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Stop 5 - On the Road - The Golden, CO Area

As we leave the Lafarge quarry, we are traveling north on U.S. Highway 40 (Colfax Ave.) along the west side of the Dakota Hogback towards the Golden area.  The Hogback becomes lower and is no longer evident.
 Photograph of U.S. Highway 40 looking towards the Golden area
Figure 1.   The Dakota Hogback at U.S. Highway 40 near Golden.  

 

As we turn left onto Sixth Avenue (U.S. Highway 6), we are crossing the yellow-tan outcrops of the Fox Hills Sandstone, and you see (to the east) the parallel ridges of white sandstone of the Laramie Formation. These two sandstone units form the Laramie-Fox Hills aquifer of the Denver Basin.
 Photograph of Laramie Sandstone  
Figure 2.   Photograph of Laramie Sandstone

 
 

Diagram of the Aquifers of the Denver Basin  
Figure 3.   Diagram of the Aquifers of the Denver Basin
The Laramie-Fox Hills aquifer extends through a 6700-square-mile area of the basin primarily to the north, east, and south of Denver and is the lowermost and largest of four bedrock aquifers in the basin. The four bedrock aquifers lie one on top of another much like a stack of pancakes, with the largest pancake on the bottom and the smallest pancake on top. These aquifers are a vital source of water for the Denver suburban area and much of eastern Colorado. More drinking water is pumped from these aquifers by municipal and domestic wells than from any other aquifer in Colorado.
 

 

The exposed sandstone beds of the Laramie Formation were deposited as nearly horizontal layers of sand separated by layers of clay. The beds have been bent upward and are almost vertical in this area as the result of the same geologic forces that formed the Dakota Hogback. The upturned edges of the sandstone beds are an important recharge area for the Laramie-Fox Hills aquifer. Here rain and snowmelt soak into the sandstone and flow to depth where the water recharges the aquifer.
Photograph of the sandstone beds of the Laramie Formation Figure 4.   The Laramie Formation beds are almost vertical in this area.



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U.S. Department of the Interior, U.S. Geological Survey
URL: http://rockyweb.cr.usgs.gov/frontrange/virtour/golden.htm
Contact: Carol Mladinich  mailto:csmladinich@usgs.gov
Updated: 05/16/2001		 Department of Interior