4-Subduction's Problems
Expansion poses no geophysical problems--the planet just keeps on growing and expanding, wherever and in whatever form it occurs, but the annual increase in diameter (~5-10 cm/yr or ~2-4 in/yr) is very small and difficult to measure.
Subduction, on the other hand, is purely hypothetical because it is based on a fundamental assumption that the planet has always been the same size since it was formed 4.5-4.6 billion years ago; something almost impossible to prove. This philosophical assumption requires that any addition of surface area to one part of the planet would require an equal compensatory loss in some other region of the planet. Maintaining a constant diameter, however, raises a number of troubling questions about the mechanics of subduction:
a. Not generally realized is that subduction, at a minimum, would require the Pacific basin to decrease in width by at least the ~2-4 cm/yr increase in width of the Atlantic basin in order to maintain Earth at a constant diameter and permit the entire Pacific Ocean basin to be swallowed! But, for subduction to be valid, another ~8-16 cm/yr of East Pacific Rise (EPR) growth (the greatest rate of new seafloor growth on the planet [Fig. 2]) also must be swallowed, for a total minimum subduction rate of ~10-20 cm/yr (~4-8 in/yr).
b. And to the above totals one must add an amount equal to additional seafloor growth along thousands of kilometers of midocean ridges in the Indian Ocean and around Antarctica. The Indian Ocean, which has opened even wider than the Atlantic, also has no evidence of subduction within its confines. How can worldwide seafloor growth in oceans outside the Pacific be vectored smoothly into the Pacific basin where the EPR is generating a prodigious volume of new seafloor in the middle of the Pacific subduction area?
c. A major flaw in subduction dogma is the very young age of the oldest Pacific Ocean sediments ever found in the Pacific basin. These sediments were cored on Ocean Drilling Program (ODP) Leg 129 at Site 801B (18° 38.52´N, 156° 21.582´E, Central Pigafetta Basin, just east of the Mariana Trench) and were found to be only ~169 Ma (Middle Jurassic) in age; roughly equal to the oldest sediments found in the Atlantic Ocean.
d. Using these ODP data and extrapolations from magnetic anomaly lineations (isochrons) in the same area, Nakanishi, et al, arrived at a slightly older age of ~195 Ma, postulating “the shape of the early Pacific plate was a rough triangle” covering an area of 0.04x10[6] km² at ~190 Ma, 0.6x10[6] km² at ~180 Ma, and 3x10[6] km² at ~170 Ma. The Pacific plate is now estimated to cover an area of 108x10[6] km²—which means that the entire Pacific plate has been generated within the last ~195 Ma, thereby constraining the age of the Pacific basin to be no more than ~200-205 Ma.
e. Proponents of subduction may argue that sediment ages less than ~200 Ma supports their contention that all the older Pacific seafloor has been subducted since the Atlantic basin first opened approximately ~160-175 Ma, and therefore none of the original Panthalassan seafloor can be found today. But this is only an inferred assumption and valid only if subduction has really existed. This is now a moot point because the evidence shown in Heezen and Tharp’s map shows that Panthalassa (Wegener's eo-Pacific Ocean) never existed.
f. If subduction were actually occurring to offset worldwide seafloor growth, there should be constant and sustained seismic activity reflecting disappearance of older seafloor at the same rate new seafloor is being generated. There is indeed a great deal of earthquake activity throughout the Ring of Fire, but it is not equally distributed around the Pacific Ocean perimeter commensurate with the constancy of new seafloor growth that must be vectored in from oceanic areas outside the Pacific basin.
g. There is no empirical proof that Pacific perimeter earthquakes are caused by subduction; this is inferred and purely hypothetical. There are more logical explanations such as crustal adjustments due to relaxed curvature and flattening of the Earth's crust as a consequence of expansion in diameter. Earthquakes, though powerful, are merely secondary effects of planetary expansion, not primary geophysical actions with independent motive power.
h. Subduction fails to explain a satisfactory causative mechanism able to force thin ocean floors only 10 km thick to dive beneath thick continental shields 25-40 km thick without leaving behind some physical evidence. There is no evidence of ocean floors and seamounts diving into the deep ocean trenches (the trenches show little or no sedimentation, and no toppled seamounts). As noted by Roger Revelle in 1955, material recovered from even the deepest trenches “resemble in many ways deposits laid down in shallow water.”
i. This exposes a related problem--the missing soft sediments that should have been scraped off the ocean floor when descending beneath a rigid continental shield over a period of two hundred million years. These soft sediments are an unconsolidated top layer of ocean floor ~10 meters thick. Massive amounts of sediments should be piled up against continental shores, or in the deep ocean trenches off the eastern coasts of Asia and Australia, the western coasts of North and South America, or in the Aleutian Trench. The sediments just aren't there; the ocean trenches are relatively free of sediments and there are no mountains of soft sediments piled up against any Pacific shore.
CONCLUSION
As noted above, subduction fails on several grounds. The current dogma of "subduction" is a theoretical concept with no physical evidence to verify it, nor a plausible causative mechanism to support the claim that one tectonic plate dives, or is driven, beneath an opposing plate. Everything about subduction, including its origin, is based on pure hypothesis and speculation, beginning with an erroneous basic assumption that Earth’s diameter was fixed at the time of its creation.
As explained in the simple hand demonstration showing subduction's fatal flaw, if subduction did exist, the Pacific Ocean basin must eventually be swallowed in its entirety if the Earth’s diameter is to remain constant. In fact, studies of Pacific plate movements that were intended to prove subduction, unwittingly included several measurements that show the Pacific Ocean basin to be increasing in width--not decreasing in width as required by subduction.
The scientific literature contains countless papers purporting to prove subduction, but if examined closely, estimates of subduction velocities are usually inferred from midocean ridge growth rates, or are based on suggestive geophysical data without empirical measurements to prove the direction and velocity of motion.
Benioff zones and deep-focus earthquakes, without directional evidence, are just as easily interpreted as obduction from beneath the continents—or, better, just a sudden shift of two crustal masses readjusting positions in response to expansion of the core and sheer gravitational weight. The epicenter depth of an earthquake bears no relationship to the direction of relative movements of the opposing masses that shifted and caused the earthquake, or the primary mechanism that caused the masses to shift.
Such lack of plausible evidence forces one to question the dogma of subduction and plate tectonics. Furthermore, there is now ample geological evidence to validate the expansion theory, so subduction is no longer viable.
With this evidence one may confidently postulate that Pangaea began to break up ~200 (~195-205?) Ma, at the end of the Triassic, when Asia and Australia broke away from North and South America to form the Pacific Ocean, followed by opening of the Atlantic, and all of today's ocean basins have been created since that moment in time.
Note
This is part 5 of a series of articles written by Lawrence S. Myers in the late 1990s on the Expanding Earth theory. Click "next" to read the subsequent article.
