24 Geologic Maps, Geophysical Maps, and Derivatives from Geologic and Geophysical Maps (Posters)

Sunday, 14 March 2010
1:30 PM - 4:15 PM
International ABCDF

BEDROCK GEOLOGIC MAP OF THE CARTERSVILLE, GEORGIA, 7.5-MINUTE QUADRANGLE: RELATIONSHIPS OF THE CHILHOWEE/SHADY CONTACT AND STRUCTURAL EVIDENCE FOR THE EMERSON-TALLEDEGA AND CARTERSVILLE-GREAT SMOKY FAULTS

Paper number: 24-25
Program: Theme Sessions
Time: 1:30 PM – 4:15 PM

Authors

Abstract

Detailed geologic mapping of the Cartersville Mining District and remaining parts of the Cartersville Quadrangle were greatly facilitated by the unprecedented access to properties owned and mined by New Riverside Ochre. Additionally, more than 100 years of exploration drilling records were made available and used to correlate the surface and subsurface geology of the mining district. Two major zones of imbricate faulting have been identified during this mapping, informally named the Cartersville and New Riverside duplexes. Both duplexes are marked by highly imbricated, foreland- and hinterland-dipping thrusts within lithologies of the Chilhowee Group and Shady Dolostone. These duplexes and the orientation of other foreland structures provides insight into the stress fields and changing stress orientations that are preserved in the Paleozoic foreland stratigraphy. In the Cartersville Mining District, and throughout the Cartersville area, the early-Cambrian system records at least two distinct, nearly orthogonal stress regimes. The earliest structures were formed by nearly east-west directed principal stresses. The orientation of this stress regime is coincident with the stresses that emplaced the Cartersville-Great Smoky and Allatoona Dam fault zones. The later deformational event resulted from maximum principal stresses that were oriented northwest-southeast. This stress orientation is nearly normal to the trace of the Emerson-Talladega Fault Zone in the area.

Former stratigraphic division of the Chilhowee could not be consistently applied during mapping due to the lack of correlation with the type section (Mack, 1980) and the abundance of imbricates in the district. Additionally, the Weisner Formation as defined by Mack was not observed in the mining district. Previous workers have identified the uppermost quartzite/sandstone unit of the Chilhowee as the Weisner; however, the uppermost continuous quartzite/sandstone, locally referred to as the “sandwall”, occurs at the base of the Shady Dolostone. Several mine and natural exposures illustrate that the sandwall is very calcareous and grades upward into Shady Dolostone. Several thin, lithologically-identical sandstones also occur within the basal Shady ochre horizon throughout the district.