Work

Deep-penetrating geochemical techniques for concealed deposits covered by semi-humid grassland: Zhaishang gold deposit, Western Qinling Orogen, China

Year: 2026

Type: article

Abstract: The Western Qinling Orogen (WQO) is a major gold region in China, with gold reserves exceeding 1, 200 tons. Its complex topography, climate, and semi-humid grassland cover provide an ideal setting for evaluating deep-penetrating geochemical (DPG) methods. In this study, three DPG methods—the Fine-Grained Soil Prospecting Method (FGSPM), leaching of mobile forms of metals in overburden (MOMEO), and soil gas geochemical survey (H 2 S, SO 2 , and CO 2 )—were employed in the southern Zhaishang concealed gold deposit, which is covered by semi-humid grassland and various overburden materials. Results indicate that no single method reliably identifies concealed orebodies or alteration zones, yet their combination improves detection, especially for deep and thin ores. Gas geochemistry exhibits higher sensitivity. Differences in response between FGSPM and MOMEO likely stem from variations in sampling and chemical analysis. For FGSPM, fine-grained soil fractions (< 75 μm and 75–125 μm) exhibit similar capacities for adsorbing mobile Au, predominantly occurs in water-soluble and clay-adsorbed forms, with strong spatial heterogeneity. H 2 S and SO 2 serve as effective gas indicators in semi-humid regions, though uncertainties affected by various factors (e.g., biological activity) require further verification. These findings offer a valuable case study for DPG applications and enhance the understanding of geochemical exploration in covered terrains.

Source: Scientific Reports

DOI: 10.1038/s41598-026-53495-3