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Research about Alabama, Georgia, South Carolina

Source-linked reports with geographic coverage including Alabama, Georgia, South Carolina.

4 recordsLinked to original sources
USGS2023

The geometry and kinematics of the latest paleozoic Allatoona Fault, one of the youngest thrusts in the southernmost Appalachian Hinterland, Alabama and Georgia, U.S.A.

The Allatoona thrust fault in the southernmost hinterland of the Appalachian Blue Ridge-Piedmont megathrust sheet is among the latest structures in the kinematic sequence of events along the west flank of the orogen. It is an out-of-sequence, craton-directed thrust fault that cuts metamorphic isograds and earlier thrusts, and it has a nearly linear trace of ≥280 km, making it one of the major thrust faults in the orogen. On the northwest, the fault cuts Pennsylvanian or younger(?) regional cross antiforms that cause significant orogenic curvature of older underlying thrust sheets and is likely Permian in age. To the southeast, however, units within the fault hanging wall maintain a nearly constant width resulting in a significant change in the regional structural architecture of the orogen. In the central segment of the fault, where it marks the western/eastern Blue Ridge domain boundary, a ~20 km-long eyelid window (Mulberry Rock window) framed by three amphibolite facies thrust sheets overlying the greenschist facies Talladega belt allochthon, allows a 3-D view into the structural architecture, kinematics, and trajectories of the regional thrusts. Two earlier thrusts within the window (Mulberry Rock and Burnt Hickory Ridge thrusts, with a combined minimum horizontal net slip component of 27 km) are cut by the Allatoona fault, which is a ~15 m-wide high strain zone with top-to-the-northwest displacement, and a >17.2 km horizontal net slip vector. Structural branch points between the Allatoona and Mulberry Rock thrusts indicate that the Mulberry Rock allochthon is a large north-trending horse beneath the Allatoona fault, centered on the Mulberry Rock window, which is likely the result of oblique ramp thrusting over the massive Mulberry Rock Gneiss. The Allatoona fault cuts down obliquely into the tectonostratigraphy progressively deeper both to the northeast and northwest, locally approaching underlying foreland thrust sheets, and cutting older regional structures. To the northeast, the Allatoona fault lies at the base of the Dahlonega gold belt, becoming an internal eastern Blue Ridge thrust at Dawsonville, Georgia. Although that sequence extends another 120 km into North Carolina, continuation of the Allatoona fault that additional distance is in debate. Regardless, the Allatoona is one of the kinematically latest and longest faults in the southern Appalachian orogen.

Alabama, Georgia, South Carolina↗
USGS2018

Improving predictions of hydrological low-flow indices in ungaged basins using machine learning

We compare the ability of eight machine-learning models (elastic net, gradient boosting, kernel-k-nearest neighbors, two variants of support vector machines , M5-cubist, random forest, and a meta-learning ensemble M5-cubist model) and four baseline models (ordinary kriging , a unit area discharge model, and two variants of censored regression) to generate estimates of the annual minimum 7-day mean streamflow with an annual exceedance probability of 90% (7Q10) at 224 unregulated sites in South Carolina, Georgia, and Alabama, USA. The machine-learning models produced substantially lower cross validation errors compared to the baseline models. The meta-learning M5-cubist model had the lowest root-mean-squared-error of 26.72 cubic feet per second. Partial dependence plots show that 7Q10s are likely moderated by late summer and early fall precipitation and the infiltration capacity of basin soils.

Alabama, Georgia, South Carolina↗
USGS1986

Hydraulic characteristics of Upper Cretaceous and Lower Tertiary clastic aquifers: Eastern Alabama, Georgia, and western South Carolina

Transmissivity and storativity data for the clastic sediments of the northern Coastal Plain of eastern Alabama, Georgia, and western South Carolina were compiled and evaluated. Transmissivity values ranged from less than 100 to about 35,000 ft sq/day; storativity ranged from about 0.00002 to 0.0002. Data for lower Tertiary sediments represented by the Clayton and Tallahatta Formations and equivalent Midwayan and Claibornian sediments are listed for 17 sites. Transmissivity values of these sediments range from about 500 to 10,000 ft sq/day. Transmissivity values for the Cretaceous Providence Sand and Cusseta Sand and equivalent Navarroan-Tayloran sediments are listed for 10 sites and range from about 500 to 34,000 ft sq/day. Transmissivity values for the Blufftown and Eutaw Formations and equivalent Cretaceous Tayloran-Austinian sediments are listed for 16 sites and range from about 3000 to 35,000 ft sq/day. Transmissivity of the Cretaceous Tuscaloosa Formation and equivalent Eaglefordian sediments is listed for 5 sites and ranges from about 30 to 500 ft sq/day. Estimates of transmissivity based on well specific capacity were computed by using the modified nonequilibrium formula and linear regression analysis. The regression analysis was based on log-transformed paired transmissivity and specific-capacity data at 48 pumping wells. The regression model provided better estimates of transmissivity than the modified nonequilibrium formula. (Author 's abstract)

Alabama, Georgia, South Carolina↗