Abstract:
Dayingezhuang Gold Deposit and Xiadian Gold Deposit are typical "Jiaojia-type" fractured zone alteration rock gold deposits within the Zhaoping Fault. Sequential alterations from the fault outward include beresitization alteration and K-feldspar alteration. However, differences in alteration-related element migration between the 2 deposits have received limited attention. This study conducted detailed petrographic, mineralogical, and geochemical investigations. K-feldspar alteration at Xiadian Gold Deposit is characterized by Fe
2O
3 and K
2O enrichment, indicating a composite alteration involving potassium feldspar replacing plagioclase with iron-bearing mineral inclusions. In contrast, the K-feldspar alteration at Dayingezhuang Gold Deposit is a composite alteration of albite-sericite-potassium feldspar, showing K
2O enrichment alongside Na
2O and Fe
2O
3 depletion. Both deposits' K-feldspar alteration rocks are enriched in gold-associated elements, but Xiadian Gold Deposit shows As depletion, whereas Dayingezhuang Gold Deposit exhibits Zn and Cd depletion. Beresitization alteration at Dayingezhuang Gold Deposit enriches K
2O, Fe
2O
3, Mg O, and LOI, while Xiadian Gold Deposit exhibits depletion in K
2O, Ca O, Mg O, and Ti O
2. These differences suggest stronger chloritization and sericitization at Dayingezhuang Gold Deposit, potentially caused by the breakdown of mafic minerals and plagioclase in amphibolite in water-rock reactions, increasing K
2O and Mg O content in fluids. Gold migration during beresitization alteration is less pronounced at Xiadian Gold Deposit compared to Dayingezhuang Gold Deposit, likely due to buffering effects from marble water-rock reactions in the Jingshan Group, stabilizing fluid pH and inhibiting gold-sulfur complex breakdown and deposition.