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<br />Project Setting and Geology <br /> <br />Paradox Valley is located on one of five major salt anticlines found <br /> <br />througnout southwestern Colorado and southeastern Utah. <br /> <br />The se sal t <br /> <br />anticlines are geologic formations that are the remnants of ancient salt <br /> <br />lakes, similar to the Great Salt Lake in Utah. The lakes evaporated away <br /> <br />approximately 300 million years ago, leaving thick salt formations <br /> <br />behind. <br /> <br />Following this, au extensive sedimentation period occurred, <br /> <br />deeply burying the salt layers. <br /> <br />The formation of the anticline resulted from a number of forces such <br /> <br />as, tectonic activity, faulting, and erosion of the anticlinal crest. <br /> <br />Briefly stated, it is thought the emergence of tertiary mountainous <br /> <br />uplifted on each side of the area placing intense lateral pressures on <br /> <br />intervening sedimentary formations, causing faulting and fracturing along <br /> <br />weak zones. Upon easing of the lateral pressures, the weight of the <br /> <br />sedimentary strata caused the deeply buried layer of salt-rich material <br /> <br />under the sedimentary strata to move by plastic flow upward into the <br /> <br />faulted and weak areas, creating an anticline. Figure I shows a schematic <br /> <br />cross-section of this process. <br /> <br />Most of the folding and piercement <br /> <br />probably occurred before Triassic time, (230 million years ago) and the <br /> <br />degree of compression and flowage of salt was much greater than appears <br /> <br />superf icially. <br /> <br />Tile salt continued to rise through Triassic and Jurassic times, as did <br /> <br />tlte topographic expression of the piercements. By the end of the Jurassic <br /> <br />time, salt flowage appears to have ceased and the anticlines were <br /> <br />gradually buried in Morrison time. In late Cretaceous and early Tertiary <br /> <br />times, folding and faulting occurred again following closely along the <br /> <br />lines of the deeply buried salt anticlines and piercements. \.Jhile these <br /> <br />tOr563 <br /> <br />2 <br />