Research about Beaufort, North Carolina

USGS1977

The use of feeding habitat by a colony of herons, egrets, and ibises near Beaufort, North Carolina

Nine species of herons were followed to their feeding sites from a nesting colony near Beaufort, North Carolina, by airplane. Except for the Cattle Egret, which flew exclusively to fields and dumps, all other species flew mainly to saltmarsh habitat. In addition, habitats were selected in relation to tidal depth and it appears, at least for the Great Egret, that low tide habitats were preferred. Most Great Egrets, White Ibises, Louisiana Herons, and Snowy Egrets flew close to the colony and numbers decreased farther from the colony. The Great Egret, Black-crowned Night Heron, and White Ibis flew farther from the colony at high than at low tide. In addition, the species differed in distance flown from the colony. Great Egrets traveled farther from the colony when they used thermals. Rate of travel to feeding sites, however, was the same whether Great Egrets used thermals or not. Aggressive encounters were observed in the Great Egret, Louisiana Heron, Snowy Egret, and Black-crowned Night Heron. Cattle Egrets and White Ibises followed other individuals to feeding sites and it appeared as though they were using the colony as an information center. The Great Egret is the only species to effectively use eelgrass beds near Beaufort. The Great Egrets use of this habitat was restricted to about 1.5 hours on either side of low tide. We suspect that other shorter legged species did not use eelgrass regularly because of its depth.

North Carolina↗

USGS1958

The relation of phosphorites to ground water in Beaufort County, North Carolina

Recent ground-water studies undertaken by the U.S. Geological Survey in cooperation with the North Carolina Division of Mineral Resources have delineated phosphorite deposits, tentatively regarded as being of middle Miocene age, in Beaufort County. These deposits lie unconforma-bly on limestone of Eocene age and are unconformably overlain by late Miocene marl. The phosphorites, buried beneath strata ranging in thickness from 45 to 250 feet, underlie an area approximating 450 square miles. The total thickness of the phosphorite column throughout the area ranges from several feet to nearly 90 feet. The phosphorite column consists of phosphatic sands and intercalated shell limestones. The sands, composed of pellets of brown sand-size collophane (probably carbonate-fluorapatite) and sand-size, flat-sided angular quartz with some silt, clay, and organic material, have a median diameter between 0.50 and 0.25 mm. Chemical analyses of representative samples of the raw sand show a variation in PaOs content from 8 to 31 percent. The P2O5 content is apparently proportionate to the collophane content throughout the area. Reconstruction of the geologic history suggests that the phosphorites were deposited as chemical precipitates and as in situ replacements in a restricted marine basin where the pH of the water acted as the primary depositional control. Reconstruction of the hydrologic history of the phosphorites indicates that the deposits were preserved under artesian conditions; they were never subjected to alteration under water-table conditions. The absence of postpositional alteration makes this area a potentially classic one for studies of phosphorite genesis. Chemical analyses of artesian waters from the phosphorites and from limestones overlain by phosphorites reveal significantly greater concentrations of iodide and bromide in solution than are present in water from overlying sediments or from underlying limestones not overlain by phosphorites. Such anomalies, if present in other similar terranes, may indicate the presence of buried phosphorites. The depth and size distribution of the material suggest a recovery method utilizing wells constructed to "pump sand."

North Carolina↗