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Research about Virginia

Source-linked reports with geographic coverage including Virginia.

At least 487 records · Page 27Linked to original sources
USGS1984

Geomorphic and vegetative characteristics along three northern Virginia streams

Geometry, sediment, and woody-vegetation data were collected from bottomland geomorphic surfaces at valley sections along three gaged perennial streams of northern Virginia. The basins of the streams differ widely in topography and physiography; mean discharges vary from 0.196 to 323 m 3 per sec. Prevalent surfaces identified were the depositional bar, the active-channel shelf, the flood plain, and terraces. The stages corresponding to active-channel–shelf levels were equivalent to flow durations of 5% to 13%. Stages corresponding to flood-plain levels were equivalent to discharges with 1.4- to 2.0-yr recurrence intervals. The discharge data and statistical tests of geomorphic-surface, sediment, and vegetative data suggest that the various alluvial features are formed and maintained by hydraulically controlled sorting processes.

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USGS1984

Feeding flights of nesting wading birds at a Virginia colony

Feeding flights of Snowy Egrets (Egretta thula), Tricolored Herons (E. tricolor), Little Blue Herons (E. caerulea), and Cattle Egrets (Bubulcus ibis) were monitored at a small nesting colony near Chincoteague, Virginia during late May and June 1979. All four species varied their flight directions over a series of days. Cattle Egrets oriented in a different direction (toward uplands) from the other three wetland-feeding species, which oriented toward Spartina marsh areas. None of the species showed a tendency to form groups while departing from or arriving at the colony. Tide level had little influence on flight directions used. Comparisons are made between these results and those from a similar study in coastal North Carolina.

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USGS1984

Maps showing mines, quarries, prospects, and exposures in the Devils Fork Roadless Area, Scott County, Virginia

The Wilderness Act (Public Law 88-577, September 3, 1964) and related acts require the U.S. Geological Survey and the U.S. Bureau of Mines to survey certain areas on Federal lands to determine their mineral resource potential. Results must be made available to the public and be submitted to the President and the Congress. This report presents the results of a survey of mines, quarries, prospects, and coal exposures in the vicinity of the Devils Fork Roadless Area in the Jefferson National Forest, Scott County, Virginia. Devils Fork Roadless Area was classified as a further planning area during the Second Roadless Area Review and Evaluation (RARE II) by the U.S. Forest Service, January 1979. The Devils Fork Roadless Area is in the Clinch Ranger district of the Jefferson National Forest, southwestern Virginia. It is located in Scott County, about 5 miles southeast of Big Stone Gap, Virginia, and is accessible from there via U.W. 23 to Duffield, Virginia, and then northeastward along State Route 653 (fig. 1). Access from the north is provided by State Routes 616, 619, and Forest Route 237. Southern access is provided by State Routes 619 and 649. The interior is accessible by foot along overgrown logging railroad grades and abandoned forest roads on the lower portions of Devil Fork, Straight Fork, and Roddy Branch. The Devils Fork Roadless Area is located at the eastern edge of the Appalachian coal region and is within the Cumberland Mountain section of the Appalachian Plateau physiographic province. Most of the area is drained by Devil Fork and its tributaries. Clinch Rock Branch of Straight Creek, Roddy Branch of Valley Creek, and Stinking Creek, all tributary to the Clinch River, drain small fringe tracts. Altitudes range from about 1,550 ft on the lower part of Straight Fork to about 3,490 ft at Cox Place on Little Mountain. Vegetation varies from mixed hardwoods in the uplands to thickets of conifer, rhododendron, and laurel in moist protected areas, as in coves along drainage courses.

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USGS1983

Industrial effluents as a source of mercury contamination in terrestrial riparian vertebrates

Eight species of piscivorous and insectivorous birds and one species of bat collected along Virginia's North Fork of the Holston River contained elevated mercury residues. The ubiquitous occurrence of mercury in riparian insectivores implicates aquatic insects as a vehicle for spreading mercury contamination from one ecosystem to another and expands the ecological ramifications of mercury-contaminated industrial effluents.

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USGS1983

The Giles County, Virginia, seismic zone

A well-defined seismic zone recently detected in Virginia has an orientation that is not related to the surrounding geologic structures. The orientation of the zone appears to be related to features below the Appalachian overthrust belt. A damaging earthquake that is important in evaluating seismic hazard in the southeastern United States may have occurred in the zone in 1897.

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USGS1983

Seismicity map of the State of Virginia

The data shown on this map and listed in table 1 are for earthquakes that were originally included in a study of seismic risk in the United States (Algermissen, 1969). This data file has been recompiled and updated through 1980. Some revisions of epicenters and intensities in the original file have been made, and intensities have been assigned to earthquakes that previouly had none assigned. Only earthquakes that had epicenters within the boundary of the State are listed in table 2, even though earthquakes that had epicenters in bordering states or countries may have been felt or may have caused damage in the State. Intensity values were updated from data sources that were not available at the time of original compilation. Some epicenters were relocated on the basis of new information. The data shown in table 1 represent best estimates of the epicenter, magnitude, and intensity of each earthquake on the basis of historical and current informaiton. Some of the aftershocks from large earthquakes are listed, but not all, especially for the earthquakes that occurred before seismic instruments were universally used.

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USGS1983

Mineral resource potential map of the Dolly Ann Roadless Area, Alleghany County, Virginia

The Dolly Ann Roadless Area comprises 7,900 acres (3,200 ha) in the George Washington National Forest in the Valley and Ridge physiographic province of west-central Virginia. The area is at the southern ·end of Warm Springs Mountain in Alleghany County just northeast of Covington, the county seat (index map). U.S. Highway 220 forms part of the western boundary, and U.S. Forest Service Road 125, which parallels Pounding Mill Creek, forms the eastern boundary. The principal streams draining the area are Pounding Mill Creek, Dry Run, and Roaring Run, all tributaries of the Jackson River. The highest point in the area is Big Knob at the north end, 4,072 ft (1241 m) above sea level; the lowest points, about 1,400 ft (427 m) above sea level, are at the south side, along Dry Run and Pounding Mill Creek. In general, the hill slopes are steep and heavily wooded with second- or third-growth hardwoods and scattered pine and hemlock. Dolly Ann Hollow near the east end of the area is a steep, boulder-strewn gorge, quite picturesque, but containing no good trails. A good trail up Dry Run connects a trail crossing the ridge between Bald Knob and Big Knob. No other trails cross the area.

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USGS1983

Application of total-count aeroradiometric maps to the exploration for heavy-mineral deposits in the coastal plain of Virginia, with a section on field-spectrometer-data reduction

Total-count contoured aeroradiometric maps for the Coastal Plain of Virginia were used in an effort to locate economic heavy-mineral placer deposits. The principle behind this approach is that heavy- mineral suites commonly contain radioactive minerals that, if the concentration of heavy minerals is exposed at or within inches of the surface, enable the deposit to be located by use of airborne instruments because of its radiometric contrast with the host sediment. Detailed and regional geologic maps, soil maps, land-use and land- cover maps, information on fertilizer use, and ground-spectrometer data were used to study aeroradiometric anomalies for efficient exploration. Aeroradiometric anomalies in the Coastal Plain of Virginia have three general causes. First, the most intense anomalies are associated with cultural features, such as roads made of granitic material. Second, most anomalies of high to intermediate intensity are associated with land used for agricultural purposes and evidently are caused by applications of radioactive fertilizer. Third, anomalies of intermediate to low intensity are associated with heavy-mineral deposits. Results of this study show that aeroradiometric anomalies associated with heavy-mineral accumulations in the Coastal Plain of Virginia have ground radiometric spectra in which thorium is the strongest component and uranium and potassium are lesser components. Heavy-mineral accumulations found in this study by use of the aeroradiometric data are not considered to be of economic importance, mostly because of the low percentage of economic minerals in the heavy-mineral suites and also because of other factors such as the very fine grained nature of the host sediments and competing land use.

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USGS1983

Seedling establishment on a landslide site

Two landslide scars (slide tracks) were plot sampled one and two years after landsliding to determine plant species involved in ecesis. The study site is located in a blockfield cove on Massanutten Mountain, northern Virginia. Old growth forest, adjacent to the slide tracks, is composed primarily of hemlock (Tsuga canadensis) and sweet birch (Betula lenta). These species are the first and foremost colonizers on the slide tracks. Dendrochronological analysis shows that landsliding is frequent at the study site and this disturbance may impart non-equilibrium conditions on the forest. Seed bed characteristics, light availability, and mode of dispersal may be important factors in plant ecesis on slide tracks

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USGS1982

Reproduction and early-life accommodations of landlocked alewives to a southern range extension

Reproduction and first-year growth and food habits of landlocked alewives Alosa pseudoharengus in Claytor Lake, Virginia were examined and compared to descriptions for populations in the species' established New England-Great Lakes range. Alewives in mesothermal (2–27 C) Claytor Lake are shorter-lived (3 years) but grow faster, mature earlier (age 1), and have higher relative and absolute fecundities than have been reported for populations in colder northern waters. The 1979 spawning period extended from early May to early August, beginning at least 1 month earlier and lasting 4–9 weeks longer than in northern lakes. Changes in ovary condition during the spawning period suggest that alewives may be fractional spawners. Evidence of spawning was found in littoral areas throughout the lower 15 km of the reservoir. Growth in length of age-0 Claytor Lake alewives was linear through September and terminated in late autumn. Total first-year growth was reduced in 1979 (maximum of 130 mm total length, TL) from previous years (average of 160 mm TL), although it was substantially greater than recorded in the Great Lakes and the northeastern United States. The longer growing season, rather than accelerated in-season growth, appears to account for larger size achieved in Claytor Lake. High annual growth limits predation by Claytor Lake game fish on early spawned age-0 alewives by late summer. As elsewhere, larval and juvenile alewives (6–70 mm TL) fed primarily on copepods and cladocerans. Age-0 alewives longer than 35 mm TL demonstrated positive size-selection for cyclopoid copepods comparable to that shown by adults. Our findings suggest that self-sustaining alewife populations can be established in many inland waters but raise concerns regarding their forage value and community impacts.

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USGS1982

Stream-grade variation and riparian-forest ecology along Passage Creek, Virginia

Passage Creek, in northwestern Virginia, flows on relatively nonresistant shales, then cuts through a gorge underlain by resistant sandstone In the gorge, the stream gradient steepens, the size of bed material increases, a braided channel forms, and riparian-forest composition and growth form changes relative to areas outside the gorge Effects of flooding are intensified within the gorge and revealed in the pattern and deformation of streamside vegetation Increased stream gradient within the gorge provides for high stream power and coarse sediment deposition relative to the flood plain outside the gorge. A more diverse upland forest grows on the flood plain in the gorge The riparian forest in the gorge may be an example of a nonequilibrium forest, resulting from periodic disturbance by destructive floods. Recognition of vegetation patterns resulting from such disturbances may be useful in detection of potential flooding.

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