History of Continents after Rifting from Pangea

• Main Authors: Rogers, John J. W., Santosh, M.
• Format: Book Part
• Language: English
• Published: Oxford University Press 2004
• Subjects: South Pole; Antarc*; Antarctica; South pole
• Online Access: http://dx.doi.org/10.1093/oso/9780195165890.003.0012

As continents moved from Pangea to their present positions, they experienced more than 100 million years of geologic history. Compressive and extensional stresses generated by collision with continental and oceanic plates formed mountain belts, zones of rifting and strike-slip faulting, and magmatism in all of these environments. In this chapter we can only provide capsule summaries of this history for each of the various continents, but many of their salient features have been discussed as examples of tectonic processes in earlier chapters. The final section analyzes the breakup of Pangea as part of the latest cycle of accretion and dispersal of supercontinents. Because it involves continuation of this cycle into the future, it is necessarily very speculative. Figure 10.1 shows approximate patterns of movement of each continent from its position in Pangea to the present. The dominant feature of this pattern is northward movement of all continents except Antarctica, which has remained over the South Pole for more than 250 million years. Shortly after geologists recognized the concept of continental drift, this movement was referred to by the German word “Polflucht” (flight from the pole) because all of the continents were seen to be fleeing from the South Pole. The only continent that did not simply move northward was Eurasia, which essentially rotated clockwise and changed its orientation from north–south to east–west. Comparison of fig. 10.1 with fig. 8.12a (locations of continents shortly before the assembly of Gondwana) shows that the net effect of the last 580 million years of earth history has been a transfer of most continental crust from the southern hemisphere to the northern hemisphere. Accretion and compression against the southern margin of Eurasia constructed a series of mountain belts from the Pyrenees in the west to the numerous ranges of Southeast Asia in the east. This collision generated extensional and transtensional forces that opened rifts and pull-apart basins. Tectonic loading created ...