Remote Sensing Investigation of Silicic and Argillic Alteration Zones in the Aska Exploration Area, Southeastern Lut Block, Iran

Hydrothermal alteration zones are among the most important indicators in mineral exploration because they reflect the interaction between hydrothermal fluids and host rocks and may represent the surface expression of mineralizing systems. Remote sensing techniques, particularly multispectral satellite imagery, provide an efficient approach for detecting alteration-related spectral responses and geological features, especially in arid regions with limited vegetation cover. The Aska exploration area is located in the southeastern part of the Lut Block, eastern Iran, and is characterized by a metamorphic-magmatic geological setting including Triassic-Jurassic metamorphic rocks, granitoid intrusions, hornfels zones, and silica vein systems. This study aims to identify and investigate silicic and argillic alteration zones using Landsat-۸ Operational Land Imager (OLI) satellite data. Landsat-۸ OLI images were processed using spectral enhancement techniques, including band ratio analysis and Least Squares Fitting (LS-Fit), to improve the spectral contrast of alteration-related features. The results indicate that silicic alteration anomalies are mainly associated with silica vein systems developed within the Jurassic metamorphic unit (Jsgs), which represents the dominant host rock of the study area. Argillic alteration zones show a concentrated distribution mainly in the southeastern part of the exploration area. Lineament analysis extracted from satellite imagery indicates dominant NW-SE and subordinate E-W structural trends. The spatial relationship between alteration anomalies, silica veins, and structural features suggests that fractures and faults played an important role in controlling hydrothermal fluid migration and alteration development. The results demonstrate that Landsat-۸ OLI data combined with spectral enhancement methods can be effectively applied for identification of hydrothermal alteration zones and provide valuable information for early-stage mineral exploration in the southeastern Lut Block.

کلیدواژه ها:

Remote sensing ، Landsat-۸ OLI ، Hydrothermal alteration ، Silicic alteration ، Argillic alteration ، Band ratio ، Lut Block