This paper reports microthermometric and noble gas isotope data for fluid inclusion assemblages (FIAs) with evidence of phase separation, i.e. coexisting vapor-rich and halite-saturated inclusions, hosted in the early-formed quartz stockwork veins and post-magmatic quartz eye crystals in two economic porphyry Cu deposits (PCDs; Sar Cheshmeh and Miduk) and two sub-economic prospects (Sar Kuh and Abdar) from the Kerman porphyry copper belt (KPCB), Iran. The multiphase halite-saturated inclusions (i.e., Type I) in all studied PCDs and prospects had the highest homogenization temperature (T_h = 525–594 °C) and salinities (63–73 wt% NaCl_equiv), whereas vapor-rich inclusions (Type II) had lower T_h (362–460 °C). Fluid inclusion data show that like economic PCDs, the sub-economic prospects were formed in a fertile hydrothermal system and benefited from a mineralizing fluid, which evolved from a primary hot (mostly > 400 °C), metal-rich and oxidized fluid (as evidenced by the presence of opaque- and hematite-bearing fluid inclusions) of unknown salinity, which underwent a phase separation process to form both brine and vapor phases in the early stage of mineralization. The helium abundance and its isotopic composition document a mantle-derived magmatic source for the primary ore fluid in the formation of the studied PCDs and prospects (³He/⁴He ratios ranging from 0.46 to 2.8 Ra, corresponding to a mantle He contribution in ore fluids between ~ 7 and 45%). However, subsequent hydrothermal processes, i.e., vapor–brine phase separation, fluid-rock interaction with crustal rocks, and mixing with meteoric pore water containing dissolved atmospheric (e.g., Ne and Xe) and some crustal noble gases (e.g., Ar), changed the initial noble gas composition of the magmatic ore fluid to predominantly atmospheric- and crustal-like compositions. A significant proportion of mantle-derived He (up to 45%) in high-temperature (513–594 °C) and high-salinity (61.5–73 wt% NaCl_equiv) FIAs may indicate the existence of buried, economic, porphyry Cu mineralization in the Abdar prospect; therefore, it is suggested to be a possible target for further exploration. Comparing the He and Ar noble gas isotope composition in porphyry copper systems of different size and economic importance in this study showed that the ore-forming fluids of the outsized PCD (i.e., Sar Cheshmeh) have higher contributions of crustal-derived fluids characterized by predominantly radiogenic noble gas signatures (⁴He and ⁴⁰Ar) than the smaller PCDs. This could have been achieved by a prolonged hydrothermal circulation in a large volume of crustal rocks containing radiogenic noble gases under a long-lived heat regime resulting from a deeply emplaced and slowly cooled composite intrusive body.

本文报告了流体包裹体组合（FIA）的微热学和稀有气体同位素数据，并有相分离的证据，即存在于早期形成的石英储层脉和后岩浆石英眼晶体中的富蒸气和盐岩饱和夹杂物共存。来自伊朗克尔曼斑岩铜矿带（KPCB）的两个经济斑岩铜矿床（PCDs； Sar Cheshmeh和Miduk）和两个次经济远景矿床（Sar Kuh和Abdar）。在所有研究过的PCD中和前景中，多相盐酸盐饱和夹杂物（即I型）均化温度（T _h  = 525–594°C）和盐度（63–73 wt％NaCl_当量）最高，而富含蒸气的夹杂物（II型）的T _h较低（362–460°C）。流体包裹体数据显示，与经济型PCD一样，亚经济前景是在肥沃的热液系统中形成的，并得益于矿化流体，该矿化流体是由初级热（大多> 400°C），富金属和氧化性流体（如盐度未知的不透明和含赤铁矿流体包裹体的存在证明了这一点，在矿化的早期阶段进行了相分离过程，既形成了盐水相，又形成了气相。氦的丰度及其同位素组成记录了被研究的PCD的形成和前景的地幔来源岩浆来源的原矿流体（³ He / ⁴He比率范围从0.46到2.8 Ra，对应于矿液中地幔He的贡献量介于7％到45％之间。然而，随后的水热过程，即汽-盐水相分离，流体-岩石与地壳岩石的相互作用，以及与含有溶解的大气（例如，Ne和Xe）和一些地壳稀有气体（例如，Ar）的大气孔隙水的混合发生了变化。岩浆矿流体的初始稀有气体成分，主要是大气和类地壳成分。在高温（513–594°C）和高盐度（61.5–73 wt％NaCl_当量）中，很大一部分地幔衍生的He（高达45％））FIA可能表明在Abdar前景中存在着埋藏的，经济的斑岩铜矿化；因此，建议将其作为进一步探索的可能目标。在这项研究中比较不同大小和经济重要性的斑岩铜系统中的He和Ar惰性气体同位素组成表明，超大型PCD的成矿流体（即Sar Cheshmeh）对地壳流体的贡献较大，其特征主要是比较小的PCD更具放射性的惰性气体特征（⁴ He和⁴⁰ Ar）。这可以通过长时间放置在深处并缓慢冷却的复合侵入体而在长寿命加热条件下，在大量含有放射性惰性气体的地壳中进行长时间的水热循环来实现。