Ground Water In Igneous And Metamorphic Rocks; Low-Angle Lithologic Contacts Related To Site-Specific Control Of Ground Water Occurrence

Abstract

Because of well-established empirical relationships, it is common practice to site water wells in igneous and metamorphic rocks near lithologic contacts. In highly eroded fold mountain ranges such as the southeastern U.S. Piedmont/Blue Ridge, major lithologic contacts generally have a structural orientation similar to that of internal compositional layering and/or foliation. There are, however, areas where the lithologic contact relations are quite different from the structural attitude of compositional layering, foliation, schistosity, or gneissosity. Recognizing, and being able to determine, the contact relationship can be a major factor in obtaining positive results in ground water exploration.