Continental displacement and expansion of the earth during the Mesozoic and Cenozoic

Abstract

Most reconstructions of Pangaea, the early Mesozoic supercontinent, assume an Earth of modern dimensions. Such reconstructions produce major geometric and geological fit inconsistencies particularly in areas such as the Arctic, Caribbean, Mediterranean, and southeast Asia and Indonesia. The ocean floor spreading history of these regions and the adjacent oceans indicates that they have grown by areal expansion since their initiation. In contrast, the various reconstructions of Mesozoic and Cenozoic stages which assume an Earth of constant dimensions, require that these regions, either initially or during their development, should contract in area. The geological evidence from the continental margins and from the Earth's oceans does not support the amount of subduction, either in whole or in part, required by the constant dimension hypothesis. It is shown that an exact fit of the various continental fragments together to reform Pangaea, which agrees with the geometric and geological matches, is obtained when the value of the Earth's surface curvature is increased to the point at which the diameter of the globe is 80% of its current mean value. This corresponds in time to the late Triassic-early Jurassic. It is asserted that the early Upper Jurassic to Recent ocean floor spreading data now available, displayed here in maps, also demonstrate progressive global expansion commensurate with an increase in diameter of 20% of the Earth's current mean value. Series of maps employing a zenithal equidistant projection are used to illustrate stages in the inferred development of certain regions during the Mesozoic and Cenozoic according to the ocean floor spreading data. The global expansion deduced from the geometric requirements of the spreading data in these maps permits a much more straightforward reading of the development of ocean basins and associated displacement of continents; one which accords with the field evidence. The inconsistencies seen in constant dimensions reconstructions do not arise. The results are summarized in outline hemisphere maps for which a new cartographic projection has been developed.