was created on top of the Carmel. A long period of erosion stripped away most of the San Rafael Group in the area along with any formations that may have been laid down in the Cretaceous period. Uplift Starting 70 million years ago and extending well into the Cenozoic, a mountain-building event called the Laramide orogeny uplifted the Rocky Mountains and with it the Canyonlands region. Even though the strata were uplifted thousands of feet (hundreds of meters) they were left at more-or-less the same horizontally. Uplift-associated-jointing did occur and has since influenced erosional patterns. When ground water seeped into the salt beds of the Paradox Formation it carried away the topmost and more soluble salts, leaving gypsum. This process was so pronounced in ‘’The Grabens’’ that the overlying rock collapsed into voids left by escaping salt. Increased precipitation during the ice ages of the Pleistocene quickened the rate of canyon excavation. Canyon widening and deepening was especially rapid for the gorges of the Green and Colorado Rivers, which were in part fed by glacier-melt from the Rocky Mountains. Alluvial-fan-creation-landslides and sand dune-migration were also accelerated in the Pleistocene. These processes continue to shape the Canyonlands landscape in the Holocene (the current epoch), but at a slower rate due to a significant increase in aridity. References Geology of National Parks: Fifth Edition, Ann G. Harris, Esther Tuttle, Sherwood D., Tuttle (Iowa, Kendall/Hunt Publishing; 1997) Furuya, M., Mueller, K., and Wahr, J., 2007, Active salt tectonics in the Needles District, Canyonlands (Utah) as detected by interferometric synthetic aperture radar and point target analysis: 1992-2002. Journal of Geophysical Research v. 112, B06418, External links Geology of Canyonlands National Park—Photographic Tour by USGS Colorado Plateau Canyonlands Canyonlands