Zhilingtou Au-Ag deposit, Suichang gold mine, Suichang County, Lishui, Zhejiang, Chinai

Regional Level Types
Zhilingtou Au-Ag deposit	Deposit
Suichang gold mine	Mine
Suichang County	County
Lishui	Prefecture
Zhejiang	Province
China	Country

Low- to medium-temperature hydrothermal gold-silver deposit, hosted in Early Proterozoic orthogneisses and paragneisses that are overlain by Late Jurassic to Cretaceous intermediate to felsic volcanic rocks.

This deposit has been mined out.

The strata of the Zhilingtou area exhibit a typical two–layered structure, comprising overlying Cretaceous felsic volcanic rocks from the Dashuang Group and the underlying Paleoproterozoic metamorphic rocks from the Badu Group, which are separated by an angular unconformity. The Dashuang Group (127 ∼ 110 Ma) predominantly comprises rhyolitic breccia–crystal and rhyolitic tuff, with additional occurrences of quartz sandstone, siltstone, volcanic lava, and spherulitic rhyolite. The Badu Group (2.5 ∼ 1.8 Ga) spans approximately 6 km2. The gold orebodies are located north of the Huafengjian volcanic edifice, predominantly trending east–west and dipping southwest to southeast. The orebodies extend over 1400 m along the strike and approximately 200 m vertically. The orebodies occur in stockwork and breccia–like forms, are hosted within Paleoproterozoic biotite–plagioclase gneiss, and do not penetrate the overlying Cretaceous volcanic cover.
The Zhilingtou gold deposit is the only significant gold deposit in Zhejiang Province in southeastern China, with a cumulative reserve of 191.84 t Au at an ore grade of 11 g/t Au. According to the 2015 update, the current remaining reserve is approximately 26.1 t, along with 594 t of silver. Twelve orebodies have been identified in the mining area, occurring within the Badu Group and concealed beneath the volcanic rocks. The orebodies are located north of the Huafengjian volcanic edifice, with a general strike nearly E–W and a dip toward the SW–SE. In contrast, most NE‒SW faults intersect the ore bodies, suggesting that their formation occurred subsequent to the mineralization event. The ore bodies can be divided into three sections: the middle, western, and eastern sections. These sections are divided by the F1 and F42 faults, with an overall extension of approximately 1400 m and a vertical distribution of approximately 200 m. There are 12 vein-like, stockwork, and breccia ore bodies, all of which are concealed and hosted by the early Paleoproterozoic biotite plagioclase gneiss, do not extend within the volcanic caprock. The No. III ore body in the middle section is high-grade and the largest, with an extension of approximately 360 m and a thickness of approximately 3 m, averaging a grade of 40.78 g/t.
The Mo orebodies are hosted within the Cretaceous granite porphyry and the surrounding Paleoproterozoic Badu Group gneiss. The mineralization is characterized by three distinct stages of mineralization and wall-rock alteration. The early stage features quartz ± K-feldspar veins associated with potassic alteration, indicating initial hydrothermal activity. The ore stage is marked by quartz–molybdenite veins with strong phyllic alteration and superimposed on the earlier potassic alteration zones. The late stage includes quartz–pyrite ± calcite veins with propylitic alteration, representing the final phase of hydrothermal activity.
According to the mineral assemblage and structural relationships, the gold mineralization can be divided into three stages: (1) pyrite–rhodonite–quartz stage, (2) polymetallic–smoky quartz stage, and (3) quartz–carbonate–sulfide stage. The second stage is the main mineralization stage.

The Zhilingtou gold deposit in Zhejiang has a long mining history, dating back to the Tang Dynasty. Lead-zinc and molybdenum deposits were subsequently discovered in the area. The area is located in the northeastern Cathaysia Block (Zhejiang Province) in Paleoproterozoic metamorphic rocks of the Badu Group.

The mining area is rich in mineral resources and exhibits a distinct “three-layer” vertical zoning pattern: Pb-Zn and pyrite deposits dominate in the shallow volcanic rocks; gold-silver, lead-zinc, and sulfur deposits develop in the middle metamorphic rock basement; and porphyry Mo deposits are distributed in the deep section. The Zhilingtou granite porphyry is classified as an I-type granite. In summary, the Zhilingtou Au-Mo-Pb-Zn polymetallic deposit is a composite mineralization system closely related to a back-arc extensional environment under the subduction of the Pacific Plate. The early Early Cretaceous Au-Ag mineralization may have primarily relied on the activation, migration, and precipitation of ore-forming elements from the country rocks driven by magmatic heat. In contrast, the late Mo-Pb-Zn mineralization was directly supplied with materials and energy by the magmatic-hydrothermal system. These two mineralization events are both linked and relatively independent in time, space, and genesis, collectively forming a composite deposit model with vertical and lateral zonation.

Other Regions, Features and Areas containing this locality

References