The Longquanzhan deposit is one of the largest gold deposits in the Yi-Shu fault zone (central section of the Tan-Lu fault zone) in Shandong Province, China. It is an altered-rock type gold deposit in which ore bodies mainly occur at the contact zone between the overlying Cretaceous rocks and the underlying Neoarchean gneissic monzogranite. Shi et al. reported that this deposit formed at 96 ± 2 Ma using pyrite Rb–Sr dating method and represents a new gold mineralization event in the Shandong Province in 2014. In this paper, we present new He–Ar–S isotopic compositions to further decipher the sources of fluids responsible for the Longquanzhan gold mineralization. The results show that the δ³⁴S values of pyrites vary between 0.9‰ and 4.4‰ with an average of 2.3‰. Inclusion-trapped fluids in ore sulfides have ³He/⁴He and ⁴⁰Ar/³⁶Ar ratios of 0.14–0.78 Ra and 482–1811, respectively. These isotopic data indicate that the ore fluids are derived from a magmatic source, which is dominated by crustal components with minor mantle contribution. Air-saturated water may be also involved in the hydrothermal system during the magmatic fluids ascending or at the shallow deposit site. We suggest that the crust-mantle mixing signature of the Longquanzhan gold deposit is genetically related to the Late Cretaceous lithospheric thinning along the Tan-Lu fault zone, which triggers constantly uplifting of the asthenosphere surface and persistent ascending of the isotherm plane to form the gold mineralization-related crustal level magma sources. This genetic model can be applied, to some extent, to explain the ore genesis of other deposits near or within the Tan-Lu fault belt.

Fluorite, a key accessory mineral associated with rare earth element (REE) deposits, exerts a significant influence on REE migration and precipitation through complexation, adsorption, and lattice substitution within fluorine-bearing fluid systems. It therefore provides a valuable archive for constraining REE enrichment processes. The Weishan alkaline–carbonatite-related REE deposit, the third-largest LREE deposit in China, is formed through a multistage magmatic–hydrothermal evolution of the carbonatite system. However, limited mineralogical constraints on REE enrichment and precipitation have hindered a comprehensive understanding of its metallogenic processes and exploration potential. Here, cathodoluminescence imaging and LA-ICP-MS trace element analyses were conducted on fluorite of multiple generations from the Weishan deposit to constrain the physicochemical conditions of mobility and precipitation mechanisms of this REE deposit. Four generations of fluorite are recognized, recording progressive evolution of the ore-forming fluids. Type I fluorite, which coexists with bastnäsite and calcite, is LREE-enriched and exhibits negative Eu anomalies, indicating precipitation from high-temperature, weakly acidic, and reducing fluids. Type II fluorite occurs as overgrowths on Type I, while Type III fluorite replaces Type II fluorite, with both displaying LREE depletion and MREE-Y enrichment, consistent with cooling during continued hydrothermal evolution. Type IV fluorite, which is interstitial between calcite grains and associated with mica, is formed under low-temperature, oxidizing conditions, reflecting REE exhaustion and the terminal stage of fluorite precipitation. Systematic shifts in REE patterns among the four generations track progressive cooling of the system. The decreasing trend in La/Ho and Tb/La further suggests that these fluorites record dissolution–reprecipitation events and associated element remobilization during fluid evolution.

沂南县南部王家坊庄Cu-Mo矿床是我国鲁西地区新发现的一个多金属矿床，矿体主要赋存于王家坊庄杂岩体中，该杂岩体以正长斑岩、二长花岗岩、二长斑岩及闪长玢岩为主。根据其地质特征，Mo矿体为斑岩型，主要赋存于早白垩世二长斑岩和二长花岗岩中；Cu矿体为矽卡岩型，赋存于侵入岩体与南华纪佟家庄组接触的矽卡岩中。该矿床的成矿时代和成矿物质来源尚不清楚，限制了对沂南地区成矿作用的系统认识。鉴于此，本文联合开展了石榴子石和锆石的LA-ICP-MS U-Pb年代学、辉钼矿LA-ICP-MS Re-Os同位素定年分析、锆石Hf同位素和全岩主微量分析。年代学研究表明，Mo矿体中的辉钼矿Re-Os模式年龄为125.1±1.1Ma和129.5±1.7Ma，含黄铁矿化矽卡岩中的石榴子石原位LA-ICP-MS U-Pb年龄为129.9±2.0Ma，侵入岩锆石LA-ICP-MS U-Pb年龄范围为129~127Ma。因此，Cu、Mo成矿作用与岩浆活动近乎同时发生，成矿期的结束时间略晚于岩浆侵位时限。Cu矿和Mo矿的成矿岩体表现出相对较低且均一的锆石Hf同位素特征ε_Hf(t)=-14.8~-8.6，大离子亲石元素(LILE)和轻稀土元素(LREE)富集，亏损Nb、Ta、Ti高场强元素(HFSE)的特征，指示来自同一地幔源区，是俯冲熔体/流体交代上覆地幔而形成富集岩石圈地幔部分熔融的产物。王家坊庄杂岩体与Cu-Mo矿体的时空耦合性表明，Cu-Mo成矿作用与早白垩世岩浆作用之间存在明显的成因联系，与沂南地区的矽卡岩型Au-Cu多金属矿床共同构成早白垩世与岩浆活动有关的斑岩-矽卡岩型矿床成矿系统，这表明沂南地区广泛分布的矽卡岩型矿床深部可能具有斑岩型成矿的潜力。该成矿系统与华北克拉通东部岩石圈减薄事件具有成因上的联系，在地球动力学上可能与古太平洋板块的俯冲回撤作用下的动力学背景密切相关。

《地球科学》(ISSN 1000-2383;CN42-1874/P) (原刊名《地球科学——中国地质大学学报》ISSN 1000-2383;CN42-1233/P)，创刊于1957年，是由教育部主管、中国地质大学主办的综合性地学学术理论期刊，月刊，2015年改名为《地球科学》,她以反映中国地质大学教学与科研最新的、高水平的基础地质、应用地质、资源与环境地质及地学工程技术研究成果为主要任务。

The Weishan rare earth element (REE) deposit, located in western Shandong, North China Block, is a typical carbonatite REE deposit and constitutes the third largest light REE resource in China. Its mineralization is closely related to the multi-stage evolution of a carbonatite magma–hydrothermal system. However, the mechanisms governing REE enrichment, migration, and precipitation remain insufficiently constrained from a mineralogical perspective, which hampers the understanding of the ore-forming processes and the establishment of predictive exploration models. Apatite is a pervasively developed REE phase in the Weishan deposit which occurs in multiple generations, and thus represents an ideal recorder of the magmatic–hydrothermal evolution. In this study, different generations of apatite hosted in carbonatite orebodies from the Weishan deposit were investigated using cathodoluminescence (CL), electron probe microanalysis (EPMA), and in situ LA-ICP-MS trace element analysis. Three types of apatite were identified. In paragenetic sequence, Ap-1 occurs as polycrystalline aggregates coexisting with calcite, is enriched in Na, Sr, and LREEs, and shows high (La/Yb)_N ratios, suggesting crystallization from an evolved carbonatite magma. Ap-2 and Ap-3 display typical replacement textures: both contain abundant dissolution pits and dissolution channels within the grains, which are filled by secondary minerals such as monazite and ancylite, and thus exhibit characteristic features of fluid-mediated dissolution–reprecipitation during the hydrothermal stage. Ap-2 is commonly associated with barite and strontianite, whereas Ap-3 is associated with pyrite and monazite and is characterized by relatively sharp grain boundaries with adjacent minerals. From Ap-1 to Ap-3, total REE contents decrease systematically, whereas Na, Sr, and P contents increase. All three apatite types lack Eu anomalies but display positive Ce anomalies. Discrimination diagrams involving LREE-Sr/Y and log(Ce)-log(Eu/Y) indicate that apatite in the Weishan REE deposit formed during the magmatic to hydrothermal evolution of a carbonatite, and that the dissolution of early magmatic apatite, followed by element remobilization and mineral reprecipitation, effectively records the progressive evolution of the ore-forming fluid.