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Geotechnical Stability Exhibit <br /> Engineering Evaluation of Highwall Design for the South Quarry of the Morrison Quarry <br /> <br /> January 2024 | 6 <br />2 Geologic Conditions <br />2.1 General Geology <br />The Morrison Quarry lies along the Colorado Front Range of the southern Rocky Mountains as <br />part of the Colorado Physiographic Province. The front range forms the margin between the <br />southern Rocky Mountains and the High Plains to the east. The region serves as the boundary <br />between two major geological provinces of North America, the American Cordillera to the west, <br />and the North American Craton to the east. <br />The Front Range consists of metamorphic and crystalline Precambrian Age bedrock, that was <br />accreted during the Proterozoic eon. The oldest rocks in the province are metasedimentary and <br />metavolcanic, and were intruded by younger granitic units dating to roughly 1.7 to 1.4 Ga. The <br />Precambrian units include north to northeast trending Proterozoic shear zones, several of which <br />were reactivated during the Laramide Orogeny. In many areas along the Front Range, the <br />Proterozoic crystalline bedrock is overlain by Paleozoic and Mesozoic sedimentary rocks. <br />Deposited in shallow inland marine and deltaic conditions, they were uplifted along with the <br />Precambrian formations during the Laramide Orogeny. Refer to Figure 3, below, for the <br />Geologic Map of the area.