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At least 631 records · Page 35Linked to original sources
USGS1956

Geology of the Ralston Buttes district, Jefferson County, Colorado: a preliminary report

The Ralston Buttes district in Jefferson County is one of the most significant new uranium districts located east of the Continental Divide in Colorado. The district is east of the Colorado Front Range mineral belt, along the east front of the range. From November 1953 through October 1956, about 10,000 tons of uranium ore, much of which was high-grade pitchblende-bearing vein material, was shipped from the district. The ore occurs in deposits that range in size from bodies containing less than 50 tons to ore shoots containing over 1,000 tons. The only other mining activity in the area has been a sporadic production of beryl, feldspar, and scrap mica from Precambrian pegmatites, and quarrying of dimension stone, limestone, and clay from sedimentary rocks. Most of the Ralston Buttes district consists of complexly folded Precambrian metamorphic and igneous rocks - gneiss, schist, quartzite, amphibolite, and granodiorite. Paleozoic and Mesozoic sedimentary rocks crop out in the northeastern part of the district. These rocks are cut by northwesterly-trending fault systems of Laramide age and by small bodies of intrusive rocks that are Tertiary in age. The typical uranium deposits in the district are hydrothermal veins occupying openings in Laramide fault breccias or related fractures that cut the Precambrian rocks. Pitchblende and lesser amounts of secondary uranium minerals are associated with sparse base-mental sulfides in a gangue of carbonate minerals, potash feldspar, and, more rarely, quartz. Less common types of deposits consist of pitchblende and secondary uranium minerals that occupy fractures cutting pegmatites and quartz veins. The uranium deposits are concentrated in two areas, the Ralston Creek area and the Golden Gate Canyon area. The deposits in the Ralston Creek area are located along the Rogers fault system, and the deposits in the Golden Gate Canyon area are along the Hurricane Hill fault system. Two geologic factors were important to the localization of the uranium deposits: (1) favorable structural environment and (2) favorable host rocks. The deposits in each of the two major areas are located where a northwesterly-trending Laramide fault system splits into a complex network of faults. Also, most of the deposits appear to be localized where the faults cut Precambrian rocks rich in hornblende, biotite, or garnet and biotite. The ore controls recognized in this relatively new uranium district may have wider application in areas of similar geology elsewhere in the Front Range.

Colorado↗
USGS1976

Preliminary report on water availability in the lower Ship Creek basin, Anchorage, Alaska : with special reference to the fish hatchery on Fort Richardson and a proposed fish-hatchery site near the Elmendorf Air Force base power-plant

The availability of surface water and shallow ground water in the lower Ship Creek basin, Anchorage, Alaska, was examined using 28 years of streamflow records and well logs. Streamflow gains and losses were estimated from 23 seepage investigations made since May 1957. A contour map of the top of the principal confining stratum and an isopach map of the saturated material were made in order to locate areas with the greatest potential for unconfined ground-water development. An adequate supply of water needed for further development of the Fort Richardson fish hatchery probably is available downstream from that site from unconfined ground-water sources. Unconfined ground water upstream from that site probably would not fulfill the water requirements of the hatchery. Additional aquifer testing is needed to verify these predictions. At the proposed fish-hatchery site on Elmendorf Air Force Base it probably is not possible to withdraw the required water either from a system of wells in the unconfined ground-water zone or from Ship Creek during periods of low flow. Two areas upstream from the site offer better potential for unconfined ground-water development; however, exploratory test wells and aquifer testing will be required to define areas of greater saturated thickness and effects of withdrawing the water needed.

Alaska↗
USGS1975

Hydrology of the Albemarle-Pamlico region, North Carolina : A preliminary report on the impact of agricultural developments

Extensive agricultural land clearing and drainage operations underway in a 650 square mile part of the Albemarle-Pamlico region--a 1,634 square mile peninsula in North Carolina lying between Albemarle Sound on the North and the Pamlico River on the south--are changing the hydrology of the area. The artificial drainage system being constructed in the region, although it will probably result in only a slight modification of the natural annual evapotranspiration, overland runoff, and ground-water discharge, will likely result in several important problems. First, changes in the water quality of the sounds and estuaries resulting from the rapid runoff of storm waters may prove harmful to the fishery resources. Second, lowering of the water table may cause relatively rapid subsidence of the land surface in an irregular pattern in the extensive areas underlain by thick peat deposits as a result of biochemical oxidation, peat fires, and wind.

North Carolina↗
USGS1983

Injection of treated wastewater for ground-water recharge in the Palo Alto Baylands, California, hydraulic and chemical interactions — Preliminary report

An injection-extraction well network in the Palo Alto Baylands along the San Francisco Bay, California, was designed to flush the shallow aquifer system of saline water and prevent further inland saline contamination. Clogging processes and solution migration in the vicinity of one injection well were studied. Cyclic evaporative concentration of bay water and infiltration have generated a concentrated ground-water brine. Montmorillonite and illite are the primary clay minerals present in the shallow aquifer system. X-ray diffraction analysis of these clays showed a marked increase in the d-spacing of the crystal lattice when native hypersaline pure water was replaced by injection water. Chloride:magnesium and chloride:potassium ratios in the aquifer system changed during injection, most likely due to ionic exchange reaction. Similar variations in chloride:boron, chloride:iron, and chloride:manganese ratios probably resulted from reduction-oxidation reactions. Ground-water quality appears to have been chiefly affected by the processes of dilution and dispersion. Extraction pump test data yielded a transmissivity value of 960 feet squared per day and a storage coefficient of 0.0005. Vertical permeability of the upper confining layer is 0.08 feet per day.

California↗
USGS1984

Ground water in the Fresno area, California; preliminary report

The U.S. Geological Survey, in cooperation with Fresno County, is developing a computer model of the unconfined aquifer system in the Fresno area. In the area, consolidated rocks are overlain by unconsolidated deposits. The unconsolidated deposits are divided into a lower fine-grained unit and an overlying coarse-grained unit. The system is assumed to be a single unconfined unit. The top of the system is the water table and the bottom is the base of the coarse-grained deposits. The northeastern boundary is the only natural lateral hydrologic boundary. The other lateral boundaries are placed so that errors along them will not affect heads in the area of interest. Initial heads for 1943, hydraulic conductivity, and bottom elevations were used in a steady-state model that generated net flux values. It is anticipated that most of the remaining effort will center on model calibration. (USGS)

Water-Resources Investigations Report↗
USGS1986

Sediment accumulation in San Leandro Bay, Alameda County, California, during the 20th century -- A preliminary report

Major changes made in the configuration of San Leandro Bay, Alameda County, California, during the 20th century have caused rapid sedimentation within parts of the Bay. Opening of the Oakland tidal channel and removal of 97% of the marshlands formerly surrounding the Bay have decreased tidal velocities and volumes. Marshland removal has decreased the tidal prism by about 25%. Comparison of bathymetric surveys indicates that sedimentation in the vicinity of the San Leandro Bay channel averaged 0.7 cm/annum between 1856 and 1984. Lead-210 data collected at four shallow water sites east of the San Leandro Bay channel indicated that sedimentation rates have averaged between 0.06 and 0.28 cm/annum. Because bioturbation of bottom sediments cannot be discounted, better definition of this range in sedimentation rates would required measuring the activity of lead-210 on incoming sediments. In addition to sediment deposited in the vicinity of the San Leandro Bay channel and open, shallow areas to the east, 850,740 cu m of sediment was deposited between 1948 and 1983 in an area dredged at the mouth of San Leandro Creek. All available data indicate that between 1 ,213,000 and 1,364,000 cu m of sediment was deposited in San Leandro Bay between 1948 and 1983. Sediment yield data from an adjacent drainage basin, when combined with inventories of lead-210 and cesium-137, indicate that most of the sediment deposited in San Leandro Bay is coming from resuspension of bottom sediments or from erosion of marshes or shorelines of San Leandro or San Francisco Bay.

California↗
USGS1932

A preliminary report on the artesian water supply of Memphis, Tennessee

Memphis is located in the part of the Gulf Coastal Plain known as the Mississippi embayment. It is underlain by unconsolidated sand and clay formations of Tertiary and Cretaceous age. The Wilcox group, of Tertiary age, and the Ripley formation, of Cretaceous age, are excellent aquifers, and all the water consumed in Memphis is derived from them. The maximum pumpage from the Wilcox group was reached about 1920; in that year an estimated average of 37,575,000 gallons a day was pumped. In 1928 the average daily pumpage from the Wilcox group was about 33,984,000 gallons, and in addition to this the Memphis Artesian Water Department pumped an average of 4,616,000 gallons a day from the Ripley formation. The static level at Memphis varies with the pumpage and the stage of the Mississippi River. The original static level was about 235 feet above mean sea level. In 1928 the average static level at the Auction Avenue plant was 202 feet above mean sea level, which was about 33 feet lower than the original level. The yield is therefore about a million gallons a day for each foot of drawdown. The drawdown is not excessive, and additional pumpage can be developed without undue lowering of head. The water from both the Wilcox group and the Ripley formation is fairly soft and has a moderately low content of dissolved mineral matter. The iron content is sufficiently high to be objectionable, but the iron is easily removed by aeration followed by either settling or filtration for removal of sediment.

Tennessee↗