USGS Science⌕ Search

Geology topics

Research about Colorado

Source-linked reports with geographic coverage including Colorado.

At least 1,711 records · Page 95Linked to original sources
USGS1975

Preliminary map of landslide deposits, Denver 1° by 2° Quadrangle, Colorado

Areas inferred to be underlain by landslide deposits resulting from landsliding, avalanching, block gliding, debris sliding or flowing, earthflows, mudflows, rocksliding, rockfalls, rotational slides, slab or flake sliding, slumping, talus accumulation, and translational sliding. Rock glacier deposits, colluvium, and solifluction deposits are included in some areas. Some till is mapped with landslide deposits because distinguishing these two deposits from one another is difficult: Furthermore, in some areas till has failed by landsliding and other types of mass movements. Movement within the deposits varies from none to rapid; rates of movement may also be variable in any given landslide within the same year. Ages of deposits' range from early Pleistocene to Holocene.

Colorado↗
USGS1975

Map showing fluorspar deposits in Colorado

Increased fluorine consumption (U.S. Bureau of Mines, 1946-1971) coupled with limited proved reserves has stimulated extensive exploration for fluorine and intensive research into developing new sources of fluorine or substitutes. A summary of the distribution, geochemical and geologic environments, and production history of selected fluorspar occurrences, deposits, and districts is provided here with the hope that this information will help to stimulate exploration and discovery of additional fluorspar resources in Colorado to augment our dwindling domestic supply.

Colorado↗
USGS1975

Influence of caustic and water leaching on analcime-bearing and analcime-free pyrolyzed oil shale from the Green River Formation, Piceance Creek Basin, Colorado

The influence of oil-shale mineral constitution on the amounts of Na 2 O, Al 2 O 3 , and SiO 2 extractable from pyrolyzed oil shale using hot water and hot caustic solvents has been examined. Samples of oil shale from two drill cores and one composite sample from the Colony mine were split and studied by X-ray diffraction methods to determine their bulk mineralogy. Oil yield data were obtained for these samples by conventional Fischer assay analysis and samples of the spent oil shale were studied by X-ray diffraction to determine the changes which resulted from pyrolysis. The amounts of Na 2 O, Al 2 O 3 , and SiO 2 extractable from 31 spent oil-shale samples were determined using hot distilled water, hot 0.1M KOH, and hot 0.5M KOH as solvents. Extractable Al 2 O and SiO 2 were also determined for the 31 spent oil-shale samples using hot 0.1M NaOH and hot 0.5M NaOH. Correlation of the relative abundance of analcime--Na[Al, Si 2 O 6 ]. H 2 0-- in raw oil-shale samples with the amounts of Na 2 O, Al 2 O 3 , and SiO 2 extracted from pyrolyzed oil shale demonstrates that analcime contributes significantly to all of these elements after it has been subjected to pyrolysis. Because of the large contribution of SiO 2 extractable from pyrolyzed analcime-bearing oil shale using caustic solvents, there may be significant problems in obtaining leachates high in Al 2 O 3 content and low in SiO 2 content where analcime is present with dawsonite--NaAl(OH) 2 CO 3 . This consideration is important to assessment of potential aluminum resources in oil shale. In addition, the concentrations of water soluble Na 2 O, Al 2 O 3 , and SiO 2 in analcime-bearing pyrolyzed oil shale are expected to be significantly greater than from oil shale which is free of analcime and dawsonite and this factor reflects the importance of oil-shale mineralogy to aspects of spent shale disposal

Colorado↗
USGS1975

Hydrologic effects of reducing irrigation to maintain a permanent pool in John Martin Reservoir, Arkansas River Valley, Colorado

The U.S. Geological Survey has evaluated a plan by the Colorado Division of Wildlife to maintain a permanent pool of 10,000 acre-feet (1.2x10 7 cubic metres) in John Martin Reservoir on the Arkansas River. The proposed pool would be maintained through the use of water formerly diverted by the Catlin Canal Company to irrigate land in the Arkansas River valley. This plan was evaluated using a mathematical simulation model developed to test management alternatives in a stream-aquifer system. A 25-year period from 1949 through 1973 was simulated using monthly time intervals. Based on this simulation, it is concluded that (1) the proposed change in water use would be adequate to maintain a permanent pool of the proposed size, (2) surface-water diversions by most other canals in the study area would increase slightly under the proposed plan, (3) the flow of the Arkansas River at the Colorado-Kansas State line would increase slightly under the proposed plan, and (4) the ground-water system would not be significantly affected by the proposed change in water-use plan.

Colorado↗