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

Other| January 01, 1958 The relation of phosphorites to ground water in Beaufort County, North Carolina Philip Monroe Brown Philip Monroe Brown Search for other works by this author on: GSW Google Scholar Author and Article Information Philip Monroe Brown Publisher: Society of Economic Geologists First Online: 02 Mar 2017 Online ISSN: 1554-0774 Print ISSN: 0361-0128 GeoRef, Copyright 2006, American Geological Institute. Abstract, Copyright, Society of Economic Geologists. Reference includes data from Bibliography and Index of North American Geology, U. S. Geological Survey, Reston, VA, United States Economic Geology (1958) 53 (1): 85–101. https://doi.org/10.2113/gsecongeo.53.1.85 Article history First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Philip Monroe Brown; The relation of phosphorites to ground water in Beaufort County, North Carolina. Economic Geology 1958;; 53 (1): 85–101. doi: https://doi.org/10.2113/gsecongeo.53.1.85 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyEconomic Geology Search Advanced Search Abstract 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 unconformably 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 cellophane (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 P 2 O 5 content from 8 to 31 percent. The P 2 O 5 content is apparently proportionate to the cellophane 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 postdepositional 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." This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.