|
Grand Junction Pipe
<br />SurScial Geology Investigation, 23 Road Proposed Gravel Pit, Grand Junction, Colorado
<br />Febntary 26, 2002 Page 2
<br />This tract is located approximately 3 miles northeast of the steep slopes and cliffs of the Colorado National
<br />Monument. The Colorado National Monument is at the northeast portion ofthe Uncompahgre Uplift and the steep
<br />cliffs overlooking the Redlaz~ds and Colorado River are the surface expression of the Redland Fault Complex. The
<br />higher elevations of the Colorado National Monument represen a vertical displacement in excess of 2000 feet.
<br />The sedimentary strata exposed on the bluff immediately south of the Colorado River represents fornations found
<br />on and below this site. Portions of the ancient Colorado River terrace, the Dakota Formation and the Mancos shale
<br />can be seen along the blulJy south of this tract. These exposures can be observed due to natural erosional processes
<br />of the Colorado River. In some azeas along Gold Star Canyon Gulch the discontinuity between the Mancos Shale
<br />and the Dakota Formation can be noted.
<br />The site is located on the north, northeastern flank of the Uncompahgre Uplift, with the sedimentary beds dipping
<br />into the Piceance Basin, to the north northeast. The structural geology on this particular site is relatively
<br />unwmplicated, with the site being located approximately 3 miles northeast of the Redlands Fault Complex and
<br />is at the southeast margin ofthe Piceance Basin. Some minor faulting is located nearthe Colorado/Utah State Line,
<br />approximately 26 miles northwest of this site. This faulting is associated with several small, mapped anticline
<br />structures. The structural geology on this particular site.is relatively uncomplicated.
<br />General information concerning the area geology is contained in:
<br />1. CASHION, W.B., 1973, Geologic and Struc: *e hiap of the Grand Junction Quadrangle, Colorado and
<br />Utah, U.S.G.S. Misc. Geol. Invest, Map I-736.
<br />2. LOHMAN,S.W.,1963, Geologic MapoftheGrandJunctionArea,Colorado,U.S.G.S.Misc.Geol,Invest.,
<br />Map I-40d
<br />3. LOHMAN, S. W., 1965, Geologic and Artesian Water Supply, Grand Junction Area, Colorado, Prof. Paper
<br />451, 149 p.
<br />4. SCHWOCHOW, S.D., 1978, Mir~ra! Rcc~erces Surve, of Mesa Court', Colo. Geol. Survey Resource
<br />Series 2, 109 p.
<br />5. WHITNEY, J.W., 1981, Surficial Geologic Map of the Grand Junction Quadrangle, Colorado and Utah,
<br />U.S.G.S. Misc. Geol. Invest., Map 1-1289.
<br />6. WILLIAMS, P.L., 1964, Geology, Structure and Uranium Deposits ofthe Moab Quadrangle, Colorado and
<br />Utah, U.S.G.S. Mis. Geol. Invest, Map I-360, 2 p.
<br />Seismic events have occurred near the greater Grand Junction area, but have not been further identified as to
<br />source. It is believed the Glade Park Fault, which is west of the Jacobs Ladder Fault Complex and the Ladder
<br />Creek Monocline would have some potential for these low intensity earth quakes. These events, within the
<br />greater Grand Junction area, were evaluated as having Richter Magnitudes up to and including 4.4, with no
<br />reported damages.
<br />
|