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Chemical character of water in the igneous and metamorphic rocks of North Carolina

Journal Article · · Econ. Geol.; (United States)
The igneous and metamorphic rocks of North Carolina vary considerably in chemical composition and, consequently, in solubility. Each major chemical type yields ground water having a distinctive chemical character; enough contrast generally exists for chemical analyses of ground water to be an aid in geologic mapping where outcrops are scarce. In their chemical character and that of the water derived from them, the rocks of North Carolina can be divided into two groups. The first includes granite, granite gneiss, mica schist, slate, and rhyolite flows and tuffs; these rocks resemble granite in composition. The second group includes diorite, gabbro, hornblende gneiss, and andesite flows and tuffs; these rocks resemble diorite in composition. The granite group yields a soft, slightly acidic water that is low in dissolved mineral constituents; the diorite group yields a hard, slightly alkaline water that is relatively high in dissolved material. Lithologic determinations based on the chemical character of ground water are generally reliable in regions of similar climate and topography. Anomalies in dissolved mineral constituents that are not due to differences in rock type, climate, or topography may indicate either abnormal structural conditions, resulting in abnormal rates of circulation of the water, or the presence of concentrated mineral deposits.
OSTI ID:
5607663
Journal Information:
Econ. Geol.; (United States), Journal Name: Econ. Geol.; (United States) Vol. 53; ISSN ECGLA
Country of Publication:
United States
Language:
English