Metamorphic Index Minerals as Exploration Vectors: Linking Metamorphic P–T Evolution to Orogenic Gold and Volcanogenic Massive Sulfide Mineralization

Abstract

Index minerals provide critical insights into the pressure–temperature (P–T) evolution of metamorphic terrains and play an increasingly important role in predictive mineral exploration. These minerals form only within specific thermodynamic conditions and therefore serve as reliable indicators of metamorphic grade and fluid evolution. In mineral exploration, the distribution of index minerals helps delineate metamorphic gradients, identify hydrothermal alteration halos, and vector toward concealed ore deposits. This study presents a comprehensive review of the application of index minerals in mineral exploration, emphasizing their role in orogenic gold and volcanogenic massive sulfide (VMS) systems. Using documented case studies from the Abitibi Greenstone Belt and the Broken Hill deposit within the Curnamona Province, the research examines how mineral assemblages such as garnet, staurolite, kyanite, sillimanite, and gahnite can guide exploration targeting. The study also evaluates limitations including retrograde metamorphism and compositional constraints, while highlighting emerging technologies such as hyperspectral spectroscopy and machine learning in mineral detection and exploration modeling. The findings demonstrate that the integration of classical metamorphic mineralogy with modern geospatial and spectral technologies significantly enhances the efficiency of mineral exploration programs.