2009-01-14_PERMIT FILE - C1996083A (2)

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2.04.6 main synclinal axis bifurcated southwest of Meeker, Colorado, and trends northwest. The Douglas Creek Arch, south of Rangely, Colorado, is characterized by extensive faulting and numerous subsidiary structural flexures present throughout the basin (Johnson, 1982). Abundant tertiary intrusive bodies, located in the southeastern portion, give the basin a northwesterly plunge. In the southwestern portion, 3 to 5 degree dips prevail while along the Grand Hogback, vertical to overturned beds are not uncommon. Although the Piceance Creek Basin was formed during the Larimide Orogeny, recent seismic activity detected near Carbondale, Colorado, may suggest the diastrophism is continuing or being reactivated. Maximum structural relief, measured from the tip of the pre-Cambrian, is estimated by Murray (1962) to be at least 27,000 ft. Elevation of the permit area ranges from 8000 feet plus in the northwestern • portion to 6000 ft. near the proposed truck loadout facilities. Exposed lithologies range in age from Upper Cretaceous Mancos and Mesaverde to Holocene alluvial fill along the North Fork of the Gunnison River. I• Permit and adjacent Area: Geologic structure of the Permit Area is relatively simple with an attitude of N66°W and 3 to 5 degree dip to the northeast. The structural dip direction changes near Terror Creek and the lineation of Terror Creek may suggest the presence of a fault. It will take additional drilling in the Terror Creek area to determine the presence of a fault or other structural anomaly. There is one indicated fault that crosses the southwest corner of the permit area. The fault system trends approximately N33°W and dip 70 to 80 degrees to the northeast. These high angle normal faults have an apparent strike slip component. The throw of the fault ranges from 7 to 30 feet. The down side is the south side of the fault. It is not certain whether the fault exists as a normal slip break or as a roll. PR-08 2-04 - 13 - 7/03 APPRo~FD q~~.s/o3