GEOLOGIC MAP OF THE ROCKMART NORTH AND SOUTH QUADRANGLES, GEORGIA

The Rockmart North and South, Georgia quadrangles occur in the Cartersville recess and thus contain some of the most outboard (SE) parts of the Appalachian foreland fold and thrust belt. A geologic map of these NW Georgia quadrangles was compiled using AutoCAD Map 2000i® software with support from the U.S.G.S. Educational Mapping Program. The stratigraphy in these quads--the Mississippian Floyd Shale and Fort Payne Chert, Middle Ordovician Rockmart Slate, Lower Ordovician Newala-Lenoir Limestone, and the lower Knox Group--is contained in southwest plunging overturned folds and has been subjected to very low-grade metamorphism. The Rockmart, with a consistent thickness of ~50 meters, lies unconformably above the Newala-Lenoir and unconformably below the Frog Mountain Sandstone/Fort Payne Chert. Three or possibly four discrete lens of polymictic diamictite occur in vertical section in the SE exposures of the Rockmart Slate but do not occur in the northwest, implying that the source of these coarse gravity flows was to the southeast. The range of clasts in the diamictite is sub-angular to rounded limestone, chert, and sandstone, all of which appear to be derived from the immediately underlying Knox Group or Newala-Lenoir Limestone, or cannibalized from the Rockmart itself. The Floyd Shale contains a slaty cleavage and no apparent post-Rockmart, pre-Fort Payne/Floyd Shale deformation can be seen in the map patterns. The Talladega-Cartersville fault borders the southernmost part of the sequence and cuts slaty cleavage in both the hanging wall and the footwall. This mapping project successfully demonstrates the effective use of AutoCAD map 2000i® software as well as the several advantages of such software beyond those of manual map drafting. Using such software, maps may be drafted and compiled with greater precision, offering hyperlink capability (i.e., rock descriptions, petrography, digital field photos), and may be stored and exchanged as electronic files.