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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 343 records · Page 19Linked to original sources
USGS1994

Quality of ground water in Harrison County, Mississippi, June - July 1993

During June and July 1993, the U.S. Geological Survey analyzed water from 145 wells in Harrison County, southeastern Mississippi. The wells are completed in five major geologic units: the Citronelle, Graham Ferry, Pascagoula, and Hattiesburg Formations and the Catahoula Sandstone. The wells ranged from 74 to 2,410 feet in depth. Specific conductance (lab) ranged from 15 to 2,020 microsiemens per centimeter; pH (lab), from 5.9 to 9.0; color, from less than 5 to 120 platinum-cobalt units; dissolved-solids concentrations (residue on evaporation), from 20 to 1,120 milligrams per liter; chloride concentrations, from 1.9 to 470 milligrams per liter; and nitrite plus nitrate as nitrogen concentrations, from less than 0.02 to 0.85 milligram per liter. Most of the larger values of specific conductance, pH, dissolved-solids concen- trations, and chloride concentrations were from wells in the southern one-half of the county.

Open-File Report↗
USGS2009

Trends in Water Quality in the Southeastern United States, 1973-2005

As part of the U.S. Geological Survey National Water-Quality Assessment Program, water-quality data for 334 streams in eight States of the Southeastern United States were assessed for trends from 1973 to 2005. Forty-four U.S. Geological Survey sites were examined for trends in pH, specific conductance, and dissolved oxygen, and in concentrations of dissolved solids, suspended sediment, chloride, sodium, sulfate, silica, potassium, dissolved organic carbon, total nitrogen, total ammonia, total ammonia plus organic nitrogen, dissolved nitrite plus nitrate, and total phosphorus. An additional 290 sites from the U.S. Environmental Protection Agency Storage and Retrieval database were tested for trends in total nitrogen and phosphorus concentrations for the 1975-2004 and 1993-2004 periods. The seasonal Kendall test or Tobit regression was used to detect trends. Concentrations of dissolved constituents have increased in the Southeast during the last 30 years. Specific conductance increased at 62 percent and decreased at 3 percent of the sites, and pH increased at 31 percent and decreased at 11 percent of the sites. Decreasing trends in total nitrogen were detected at 49 percent of the sites, and increasing trends were detected at 10 percent of the sites. Ammonia concentrations decreased at 27 percent of the sites and increased at 6 percent of the sites. Nitrite plus nitrate concentrations increased at 29 percent of the sites and decreased at 10 percent of the sites. These results indicate that the changes in stream nitrogen concentrations generally coincided with improved municipal wastewater-treatment methods. Long-term decreasing trends in total phosphorus were detected at 56 percent of the sites, and increasing trends were detected at 8 percent of the sites. Concentrations of phosphorus have decreased over the last 35 years, which coincided with phosphate-detergent bans and improvements in wastewater treatment that were implemented beginning in 1972. Multiple regression analysis indicated a relation between changes in atmospheric inputs and agricultural practices, and changes in water quality. A long-term water-quality and landscape trends-assessment network for the Southeast is needed to assess changes in water quality over time in response to variations in population, agricultural, wastewater, and landscape variables.

Scientific Investigations Report↗
USGS2008

Geology and geochemistry of the Mammoth breccia pipe, Copper Creek mining district, southeastern Arizona: Evidence for a magmatic-hydrothermal origin

The Copper Creek mining district, southeastern Arizona, contains more than 500 mineralized breccia pipes, buried porphyry-style, copper-bearing stockworks, and distal lead-silver veins. The breccia pipes are hosted by the Copper Creek Granodiorite and the Glory Hole volcanic rocks. The unexposed Mammoth breccia pipe, solely recognized by drilling, has a vertical extent of 800 m and a maximum width of 180 m. The pipe consists of angular clasts of granodiorite cemented by quartz, chalcopyrite, bornite, anhydrite, and calcite. Biotite 40Ar/ 39Ar dates suggest a minimum age of 61.5??0.7 Ma for the host Copper Creek Granodiorite and 40Ar/39Ar dates on hydrothermal sericite indicate an age of 61.0??0.5 Ma for copper mineralization. Fluid inclusion studies suggest that a supercritical fluid with a salinity of approximately 10 wt.% NaCl equiv. condensed to a dilute aqueous vapor (1-2.8 wt.% NaCl equiv.) and a hypersaline brine (33.4-35.1 wt.% NaCl equiv.). Minimum trapping temperatures are 375??C and trapping depths are estimated at 2 km. Sulfur isotope fractionation of cogenetic anhydrite and chalcopyrite yields a temperature of mineralization of 469??25??C. Calculated oxygen and hydrogen isotope values for fluids in equilibrium with quartz and sericite range from 10.2??? to 13.4??? and -60??? to -39???, respectively, suggesting that the mineralizing fluid was dominantly magmatic. Evidence from the stable isotope and fluid inclusion analyses suggests that the fluids responsible for Cu mineralization within the Mammoth breccia pipe exsolved from a gray porphyry phase found at the base of the breccia pipe. ?? Springer-Verlag 2008.

Mineralium Deposita↗
USGS1979

Monazite in the granitic rocks of the southeastern Atlantic States: An example of the use of heavy minerals in geologic exploration

The principal part of this report is a discussion of the three monazite belts and the descriptions of the panned concentrates that justify their delineation, details that constitute an example of the use of heavy minerals in regional geologic exploration. The tenors of accessory minerals in rocks from the monazite belts in Viginia, North Carolina, South Carolina, Georgia, and Alabama are listed, and where possible these mineralogical data are translated into genetic interpretations. The origin of the monazite belts is discussed in the light of the mineralogical data, from which it is concluded that the beltlike distribution of monazite is analogous to a petrographic province.

Alabama, Georgia, North Carolina, South Carolina, ↗