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<br />1 <br />1 <br /> <br /> <br />1 <br />1 <br /> <br />1 <br /> <br /> <br />1 <br />LJ <br />1 <br /> <br />1 <br />LJ <br />1 <br /> <br /> <br />Geology -Salt Anticlines <br />The area to the west by northwest of the Norwood Pit is domiated <br />by two (2) major salt anticline valleys called Paradox Valley, <br />and Gypsum Valley. These valleys are oriented in a northwest <br />trending linement approximately parallel to the Uncomphagre <br />Plateau. The cause for the trend is interpreted to be similar <br />structural weakness in the basement rocks. <br />Salt anticline structures aie common occurances in southwestern <br />Colorado and eastern Utah. These were caused in the <br />Pennsylvanian Period when a very large area of continental crust, <br />centered below what today is the Manti La Sal Mountains, began to <br />sag. This area was covered by a shallow sea when surrounding <br />areas including the Uncomphagre Plateau, began to rise. The <br />result was a large isolated bay in which salt water was able to <br />evaporate, and layers of salt and other chemicals precipitaed out <br />and fell in the brine. The bay was continually recharged with <br />sea water due to rising and falling global sea level. Twenty <br />nine (29) cycles of precipitation and flooding have been counted <br />to depth of five (5) to six (6) thousand feet of salty <br />accumulation. Finally, the Uncomphagre Plateau rose with the <br />Ancestral Rockies Oroseny, and mixtures of land and marine <br />sediments were deposited in the basin. The sediment weight and <br />the uplift of the Uncomphagre produced downard pressure that <br />caused the salt deposits to begin "plastic flow" along parallel <br />ridges with the Uncomphagre Plateau. As the salt rose (up to <br />17,000 feet of relief in Paradox Valley) it warped up the <br />overlying layers into an anticlinal structure and promoted <br />fracturing in the upper layers, which promoted erosion and valley <br />forming processes. <br />4 <br />