Gravity, aeromagnetic and electromagnetic study of the gold and pyrite mineralized zones in the Haile Mine area, Kershaw, South Carolina

摘要

New high resolution gravity, electromagnetic (EM) and magnetic data are tested for the detection of disseminated sulfides in the area of the Haile Gold Mine, South Carolina. Geophysical interpretations were constrained with densities and mineral concentrations measured for 49,183 samples from 448 drill holes. Positive residual gravity anomalies from spectral analysis correlate with the mineralized ore zone. Similar correlations between positive anomalies and the ore zones are observed in the first vertical derivative of Bouguer anomaly and tilt derivatives of the residual gravity. Euler deconvolution of the gravity field also shows numerous shallow sources in the ore zone. Drill core measurements show that metasediments (Richtex unit), (2.76 g/cm(3)) and gold bearing samples (2.73 g/cm(3)) are slightly denser than metavolcanics (Persimmon Fork Formation), (2.69 g/cm(3)). Correlation coefficients for sample density and mineral percentages are pyrite (0,18) and sericite (0.15), indicating that pyrite is the main mineral increasing sample density. 2D forward gravity models constrained by dense drilling match the predicted depth range of density anomalies from Euler deconvolution. Drilling results confirm a spatial correlation between high densities, high pyrite concentrations, and the mineralized zones. High conductivity anomalies are observed over the Haile ore zone as well as over the metasediments. Core drilling and 2D inversion show that high conductivity anomalies coincide with zones of high pyrite concentrations. The magnetic field is dominated by anomalies produced by granite plutons 3 km north and 5 km west of Haile and northwest-trending Jurassic diabase dikes. East-northeast trending linear anomalies have been sampled and dated as Alleghanian lamprophyre dikes providing the first magnetic map of these intrusions in the southeastern United States. (C) 2019 Elsevier B.V. All rights reserved.