network, which has been dubbed 'the earth's cardiovascular system'. Active surge channels are characterized by high heat flow and microearthquakes. Magma from the asthenosphere flows slowly through active channels at the rate of a few centimeters a year. This horizontal flow is demonstrated by two major surface features: linear, belt-parallel faults, fractures, and fissures; and the division of tectonic belts into fairly uniform segments. The same features characterize all lava flows and tunnels, and have also been observed on Mars, Venus, and several moons of the outer planets.
    Surge tectonics postulates that the main cause of geodynamics is lithosphere compression, generated by the cooling and contraction of the earth.* As compression increases during a geotectonic cycle, it causes the magma to move through a channel in pulsed surges and eventually to rupture it, so that the contents of the channel surge bilaterally upward and outward to initiate tectogenesis. The asthenosphere (in regions where it is present) alternately contracts during periods of tectonic activity and expands during periods of tectonic quiescence. The earth's rotation, combined with differential lag between the more rigid lithosphere above and the more fluid asthenosphere below, causes the fluid or semifluid materials to move predominantly eastward.


*Earth scientists hold widely divergent views on the changes in size that the earth has undergone since its formation. From a theosophical perspective, after its formation in an ethereal state some 2 billion years ago, the earth gradually physicalized and contracted to some extent. This downward arc of the earth's evolution came to an end a few million years ago, and the upward arc of reetherealization began. The earth may be expected to expand slightly as the forces of attraction begin to relax.
« Last Edit: July 28, 2008, 11:14:20 pm by Carolyn Silver » Report Spam   Logged
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« Reply #10 on: July 28, 2008, 11:19:20 pm »

The continents

It is a striking fact that some nine tenths of all the sedimentary rocks composing the continents were laid down under the sea [6]. The continents have suffered repeated marine inundations, but because the seas were mostly shallow (less than 250 m), they are described as 'epicontinental'. Marine transgressions and regressions are usually attributed mainly to eustatic changes of sea level caused by alterations in the volume of midocean ridges. T.H. Van Andel points out that this explanation cannot account for the 100 or so briefer cycles of sea-level changes, especially since transgressions and regressions are not always simultaneous all over the globe. He proposes that large regions or whole continents must undergo slow vertical movements. He admits that such movements 'fit poorly into plate tectonics', and are therefore largely ignored [7].





Figure 8. Maximum degree of marine inundation for each Phanerozoic geological period for the former USSR and North America. The older the geological period, the greater the probability of the degree of inundation being underestimated due to the sediments having been eroded or deeply buried beneath younger sediments. (Reprinted with permission from Hallam [8]. Copyright by Nature.)
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« Reply #11 on: July 28, 2008, 11:20:02 pm »


Figure 9. Sea-level changes for six continents. For each time interval, the sea-level elevations for the various continents differ widely, highlighting the importance of vertical tectonic movements on a regional and continental scale. (Reprinted with permission from Harrison et al. [9]. Copyright by the American Geophysical Union.)

    Van Andel asserts that 'plates' rise or fall by no more than a few hundred meters -- this being the maximum depth of most 'epicontinental' seas. However, this overlooks an elementary fact: huge thicknesses of sediments were often deposited during marine incursions, often requiring vertical crustal movements of many kilometers. Sediments accumulate in regions of subsidence, and their thickness is usually close to the degree of downwarping. In the unstable, mobile belts bordering stable continental platforms, many geosynclinal troughs and circular depressions accumulated sedimentary thicknesses of 10 to 14 km, and in some cases of 20 km. Although the sediments deposited on the platforms themselves are mostly less than 1.5 km thick, here too sedimentary basins with deposits 10 km or even 20 km thick are not unknown.
    Subsidence cannot be attributed solely to the weight of the accumulating sediments because the density of sedimentary rocks is much lower than that of the subcrustal material; for instance, the deposition of 1 km of marine sediment will cause only half a kilometer or so of subsidence. Moreover, sedimentary basins require not only continual depression of the base of the basin to accommodate more sediments, but also continuous uplift of adjacent land to provide a source for the sediments. In geosynclines, subsidence has commonly been followed by uplift and folding to produce mountain ranges, and this can obviously not be accounted for by changes in surface loading. The complex history of the oscillating uplift and subsidence of the crust appears to require deep-seated changes in lithospheric composition and density, and vertical and horizontal movements of mantle material.
    In regions where all the sediments were laid down in shallow water, subsidence must somehow have kept pace with sedimentation. In eugeosynclines, on the other hand, subsidence proceeded faster than sedimentation, resulting in a deep marine basin several kilometers deep. Examples of eugeosynclines prior to the uplift stage are the Sayans in the Early Paleozoic, the eastern slope of the Urals in the Early and Middle Paleozoic, the Alps in the Jurassic and Early Cretaceous, and the Sierra Nevada in the Triassic. Although plate tectonicists often claim that geosynclines are formed solely at plate margins at the boundaries between continents and oceans, there are many examples of geosynclines having formed in intracontinental settings.

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« Reply #12 on: July 28, 2008, 11:20:25 pm »

The oceans

In the past, sediments have been transported to today's continents from the direction of the present-day oceans, where there must have been considerable areas of land that underwent erosion. For instance, the Paleozoic geosyncline along the seaboard of eastern North America, an area now occupied by the Appalachian mountains, was fed by sediments from a borderland ('Appalachia') in the adjacent Atlantic. Other submerged borderlands include the North Atlantic Continent or Scandia (west of Spitsbergen and Scotland), Cascadia (west of the Sierra Nevada), and Melanesia (southeast of Asia and east of Australia). A million cubic kilometers of Devonian sediments from Bolivia to Argentina imply an extensive continental source to the west where there is now the deep Pacific Ocean. During Paleozoic-Mesozoic-Paleogene times, the Japanese geosyncline was supplied with sediments from land areas in the Pacific.
    When trying to explain sediment sources, plate tectonicists sometimes argue that sediments were derived from the existing continents during periods when they were supposedly closer together. Where necessary, they postulate small former land areas (microcontinents or island arcs), which have since been either subducted or accreted against continental margins as 'exotic terranes'. However, mounting evidence is being uncovered that favors the foundering of sizable continental landmasses, whose remnants are still present under the ocean floor.
    Oceanic crust is regarded as much thinner and denser than continental crust: the crust beneath oceans is said to average about 7 km thick and to be composed largely of basalt and gabbro, whereas continental crust averages about 35 km thick and consists chiefly of granitic rock capped by sedimentary rocks. However, ancient continental rocks and crustal types intermediate between standard 'continental' and 'oceanic' crust are increasingly being discovered in the oceans, and this is a serious embarrassment for plate tectonics. The traditional picture of the crust beneath oceans being universally thin and graniteless may well be further undermined in the future, as seismic research and ocean drilling continue
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« Reply #13 on: July 28, 2008, 11:21:04 pm »

Figure 10. Worldwide distribution of oceanic plateaus (black). (Reprinted with permission from Storetvedt,1997. Copyright by Fagbokforlaget and K.M. Storetvedt.)

    There are over 100 submarine plateaus and aseismic ridges scattered throughout the oceans, many of which were once above water. They make up about 10% of the ocean floor. Many appear to be composed of modified continental crust 20-40 km thick -- far thicker than 'normal' oceanic crust. They often have an upper 10-15 km crust with seismic velocities typical of granitic rocks in continental crust. They have remained obstacles to predrift continental fits, and have therefore been interpreted as extinct spreading ridges, anomalously thickened oceanic crust, or subsided continental fragments carried along by the 'migrating' seafloor. If seafloor spreading is rejected, they cease to be anomalous and can be interpreted as submerged, in-situ continental fragments that have not been completely 'oceanized'.
    Shallow-water deposits ranging in age from mid-Jurassic to Miocene, as well as igneous rocks showing evidence of subaerial weathering, were found in 149 of the first 493 boreholes drilled in the Atlantic, Indian, and Pacific Oceans. These shallow-water deposits are now found at depths ranging from 1 to 7 km, demonstrating that many parts of the present ocean floor were once shallow seas, shallow marshes, or land areas [10]. From a study of 402 oceanic boreholes in which shallow-water or relatively shallow-water sediments were found, E.M. Ruditch concluded that there is no systematic correlation between the age of shallow-water accumulations and their distance from the axes of the midoceanic ridges, thereby disproving the seafloor-spreading model. Some areas of the oceans appear to have undergone continuous subsidence, whereas others experienced alternating episodes of subsidence and elevation. The Pacific Ocean appears to have formed mainly from the late Jurassic to the Miocene, the Atlantic Ocean from the Late Cretaceous to the end of the Eocene, and the Indian Ocean during the Paleocene and Eocene [11]. This corresponds closely to the theosophical teachings on the submergence of Lemuria in the Late Mesozoic and early Cenozoic, and the submergence of Atlantis in the first half of the Cenozoic [12].
    Geological, geophysical, and dredging data provide strong evidence for the presence of Precambrian and younger continental crust under the deep abyssal plains of the present northwest Pacific. Most of this region was either subaerially exposed or very shallow sea during the Paleozoic to early Mesozoic, and first became deep sea about the end of the Jurassic. Paleolands apparently existed on both sides of the Japanese islands, and they were submerged during Paleogene to Miocene times. There is also evidence of paleolands in the southwest Pacific around Australia and in the southeast Pacific during the Paleozoic and Mesozoic.
    Oceanographic and geological data suggest that a large part of the Indian Ocean, especially the eastern part, was land (called by some scientists 'Lemuria') from the Jurassic until the Miocene. The evidence includes seismic and pollen data and subaerial weathering which suggest that the Broken and Ninety East Ridges were part of an extensive, now sunken landmass; extensive drilling, seismic, magnetic, and gravity data pointing to the existence an Alpine-Himalayan foldbelt in the northwestern Indian Ocean, associated with a foundered continental basement; data that continental basement underlies the Scott, Exmouth, and Naturaliste plateaus west of Australia; and thick Triassic and Jurassic sedimentation on the western and northwestern shelves of the Australian continent with characteristics pointing to a western source.




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« Reply #14 on: July 28, 2008, 11:21:36 pm »


Figure 11. Former land areas in the present Pacific and Indian Oceans. Only those areas for which substantial evidence already exists are shown. Their exact outlines and full extent are as yet unknown. G1 -- Seychelles area; G2 -- Great Oyashio Paleoland; G3 -- Obruchev Rise; G4 -- Lemuria; S1 -- area of Ontong-Java Plateau, Magellan Sea Mounts, and Mid-Pacific Mountains; S2 -- Northeast Pacific; S3 -- Southeast Pacific including Chatham Rise and Campbell Plateau; S4 -- Southwest Pacific; S5 -- area including South Tasman Rise; S6 -- East Tasman Rise and Lord Howe Rise; S7 -- Northeast Indian Ocean; S8 -- Northwest Indian Ocean. (Reprinted with permission from Dickins [13]. Copyright by J.M. Dickins.)

    In the North Atlantic and Arctic Oceans, modified continental crust (mostly 10-20 km thick) underlies not only ridges and plateaus but most of the ocean floor; only in deep-water depressions is typical oceanic crust found. Since deep-sea drilling has shown that large areas of the North Atlantic were previously covered with shallow seas, it is possible that much of the North Atlantic was continental crust before its rapid subsidence. Lower Paleozoic continental rocks with trilobite fossils have been dredged from seamounts scattered over a large area northeast of the Azores, and the presence of continental cobbles suggests that the area concerned was a submerged continental zone. Bald Mountain, from which a variety of ancient continental material has been dredged, could certainly be a foundered continental fragment. In the equatorial Atlantic, continental and shallow-water rocks are ubiquitous.
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