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David L. Daniels

Publications and source records attributed to David L. Daniels.

34 records · Page 2Linked to original sources
USGS1993

Mineral resource assessment of rare-earth elements, thorium, titanium, and uranium in the Greenville 1° x 2° quadrangle, South Carolina, Georgia, and North Carolina

Mineral resources of the Greenville 1° x 2° quadrangle, South Carolina, Georgia, and North Carolina, were assessed between 1984 and 1990 under the Conterminuous United States Mineral Assessment Program (CUSMAP) of the U.S. Geological Survey (USGS). The mineral resource assessments were made on the basis of geologic, geochemical, and geophysical investigations and the presence of mines, prospects, and mineral occurrences from the literature. This report is an assessment of the rare-earth elements (REE), thorium, titanium, and uranium resources in the Greenville quadrangle and is based on heavy mineral concentrates collected in 1951-54 by the USGS (Overstreet and others, 1968; Caldwell and White, 1973; Cuppels and White, 1973); on the results of the U.S. Department of Energy, National Uranium Resource Evaluation (NURE) sampling program (Ferguson, 1978, 1979); on analyses of stream-sediment and heavy-mineral-concentrate samples (Jackson and Moore, 1992, G.C Cullin, USGS, unpub. data, 1992) on maps showing aerial gamma radiation in the Greenville quadrangle (D.L. Daniels, USGS, unpub. data, 1992); and on the geology as mapped by Nelson and others (1987, 1989).

Georgia, North Carolina, South Carolina↗
USGS1991

E-4 Central Kentucky to the Carolina Trough

E-4 is one of eight Geodynamics transects that cross the Atlantic margin of North America between Georgia and Newfoundland. Five of the transects are in the United States and three are in Canada. Transect E-4, which is 110 km wide and more than 1,100 km long, extends from the stable North American craton just west of the Grenville front near Lexington, Kentucky southeastward across Cape Fear, North Carolina, on the Atlantic coast to oceanic crust east of the Blake Spur magnetic anomaly. Like all of the other U.S. Atlantic coast transects, it crosses Cambrian and Jurassic continental margins of North America as well as the Appalachian orogen. The display, based upon published information, portrays the geology, tectonic style and geophysical expression of this segment of the eastern North American continental margin and interprets its Phanerozoic history. The Decade of North American Geology 1983 geologic time scale (Palmer, 1983) is used throughout the display and text.

Book↗
USGS1985

Aeromagnetic map and selected aeroradiometric data for the Ellicott Rock Wilderness and additions, South Carolina, North Carolina, and Georgia

The aeromagnetic and aeroradiometric data presented herin for the Ellicott Rock Wilderness and additions are taken from an airborne survey that covered a larger area in Georgia, North Carolina and South Carolina, and that was flown in December 1980 and January 1981 under contract to the U.S. Geological Survey. The flight lines were oriented northwest-southeast, approximately perpendicular to the general strike of the geology, at 0.5-mi (0.8-km) separation and at a nominal altitude of 500 ft (150 m) above mean terrain. A small amount of areomagnetic data from previous survey (Riggle and others, 1980) along the southeast edge of the study area is based on east-west flight lines spaced 1 mi (1.6 km) apart. Because of the rugged topography in the region, holding the airplane at a constant elevation abive the terrain was not possible. Actual ground clearance over short distances ranged between about 200 and 1200 ft. The International Geomagnetic Reference Field (IGRF) has been removed from the magnetic data (Barraclough and Fabiano, 1975) and 5000 gammas were added to make all values positive.

Georgia, North Carolina, South Carolina↗
USGS1985

Aeromagnetic map and analysis of aeromagnetic and aeroradioactivity data in the Blood Mountain, Chattahoochee, and Tray Mountain Roadless Areas, northern Georgia

The data for the aerornagnetic map of the Blood Mountain, Chattahoochee, and Tray Mountain Roadless Areas and vicinity were compiled from two separate airborne surveys {U.S. Geological Survey, 1977, 1981) produced in cooperation with the State of Georgia. These surveys were flown by fixed - wing aircraft in 1976 and 1981 at 500 ft (150 m) above mean terrain along rarallel flight lines oriented northwest-southeast. Flight-line spacing is 0.5 mi (0.8 km} for the 1981 survey, which covers the major part of the map, and l mi (1.6 km) for the 1976 survey, which covers the southeast corner of the map. The 1976 survey was adjusted to the magnetic level of the 1981 survey and recontoured where the surveys join. The International Geomagnetic Reference Field (Barraclough and Fabiano, 1975) has been removed from the data of each survey.

Georgia↗
USGS1983

Studies related to the Charleston, South Carolina, earthquake of 1886 — Tectonics and seismicity

Since 1973, the U.S. Geological Survey (USGS), with support from the Nuclear Regulatory Commission, has conducted extensive investigations of the tectonic and seismic history of the Charleston, S.C., earthquake zone and surrounding areas. The goal of these investigations has been to discover the cause of the large intraplate Charleston earthquake of 1886, which dominates the record of seismicity in the Southeastern United States, through an understanding of the historic and modern seismicity at Charleston and of the tectonic setting of the seismicity. This goal is being pursued to evaluate the potential for additional large earthquakes in the Charleston area and surrounding regions and to determine whether the Charleston area differs tectonically in any significant fashion from other parts of the Southeastern United States. An understanding of the specific cause for the 1886 event and of the regional distribution of any structures that are generically related to or geometrically and mechanically similar to the source structure is essential for evaluation of seismic hazards throughout the Southeast. The results given herein represent significant progress toward understanding the tectonic setting of the Charleston-area seismicity. Several chapters in the volume address the distribution and origin of pre-Cretaceous rocks and structures beneath Coastal Plain sediments in the Charleston area and regionally beneath the southern Atlantic Coastal Plain and adjacent Continental Shelf. The modern seismicity at Charleston is occurring at depths equal to or greater than the known extent of these older structures, and rejuvenation of an older fault in the modern stress field is a possible cause of the seismicity. Accordingly, several chapters discuss the possible relationships of the various pre-Cretaceous structures to faults identified near Charleston that have a known Cretaceous and Cenozoic movement history and to the historic and instrumentally recorded seismicity. However, at the present time, none of the young structures can be related unequivocally to the seismicity because earthquake fault-plane solutions and hypocenter distributions do not agree with the locations and orientations of these structures. Therefore, a major emphasis of continuing USGS investigations near Charleston will be to identify additional faults, if any exist, to delineate fault movement histories, and to further refine earthquake locations, focal mechanisms, and related seismological interpretations.

Florida, Georgia, South Carolina↗
USGS1980

Geophysical-geological analysis of Fairfax County, Virginia

Aeromagnetic, aeroradioactivity, and gravity surveys of Fairfax County, Virginia, are interpreted with the aid of existing geologic data and local geophysical measurements. Highly magnetic metasedimentary rocks of the Peters Creek Schist and Sykesville Formation produce most of the magnetic anomalies of Fairfax County. In contrast, the granitoid rocks of the Occoquan pluton are relatively non-magnetic and are characterized by broad magnetic and gravity lows. Linear magnetic highs without corresponding gravity anomalies, plus samples from a test well, indicate that Peters Creek Schist underlies the east side of the Triassic-Jurassic Culpeper basin. The continuation of the Piney Branch mafic-ultramafic complex beneath the basin is indicated by a gravity high. Basement lithology beneath the Coastal Plain sediments is interpreted by the following anomaly combinations: Sykesville Formation - magnetic high with no gravity expression; Chopawamsic Formation -magnetic and corresponding gravity high; Occoquan granitoid rocks -magnetic and corresponding gravity low. Analysis of a detailed gravity profile across a diabase body near Herndon indicates that the intrusive is a sill which is partly discordant with the sedimentary rocks of the Culpeper basin. The limbs of the horseshoe-shaped exposure dip gently toward the center; the west limb, 500 m thick, dips 15° east and the east limb, 250 m thick, dips west 3° or less. A second gravity profile across a similar diabase body near Centreville suggests that part of its western limb consists of a narrow dike-like body projecting upwards from a 200 m-thick buried sill. Both of these bodies apparently have a spoon-shaped structure with a discordant northern edge which was probably controlled by faulting. Similarities between these intrusives apply also to the small Boyds diabase in Maryland. The three diabase bodies are aligned, have similar magnetic expressions, and abut the edge of the Culpeper basin, suggesting that they were intruded under similar structural settings at about the same time. The northward decrease in size of these intrusives may be a consequence of the inward-dipping shape and a greater degree of uplift and deeper erosion to the north. By this reasoning, the Boyds body represents only the basal remnant of a largely eroded structure with the Centreville body preserving more of the original form. A ground magnetometer survey and an aeroradioactivity survey indicate the presence of additional zones in the thermal metamorphic aureole in the sedimentary rocks around the large diabase bodies. A 150-300-m-wide inner magnetite-rich zone above and below the Herndon sill is inferred from anomalies on a detailed ground magnetic profile. Aeroradioactivity data show a rim of high values outside the geologically mapped aureole of both the Herndon and Centreville bodies. This suggests a subtle outer zone slightly enriched in thermally expelled radio-elements. Deep resistivity soundings in the Culpeper basin indicate that the sedimentary rocks may reach a thickness of about 3600 feet (1100 m) at the western edge of the county.

Virginia↗
USGS1980

Preliminary aeromagnetic map of the Charlotte 1 x 2 degree quadrangle, North Carolina, South Carolina

The aeromagnetic map of the Charlotte 1 x 2 degree quadrangle was assembled by 6 individual detailed aeromagnetic surveys flown between 1956 and 1976 (see index map). The International Geomagnetic Reference Field had been subtracted from the data prior to assembly. An arbitrary common datum was selected and the surveys were recontoured at the joins. The 100 gamma contour was selected because it shows the magnetic contrast to best advantage. To complement the magnetic data a gravity survey was conducted by the U.S. Geological Survey and this data is available in a companion map (Wilson and Daniels, in press). Each of these maps has been interpreted in relation to the other and to the geologic map prepared as part of the same program (Goldsmith and others, 1978). It should be noted that the geophysics has had a measurable influence on some of the geologic mapping.

North Carolina, South Carolina↗
USGS1974

Correlation between geophysical data and rock types in the Piedmont and coastal plain of northeast Virginia and related areas

Physical, chemical, and mineralogic characteristics of rock units in parts of the northeast Virginia Piedmont are reflected in the aeromagnelic, aeroradioactivity, and gravity data for this area. Magnetic anomalies show the areal distribution of rocks containing magnetite. Aeroradiometric anomalies in the Piedmont and Coastal Plain provinces are directly related to the K 2 O content of the formations. In the crystalline rocks of the Piedmont this is reflected in their muscovite and microcline content, whereas in the Coastal Plain province it is related to the glauconite content of the Aquia Formation. Locally, in the crystalline rocks of the Piedmont, uranium- and thorium-bearing mineral content is of greater importance than K 2 O-bearing mineral content in producing aeroradiometric anomalies. The region also is characterized by (1) a northern gravity high, (2) a southern gravity high presumed to be caused by mafic rocks, and (3) an intervening zone characterized by low gravity relief and underlain by schist and gneiss. Geologic and geophysical extrapolation southward toward the Arvonia area show that the Chopawamsic Formation and the volcanic rocks of the Evington group are coeval. Also, on the northwest side of these volcanic rocks is a belt of small rootless mafic and ultramafic rocks diapirically ceplaced in folded rocks of Early Cambrian (?) age.

Virginia↗