This open-file report for Adams, Arapahoe, and Denver Counties includes an introduction to the geology and mineral resources of the county along with an index map of tract locations, maps of oil and gas test wells with oil field locations, coal resources, and industrial mineral prospects. A map for metallic mineral prospects is not applicable in these counties. The main body of the report is an evaluation of each individual tract, which includes text as well as a topographic map and a geologic map. Digital ZIP/PDF download. OF-03-11D
Four general categories of resources are included in this inventory:
- oil and gas
- metallic minerals
- industrial minerals and construction materials
Each individual tract evaluation includes:
- A bar graph which ranks each tract’s resource potential for each of the four mineral categories. An explanation of the categories may be found at the end of this introduction
- Tract identifier number, county name, and county location map
- Tract location on a 7-1/2-minute United States Geologic Survey topographic map
- Tract location on a United States Geologic Survey surface outcrop map
- Location as to section, township, and range and approximate acreage
- Overview of tract geology
- Specific assessment of the resource potential for the four resource categories
- References used in assessing tract potential
From the Introduction:
All or part of the three counties are located on the High Plains of eastern Colorado. Adams County includes the Denver and Cheyenne sedimentary basins; whereas Arapahoe County lies within the Denver Basin. The western third of Denver County is located in the Foothills region (or Piedmont) that lies immediately east of the Front Range. This evaluation of the mineral and mineral fuel resource potential was conducted for approximately 108,047 acres of state mineral lands located in the three counties. It was conducted as part of its long-term evaluation of approximately 4 million acres of state lands administered by the State Land Board. For evaluation purposes, the three counties were divided into 139 individual tracts that range from approximately 40 to 26,182 acres in size.
In 2000, Adams County ranked 5th among Colorado’s counties in annual oil production and 17th in annual natural gas production from 132 producing fields. In 2000, Arapahoe County ranked 18th among Colorado’s counties in annual oil production and 23rd in annual natural gas production from 47 producing fields. In 1998, Denver County ranked 23rd among Colorado’s counties in annual oil production and 24th in annual natural gas production.
The Late Cretaceous Laramie Formation contains coal beds, which have been exploited in past years in the Denver Basin and to a lesser extent, in the Cheyenne Basin. A very small part of the Boulder Weld coal field, the most productive coal field in the Denver Basin, is located in the northwest corner of Adams County. There are no known coal deposits or coal mines in Denver County.
There are no known metallic mineral resources in Adams, Arapahoe, or Denver Counties. The only industrial mineral resource is sand and gravel.