THE EVOLUTION OF RIVER SYSTEMS DURING THE BREAKUP OF PANGEA (240 - 80 MYA)

Digital elevation models (paleoDEMs) were constructed for five intervals during the Mesozoic: Triassic (240 Ma), Jurassic (200 Ma and 160 Ma), and Cretaceous (120 Ma and 80 Ma). The Hydrology tools (ArcGIS, ESRI) were then used to map the paleodrainage patterns and the location of ancient river systems for five time intervals. During this period of Earth History the supercontinent of Pangea, which occupied over 40% of Earth's surface, rifted apart to form the modern continents and ocean basins. A statistical analysis was performed to characterize the average length of river systems and the average area of drainage basins before, during and after breakup of Pangea. As expected, the average length of rivers and the average area of drainage basins decreased as consequence of continental fragmentation. However, other variables turned out to be equally, or more important. River length and drainage area were also affected by: changes in global sealevel, mountain-building, and the changing location of land areas with respect to the Equatorial Rainy belt and Subtropical Arid belt.