Trace and Rare-Earth-Element Chemistry of Quartz from the Tuztası Low-Sulfidation Epithermal Au-Ag Deposit, Western Türkiye: Implications for Gold Exploration from Quartz Mineral Chemistry

ÖZBAŞ F., Bilal E., Touil A.

MINERALS, vol.15, no.7, 2025 (SCI-Expanded, Scopus) identifier identifier

  • Publication Type: Article / Article
  • Volume: 15 Issue: 7
  • Publication Date: 2025
  • Doi Number: 10.3390/min15070758
  • Journal Name: MINERALS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, ABI/INFORM, INSPEC
  • Istanbul University Affiliated: No

Abstract

The Tuztas & imath; low-sulfidation epithermal Au-Ag deposit (Biga Peninsula, T & uuml;rkiye) records a multi-stage hydrothermal history that can be interpreted through the trace and rare-earth-element (REE) chemistry of quartz. High-precision LA-ICP-MS analyses of five representative quartz samples (23 ablation spots; 10 analytically robust) reveal two fluid stages. Early fluids were cold, dilute meteoric waters (delta(O(H2O))-O-18 approximate to -6.8 to +0.7 parts per thousand), whereas later fluids circulated deeper, interacted with felsic basement rocks, and evolved in composition. Mineralized quartz displays marked enrichment in As (raw mean = 2854 +/- 6821 ppm; filtered mean = 70 +/- 93 ppm; one spot 16,775 ppm), K (498 +/- 179 ppm), and Sb (57.8 +/- 113 ppm), coupled with low Ti/Al (<0.005) and elevated Ge/Si (0.14-0.65 mol mol(-1)). Chondrite-normalized REE patterns show pronounced but variable LREE enrichment ((La/Yb)(n) <= 45.3; Sigma LREE/Sigma HREE up to 10.8) and strongly positive Eu anomalies (delta Eu <= 9.3) with slightly negative Ce anomalies (delta Ce approximate to 0.29); negligible Ce-Eu covariance (r(2) approximate to 0.05) indicates discrete redox pulses. These signatures indicate chemically evolved, reducing fluids conducive to Au-Ag deposition. By contrast, barren quartz is characterized by lower pathfinder-element contents, less fractionated REE profiles, higher Ti/Al, and weaker Eu anomalies. A composite exploration toolkit emerges: As > 700 ppm, As/Sb > 25, Ti/Al < 0.005, Ge/Si > 0.15 mu mol mol(-1), and delta Eu >> 1 reliably identify ore-bearing zones when integrated with delta O-18 data and fluid-inclusion microthermometry from earlier studies on the same vein system. This study provides one of the first systematic applications of integrated trace-element and REE analysis of quartz to a Turkish low-sulfidation epithermal system, offering an applicable model for vectoring mineralization in analogous settings worldwide.