## 1 Introduction  
Volcanogenic massive sulfide (VMS) deposits are globally significant sources of both base and precious metals, carrying substantial economic value [1; 2; 3; 4; 5]. In addition to Cu and Zn, VMS deposits often contain important precious metals such as Au and Ag, as well as other critical metal elements, including Ni, Co, Pb, and rare earth elements (REEs). These elements have wide applications in modern industries, such as electronics, new energy, aerospace, and other fields, making the study of VMS deposits of great economic and strategic significance [6]. These VMS deposits typically form beneath or directly on the seafloor from the discharge of evolved, high-temperature hydrothermal fluids [7; 8]. The metals found in these deposits originate from hydrothermal reaction zones, where they have been leached out by heated seawater that has undergone compositional modifications. This seawater, driven by a steep geothermal gradient, has permeated through the volcanic pile, with or without contributions from magmatic sources for the metals [7; 9]. The Hongtoushan Cu-Zn deposit, located in the Hunbei granite-greenstone terrane in the northeastern section of the North China Craton, Liaoning Province, has been extensively studied due to its unique geological features. The terrane itself hosts over a hundred VMS deposits, making it a highly significant mineralization belt for VMS deposits in China. Notably, the Hongtoushan deposit stands out as the only large-scale Archean Cu-Zn VMS deposit identified in China thus far [10; 11]. The metallogenesis of the Hongtoushan VMS deposit is quite complex and multistage, as evidenced by the diverse mineralogy, textures, and geochemical characteristics of the ores. Previous studies have made significant progress in understanding the geology and genesis of this deposit. For example, [PERSON] et al. (2015) [12] obtained a hydrothermal zircon age of 2507 Ma, which is close to the regional metamorphic timing, indicating that the superimposed hydrothermal system is related to metamorphism. [PERSON] et al. (1984) [10] conducted a systematic study on the geological characteristics of the Hongtoushan deposit, identifying the volcanic-sedimentary sequence that hosts the deposit, suggesting it might be a syngenetic VMS deposit. [PERSON] et al. (2007) [11] further revealed the multistage nature of the mineralization through mineralogical and geochemical investigations, and pointed out that the ore-forming fluids may have undergone an evolution from high to low temperatures. However, there are still significant knowledge gaps regarding the specific mineralization processes and sources of ore-forming elements and fluids in the Hongtoushan deposit. For example, the relative contributions of magmatic fluids versus metamorphic fluids in remobilizing and upgrading the ores remain unclear [13; 14]. Additionally, the role of post-mineralization metasomatism in modifying metal distributions and ore grades warrants further investigation using integrated textural and geochemical approaches [14]. Resolving these uncertainties is crucial for refining the genetic model of the Hongtoushan deposit and advancing our understanding of fluid-rock interactions in the broader context of metamorphosed VMS systems. Insights gained from this deposit have important implications for exploration targeting and resource assessments of similar deposits in the region. Therefore, this study aims to provide new constraints on the mineralization processes, fluid sources, and post-mineralization modifications through a comprehensive analysis of the mineral textures, alteration assemblages, and in situ geochemical and isotopic data. Fluid inclusions, stable isotopes, and analyses of trace elements of minerals, especially pyrite, pyrrhotite and sphalerite, are powerful tools for tracing the sources of ore-forming fluids, reconstructing the hydrothermal evolutionary conditions, and unraveling the origins of the materials involved in the formation of VMS deposits [3; 15; 16; 17; 18; 19; 20; 21; 22; 23; 24; 25; 26; 27].