Prospectivity mapping of high-purity barite mineralization in the Eastern Nigerian basement terrane using generalized algorithm-decoded thermal infrared data

Abstract

The Eastern Nigerian Basement Terrane hosts significant barite deposits critical for Nigeria’s oil and gas industry, yet exploration remains limited to shallow artisanal mining that yield low-quality barite. This study presents a novel integration of Landsat-7 ETM + thermal infrared data and Shuttle Radar Topography Mission (SRTM) elevation data with the Thermal Generalization Method (TGM), a multichannel algorithm that transforms TIR-SRTM data into 3D thermodynamic models. Using algebraic-geometric transformations and algorithms including generalization (G), automatic identification of cell-block structure (AICDS), litho-temperature (LT), vertical temperature (VT), first/second Vertical Derivatives (IVD, 2VD), the method delineates high-purity barite mineralization at depths surpassing typical artisanal operations. Seasonal analysis quantified a 17 % drop in mean surface thermal radiation (10.42 to 8.67 W m⁻2) and a 37 % rise in mean surface water saturation (0.46 to 0.63), showing a strong negative correlation (r = –0.72) that confirms seasonal heat-fluid coupling enhances mineralization potential at depth. TGM analysis identified two potential barite fields (PBF1 and PBF2) in the Mayo-Belwa and Jada-Ganye basement terranes, representing substantial, previously unrecognized high-grade targets within Nigeria’s estimated 22 Mt barite reserves. These fields are characterized by dominant NNE-SSW lineaments and NW-SE stresses interact, with subordinate NNE-SSW stresses enhancing permeability through localized deformation, creating structural/thermochemical fluid pathways. PBF1 (Taso-Tola deposits), hosted in a deflection zone dominated by granite-gneisses, shows strong thermal anomalies (∇T > 0.5 K/m; ∂2T/∂z2 <  − 0.3 K/m2), indicative of exothermic barite precipitation at temperatures of 60–80 °C. Economic mineralization occurs along ENE lineaments at 180–300 m depth (ΔT = 1.2 K, signal-to-noise ratio [SNR] 2000:1), with 70–90 % water saturation. These anomalies exceed Landsat’s thermal resolution threshold by > 3 orders of magnitude, providing a robust, deterministic confidence framework. The Taso sector shows sharp thermal boundaries (∂T/∂z > 0.6 K/m) along 540 m fractures, whereas Tola’s mineralization persists to 1,200 m (ΔT = 0.3 K, SNR 2700:1) beyond optimal mineralization depths. PBF2, hosted in syn- to post-tectonic granites within zones of intense uneven uplift, exhibits subdued thermal signatures (40–60 °C) and moderate water saturation (50–70 %). NW‒SE compression generates ENE uplift blocks controlling mineralization: Yebbe extends 610–750 m (60–300 m), Zeibei is vertically reoriented below 240 m, and Ngurore exhibits propeller geometry (870–780 m). High thermal gradients (∇T > 0.7 K) and water saturation (W > 0.3) favour barite deposition at 60–300 m depth, controlled by NNW-trending faults, although deeper anomalies (ΔT = 0.08 K at 1,800 m) lie beyond viable exploitable limits. Both systems demonstrate barite deposition controlled by NW-SE compressive stress. TGM-decoded TIR identifies barite mineralization at optimal exploitable depths (60–300  m), overcoming artisanal mining limits (<15  m) and enabling the targeting of high-purity, API-compliant reserves vital to Nigeria oil and gas sector.