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Research about Colorado, Utah

Source-linked reports with geographic coverage including Colorado, Utah.

139 records · Page 8Linked to original sources
USGS1958

Uranium deposits under conglomeratic sandstone of the Morrison Formation, Colorado and Utah

In southwestern Colorado and southeastern Utah, strata of conglomeratic sandstone are localized at the base of the Brushy Basin Member of the Morrison Formation of Jurassic age. These discrete lithologic units contain sedimentary structures oriented in a prevailing easterly direction. They are believed to cover about one-third of the underlying Salt Wash Member in southwestern Colorado and southeastern Utah, and they locally rest on ore-bearing sandstone in the Salt Wash Member. Eastward-trending planar cross-stratification and trough cross-stratification and a general westward coarsening of sediments in the conglomeratic sandstone strata suggest that they are the products of stream aggradation from westerly source areas. Uranium-vanadium deposits in the uppermost, almost continuous, layer of sandstone of the Salt Wash Member are classified according to their association with the conglomerate strata. Of the 363 deposits studied in the uppermost sandstone layer of the Salt Wash Member, 101 are known to be directly beneath conglomeratic sandstone strata, 211 are below the projected extension of conglomeratic sandstone strata, 33 are beyond the safe limits of such projection, and 18 are lateral to the margins of conglomeratic sandstone strata. At places, near clusters of deposits in the uppermost sandstone of the underlying Salt Wash Member, conglomeratic sandstone strata of the Brushy Basin Member are also mineralized. It is postulated that ground-water movement during deposition of the Morrison Formation in Late Jurassic time localized the uranium and vanadium. The direction of this ground-water movement is believed to have been related to streams that deposited the conglomeratic strata, so that in the ore-bearing sandstone metal ions contained in the ground water were localized in places of high transmissibility and in the vicinity of decaying organic debris. According to the age of the ores, precipitation of the metals was much later than their localization, probably during Late Cretaceous or early Tertiary time.

Colorado, Utah↗
USGS1955

Conglomeratic sandstone strata at the base of the Brushy Basin member of the Morrison formation as related to uranium-vanadium deposits, southwestern Colorado and southeastern Utah

In southwestern Colorado and southeastern Utah strata of conglomeratic sandstone are localized at the base of the Brush Basin shale member of the Morrison formation of Jurassic age. These strata are discrete lithologic units that contain sedimentary structures oriented in a prevailing easterly direction, they locally rest upon sandstone in the Salt Wash that is ore bearing, and they are believed to cover about one-third of the underlying Salt Wash sandstone member in southwestern Colorado and southeastern Utah. Easterly trending planar cross-stratification and trough cross-stratification-type bedding and a general westward coarsening of sediments in the strata suggest they are the products of stream aggradation from westerly source areas. Uranium-vanadium deposits in the uppermost, almost continuous, layer of sandstone of the Salt Wash member have been classified according to their association with the conglomerate strata. Of the 364 deposits that have been studied in the uppermost sandstone layer of the Salt Wash, 29 percent of the total are directly below a conglomeratic sandstone stratum, 61 percent are below their projected trend, 6 percent are beyond the safe limits of projection, and 4 percent are lateral to their margins. Locally, a conglomeratic sandstone stratum may be mineralized. Where this happens, it is usually near clusters of deposits in the uppermost sandstone of the underlying Salt Wash member. Late Jurassic Morrison ground-water conditions can be postulated to localize uranium-vanadium rich ground water below the conglomerate strata.

Colorado, Utah↗
USGS1952

Hydrologic reconnaissance of the Green River in Utah and Colorado

The Green River, rising in Wyoming and draining high mountains in that state, northeast Utah and northwest Colorado, is a major tributary of the Colorado River. In the late summer, after the snow has melted from these mountains, the flow in the Green River reaches its minimum for the year. At that time a large proportion of the water in the river is returned to the atmosphere by evaporation and transpiration. During a 21-day period in September 1948, when the flow was least for the year, the average flow of the river as it entered Utah from Wyoming was 515 cfs. In the 437 miles of its course through Utah and Colorado evapotranspiration losses averaged 430 cfs. The average discharge of the Green River into the Colorado was about 975 cfs. Contributions to the river in Utah and Colorado totalled 890 cfsi including 560 from tributaries. The calculated ground-water inflow was about 330 cfs, of which about 75 percent was contributed within the Uinta Basin. Verv little ground water was contributed to the river in the lower 180 miles of its course, where the river flows through canyon lands of the Colorado Plateaus. These estimates are based upon information collected during a boat reconnaissance in September 1948, and upon data available from stream-gaging stations along the Green River and many of its tributaries. From these data an accounting was made of the water--as to both quantity and quality--in several segments of the river. For each segment determinations were made of the surface outflow, loss by evapotranspiration, and surface- and ground-water inflow. During the reconnaissance information was also obtained as to the relation of stream flow to regional geology and ground-water hydrology. No detailed hydrologic studies have yet been made within the drainage basin of the Green River. On the basis of this recomiaissance, detailed studies in the Uinta Basin, Browns Park, and Echo Park areas are recommended as highly desirable, because of the possible relations of ground-water hydrology to river-basin development projects. Similar reconnaissance can be of value in delineating the areas where detailed hydrologic studies would be most fruitful throughout the upper Colorado River basin.

Colorado, Utah↗
USGS1952

Photogeologic maps of the Verdure 1, 2, 4, 6, 7, and 8 quadrangles, Utah and Colorado

Base maps compiled by Soil Conservation Service, U.S. Department of Agriculture. These maps are compilations of photogeology and surface geology, Colorado Plateau area, United States. They are also known as: Trace Elements Memorandum Report 399 (Verdure 1) Trace Elements Memorandum Report 406 (Verdure 2) Trace Elements Memorandum Report 438 (Verdure 4) Trace Elements Memorandum Report 405 (Verdure 6) Trace Elements Memorandum Report 395 (Verdure 7) Trace Elements Memorandum Report 403 (Verdure 8)

Colorado, Utah↗
USGS1952

Present and past ground-water conditions in the Morrison Formation in southwestern Colorado and southeastern Utah

Field and laboratory studies of ground-water conditions in the carnotite-bearing Morrison formation in southwestern Colorado and southeastern Utah were undertaken to determine possible relations between ground waters and the carnotite deposits. The ore-bearing sandstone consists of lenticular sandstone strata, interbedded within discontinuous layers of mudstone; these strata were deposited in a stream environment. The porosity and permeability of the ore-bearing sandstone in one area are relatively low, porosity averaging about 15 percent and permeability ranging between 30 and 3300 millidarcys. Permeability studies in this same area show that sandstone classed as favorable for ore is slightly more permeable than and has nearly twice the transmissibility of sandstone classed as semifavorable; outcrop studies also suggest a lower transmissibility for sandstone that is unfavorable. Samples of water from the ore-bearing and associated strata show considerable variation in chemical charter. These water samples are generally low in uranium, vanadium, copper, and lead, most samples containing less than 1 part per million (ppm) of each metal. General geologic relations suggest that ground-water movement probably was active through the ore-bearing strata during their deposition and shortly afterward. Movement during this time probably occurred largely through the more permeable sand strata and in the general direction of initial dip and stream flow. During Cretaceous time, when several thousand feet of marine sediments accumulated over the Morrison, the water contained in the ore-bearing strata probably was immobile or nearly so and was protected from escape or contamination. Following Tertiary deformation and erosion, active ground-water circulation no doubt was restored, but because of the low permeability and the lenticular character and therefore low transmissibility of the ore-bearing sandstone, ground-water movement probably was slow. Faulting probably also influenced the direction and rate of ground-water movement during Tertiary time. Movement and localization of ground water would permit the concentration of metal-bearing solutions during Salt Wash and early Brushy Basin time in the beds that now contain ore deposits. It is more difficult to explain the formation of these deposits, which have a wide geographic distribution at a restricted stratigraphic position, from solutions circulating through the rocks at a later date. Whatever mode of origin is used to explain the deposits, geologists almost without exception, agree that the metals were transported by solutions that have migrated through the sediments for considerable distances. For this reason, a study of the horizontal and vertical transmissibility characteristics of all exposed sedimentary formations on the Colorado Plateau is planned.

Colorado, Utah↗