mirrored file at http://SaturnianCosmology.Org/ For complete access to all the files of this collection see http://SaturnianCosmology.org/search.php ========================================================== Problems with Wegener's Model of Continental Drift Wegener's model was not accepted by all geologists. Some thought that dispersion by winds or ocean currents could explain the distribution of fossil species. Other geologists thought the poles might wander and continents remain stationary. Many geologists thought Wegener's evidence was insufficient. The greatest shortcoming, at least in the eyes of American geologists, was the lack of an adequate mechanism for moving the continents. Wegener proposed that the Earth's spin caused the continents to move, plowing through the oceanic plate and producing mountains on their leading edges. Geologists at that time understood enough about the strength of rocks to know that this was highly unlikely. Wegener's work was largely unaccepted in the northern hemisphere. In the southern hemisphere, where geologists were familiar with the rocks that Wegener used to support his hypothesis, continental drift was generally accepted. A mechanism to move continents was proposed by Arthur Holmes, Scottish geologist in 1928. He believed heat trapped in the Earth caused convection currents, areas where fluids beneath the Earth's crust rise, flow laterally, and then fall. The currents would rise beneath continents, spread laterally, then plunge beneath the oceans. (Geologists now know that solid rock, not fluids, convect in the mantle). Unfortunately, Wegener died in 1930 while exploring the Greenland ice cap. He never had the opportunity to adapt Holmes' ideas to his views of continental drift. _________________________________________________________________ [1][LINK] Previous Section [2][LINK] Back to Teacher's Guide [3][LINK] To VolcanoWorld [4][LINK] Next Section _________________________________________________________________ References 1. file://localhost/vwdocs/vwlessons/plate_tectonics/part5.html 2. file://localhost/vwdocs/vwlessons/atg.html 3. file://localhost/vw.html 4. file://localhost/vwdocs/vwlessons/plate_tectonics/part7.html