GEOLOGIC MAP ILLUSTRATING THE STRATIGRAPHY AND STRUCTURAL GEOLOGY OF THE ALLATOONA DAM, AND THE NORTHERN PART OF THE ACWORTH, GEORGIA, 7.5-MINUTE QUADRANGLES

Geologic mapping of the Allatoona Dam and Acworth, Georgia, 7.5-minute quadrangles by Thomas J. Crawford began in 1966 as a part of a cooperative minerals exploration program by the Coosa Valley Area Planning and Development Commission; the U.S. Economic Development Administration, U.S. Department of Commerce; and the University of Georgia. Crawford, working with the U.S. Geological Survey, continued geologic mapping in these two quadrangles in 1977 and 1978, 1994 and 1996. John Costello mapped in these quadrangles in 1984 and 1985, as part of his PhD dissertation, University of South Carolina and from 2008 to the present with support from the USGS STATEMAP program. Crawford and Randy L. Kath are mapping in these two quadrangles (2008 – Present) as part of a long-term study to more precisely define areal distribution of lithologic units, major geologic structures, and relationships between igneous, metamorphic, and unmetamorphosed sedimentary rocks of northwest Georgia.

In the Cartersville area, Ocoee rocks have been thrust over Chilhowee and Shady rocks along the north-trending Great Smoky (Cartersville) Fault. A short distance east of the Great Smoky (Cartersville) Fault, igneous rocks of the Corbin Metagranite and its contained metasediments and metavolcanics (?), along with the Red Top Mountain Formation and Rowland Spring Formation have been juxtaposed with Ocoee rocks along the Allatoona Dam Fault, tentatively interpreted as a high-angle reverse fault. In this area, the east- and northeast-trending Emerson-Talladega Fault has brought a rock sequence from the south and southeast to override the Shady, Chilhowee, Ocoee, and Corbin rocks; as well as overriding the Great Smoky (Cartersville) Fault and the Allatoona Dam Fault. Both the Great Smoky (Cartersville) Fault and the Emerson-Talladega Fault have large numbers of associated imbricate faults and horses involving both hinterland and foreland rock units. Further to the southeast, another major structural feature, the Allatoona Fault has brought “Piedmont” rocks over “Blue Ridge” rocks. All of these features and interpretations have been controversial for many decades ¯ and will continue to be.