Geology Reports⌕ Search

Geology topics

O. B. Lloyd

Publications and source records attributed to O. B. Lloyd.

6 recordsLinked to original sources
USGS1993

Hydrogeologic framework of U.S. Marine Corps Base at Camp Lejeune, North Carolina

The hydrogeologic framework at Camp Lejeune consists of the surficial, Castle Hayne, Beaufort, and Peedee aquifers and intervening confining units. The Castle Hayne aquifer furnishes about 7 million gallons of water per day to Camp Lejeune, but the surficial, Beaufort, and Peedee aquifers, which contain freshwater in places, are not used for supply. The Castle Hayne aquifer is composed of 60 to 90 percent sand and limestone with clay and silt beds, and ranges from 156 to 400 feet thick. Hydraulic conductivity of the aquifer ranges from 14 to 91 feet per day. The Castle Hayne confining unit, which overlies the Castle Hayne aquifer, is composed of silt and sandy clay and averages 9 feet thick where present. This confining unit is incised by the New River and its tributaries, as well as some paleochannels. The effects of pumping from the Castle Hayne aquifer have not significantly affected natural head gradients in the aquifer. However, the potential exists for lateral migration of saltwater where wells are located near streams or paleochannels that have incised the confining unit. Except for one measurement of 960 milligrams per liter chloride in a water sample from the bottom of the Castle Hayne aquifer, dissolved-chloride concentrations in water samples from the Castle Hayne aquifer were less than 120 milligrams per liter. It is not known whether this occurrence of saltwater in the Castle Hayne aquifer is widespread or localized, but its presence indicates a potential for upward movement of saltwater beneath pumped wells.

North Carolina↗
USGS1991

National water-quality assessment program : the Albemarle- Pamlico drainage

In 1991, the U.S. Geological Survey (USGS) began to implement a full-scale National Water-Quality Assessment (NAWQA) program. Long-term goals of the NAWQA program are to describe the status and trends in the quality of a large, representative part of the Nation's surface- and ground-water resources and to provide a sound, scientific understanding of the primary natural and human factors affecting the quality of these resources. In meeting these goals, the program will produce a wealth of water quality information that will be useful to policy makers and managers at the national, State, and local levels. Study-unit investigations constitute a major component of the NAWQA program, forming the principal building blocks on which national-level assessment activities are based. The 60 study-unit investigations that make up the program are hydrologic systems that include parts of most major river basins and aquifer systems. These study units cover areas of 1,200 to more than 65,000 square miles and incorporate about 60 to 70 percent of the Nation's water use and population served by public water supply. In 1991, the Albemarle-Pamlico drainage was among the first 20 NAWQA study units selected for study under the full-scale implementation plan. The Albemarle-Pamlico drainage study will examine the physical, chemical, and biological aspects of water quality issues in a coordinated investigation of surface water and ground water in the Albemarle-Pamlico drainage basin. The quantity and quality of discharge from the Albemarle-Pamlico drainage basin contribute to some water quality problems in the biologically sensitive waters of Albemarle and Pamlico Sounds. A retrospective analysis of existing water quality data will precede a 3-year period of intensive data-collection and analysis activities. The data resulting from this study and the improved understanding of important processes and issues in the upstream part of the study unit will enhance understanding of the quality of water in Albemarle-Pamlico Sounds, the second largest estuarine system in the United States.

Open-File Report↗
USGS1988

Hydrogeologic setting, water levels, and quality of water from supply wells at the U.S. Marine Corps Air Station, Cherry Point, North Carolina

The Marine Corps Air Station is located in the Coastal Plain province of North Carolina. Four freshwater aquifers of sand and limestone underlie the area to a depth of about 500 feet. Saline water occurs below this depth. The aquifers are separated by three confining units that are thin and discontinuous in the southern part. Water supply is obtained from 195- to 330 feet wells in the Castle Hayne aquifer. Many wells are near landfills that have received hazardous wastes. Groundwater withdrawals have reduced hydraulic heads in the Castle Hayne some 20 feet around active production wells, creating potential for downward movement of contaminated water from the surface and for upward movement of saline water that occurs at depth. Chemical analyses of water from the Castle Hayne aquifer indicate median concentrations of iron and manganese are 0.78 and 0.08 milligrams per liter, respectively, and lead and (or) nickel exceed drinking water standards in three wells. Chloride increased from 10 to more than 40 milligrams per liter in the deepest operating well over a 45-year period. Benzene concentrations range from 0.5 to 1.9 milligrams per liter in the southern part of the Air Station but were below the 5 milligrams per liter maximum contaminant level for drinking water. Fatty acids were found in concentrations as much as 28 micrograms per liter in water from wells in an area centered around the intersection of Roosevelt Boulevard and Slocum Road. Resampling is needed to verify all constituents that indicate contamination.

North Carolina↗
USGS1979

Evaluation of the geologic and hydrologic factors related to the waste-storage potential of Mesozoic aquifers in the southern part of the Atlantic Coastal Plain, South Carolina and Georgia

The report describes the subsurface distribution of rocks of Cretaceous to Late Jurassic( ) age in the Atlantic Coastal Plain , South Carolina, and Georgia, and examines their potential for deep-well waste storage into th part of the regional sediment mass which lies below the deepest zones containing usable ground waters. For the study, usable ground water is considered to be that which contains less than 10,000 mg/L dissolved solids. Using a group of geohydrologic parameters derived from or combining 21 categories of basic data, established from study and interpretation of well cuttings and geophysical logs, a series of 32 regional maps and 8 stratigraphic cross sections was constructed. For each of the eight geologic units delineated in the subsurface, the maps illustrate the distribution of waste-storage potential in terms of areal extent, depth below land surface, sand-shale geometry, and the approximate sodium chloride concentration of a unit 's nonusable ground water. In areas where the geologic units contain nonusable ground water, the depth below land surface and the thickness of potential waste-storage reservoir and reservoir-seal combinations are variable. The range in variability appears to be broad enough to meet the need for a wide choice among the geologic requirements that would normally be considered in selecting specific waste-storage sites for detailed examination. (Woodard-USGS)

Georgia, South Carolina↗
USGS1978

Evaluation of the geologic and hydrologic factors related to the waste-storage potential of Mesozoic aquifers in the southern part of the Atlantic Coastal Plain, South Carolina and Georgia

This report describes the subsurface distribution of rocks of Cretaceous to Late Jurassic(?) age in the Atlantic. Coastal Plain, South Carolina and Georgia, and examines their potential for deep-well waste storage. For mapping purposes a waste-storage "operational unit" is established and defined. It is a sand or sandstone layer, 20 feet or more in thickness, that is immediately overlain and underlain by a layer of shale or clay, 20 feet or more in thickness, and which occurs in regional chronostratigraphic units (Units A, B, C, D, E, F, G(?), and H(?)) of Mesozoic age in areas where each of these units contains nonusable ground water. Nonusable ground water is defined as water that contains sodium chloride in excess of 10,000 mg/L. Using a group of geohydrologic parameters derived from or combining 21 categories of basic data, established from study and interpretation of well cuttings and geophysical logs, a series of 32 regional maps and 8 stratigraphic cross sections was constructed. For each of the eight geologic units delineated in the subsurface, the maps illustrate the distribution of waste-storage potential in terms of areal extent, depth below land surface, sand-shale geometry, and the approximate sodium chloride concentration of a unit's nonusable ground water.

Georgia, South Carolina↗