Laserfiche WebLink
<br />0932 <br /> <br />3.5 GEOLOGY <br /> <br />NOSR 1 is located in the southeastern portion of the Piceance CreeK <br />basin which contains the world's richest deposit of oil shale. The <br />~ <br />Piceance basin, a major structural feature of the Colorado Plateau <br />physiographic province, includes an area of approximately 6,700 square <br />miles (Figure 3-2). The Piceance structural basin is bounded on the north <br />by the White River, on the east by the Grand Hogback Monocline and Elk <br />Mountains, on the south by the West ElK Mountains and Uncompaghre Plateau, <br />and on the west by the Douglas CreeK arch and the Cathedral Bluffs. The <br />basin axis, which trends generally N 50oW, is approximately coincident with <br />the topographic expression of the basin. Oil shale, found in the Green <br />River Formation, occurs in an area of about 1,600 square miles in the <br />northern portion of the basin, between the Colorado River and the White <br />River. <br /> <br />3.5.1 Stratigraphy <br /> <br />. <br />Exposed stratigraphic units on NOSR 1 and 3 include, from oldest to <br />youngest, the Wasatch, Green River and ,Uinta Formations. All are Eocene in <br />age and record the evolution from a moderate energy fluvial environment <br />(Wasatch Formation) through a widespread low energy lacustrine environment, <br />(Green River Formation) into a lake-filling fluvial-lacustrine environment <br />(Uinta Formation). The Uinta Formation is conformable and intertongues <br />with the underlying Green River Formation. On NOSR 1 this formation is <br />found along the tops of the ridges and in the upland areas. On NOSR 1, the <br />Green River Formation outcrops on the upper part of the Roan Cliffs and in <br />the valleys of East Fork and East Middle Fork Parachute CreeKs. The 'Green <br />River Formation is conformable with the underlying Wasatch Formation. The <br />, Wasatch Formation crops out on NOSR 3, near the base of the Roan Cliffs. <br />Figure 3-3 is a generalized stratigraphic section of the Piceance CreeK <br />basin. <br /> <br />3.5.1.1 Wasatch Formation <br /> <br />The Wasatch Formation is characterized by varicolored shale and Clay <br />with locally prominent lenticular sandstone beds. Other minor, local <br />lithologic components include, conglomerate, pebbly sandstone, limestone, <br /> <br />3-4 <br />