With regard to wind-blown sands submerged two and three miles on the sea bottom of the Atlantic, 1,200 miles from land, Professor Ewing, in National Geographic Magazine, November, 1949, says (p. 613):
Either the land must have sunk two or three miles or the sea must have been two or three miles lower than now. Either conclusion is startling. If the sea was once two miles lower, where could all the water have gone?
Many inland seas and partially enclosed basins have erosions in their banks far below the sills which intervene between them and the open ocean. For instance, canyons of the Mediterranean banks, according to Shepard, are a mile deep; yet the sill at Gibraltar is only 400 meters below sea level. Brooks says that the Mediterranean canyons are 400 meters and those of the Japan Sea 200 meters below the respective sills of those seas. Kuenans figures differ somewhat from those of either of the above quoted gentlemen. He says in Marine Geology (p. 509), that the canyons of the Mediterranean descend at least 500 meters below the sill and that those of the Japan Sea extend 1,000 meters below sill depths. Although the statements vary, they all testify that the canyons continue down very considerably below the sills. As in the case of canyons on the shores of the open oceans, erosions in the shores of the inland seas have defied all attempts to explain them.
The floors of many shallow embayments show conclusively that deposits on them accumulated prior to present submergence. Submerged forests found on coasts in many places around the world, are prima-facie proof that their submergence occurred after the trees had grown, either because of subsidence of the land or because of encroachment by a rising sea level. In such cases, however, the extent of submergence is insignificant— limited to a few fathoms—which could very well have been due to melting of Pleistocene glacial ice. Significant evidences, which primarily concern us, are those which indicate former levels thousands of feet below the present levels.
Raised Strand Lines
Neither are we concerned about raised strand lines found here and there. Such formerly raised beaches should not be taken to indicate that oceans once stood higher than at present. They are localized, limited to but a few feet, are variant in height and often out of level. In the latter instances they can logically be ascribed to isostatic adjustment following removal of the burden of glacial ice. In other cases they were clearly caused by orogeny.
Untold billions of tons of sediment which rivers have carried to the seas have caused ocean floors to sink and the borders of land platforms to rise. Such adjustments will continue so long as rivers flow; but they do not nullify decisive evidence that ocean level has been raised thousands of feet within geological time.
Three Causes Envisioned
Only three possible causes of former lower sea level have been envisioned. One is that the water was imprisoned in the ice sheets during glacial episodes. As we have noted, this hypothesis is definitely refuted because of the great magnitude of the difference in level. The other two possibilities which have been suggested are: one, that continental platforms were temporarily uplifted; two, that ocean floors had temporarily subsided. As noted in our study of submarine canyons, grave doubts exist that land platforms could have bobbed up and down enough to account for the fluctuations. Various geologists have said in effect: “You cannot make me believe that the continents have moved up and down 12,000 feet in the very last geological episode.”
Subsidence of Land Platforms
The theory that ocean levels have been raised because continental masses have subsided is questionable because evidence proves that ocean waters have crept higher upon and over land surfaces to the same extent and at the same time all over the globe. Would it not be multiplying probabilities a bit too much to assume that land areas everywhere on Earth sank simultaneously and to the same extent, to account for world-wide and uniform rise of ocean level? Furthermore, had this happened, ocean floors, under the physical law of isostatic equilibrium, necessarily would have had to rise concurrently, thereby decreasing ocean depths. But the latter did not happen. Ocean depths, instead of decreasing, very obviously and irrefutably have increasedl
Subsidence of Ocean Floors
To account for submergence of mid-oceanic islands, ridges and sea mounts, the very same idea is advanced as is used to explain the rise of waters over continental shelves and slopes. It is alleged that those mid-oceanic lands, together with the ocean floors upon which they rest, have sunk. It is said that a former mid-Pacific continent, some 1,200 miles broad and 2,000 miles long, sank more than 3,000 feet. Is it not perfectly obvious that subsidence of such a large land area by even much less than 3,000 feet would have withdrawn waters all over the world from the shores of other lands which did not sink, and would have increased the gradient of every river on Earth which empties into the sea? There is no doubt that the very opposite of this has transpired. Ocean waters have climbed higher upon lands all over the globe and the gradients of river estuaries everywhere obviously have been decreased. At the same time former islands in all oceans have been submerged.
It would seem inconsistent to believe that former mid-oceanic lands have been submerged because ocean floors have sunk and at the same time to maintain that oceans have encroached upon continental platforms because the platforms have sunk! The two concepts are contradictory. If one is true the other must be false. In other words, if the African coast at the Congo, the Pacific coast at La Jolla and the Columbia, the Atlantic shore at the Hudson, the coast of India at the Ganges and Indus, the Brazilian coast at the Sao Francisco, together with land borders at numberless other places around the globe, sank into the sea after the submarine canyons at all those places were eroded, then all ocean floors must necessarily have risen simultaneously in order to maintain isostatic equilibrium of the globe. How then can it be that ridges, islands and mountain peaks which rise from mid-ocean floors in every ocean were also submerged and still remain submerged, just as the continental borders were drowned and still remain drowned. Obviously the ocean floors did not rise; and if they did not rise, the platforms could not have sunk.
- Mysteries of glaciation
- The true origin of ice ages