With today’s technology, it feels like we are all connected to each other, like there are no boundaries separating New York and London, nothing to keep South Americans from chatting with people of the Ivory Coast. Every passing day, we feel as if the world is becoming a smaller place. 250 million years ago, the sensation would have been even greater, because it was then that Pangea was forming. Pangea: the supercontinent that looks like the all the contemporary continents of the world put together like a jigsaw puzzle. The mountains weren’t that high and the oceans weren't wide, and it was a small, small world after all. Pangea came together 250 million years ago, changing climates and affecting all the organisms on and around it. 50-70 million years later, it started to brake apart, once again putting the poor creatures on it through dramatic climate changes.
When Pangea was assembling, many coastal areas and shallow pools on shorelines disappeared, and arid deserts formed where lush environments had once been. Combining landmasses to make Pangea destroyed the part of a continent where many marine organisms thrived: continental margins, or the shallow water areas just off the coastline (McKeegan, 2002). This was the environment that gave rise to life on planet Earth. These special areas just beyond land were climatically ideal for many types of flora and fauna, and with the creation of the supercontinent came the end of most such places. In addition, there were dramatic climate fluctuations in the center of Pangea, some of the middle sections having formerly been coastal regions. Due to the enormity of Pangea, there were large parts of the interior that "could no longer be cooled or warmed by steadying, maritime influences" which would result in summer weather over 100 degrees Fahrenheit during the day and extremely cold temperatures during the night (Ward, 1994). Winter conditions would also be extreme: "freezing, dry cold" and drought all year round would have plagued the middle of the supercontinent. Climatic changes were drastic as Pangea formed. Places that once supported life and enjoyed a smaller range of temperatures became barren and arid lands.
Obviously, when Pangea split, the reverse happened. Those dry, waterless areas became once again fertile coastal regions, and climates became less extreme overall. Both the creation and separation of this vast supercontinent had extreme climatic effects, and both affected evolution. There was another side affect, however, to the break up of Pangea that involved the salinity of the oceans. Evaporite deposits remove salt from the oceans. This usually occurs when there are excess amounts of salt in the ocean due to times of increased evaporation and little precipitation. These evaporites trap CaSO4, CaSO42H2O, NaCl, and KCl – the major contributors to salinity in ocean waters. Many of the major causes of salt reduction occurred in evaporites "in rifts and proto oceans during the initial stages of continental separation" (Windley, 1984). There is a correlation in Pangea’s division and the creation of evaporites as new oceans were formed. A drop in ocean salinity is considered a climatic change because it affects all the creatures living in salt-water pools. Salt can be just as significant to a creature as sunlight is to a plant, and there are many organisms that require certain levels of salt to survive. |
