Early evolution of faults in crystalline basement by organized fracturing and damage zonation

We analyze the internal structure of the Off-Road Fault Zone (ORFZ) that is an immature fault zone exposed in the texturally homogenous granitic basement of southern Oklahoma. The internal structure of this ~260 m-wide fault zone is dominated by multiple fracture systems, and we utilize satellite, high-resolution drone images, and field observations to map and characterize these fault-fracture systems. We also applied a 2-D shallow electrical resistivity imaging to investigate the down-dip structure of the fault zone. It was found that ORFZ hosts steep NE-striking fracture clusters with predominantly tensile fractography, enechelon segmentation, few horizontally striated slickensided surfaces, hematite-veins, epidote veins, and distributed gouge-lenses. Scan-line fracture mapping revealed systematic fracture intensity zonation: a. Intensity of >10 m-1 interpreted as the core-cluster (CC); b. Intensities of 1-9.99 m-1 , and 0.1-0.99 m-1 , regarded as the inner cluster and outer cluster of the damage zone; and c. Fracture intensity