Seismic imaging of the Elberton granite, Inner Piedmont, Georgia, using COCORP southern Appalachian data.

Seismic imaging of the Elberton granite in the Georgia Inner Piedmont was undertaken to define its shape and to determine its relation to the southern Appalachian thrust. The recent Consortium for Continental Reflection Profiling (COCORP) lines in the S Appalachians suggest a major thrusting of a crystalline block over sediments, although the extent of this thrust is subject to interpretation. The fine-grained Elberton, of Late Devonian age, is the only major pluton crossed by the seismic traverse and is not well defined on the unmigrated common depth point (CDP) seismic section. Migration by beam-forming reveals considerable variation in the direction of returning signal and provides a clearer image of the laminated reflections, ubiquitous in the S Appalachians, which have been interpreted as the equivalents of the Valley and Ridge sediments beneath an allochthonous sheet. -Authors Dept of Geol Sci, Northwestern Univ, Evanston, Illinois 60201, USA. English