3D Modeling of Magnetic Anomalies For Estimating The Depth & Distribution of Gold Deposits in The Camp Bird Mine Area, Colorado

Abstract

Gold mineral exploration requires effective geophysical approaches to non-invasively identify subsurface prospective zones. Among these, magnetic methods are widely applied due to their sensitivity to variations in the physical properties of rocks associated with metallic mineralization. This study aims to analyze the characteristics of magnetic anomalies potentially related to gold mineralization in the Camp Bird Mine area, Colorado, and to estimate the lateral distribution and depth of magnetic sources using 3D modeling. The data utilized include Total Magnetic Intensity (TMI) from airborne magnetic surveys provided by the United States Geological Survey (USGS), radiometric data for potassium (K) and thorium (Th), and regional geological maps as interpretative support. Magnetic data were corrected for diurnal variation and the IGRF. Regional-residual anomaly separation was performed using Butterworth and bandpass filters. Further analysis involved Euler deconvolution for depth estimation and 3D inverse modeling to visualize source distribution. The interpretation was supported by K/Th ratio analysis as an indicator of hydrothermal alteration. The results reveal that the residual anomalies exhibit spatial patterns aligned with local geological structures such as faults and intrusive bodies. Depth estimation indicates that most magnetic sources are located at depths shallower than 12 meters, suggesting potential near-surface mineralization. High K/Th ratios in specific zones strengthen the evidence of hydrothermal alteration typically associated with gold systems. The integration of magnetic, radiometric, and geological data leads to the identification of several prospective zones that warrant further exploration.