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At least 73 records · Page 4Linked to original sources
USGS2005

Surface water-quality and water-quantity data from selected urban runoff-monitoring sites at the Rocky Mountain Arsenal, Commerce City, Colorado, water years 1988-2004

The U.S. Geological Survey has monitored the quality and quantity of streamflow at the Rocky Mountain Arsenal (RMA) northeast of Denver, Colorado, since the early 1990s in cooperation with the U.S. Army. This report, prepared in cooperation with the U.S. Fish and Wildlife Service, documents existing surface-water-quality conditions on the RMA. All RMA water-quality data for the Irondale Gulch and First Creek Basins adjacent to and on the RMA were reviewed. Where applicable, water-quality data were compared to State standards established by the Colorado Department of Public Health and Environment. At both the Havana Interceptor below 56th Avenue gaging station and the Uvalda Interceptor below 56th Avenue gaging station, all of the dissolved-oxygen concentrations met the State standard requiring at least 5.0 milligrams per liter (mg/L) of dissolved oxygen for the protection of aquatic life. In contrast, the dissolved-oxygen concentrations at the Peoria Interceptor below 56th Avenue gage commonly were less than 5.0 mg/L. Excluding one suspect concentration of 1.6 mg/L, the dissolved-oxygen concentrations for the First Creek Basin ranged from 4.2 to 12.6 mg/L. Excluding the one suspect value, three dissolved-oxygen concentrations failed to meet the State standard of 5.0 mg/L at the First Creek below Buckley Road site. At the Peoria Interceptor below 56th Avenue site, all pH values were within the range specified by the State standard (6.50-8.99). Results of seven sampling events at the Havana Interceptor below 56th Avenue gaging station indicated a pH greater than or equal to 9 (pH values of 9 or greater exceed the upper limit of the standard). No sampling events indicated a pH less than 6.50. Results from one sampling event at the Uvalda Interceptor below 56th Avenue indicated pH values outside the range specified by the State standard. The concentrations obtained for chloride, magnesium, and sodium generally were below 200 mg/L at all three Irondale Gulch monitoring stations for the entire period of record, but there were a few sampling events at each of these sites where much higher concentrations for these analytes were obtained. The median concentrations for calcium, magnesium, and sodium generally were higher at the First Creek below Buckley Road site than in the three Irondale Gulch sites, while the 90th percentile and maximum concentrations for magnesium and sodium generally were higher at the three Irondale Gulch sites than at the First Creek below Buckley Road site. The urban runoff flowing onto the RMA had low concentrations and few, if any, detections for most organic contaminants. Part of the reason for low detections of organic contaminants may be in how the samples are collected. The existing surface-water sampling program was not designed specifically to target storm runoff and therefore does not characterize water quality for all hydrologic regimes, most notably storm runoff. As a result, the existing data may not adequately represent potential contaminant transport onto the RMA. In addition, during stormwater-runoff events, the sites examined for this report frequently are subject to sharp increases in discharge, and just as quickly the discharge rapidly recedes. These types of transient flow events make water-quality sampling difficult, and none of the sites have a safe place to sample the higher flows that occur in any given year. As a result, most of the surface-water-quality samples were collected after the flow had decreased substantially from the peak flow, which may have transported much of the chemical contaminant load through the system. Thus, little is known about the water quality during the critical initial stormwater-runoff period when contaminants are most likely to be mobilized and transported through the stormwater conveyances past the locations where gaging stations are located.

Colorado↗
USGS1943

Geology of the Cimarron Range, New Mexico

In north-central New Mexico the rugged Cimarron Range marks the eastern margin of the Southern Rocky Mountains, abruptly rising more than 5000 feet above the adjacent Great Plains. Structurally the range is a northward-plunging anticline with a core of pre-Cambrian crystalline rocks. Faulting along the eastern and western margins of the anticline separates the mountains from the Great Plains and the Moreno Valley. North of Cimarron Canyon the anticline plunges beneath the Tertiary sediments of the Raton Coal Basin. To the south the structure is obscured by the basaltic flows of the Ocaté Mesa. Upturned Paleozoic to Tertiary sedimentary rocks crop out along the eastern and northern margin of the anticlinal uplift. Regional relations are obscured by extensive Tertiary intrusions in the northern portion of the area and by the lava flows to the south. In the valley of Rayado Creek a volcanic plug which fed some of the lava flows has been exposed by erosion. In this region there is evidence for a Mid-Tertiary surface of low relief in the central portion of the mountains, a later lava-capped surface believed to be the equivalent of the Broad Valley Stage, the surface of the Park Plateau, and the Ocate Mesa. Three well-developed gravel-capped Pleistocene pediment surfaces extend steplike from the mountain front into the Great Plains. Both structurally and topographically the Cimarron Range is similar to the Colorado Front Range. An attempt is made to reconstruct the geologic history of the Cimarron Range and to fit it into the broader story of the development of the Southern Rocky Mountains in New Mexico. © 1943 Geological Society of America.

New Mexico↗
USGS2000

Relations between basin characteristics and stream water chemistry in alpine/subalpine basins in Rocky Mountain National Park, Colorado

Relations between stream water chemistry and topographic, vegetative, and geologic characteristics of basins were evaluated for nine alpine/subalpine basins in Rocky Mountain National Park, Colorado, to identify controlling parameters and to better understand processes governing patterns in stream water chemistry. Fractional amounts of steep slopes (≥30°), unvegetated terrain, and young surficial debris within each basin were positively correlated to each other. These terrain features, which commonly occur on steep valley side slopes underlain by talus, were negatively correlated with concentrations of base cations, silica, and alkalinity and were positively correlated with nitrate, acidity, and runoff. These relations might result from the short residence times of water and limited soil development in the talus environment, which limit chemical weathering and nitrogen uptake. Steep, unvegetated terrains also tend to promote high Ca/Na ratios in stream water, probably because physical weathering rates in those areas are high. Physical weathering exposes fresh bedrock that contains interstitial calcite, which weathers relatively quickly. The fractional amounts of subalpine meadow and, to a lesser extent, old surficial debris in the basins were positively correlated to concentrations of weathering products and were negatively correlated to nitrate and acidity. These relations may reflect more opportunities for silicate weathering and nitrogen uptake in the lower‐energy environments of the valley floor, where soils are finer‐grained, older, and better developed and slopes are relatively flat. These results indicate that in alpine/subalpine basins, slope, vegetation (or lack thereof), and distribution and age of surficial materials are interrelated and can have major effects on stream water chemistry.

Colorado↗
USGS1993

Geologic and geomorphic controls of coal development in some Tertiary Rocky Mountain basins, USA

Previous investigations have not well defined the controls on the development of minable coals in fluvial environments. This study was undertaken to provide a clearer understanding of these controls, particularly in of the lower Tertiary coal-bearing deposits of the Raton and Powder River basins in the Rocky Mountain region of the United States. In this region, large amounts of coals accumulated in swamps formed in the flow-through fluvial systems that infilled these intermontane basins. Extrabasinal and intrabasinal tectonism partly controlled the stratigraphic and facies distributions of minable coal deposits. The regional accumulation of coals was favored by the rapid basin subsidence coupled with minimal uplift of the source area. During these events, coals developed in swamps associated with anastomosed and meandering fluvial systems and alluvial fans. The extensive and high rate of sediment input from these fluvial systems promoted the formation of ombrotrophic, raised swamps, which produced low ash and anomalously thick coals. The petrology and palynology of these coals, and the paleobotany of the associated sediments, suggest that ombrotrophic, raised swamps were common in the Powder River Basin, where the climate during the early Tertiary was paratropical. The paleoecology of these swamps is identical to that of the modern ombrotrophic, raised swamps of the Baram and Mahakam Rivers of Borneo.

International Journal of Coal Geology↗
USGS1999

Laramide to Holocene structural development of the northern Colorado Front Range

The Rocky Mountain province of the United States is a classic basement-involved foreland orogen. Deformation during the Late Cretaceous to Eocene Laramide orogeny created an anastomosing system of basement-cored arches that bound the northern and eastern margins of the Colorado Plateau and the elliptical sedimentary basins of the Rockies. The tectonic mechanism for Laramide deformation remains controversial, with proposed mechanisms ranging from subcrustal shear during low-angle subduction (Bird, 1988, 1998; Hamilton, 1988) to detachment of the upper crust during plate collision to the west (Oldow and others, 1990; Erslev, 1993). The Rocky Mountains south of Wyoming have the additional complication of a period of mid-Tertiary igneous activity and sedimentation that coincides with Neogene extension along the Rio Grande rift. This field trip (Fig. 1) will explore the Laramide to Holocene structural development of the southern Rocky Mountains by examining the geologic record exposed in the northern Front Range of Colorado. The Front Range starts north of Canon City, Colorado, and trends north-northwest to Golden, Colorado. North of Golden, the range takes a more northerly trend toward the Wyoming border where it bifurcates into the north-trending Laramie Range (Brewer and others, 1982) and the north-northwest-trending Medicine Bow Range.

Colorado↗
USGS1879

Report on the lands of the arid region of the United States with a more detailed account of the land of Utah with maps

A report from Maj. J. W.Powell, geologist in charge of the United States Geographical and Geological Survey of the Rocky Mountain Region, upon the lands of the Arid Region of the United States, setting forth the extent of said region, and making suggestions as to the conditions under which the lands embraced within its limit may be rendered available for agricultural and grazing purposes. With the report is transmitted a statement of the rainfall of the western portion of the United States, with reports upon the subject of irrigation by Capt. C. E. Button, U. S. A., Prof. A. H. Thompson, and Mr. G. K. Gilbert.

Utah↗
USGS2014

The USGS at Embudo, New Mexico: 125 years of systematic streamgaging in the United States

John Wesley Powell, second Director of the U.S. Geological Survey, had a vision for the Western United States. In the late 1800s, Powell explored the West as head of the Geographical and Geological Survey of the Rocky Mountain Region. He devoted a large part of “Report on the Lands of the Arid Region of the United States with a more detailed account of the land of Utah with maps,” his 1878 report to the General Land Office on the lands west of the 100th meridian, to the feasibility of “reclaiming” large portions of this arid land. Powell recognized that the availability of water was key to the wise settlement of the region. He proposed to inventory all streams in the West to evaluate the potential for irrigation. The essential first step was to gage the flows of the rivers and streams. A few cities in the Eastern United States had established primitive streamgages as early as the 1870s to acquire data needed for the design of their water supply systems. Their methods generally used constructed channels and dams to enable accurate gaging. These methods were not feasible in the West, and certainly not on the vast scale and extreme range of flows common to western streams. New, more flexible techniques were needed. A site was chosen where these methods could be worked out and developed in a practical setting.

New Mexico↗
USGS1978

Biostratigraphic guide to Upper Devonian and Mississippian rocks along the Wasatch Front and Cordilleran hingeline, Utah

This paper provides a guide to measured sections of Upper Devonian (Famennian) and Mississippian (Kinderhookian, Osagean, and Meramecian) rocks visited on a three-day field trip between Provo, Utah, on the Wasatch Front and the Crawford Mountains in the Overthrust Belt along the Utah-Wyoming State line. The field trip, sponsored by the Pander Society, was held on April 30-May 2, 1978 in conjunction with the meeting of the Rocky Mountain section of the Geological Society of America at Provo, Utah. The rocks that may be sampled for conodonts are represented by the Middle to Upper Scaphignathus velifer (middle Famennian) through Cavusgnathus (middle Meramecian) conodont Zones. The measured sections and field trip provide a west to east traverse of the Sevier thrust system. The sections demonstrate the biostratigraphic, paleogeographic, and sedimentational differences among equivalent Famennian rocks as well as the transition from the Osagean and early Meramecian starved phosphatic basin on the west to time-equivalent carbonate rocks of the shelf margin on the east.

Utah↗
USGS2002

A summary of the U.S. Geological Survey 1999 resource assessment of selected coal zones in the Northern Rocky Mountains and Great Plains region, Wyoming, Montana, and North Dakota

In 1999, 1,100 million short tons of coal were produced in the United States, 38 percent from the Northern Rocky Mountains and Great Plains region. This coal has low ash content, and sulfur content is in compliance with Clean Air Act standards (U.S. Statutes at Large, 1990).The National Coal Resource Assessment for this region includes geologic, stratigraphic, palynologic, and geochemical studies and resource calculations for 18 major coal zones in the Powder River, Williston, Green River, Hanna, and Carbon Basins. Calculated resources are 660,000 million short tons. Results of the study are available in U.S. Geological Survey Professional Paper 1625?A (Fort Union Coal Assess-ment Team, 1999) and Open-File Report 99-376 (Flores and others, 1999) in CD-ROM format.

Bulletin↗
USGS2021

Evidence of glacial activity during MIS 4 in the Rocky Mountains, Colorado, USA

The Ziegler Reservoir fossil site near Snowmass Village, Colorado, provides a rare opportunity to examine environmental conditions in the Rocky Mountains during marine isotope stage (MIS) 4 (71–57 ka). Although recognized as a global-scale cold event, MIS 4 is typically absent from Rocky Mountain glacial chronologies because the geologic evidence was covered or destroyed during the subsequent, and more extensive, MIS 2 (Pinedale; 29–14 ka) glaciation. Ziegler Reservoir lies beyond the Pinedale glacial extent, which allowed for the preservation of a long-lived sequence of eolian sediments deposited in a lacustrine environment that spans from late MIS 6 (ca. 140 ka) through early MIS 3 (ca. 55 ka). Sediments dating to MIS 4 exhibit a significant increase in clay-sized particles, suggesting that the source areas, most likely nearby glacio-fluvial deposits, were enriched with fine-grained material at that time. We hypothesize that the elevated clay content was the result of rock flour production by nearby valley glaciers that were active in the Rocky Mountains during MIS 4. The results of our study illustrate how recognizing indirect evidence of glacial activity can result in a more complete record of past climate conditions than what could be achieved by the study of moraines alone.

Colorado↗
USGS2007

Rocky Mountain Snowpack Chemistry at Selected Sites, 2004

During spring 2004, the U.S. Geological Survey in cooperation with the National Park Service and the U.S. Department of Agriculture, Forest Service collected and analyzed snowpack samples for 65 sites in the Rocky Mountain region from New Mexico to Montana. Snowpacks were sampled from late February through early April and generally had well-below-average- to near-average snow-water equivalent. Regionally, on April 1, snow-water equivalent ranged from 50 to 89 percent. At most regional sites monitored during 1993-2004, snowpack ammonium, nitrate, and sulfate concentrations for 2004 were lower than the 12-year averages. Snowpack ammonium concentrations in the region were lower than average concentrations for the period at 61 percent of sites in the region, but showed a new pattern compared to previous years with three of the four highest 2004 concentrations observed in northern Colorado. Nitrate concentrations in 2004 were lower than the 12-year average for the year at 53 percent of regional sites, and typically occurred at sites in Wyoming, Idaho, and Montana where powerplants and large industrial areas were limited. A regional decrease in sulfate concentrations across most of the Rocky Mountains (with concentrations lower than the 12-year average at 84 percent of snowpack sites) was consistent with other monitoring of atmospheric deposition in the Western United States. Total mercury concentrations, although data are only available for the past 3 years, decreased slightly for the region as a whole in 2004 relative to 2003. Ratios of stable sulfur isotopes indicated a similar regional pattern as observed in recent years with sulfur-34 (d34S) values generally increasing northward from northern New Mexico and southern Colorado to northern Colorado, Wyoming, Idaho, and Montana.

Open-File Report↗
USGS2024

Testing tree-ring cellulose δ18O with water isotopes for Holocene lake δ18O interpretations in the central Rocky Mountains USA

Stable isotopes of water preserved in geologic archives, primarily as oxygen (δ18O), have proven critical for documenting Earth’s climatic and hydrologic systems past and present. However, timescale differences of water isotope inputs to proxy systems and the signal embedded in long paleorecords often confound translation to observed hydroclimatic metrics. Here, a unique 20-year dataset of meteorology, hydrology, and the isotopic composition of weekly meteoric and surface water samples (δ18O, δ2 H) are combined with paleoclimate δ18O data from tree-ring cellulose and lake carbonate to better understand proxy signals of Upper Colorado river basin drought. Annual tree-ring cellulose δ18O from Picea engelmannii growing within a glacier-fed creek and a spring discharge area were used to derive annual source water δ18O using a cellulose source-water isotope model. Comparisons with the monitoring record indicates that tree-ring cellulose δ18O tracks variations in wet and dry hydroclimatic extremes. Source water isotopes are shown to reflect the hydroclimate of the current year and some number of previous years as an effective moisture-discharge proxy rather than a precipitation isotope proxy. Results contextualize Holocene lake carbonate δ18O data. The contemporary-to-paleo comparison identifies changes in seasonal precipitation extremes during recent millennia and several earlier arid and monsoon-dominated Holocene periods that exceed the arid maximum of the calibration period.

Colorado↗
USGS2019

Recognition and significance of Late Devonian fluvial, estuarine, and mixed siliciclastic-carbonate nearshore marine environments in the San Juan Mountains (southwestern Colorado, U.S.A.): Multiple incised valleys backfilled by lowstand and transgressive system tracts

The Upper Devonian Ignacio Formation (as stratigraphically revised) comprises a transgressive, tide-dominated estuarine depositional system in the San Juan Mountains (Colorado, USA). The unit backfills at least three bedrock paleovalleys (10–30 km wide and ≥42 m deep) with a consistent stratigraphy of tidally influenced fluvial, bayhead-delta, central estuarine-basin, mixed tidal-flat, and estuarine-mouth tidal sandbar deposits. Paleovalleys were oriented northwest while longshore transport was to the north. The deposits represent Upper Devonian lowstand and transgressive systems tracts. The overlying Upper Devonian Elbert Formation (upper member) consists of geographically extensive tidal-flat deposits and is interpreted as mixed siliciclastic-carbonate bay-fill facies that represents an early highstand systems tract. Stratigraphic revision of the Ignacio Formation includes reassigning the basal conglomerate to the East Lime Creek Conglomerate, recognizing an unconformity separating these two units, and incorporating strata previously mapped as the McCracken Sandstone Member (Elbert Formation) into the Ignacio Formation. The Ignacio Formation was previously interpreted as Cambrian, but evidence that it is Devonian includes reexamined fossil data and detrital zircon U-Pb geochronology. The Ignacio Formation has a stratigraphic trend of detrital zircon ages shifting from a single ca. 1.7 Ga age peak to bimodal ca. 1.4 Ga and ca. 1.7 Ga age peaks, which represents local source-area unroofing history. Specifically, the upper plate of a Proterozoic thrust system (ca. 1.7 Ga Twilight Gneiss) was eroded prior to exposure of the lower plate (ca. 1.4 Ga Uncompahgre Formation). These results are a significant alternative interpretation of the geologic history of the southern Rocky Mountains.

Colorado↗
USGS1875

Annual report upon the geological exploration of the fortieth parallel from the Sierra Nevada to the eastern slope of the Rocky Mountains: Being Appendix KK of the Annual Report of the Chief of Engineers to the Secretary of War for 1875

I have the honor herewith to present a brief annual report of the operations of the geological exploration of the fortieth parallel, under my charge, for the year ending June 30, 1875, and to state in explanation of its delay that, since the date when it should properly have been rendered, I have been severely ill, and confined to my bed more than half of the time. The entire year bas been spent in office here in New York, and devoted to the preparation of reports and their accompanying illustrations. I had hoped ere this to have been able to go to press with a completed work, and could easily have done so but for the impossibility of getting from the various paleontological authorities (to whom we were obliged to commit our collections of fossils) any final lists. It is the misfortune of geology to be more or less dependent on this branch of specialists. Without their specific determinations, the geological maps, even, cannot receive their ultimate color-designations, nor can reports, which like ours, involve a wide range of stratigraphy, be safely written. So it has happened, in spite of every effort on my part, that these scientific autocrats, although abundantly promising, have again and again disappointed me, and caused a wearying delay in the publication of our report. Vexatious as this has been, it has not, however, failed to add a compensating value to the work at large, in that it has yielded us the time to elaborate certain important branches, as I shall presently show. The following statement of what has been done in each special branch will give a clear idea of the present status of our work.

Sierra Nevada Mountains, Rocky Mountains↗
USGS2011

The key to commercial-scale geological CO2 sequestration: Displaced fluid management

The Wyoming State Geological Survey has completed a thorough inventory and prioritization of all Wyoming stratigraphic units and geologic sites capable of sequestering commercial quantities of CO 2 (5–15 Mt CO 2 /year). This multi-year study identified the Paleozoic Tensleep/Weber Sandstone and Madison Limestone (and stratigraphic equivalent units) as the leading clastic and carbonate reservoir candidates for commercial-scale geological CO 2 sequestration in Wyoming. This conclusion was based on unit thickness, overlying low permeability lithofacies, reservoir storage and continuity properties, regional distribution patterns, formation fluid chemistry characteristics, and preliminary fluid-flow modeling. This study also identified the Rock Springs Uplift in southwestern Wyoming as the most promising geological CO 2 sequestration site in Wyoming and probably in any Rocky Mountain basin. The results of the WSGS CO 2 geological sequestration inventory led the agency and colleagues at the UW School of Energy Resources Carbon Management Institute (CMI) to collect available geologic, petrophysical, geochemical, and geophysical data on the Rock Springs Uplift, and to build a regional 3-D geologic framework model of the Uplift. From the results of these tasks and using the FutureGen protocol, the WSGS showed that on the Rock Springs Uplift, the Weber Sandstone has sufficient pore space to sequester 18 billion tons (Gt) of CO 2 , and the Madison Limestone has sufficient pore space to sequester 8 Gt of CO 2 .

Energy Procedia↗