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Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

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At least 703 records · Page 39Linked to original sources
USGS1976

Compositional variations in wolframite from the Hamme (Tungsten Queen) mine, North Carolina

A microprobe study of wolframite from the Tungsten Queen mine, Hamme district, North Carolina, proves it to be almost pure huebnerite. Concentric zoning, which shows up as light-brown and dark-brown bands, indicates small variations in the content of FeO. There is no apparent correlation between the small variations in the composition of the wolframite and its position in the mine. The Fe/Mn ratio of the wolframite is not indicative of the temperature of crystallization.

North Carolina↗
USGS1976

Gamma-ray spectrometer measurement of 238 U/ 235 U in uranium ore from a natural reactor at Oklo, Gabon

About 20 years ago, Kuroda theorized that a high-grade uranium deposit emplaced about 2x10 9 years ago could achieve criticality and sustain a nuclear chain reaction, given a sufficient thickness of high-grade ore and an appropriate water content. Such a natural reactor was found in 1972 at the Oklo deposit, Gabon. The ore contains as much as 60 percent uranium, but the isotopic abundance of 235 U is as little as 0.4 percent in contrast to the normal abundance of 0.7110 percent 235 U. A sample from the Oklo deposit containing about 0.51 atom percent 235 U (by mass spectrometer) was analyzed by a gamma-ray spectrometer system, using a high-purity planar germanium detector. The 235 U was determined from its daughter's ( 234 Th) 63.3 keV photopeak; the 235 U was determined from its 143.8 and 163.4 keV photopeaks. The ratios of these photopeaks were compared with that from a standard having normal uranium isotopic content; the resulting calculations give a 235 U abundance of 0.54 atom percent in the Oklo sample. The gamma-ray spectrum also contains lines from five other isotopes in the uranium series, which indicate the Oklo sample to be at or near secular equilibrium, as the time elapsed since the nuclear reaction ended was sufficient to permit the daughters to achieve equilibrium.

Journal of Research of the U.S. Geological Survey↗
USGS1976

Pre-Eocene rocks of Java, Indonesia

The exposed pre-Eocene rocks of Java can be divided into two compound units for purposes of reconnaissance mapping and structural interpretation: a sedimentary sequence and melange. The sedimentary sequence consists of moderately deformed and little-metamorphosed conglomerate, sandstone, mudstone, claystone, chert, and limestone. The melange consists of a chaotic mechanical mixture of rocks identical to those of the sedimentary sequence and their metamorphic equivalents, such as schist, phyllite, quartzite, and marble. In addition, it contains a large proportion of quartz porphyry and smaller amounts of granite, basalt, gabbro, peridotite, pyroxenite, and serpentinite. The sedimentary sequence is at least partly of Early Cretaceous age and the melange is of Early Cretaceous to very early Paleocene age. They are overlain unconformably by Eocene rocks. The presence in the melange of blocks of quartz porphyry and granite is not easily reconcilable with current plate tectonic concepts in which the sites of formation of melange and plutonic rocks should be hundreds of kilometres apart.

Java↗
USGS1976

Sedimentary depositional environments of uranium and petroleum host rocks of the Jackson Group, south Texas

Determination of depositional environments in rocks of the Jackson Group of late Eocene age aids in the exploration for uranium and petroleum in south Texas. During deposition of the Jackson Group, conditions were similar to those existing along the modern Gulf Coast of Texas except for a less arid climate and a greater supply of volcanic sediment. Sedimentary depositional environments recognized in both the modern coast and the Jackson rocks, in order from sea toward land, are: shoreface, beach, lagoon and bay, and paludal. Sediment deposited in these environments in places is interbedded with or transected by fluvial sediment. Both uranium and petroleum are found in the shoreface, beach, and fluvial facies. These facies are characterized by permeable well-sorted sandstone, which is commonly overlain and underlain by less permeable mudstone. A typical vertical sequence in ascending order through a unit containing a beach sandstone facies is (1) lagoonal or paludal clay stone and siltstone, (2) crossbedded fine-grained beach sandstone which contains Ophiomorpha burrows and, which, in places, is locally interbedded with lacustrine or lagoonal mudstone, (3) weakly laminated beach sandstone which contains root impressions at the top and Ophiomorpha , and (4) lagoonal or paludal claystone and siltstone. Gulfward, the beach sandstone apparently grades into highly burrowed, generally finer grained, more poorly sorted, less porous shoreface rocks. The beach facies may include barrier island beaches and mainland beaches, some of which were probably cheniers. Beach facies sandstone units extend many miles along the depositional strike, which nearly parallels the present outcrop strike, but extend only a mile or two (2-3 km) normal to the depositional strike into the subsurface. Recognition of the various facies in outcrops and drill holes is necessary for determination of true stratigraphic relations and for aid in exploration for beach and fluvial sandstone favorable for uranium and petroleum accumulations.

Texas↗
USGS1973

A rapid method for the determination of radioactive cesium isotopes in water

Radioactive cesium in water is concentrated by ion-exchange on finely divided ammonium hexacyanocobalt ferrate (NCFC), and then determined by beta counting. No carrier is added, and the method can be used to determine beta-emitting cesium isotopes at the 10-pCi/l level using a 100-ml sample. Five samples can be prepared for counting, in approximately 3 hours, and the method is applicable to fresh and saline waters.

Journal of Research of the U.S. Geological Survey↗
USGS1973

Effects of laboratory treatments on silver and other elements in native gold

Interpretation of the element content of gold and of alloy proportions of gold and silver may have useful applications in prospecting and ore genesis studies. The commonly used methods of concentration and recovery of gold for analysis (acid leach, roasting, or amalgamation), however, alter the content of silver and other elements in the gold. The treatment of gold with four mineral acids (HF, HCL, H 2 S0 4 , and HNO 3 ) and combinations of these acids, amalgamation of the gold, and roasting the gold in a muffle furnace at 650°C for 8 hours caused losses of 0-100 percent of the elements studied. In some of the samples studied these treatments also caused losses totaling as much as 50 percent, by weight, of the silver content (which made up 20 percent of the total sample weight). The other elements studied show similar behavior to a lesser extent. The results of these studies show that before one interprets compositional analyses for prospecting or other applications he must know to what extent a recovery treatment changes the composition of the elements.

Journal of Research of the U.S. Geological Survey↗
USGS1973

Tests of rhodamine WT dye for toxicity to oysters and fish

Because of the toxicity to oyster larvae and eggs of rhodamine B dye in concentrations greater than 1 mg/l in earlier tests, there was a concern that rhodamine WT, a similar tracer dye, would have a detrimental effect on marine life being developed under the aquaculture program of the Lummi Indian Tribe near Bellingham, Wash. Tests showed that 48-hour exposures at 24° C of 11,000 oyster eggs per liter and 6,000 12-day-old larvae per liter, in sea water with concentrations of rhodamine WT ranging from 1 μg/l to 10 mg/l, resulted in development of the eggs to normal straight-hinge larvae and no abnormalities in the larvae development. Tests made on the smolt of both silver salmon and Donaldson trout, with the fish held for 17.5 hours in a tankfull of sea water with a dye concentration of 10 mg/l at 22°C showed no mortalities or respiratory problems. With the concentration increased to 375 mg/l, and the time extended an additional 3.2 hours, still no mortalities or abnormalities were noted. The fish remained healthy in dye-free water when last checked a month after the test.

Journal of Research of the U.S. Geological Survey↗
USGS1973

An accurate Invar-wire extensometer

Stevens Type F water-level recorders have been modified to measure changes in the distance between two points, with amplification of up to 10 times. Such recorders are capable of measuring strains of 10 -5 and possibly 10 -6 over 10-m distances when corrections are made for frictional effects and temperature. In two field experiments, one on Kilauea Volcano in Hawaii, and the other on the San Andreas fault in central California, measurements by the recorders agree well with those by several different methods for the same episodes of ground deformation. Equipment for the entire system costs about $300 and requires 1 to 2 man-days for installation.

Journal of Research of the U.S. Geological Survey↗
USGS1973

Notes on the bromine pentafluoride technique of oxygen extraction

The necessity to use a dry box when loading silicate samples into reaction vessels prior to fluorination is eliminated by the use of a simple loading technique. Data presented show the reproducibility of the fluorination reaction using this technique. Sodium fluoride, when added to saline waters prior to fluorination, improves the precision of the overall technique.

Journal of Research of the U.S. Geological Survey↗
USGS1974

Stabilities of calcite and aragonite

A revaluation of the 25° C activity-product constants of calcite ( K C ) and aragonite ( K A ) was made on the basis of the known solubilities of these phases for which the activity of total dissolved calcium was corrected for the presence of the ion pair CaHCO 3 + in the aqueous phase. The value of the dissociation constant of CaHCO 3 + was taken to be 10 -1.225±0.02 . This value, combined with values of the analytical concentrations in solutions with partial pressure P CO2 =0.97 atmosphere, leads to K C =l0 -8.52±0.04 and K A = 10 -8.36±0.04 . Based on these K values, standard free energies of formation of calcite and aragonite were calculated to be -270,144±375 and -269,926±375 calories mole -1 , (-1,130,282±1,569 and -1,129,370±1,569 joules mole -1 ), respectively. From the 25°C K values, using appropriate entropy and heat capacity data, values of K C and K A were calculated over the temperature range 0° to 200°C. Possible errors in interpretation of measured pH values and inferred P CO2 values and the bearing of these errors on calculations of K values are discussed.

Journal of Research of the U.S. Geological Survey↗
USGS1974

Lunar highlands volcanism implications from Luna 20 and Apollo 16

Highlands materials sampled at the Apollo 16 and Luna 20 sites represent units of distinctive morphology that are widespread on the lunar nearside. Samples from the Apollo 16 site represent hilly and furrowed materials of the Descartes highlands and Cayley Formation. Materials were collected by Luna 20 from terrain resembling the Descartes terrain. Most photogeologic interpretations of these units favored volcanic origins, but the samples fail to support this interpretation. Luna 20 soil fragments are mainly glassy microbreccia with lithic inclusions of fine-grained hornfels; less than 3 percent of the fragments have textures of volcanic rocks, and most of these are likely crystalline products of impact melting. Apollo 16 soils formed on ejecta derived from a plutonic anorthosite-norite-troctolite suite. The similarity of Luna 20 soils indicates that these too formed as regolith on ejecta of anorthosite-norite-troctolitc composition. Interpretation of the samples from the two locations now suggests that hilly and furrowed terrains, previously thought to be of volcanic origin, are impact ejecta; in view of the plutonic nature of the source rocks and their extensive fusion and metamorphism, it is likely that the ejecta were derived from multiring basins. At one point, the Apollo 16 site, the Cayley Formation is composed of basin ejecta.

Journal of Research of the U.S. Geological Survey↗
USGS1974

The calculation of aquifer chemistry in hot-water geothermal systems

The temperature and chemical conditions (pH, gas pressure, and ion activities) in a geothermal aquifer supplying a producing bore can be calculated from the enthalpy of the total fluid (liquid + vapor) produced and chemical analyses of water and steam separated and collected at known pressures. Alternatively, if a single water phase exists in the aquifer, the complete analysis (including gases) of a sample collected from the aquifer by a downhole sampler is sufficient to determine the aquifer chemistry without a measured value of the enthalpy. The assumptions made are that the fluid is produced from a single aquifer and is homogeneous in enthalpy and chemical composition. These calculations of aquifer chemistry involving large amounts of ancillary information and many iterations require computer methods. A computer program in PL-1 to perform these calculations is available from the National Technical Information Service as document PB-219 376.

Journal of Research of the U.S. Geological Survey↗
USGS1974

A mineral separation procedure using hot Clerici solution

Careful boiling of Clerici solution in a Pyrex test tube in an oil bath is used to float minerals with densities up to 5.0 in order to obtain purified concentrates of monazite (density 5.1) for analysis. The "sink" and "float" fractions are trapped in solidified Clerici salts on rapid chilling, and the fractions are washed into separate filter papers with warm water. The hazardous nature of Clerici solution requires unusual care in handling.

Journal of Research of the U.S. Geological Survey↗
USGS1974

Spectrofluorimetric procedure using 2,3-napthalenediamine for determining selenium in rocks

A spectrofluorimetric procedure using 2,3-naphthalenediamine is given for determining submicrogram and microgram quantities of selenium in mineralized rocks. Conditions for the satisfactory isolation and concentration of the selenium are investigated and tested on six USGS standard rocks of various types. Selenium contents of samples treated by an alkaline sinter and leach are compared with those obtained by acid decomposition and with published values determined by neutron-activation analyses. In pure solutions, 0.01 μg of selenium can be determined with a relative standard deviation of 25 percent, thus setting the determination limit at approximately 0.01 ppm Se in a 1.0-g sample. When the amount of selenium is ≥0.1 ppm, a relative standard deviation of 10 percent or less is obtained.

Journal of Research of the U.S. Geological Survey↗
USGS1975

Pyrrolidone - a new solvent for the methylation of humic acid

In the past, humic acid has been methylated by suspending it in a solution of diazomethane in diethyl ether, and degrading the partly methylated humic acid to release those parts of the molecule that were methylated. Only small fragments of the molecule have been identified by this technique. In the procedure described here the humic acid is dissolved in 2-pyrrolidone and methylated by the addition of diazomethane in diethyl ether and ethanol to the solution. Because the humic acid is completely dissolved in the reaction medium, disaggregation of the humic acid particles takes place and much more complete methylation is obtained. The methylated products may be fractionated by countercurrent distribution and analyzed by mass spectrometry.

Journal of Research of the U.S. Geological Survey↗
USGS1973

Two-garnet rodingite from Amador County, California

Two distinct phases of garnet have been discovered in rodingite from Amador County, Calif. The two garnets are hydrogrossular and (hydro?) grossular-andradite. Only one, generally hydrogrossular, has been reported in rodingitcs studied by other workers. The rodingite of this study formed from a mafic dike with abundant euhedral plagioclase laths. The hydrogrossular is concentrated within the areas of these laths and is volumetrically about as abundant. The (hydro?) grossular-andradite is concentrated in the groundmass and as incursions into the plagioclase laths. The garnets apparently grew during one general episode of metasomatism, and their spatial distribution and compositions were controlled principally by the unequal distribution of iron and aluminum caused by the presence of plagioclase laths (and mafic minerals?) in the original unaltered dike.

California↗
USGS1973

Interpretation of depositional environment in the Plympton Formation (Permian), Southern Pequop Mountains, Nevada, from physical stratigraphy and a faunule

Field mapping in the southern part of the Pequop Mountains has shown the presence of a major structural high which has profoundly affected the stratigraphy of Pennsylvanian and Lower Permian beds; lesser effects of this high persisted into the later Permian. Within the Park City Group (Permian), the Plymton Formation, overlying the Kaibab Limestone, is divided informally into five parts. The uppermost Plympton has yielded silicified fossils. The faunule studied is characterized by the scaphopod Plagioglypta and by bellerophontacean and neritacean gastropods, suggestive of a middle Permian age. Specimens are worn, and several lines of evidence suggest that this is a high-energy beach deposit associated with a residual high. The interpretation supplements the field evidence of a hiatus between the Plympton and the overlying Gerster Formation. Other occurrences of elements of the faunule in the equivalent Phosphoria rock complex are noted, but only a few were probably deposited in a high-energy beach environment. A new species of Naticopsis that has the color pattern preserved is named and described.

Nevada↗
USGS1973

Graptolites from the Martinsburg Formation, Lehigh Gap, Eastern Pennsylvania

Graptolites collected from the uppermost part of the Martinsburg Formation (Pen Argyl Member) at and near the contact with the overlying Shawangunk Formation at Lehigh Gap, Pa., indicate that the uppermost Martinsburg is as young as Edenian to early Maysvillian (upper subzone [Climacograptus spiniferus subzone] of zone 13 | Orthograptus truncatus intermedius zone]). The Martinsburg gradationally overlies the Jacksonburg Limestone of late Middle Ordovician age, suggesting a lower age limit for the Martinsburg.

Pennsylvania↗