The magmatic to hydrothermal evolution in the Weilasituo Sn-polymetallic deposit, NE China: Insights from quartz texture and trace elements

Abstract

Global tin resources are dominantly sourced from granite-related deposits formed through cassiterite precipitation. However, the mechanisms controlling metal enrichment remain unclear. Quartz commonly spans the entire evolution of magmatic-hydrothermal tin deposits capturing geochemical fingerprints. Here, we integrate cathodoluminescence (CL) textural analysis with laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) of quartz from the Weilasituo giant Sn-polymetallic deposit in northeastern China to decode the tin enrichment process. Five quartz types (Q1 to Q5) were identified across the magmatic period to the hydrothermal stage. From quartz of potassic granite (Q1a) to Nb-Ta mineralization albitized granite (Q1b) and Sn-Zn mineralized albitized granite (Q1c), the Al/Ti and Ge/Ti ratios increase and Ti contents decrease indicating a higher degree of magmatic differentiation with temperature decreasing. Sulfide droplets and snowball-textured quartz in Sn-Zn mineralized albitized granite indicate fluid saturation and exsolution from the silicate melt. This corresponds to vertically zoned Sn enrichment in quartz from deep potassic-altered granite (median 0.24 ppm) through intermediate Nb-Ta-mineralized albitized granite (0.24 ppm) to shallow Sn-Zn-mineralized albitized granite (0.29 ppm). Moreover, quartz within the greisen (Q3) records the magmatic-hydrothermal transition, exhibiting significantly higher Sn concentrations (0.76 ppm) compared to those in Q1 (0.18-0.29 ppm). This demonstrates enhanced metal scavenging efficiency during fluid exsolution. Shallow quartz vein (Q5*) exhibits increased Sn and Ge contents and decreased Al/Ti and Ge/Ti ratios relative to deep veins (Q5), demonstrating cooling facilitates cassiterite precipitation. Quartz trace elements indicate that highly differentiated magma, high fluid extraction efficiency, and fluids cooling collectively enabled tin deposition. Furthermore, quartz Sn signatures could be a proxy in targeting Sn mineralization.