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I I I I I I I I I I I I I I I I I I I Orogeny, the last major uplIft of the Front Range. Paleozoic and Mesozoic rock strata located at the flanks of the uplIfting mountains folded and faulted from the pressures created during the orogeny resulting In the Front Range anticlIne or anticlInorium. The strata once located over the mountainous areas had since been eroded exposing tilted strata of sandstones and lImestones (hogbacks) adjacent to the Front Range In an eastward dipping pattern. Figure No. V-I shows the site area geology as complied from various sources. . Folds - The reservoir lIes to the east of echelon folds which strike primarily north-south. More locally, the site lies near a north-south striking syncline located between the Douglas Lake AnticlIne and Wellington AnticlIne. The syncline appears to be slightly asymmetrical with the crest of the Douglas Lake Anticline being approximately 2 miles to the west and crest of the Wellington Anticline being approximately 112 mile to the west. Dips of the stratum appear to be eleven degrees at the east 11mb of the Douglas Lake Anticline and six degrees to twelve degrees at the west 11mb of the Wellington Anticline near the site. Figure V-I shows the structural geology near the site with a section drawn through the anticlines and synclines near the site. The dam for No. 6 appears to be founded on pediment and fan deposits In an erosional depression that has removed the Richards sandstone. . Faults - A few faults are known to exist In this general area and are usually limited to the foothill areas. Most of the faults In this area are related to the anticlInal warping In Larlmlne times along narrow zones controlled by Intense zones of basement weakness. The most noticeable fault near the site lies approximately twelve miles to the north and northwest. It trends In a northeast to southwest direction for approximately twelve miles where It disappears Into synclinal relntrant to the southwest. A smaller north-south trending fault In located approximately fifteen miles to the north and Is about three miles long. The folds described near the site are not known to have associated faults near the surface. 4. Mineral and Energy Resources. Northeastern Colorado contains various economical mineral resources Including petroleum, natural gas, uranium, gravel and crushed-rock aggregate, and limestone. 011 and gas recovery operations have taken place since the 1920's In the area and have had concentrated efforts locally In the Wellington Field approximately three miles to the north and 3 miles to the east, and the Fort Collins Field approximately four miles to the South of Reservoir NO.6. Gravel and crushed-rock aggregates are currently mined from various localities In Northern Colorado, but are not believed to exist at the site. Limestone Is being mined from the Niobrara Formation approximately five miles to the southwest for production of Portland Cement and In the Ingleslde Formation approximately seven miles to the west for Industrial and agricultural uses. Uranium deposits are known to exist In the Fox Hill Sandstone and Laramie Formations In Larimer County, but the exact locations are not available at this time. PAGK 5 ChJpter V - No. 6 reulbUlty