The Cretaceous calc-alkaline granodioritic rocks in north-western Kohistan island arc host porphyry-type mineralization at Mirkhani in the Khyber Pakhtunkhwa province of Pakistan. In this paper, we present whole-rock geochemistry, mass-change calculations, and type and degree of element mobility regarding the hydrothermal mineralization-alteration processes. There are two distinct types of pyrite mineralization: (1) euhedral to subhedral pyrite (Py1) and cataclastic pyrite (Py2). To comprehend the source of hydrothermal fluids and their physicochemical conditions, trace element and S (sulfur) isotope compositions of the two types of pyrite were determined. Besides, the pyrite and silicate minerals were investigated through electron probe microanalysis (EPMA).

The average low Ni (46), Zn (5), Cd (below detection level), and Bi (1) contents (in ppm), high Co/Ni ratio (>10) of both Py1 and Py2, and the range of sulfur isotope values for Py1 (−0.84‰ to 1.49‰) and Py2 (−0.93‰ to 1.84‰) indicate the affiliation of the mineralization with felsic magma-derived hydrothermal fluids. The average low and high contents (ppm) of Se (0.7), As (2.6) and Zn (2), and Co (1089), respectively, in Py1 than Py2 (Se=1.3, As=4, Zn=6 and Co=747) indicates that former pyrite grains crystallized at a higher temperature than the latter, however, both types of pyrites were formed in medium to high-temperature conditions.

The observed strong mobility of REE (rare earth elements) and HFSE (high field strength elements), high La/Yb ratios (avg. 23), and low (<1) Nb/La and Th/La ratios in the altered rocks reflect mobilization by slightly acidic solutions dominated by chloride and fluoride-rich complexes (±SO₄ and OH). The gain-loss calculations reveal that SiO₂, CaO, and TiO₂ were leached out, whereas Al₂O₃, Fe₂O₃, MgO, P₂O₅, K₂O, Cu, As, Mo, Ag, Au, Bi, and REE, HFSE, and LILE (large-ion lithophile elements) were variably added to the rocks during the hydrothermal process.

Temperature calculation for chlorite formation and the type of gangue and ore mineral assemblage (epidote + sericite + albite + pyrite) implies a mineralization temperature range between ∼215°C and ∼322°C. The porphyry style of hydrothermal alteration-mineralization, trace element and S isotope composition of pyrite, and elemental gain and loss indicates that the mineralization at Mirkhani could be a part of a major porphyry Cu-Au system.

西北科希斯坦岛弧线上的白垩纪钙碱性花岗闪长岩在巴基斯坦开伯尔-普赫图赫瓦省的米尔哈尼拥有斑岩型矿化带。在本文中，我们介绍了与热液成矿-蚀变过程有关的全岩石地球化学，质量变化计算以及元素迁移的类型和程度。黄铁矿成矿有两种不同的类型：（1）从半面到半面的黄铁矿（Py1）和碎裂性黄铁矿（Py2）。为了了解水热流体的来源及其理化条件，确定了两种黄铁矿的痕量元素和S（硫）同位素组成。此外，通过电子探针显微分析（EPMA）研究了黄铁矿和硅酸盐矿物。

Py1和Py2的平均低Ni（46），Zn（5），Cd（低于检测水平）和Bi（1）含量（ppm），高Co / Ni比（> 10）以及Py1（-0.84‰至1.49‰）和Py2（-0.93‰至1.84‰）的硫同位素值表明矿化作用与长英质岩浆衍生的热液流体有关。Py1中的Se（0.7），As（2.6）和Zn（2）和Co（1089）的平均低含量和高含量（ppm）分别高于Py2（Se = 1.3，As = 4，Zn = 6和Co ＝ 747）表明前者的黄铁矿晶粒在比后者更高的温度下结晶，然而，两种类型的黄铁矿都是在中至高温条件下形成的。

在蚀变的岩石中观察到的REE（稀土元素）和HFSE（高场强元素）的强迁移率，高La / Yb比（平均23）和低（<1）Nb / La和Th / La比反映了通过以富含氯化物和氟化物的复合物（±SO ₄和OH）为主的弱酸性溶液进行迁移。增益损耗计算表明，SiO ₂，CaO和TiO ₂被浸出，而Al ₂ O ₃，Fe ₂ O ₃，MgO，P ₂ O ₅，K ₂ O，Cu，As，Mo，Ag，Au被浸出，Bi和REE，HFSE和LILE（大型亲石元素）在水热过程中被可变地添加到岩石中。

绿泥石形成的温度计算以及脉石和矿石矿物组合的类型（闪石+绢云母+钠长石+黄铁矿）意味着成矿温度范围在215°C至322°C之间。水热蚀变-矿化的斑岩类型，黄铁矿的微量元素和S同位素组成以及元素的得失，表明Mirkhani的成矿作用可能是主要斑岩型Cu-Au体系的一部分。