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This study aims to differentiate between Cu-Mo and Cu-Au porphyry deposits within Iran through fractal modeling, utilizing the Mo/Au geochemical index as a primary determinant. Employing the Concentration-Number (C-N) fractal model, the Mo and Au values within Iranian copper porphyry deposits were comprehensively classified. The findings from the fractal modeling reveal distinct criteria for separating these deposits. Cu-Mo porphyry deposits are identified by Mo concentrations ≥141 ppm, while Cu-Au porphyry deposits are characterized by Au concentrations ≥398 ppb. The pivotal threshold for the Mo/Au ratio stands at 1585, facilitating the division between these distinct types of porphyry deposits. Within the Urumieh-Dokhtar magmatic arc, numerous Cu-Mo porphyry deposits, exemplified by globally recognized sites like Sarcheshmeh and Sungun, are prevalent. Conversely, Cu-Au porphyry deposits are found in the NW and SW regions of the Urumieh-Dokhtar magmatic arc and eastern Iran, typified by occurrences like Dalli. The study's findings reveal a correlation between geological characteristics and the ages of porphyry deposits, indicating that those formed during the Miocene period and later are predominantly of the Cu-Mo (Copper-Molybdenum) porphyry type. [Display omitted] • Separation Cu-Mo and Cu-Au porphyry deposits in Iran • Using fractal modeling based on a geochemical index as Mo/Au • There are Cu-Mo porphyry deposits with Mo ≥ 141 ppm. • Cu-Au porphyry deposits are distinguished by Au ≥ 398 ppb. [ABSTRACT FROM AUTHOR]

[Display omitted] • Based on the EPMA analyses, sulfosalts were identified at the Chodarchay deposit. • The chalcopyrite and sphalerite host solid-solution Ag, and the chalcopyrite hosts Ag-sulfosalt. • The sphalerite hosts nano-Au. The Au-Ag exists in the neyite, emplectite and gustavite. • The sphalerite precipitated from 220 to 280 °C, Bi assemblages at > 350 °C. • The supergene enrichment of Ag and Au depends on the presence of Mn. The Chodarchay overprinting epithermal on porphyry mineralization occurs in the Tarom-Hashtjin subzone of the Alborz magmatic arc in northwestern Iran. Rock units include intrusions (phases I and II) and volcano-volcaniclastic rocks. The alteration types consist of potassic, phyllic, argillic, and propylitic. The porphyry type is mostly accompanied by potassic alteration. The Chodarchay Fault implies two extensional and compressional mechanisms. The porphyry type is associated with the extensional and the epithermal type with the compressional stage of the fault. Mineralization occurred mainly inside the Eocene volcanic and volcano-sedimentary rocks; some ores are associated with the Late Eocene quartz monzonite. The mineralization is divided into three zones from depth to surface: 1) Hypogene sulfide zone (deep); 2) Enriched supergene sulfide zone (near-surface); 3) Oxidized and leached zone (surface). The major sulfide minerals consist of chalcopyrite, pyrite, sphalerite, and galena. Based on the results of the new analyses, chalcopyrite hosts Ag as a solid-solution and contains Ag-rich Bi-sulfosalt micro-inclusions. Non-constant Cd/Zn ratio in the chalcopyrite can indicate varying physiochemical conditions during its crystallization. Low As contents in the pyrite caused relatively clean pyrite with very few elements. The Ni concentrations in the pyrite imply that it was sourced from mantle mafic–ultramafic rocks. Sphalerite is the only Au-host mineral among the sulfide minerals as a nano-mineral phase. Solid-solution Ag exists in the sphalerite. The sphalerite Fe/Zn ratios show that it was precipitated between 220 and 280 °C. Silver and Bi have the highest measured concentrations among all analyzed elements in the galena, mainly partitioning within the galena, but Hg and Cd are abundant in the sphalerite. Bornite is one of the major carriers of Ag and Bi. Silver and Bi exhibit considerable variations in the Cu-(Fe) sulfides. A new occurrence of sulfosalt minerals was identified at Chodarchay (N = 14). The discovered Bi-sulfosalts include cuprobismuthite group minerals (cuprobismuthite, hodrushite, and paderaite), aikinite-bismuthinite series (aikinite and friedrichite), emplectite, makovickyite, galenobismutite, gustavite, heyrovskyite, neyite, cupropavanite; and As-Sb-bearing Cu sulfosalts (watanabeite and colusite). This number of sulfosalts had not previously been reported from any of the Tarom or Alborz deposits or mines. The Au-Ag occurrence was reported from the neyite, emplectite, and gustavite. The Ag-rich minerals crystallize from fractionated fluids that cooled during rising. Silver-carrier sulfosalts may have been exsolution from pre-existing Ag-bearing chalcopyrite in the cooling system. Most of the Ag-bearing sulfosalt minerals formed at the margins and fractures of the chalcopyrite, indicating that the cooling started from these points. Thus, Ag at Chodarchay is hosted inside Cu-(Fe) sulfides, the significant part of them being chalcopyrite and Ag-rich sulfosalt micro-inclusions inside the chalcopyrite. The fluid temperature for the Ag and chalcopyrite precipitation is from 200 to 350 °C. Bismuth assemblages precipitated at > 350 °C. The cuprobismuthite group crystallizes at temperatures > 300 °C. The supergene process and rare secondary enrichment of Ag and Au took place in the oxidation zone; this enrichment is dependent on the presence of manganese. Based on the fire-assay results, the concentration of gold is greater at shallower depths. [ABSTRACT FROM AUTHOR]

Khajeh-Nezam area is situated within the Bam 1:100,000 geological sheet, SE Iran. The area was the subject of silt geochemical studies and consists of highly prospective Cu, Pb, Ba, and Fe veins and veinlets that demonstrate a northwest-southeast trend. A total of 149 silt samples were collected from the area and analyzed for 7 elements (As, Cu, Mo, Pb, Zn, Sb, Ba) using Inductively Coupled Plasma-Optical Emission Spectrometry. Univariate-multivariate statistical analysis the majority of variables demonstrate a distribution that is slightly too moderately positively skewed, which can be accurately explained using a log-normal model. Only Cu, Zn, and Pb demonstrate a normal distribution. The number-size (N-S) fractal model show that. The variables can be classified into two main groups. The first group comprises the main ore-forming elements, namely Cu, Ba, As, and Sb, which are associated with the epithermal system. On the other hand, Mo, Pb, and Zn demonstrate a stronger affiliation with vein and veinlet mineralization that could be linked to the margin of a possible hidden porphyry system. The geochemical halo in the southwestern part of the study area, which overlaps with volcanic rocks, has experienced significant alterations attributed to local intrusions, leading to a level of modification. A secondary weak anomaly, of relatively lesser significance, is observed in Pb, Zn, and Mo. Although these elements are not the primary constituents of the ore, they serve as pathfinder elements in marginal copper porphyry. The results obtained from the study have been utilized to identify concealed ore bodies using the classes defined by N-S classification model. Fieldwork conducted in the area confirms the presence of Fe oxide veins and veinlets that contain copper mineralization, along with carbonate Pb and Cu minerals. Various types of alteration have been identified, including argillic alteration accompanied by quartz and hematite in the vicinity of the veins and veinlets. The findings serve as probable evidence for the existence of a new copper porphyry system in the study area. [Display omitted] • Cu-Pb veins in Khajeh-Nezam area have a significant role in mineral exploration. • Cu and Pb in veins imply economic mineralization potential. • Cu-Pb vein alteration indicates hydrothermal activity. • Multifractal analysis uncovers Cu, Pb, and Ba patterns, revealing spatial relationships and mineralization potential. [ABSTRACT FROM AUTHOR]

This research is aimed at comparing the performance of a proposed data-driven VIKOR method with its knowledge-driven version for porphyry copper prospectivity modeling in the Sardouyeh district, Kerman province, SE Iran. Sixteen exploratory layers from various sources were first nominated for this purpose. These layers were provided from the following sources: (1) multi-element geochemical signatures derived from principal component analysis (PCA); (2) distribution of geophysical footprints derived from aeromagnetic and potassium radioelement surveys; (3) proximity to ore host rocks and tectonic controls; and (4) proximity to hydrothermal alterations. For better comprehension of exploration layers, their values were transferred to the same range [0–1] using fuzzy logic. For predictive modeling of porphyry-type copper mineralization, an improved data-driven VIKOR model was introduced in this paper that its main foundation is based on the calculation of criteria and their relevant classes weights in a data-driven way using prediction-area (P-A) plots and normalized density index (N d), respectively. This methodology was applied twice: once on all exploratory layers and again only on efficient evidence layers. In order to compare and evaluate the performance of the novel methodology introduced for predicting high-favorable areas associated with Cu-porphyry deposits, on the basis of expert opinion and an Analytic hierarchy process (AHP) approach, the AHP-VIKOR procedure was implemented as a knowledge-driven method. A success-rate curve was employed to accurately compare the performance of three models, quantitatively. The findings reveal that the improved data-driven VIKOR approach using efficient evidence layers covered 80 % of Cu occurrences in only 6 % of the total area of the region, which led to much more precise and high-quality outcomes. Moreover, it provides more effective performance to be employed for more detailed exploration programs in this study area and similar studies in other regions. • Discovery of mineral reserves plays a major role in economy and industry. • Knowledge-based and data-based methods are used to explore mineral deposits. • Unlike knowledge-based methods, data-driven methods reduce uncertainty. • Developing a novel data-based VIKOR algorithm is useful in Cu prospectivity mapping. • Using data-based VIKOR is more accurate with involvement of only efficient criteria. [ABSTRACT FROM AUTHOR]

[Display omitted] • Surface exploration proxies related to distal porphyry mineralization were identified from geological, geochemical, and geophysical datasets. • Conventional cell-based association (CBA) applied to exploration proxies to define their association with Cu–Au mineralization. • By assigning proper weights to exploration proxies, an innovative CBA method was used to locate potential targets for drilling. The presence of various spatial exploration proxies (predictor patterns) as vectors to distal porphyry mineralization in surrounding areas of a known outcropping mineralized porphyry center at the Dalli Cu–Au deposit in Iran provided evidence for the occurrence of similar porphyry mineralization in the subsurface. Factor analysis was applied to soil geochemical data from the Dalli South Hill area to define favorable geochemical variables and to create surface multi-element anomaly maps reflecting the presence of porphyry Cu–Au mineralization in the subsurface. Reduction-to-pole and analytical signal filters were applied to ground total magnetic field data to define high magnetic signatures that could be associated with potassic alteration and porphyry mineralization in the subsurface. Then, a data-driven cell based association (CBA) data integration method was applied to the favorable spatial proxies to define their association with Cu–Au mineralization and locate subtle high potential targets (cells) for drilling. The conventional CBA algorithms did not consider weights for the spatial proxies, and by using the ascendant hierarchical clustering (AHC) algorithm the results were classified into a binary map to show favorable and unfavorable cells with scores of 1 and 0, respectively. Predicting high potential targets for high-priced drilling, just based on using the binary map, could be very risky. Therefore, an innovative CBA data integration approach was employed to assign proper weights between 0 and 1 to the spatial proxies by calculating the importance of the presence of an exploration proxy in a cell using training (labeled) trenching geochemical data. A final continuous predictor map was generated and it successfully mapped the known outcropping porphyry center and its subsurface extension to the northeast as a high prospectivity class. This map also identified a narrow NE-trending high potential target (a few cells) of 200 m long in the southern part of the known porphyry center for drilling. [ABSTRACT FROM AUTHOR]

The Zafarghand pluton, having ~10 km2 of outcrop exposure, lies within the central Urumieh–Dokhtar magmatic arc (UDMA) in Iran, of ~34 Ma age. Zafarghand plagioclase is albitic, with amphibole and chlorite being the distinctive mafic minerals. Although productive porphyry Cu deposits (PCDs) occur nearby, Zafarghand and its immediate neighboring plutons are sub-productive. Values of SiO 2 and K 2 O span a narrow compositional range from 69 to 73 wt% and 2.2 to 3.5 wt%, respectively, corresponding to granodiorite or granite and calc-alkaline in affinity. εNd (t) values are ranging from ~0 to +1.2, a diagnostic range for the mantle-dominant melts. The Sr Nd isotopic values are significantly lower and higher than those of slab melting- and crust melting adakites, respectively. The 34 Ma age of Zafarghand plutons make them to be the oldest Cu porphyry deposits yet to be found in the UDMA, in which mineralization had occurred during a mature, late stage of subduction (pre -collisional). We propose multi-stage refertilizing of Cu in lithospheric mantle beneath the UDMA, negligibly during Eocene to Early Oligocene slab roll-back accompanied by middle to rather high f O 2 context, and dominantly, during the Middle–Late Miocene slab break-off, the latter significantly tapping into influxing of asthenosphere mantle melt. Buffering of f O 2 at a sufficiently high level (and not partial melting of slab or thickened crust) is the most plausible explanation for forming Late Eocene–Oligocene sub-productive (–and non-adakitic) Zafarghand Cu-bearing plutons. • Radiometric dating yield ~34 Ma for Zafarghand host rocks • The oldest hitherto known porphyry copper deposit in the UDMA • ~96 % mantle-derived magma with contributions of ~4 % upper crustal material • Multi-stage refertilizing of Cu in lithospheric mantle beneath the UDMA • Change in f O 2 (not melting of slab or thickened crust) as the reason for PCDs [ABSTRACT FROM AUTHOR]

This study presents copper isotope compositions of mineralized whole-rock samples from the Kerman porphyry copper belt (KPCB) southeast of the Urumieh Dokhtar magmatic arc. Samples for this study were specifically collected from the Sar Cheshmeh, Meiduk, Iju, SarKuh, Darreh Zar, Bagh Khoshk, and Jebal Barez deposits and investigated to study the application of Cu isotopes to mineral exploration. While in the leached cap zone of the deposits, δ65Cu values range between −3.41 to 5.82 ‰ (avg. 0.42 ‰), in the supergene enriched zone of these deposits the relatively higher δ65Cu content ranges from 5.18 to 8.71 ‰ (avg. 7.17 ‰), and in the hypogene zone, the intermediate δ65Cu values range from 1.49 to 7.31 ‰ (avg: 4.36 ‰). Most measured δ65Cu values in these investigated porphyry copper deposit are positive, which indicates the presence of a Cu − enriched zone. In the enriched leached cap zones, the δ65Cu of the Darreh Zar and Sar Cheshmeh deposits are overall higher relative to the Iju, Meiduk, SarKuh, and Bagh Khoshk deposits, and these higher δ65Cu values are associated with the highest Cu grade and tonnage in the Sar Cheshmeh and Darreh Zar deposits. It is therefore plausible to conclude that the higher δ65Cu value in the leached areas are diagnostic of the high concentration of copper. These findings are complemented by the presence of Cu (II) carbonates, silicates, and Fe − oxides in each sample that has resulted in the enrichment of 65Cu, relative to the remnant sulfides with a wider copper isotope range. In addition, there is a general shift toward higher δ65Cu isotope values relative to the inferred precursor minerals. The overall apparent weathering and oxidative dissolution is likely to have generated isotopically heavier fluids and lighter residual minerals. The elevated δ65Cu of the bulk samples from porphyry Cu deposits in KPCB is consistent with a preferential loss of 63Cu into fluids during the segregation of aqueous fluid–melt. This is best explained by several pulses of hypogene magmatic fluid which led to repeated enrichment in 65Cu in the magmatic system. It is plausible to conclude that copper isotope values in these mineralized samples can be used as an effective exploration tool to identify buried porphyry Cu systems. • Copper isotopic composition of whole rock samples shows a wide range up to 8 ‰. • High Cu isotope can be an indicator for the presence of an inherited Cu–enriched magma. • Oxidative dissolution generate isotopically heavier fluids and lighter residual minerals. • Whole-rock Cu isotope seem closely related to the Cu grade and tonnage of KPCB deposits. • Whole-rock Cu isotope is a helpful tool for prospecting means ore exploration. [ABSTRACT FROM AUTHOR]

The Saveh-Yazd porphyry copper (the middle segment) and the Kerman porphyry copper (the Southeastern segment) belts of the Urumieh–Dokhtar Magmatic Arc (UDMA) in Iran consist of two Eocene and Miocene magmatic flare-ups and coincide with barren and ore-bearing intrusions, respectively. The Eocene barren intrusions show characteristics of high-K calk-alkaline to shoshonitic, normal arc and composed of amphibole and plagioclase fractionation during the Eocene magmatism. Base on trace element–REE contents and ratios, the Eocene magmas were mainly derived from lithospheric mantle and enriched by the melt-component of subducted slab. Also, the geochemical data (e.g., Eu/Eu*, La/Yb, Y contents and Sr-isotope compositions) indicate that Eocene magmas formed during crustal thinning and had low water contents content and oxidized. Subsequent the Miocene ore-bearing intrusions exhibited features of calc-alkaline to high-K calc-alkaline, adakite-like and amphibole with minor amount of garnet fractionation in the absence of plagioclase during Miocene magmatism. These ore-bearing intrusions derived from partial melting of a thickened and delaminated juvenile lower crust intruded by mantle material of the underlying metasomatized lithospheric mantle during the Miocene in a post-collision tectonic setting. Progressive trends of crustal thickening were recognized in the middle (Saveh-Yazd porphyry copper belt) to southeastern segment (Kerman porphyry copper belt belt) in the UDMA from the early to middle Miocene. Also, magmas tend to be more hydrous and oxidized associated with increasing crustal thickness. These trends probably explain cause of occurrence of major porphyry copper deposits mostly along the Kerman porphyry copper belt and in the middle Miocene epoch. • The UDMA in Iran consists of Eocene barren and Miocene bearing intrusions, respectively. • Eocene intrusions derived from a thin crust with low water content and oxidized. • Miocene ore-bearing intrusions exhibit progressive trends of crustal thickening. • Magmas evolved to be more hydrous and oxidized in the UDMA. [ABSTRACT FROM AUTHOR]

[Display omitted] • Plurigaussian simulation is used for geological modeling of a porphyry deposit. • Local proportions of geological domains are used to model non-stationarity. • Our proposal outperforms simplistic approaches that ignore local domain proportions. In mineral resources extraction projects, the morphology of geological domains that make up the ore types in a mineral deposit is essential for mine and plant planning and design. Modeling the layout of these domains and quantifying the uncertainty associated with such a layout can be performed via geostatistical simulation in order to provide multiple geological outcomes that are equally likely to occur. This work focuses on showing how plurigaussian simulation can help to model ore type domains exhibiting spatially varying probabilities of occurrence, through an application to a porphyry copper deposit in northwestern Iran. The results demonstrate the advantage of incorporating spatial variations of the domain proportions, in accordance with the geological interpretation of the deposit, to obtain geologically consistent and realistic outcomes. [ABSTRACT FROM AUTHOR]

The Miocene Kuh-Panj porphyry copper deposit, with reserve estimated at about 100 Mt. at 0.21 % Cu, is located 120 km SW of Kerman in the southern part of the Urumieh-Dokhtar magmatic arc. The Eocene host rocks consist of tuff, lithic tuff, breccia tuff, and lava flows, ranging in composition from rhyodacite to andesite. A late Miocene granodiorite porphyry stock (8.57 ± 0.49 Ma, U/Pb zircon) intruded into the Eocene sequence. Subvolcanic dykes cut the Eocene rocks and porphyry stock. The Kuh-Panj porphyry system has an extensive and typical hydrothermal alteration zoning pattern, which is comprised of potassic, phyllic, argillic, and propylitic alteration types from inner proximal to outer distal zones. Copper mineralization occurs in potassic and to some extent in phyllic zones. Mineralization is mostly observed as disseminated, stockwork, and vein-veinlets forms in the porphyry stock. Vein paragenesis includes barren quartz, M-type (magnetite+biotite), A 1 -type (quartz+magnetite+chalcopyrite±chlorite±biotite), A 2 -type (quartz+chalcopyrite±pyrite), D-type (quartz+pyrite±chalcopyrite), and L-type (galena+sphalerite±chalcopyrite±pyrite) veins. The I-type granitoids with calc-alkaline affinity have enrichments of LILE (Pb, K, U, Sr, and Cs), depletion of HFSE (P, Nb, Ta, Zr, and Ti), and enrichment in LREE displaying geochemical similarity to arc-related magmatic rocks. The high SiO 2 (ave. 68.9 wt%), high Al 2 O 3 (ave. 14.5 wt%), low MgO (ave. 1.3 wt%), low P 2 O 5 (< 0.2 wt%), high Sr (ave. 365 ppm), high Sr/Y (ave. 45), relatively high La N /Yb N (ave. 28), relatively high Th (ave. 8 ppm), low Y (ave. 8 ppm), and low Yb (0.5 ppm) contents are similar to those of fertile porphyries and lower crust-derived adakites. The most dominant type of fluid inclusions in quartz from mineralized veins are liquid-vapor-halite-solid (LVHS), liquid-vapor-halite (LVH), liquid-vapor (LV), and vapor-liquid (VL) fluids. Homogenization temperatures of LVHS, LVH, LV, and VL fluids range from 306 to 574 °C, 141–566 °C, 215–422°, and 349–571 °C, respectively. Salinities of LVHS, LVH, LV, and VL fluid inclusions range from 30 to 69, 29.0–65.5, 0.35–22.0, and 0.7–13.0 wt% NaCl eq., respectively. The extreme variations in salinities of fluid inclusions represent the combined effects of varying salinity of the magmatic fluid, aqueous fluid-phase immiscibility (boiling), and mixing with lower salinity meteoric water later in the cooling history of the porphyry system. Normal cooling, water-rock interaction, surface fluid dilution, and boiling are dominant factors that control both the distribution and abundance of mineralization. Zircon from the Kuh-Panj system has high Th/U (0.53 to 0.83), low Dy/Yb (<0.3) ratios, positive Eu/Eu* (1.28–1.85), strong positive Ce/Ce* (1.36 to 197) reflecting high Ce4+/Ce3+ ratios, and enrichment in HREEs relative to LREEs, which indicate the magmatic origin of zircon, oxidized, and hydrous conditions of the primary magma. This magma with adakitic affinities is favorable for producing fertile porphyry systems. Based on these multidisciplinary studies, the Kuh-Panj deposit is classified as a continental arc-related porphyry copper system hosted predominantly at the transition zone between potassic and phyllic alteration zones due to decreasing temperature, boiling, and fluid-rock reaction that all enhance Cu Fe sulfide saturation. [Display omitted] • Mineralization in Kuh-Panj occurred in a Miocene granodiorite stock that intruded Eocene volcanic host rocks. • Alteration zoning pattern and vein paragenesis are similar to porphyry Cu deposits elsewhere. • Geochemical features of the Kuh-Panj system are similar to those of fertile porphyries. • The zircon 206Pb/238U ages of the porphyry stock ranging from 7.7 to 9.7 Ma (ave. 8.57 ± 0.49 Ma). • The Kuh-Panj deposit is classified as continental arc-related porphyry copper deposit. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Serenu prospect is a porphyry Cu system located in the Kerman porphyry copper belt. The mineralization and alteration are related to a porphyry diorite to quartz-diorite stock. • Geochemical characteristics of the Serenu prospect suggest adakitic nature for the host rocks. • Zircon U-Pb dating shows 9.83 ± 0.4 Ma and 10.2 ± 0.17 Ma (±2σ) Ma for the emplacement/crystallization, implying the late Miocene and a post-collisional tectonic regime. • The ε Hf values of +8.52 to +12.27 along with the adakitic nature of the Serenu porphyry imply a juvenile lower crust with contribution from the depleted mantle for the parent magma source. Serenu porphyry copper prospect is situated 22 km northwest of the Meiduk copper mine, Kerman Cenozoic magmatic arc in southeastern Iran. The study area is characterized by a simple lithology including Eocene volcanic and volcaniclastics, Neogene sediments, and sub-volcanic rocks (Hezar complex) which is intruded by a late Miocene porphyry diorite to quartz-diorite stock that has developed alteration and mineralization in the area. Phyllic, argillic, and propylitic alteration types are well-distributed in the Serenu prospect; potassic alteration is only locally observed. Hypogene mineralization occurs in the Serenu porphyry and the host Eocene volcanic rocks as scattered vein-veinlets, stockworks, and disseminated mineralization related to potassic and phyllic alteration types. The mineralogy and cross-cutting relationships, allow the vein-veinlets to be classified into five groups including (I) magnetite ± quartz, (II) quartz ± magnetite ± chalcopyrite ± pyrite ± chlorite ± anhydrite (III) quartz ± pyrite ± chalcopyrite ± anhydrite, (IV) pyrite, and (V) quartz ± calcite veinlets. Oxide and supergene enriched ores are poorly developed in the area. Zircon U-Pb dating on two samples from the Serenu porphyry provided consistent ages at 9.83 ± 0.4 Ma and 10.2 ± 0.17 Ma (±2σ) indicative of late Miocene emplacement of the intrusion. The zircons are characterized by positive ε Hf (t) values of 8.52 to 12.27 and T DM of 200–370 Ma and a TC DM of 310–590 Ma indicating that they originated from a juvenile mafic and thickened lower crust and depleted mantle-derived magma. The late Miocene age determined for the Serenu porphyry copper prospect is consistent with the ages reported for many other shallow intrusions related to porphyry-type mineralization in the Kerman belt and further emphasizes the Miocene metallogenic epoch as the preferred time for porphyry Cu-Mo-Au mineralization in this belt, coinciding with a significant stage of continental collision between the Arabian and Iranian plates. The results of this study reveal that the juvenile mafic lower crust together with input from a depleted mantle and older subduction-related magma has a very significant impact on the formation of the Serenu porphyry host magma. [ABSTRACT FROM AUTHOR]

The Siah-Kamar porphyry Mo deposit (SKD) is located at the north-western termination of the Urumieh-Dokhtar magmatic arc and it is the only known porphyry Mo ore reserve in Iran. The SKD formed in two main mineralisation stages, at ~33–32 Ma (late-stage, disseminated) and ~ 29–28 Ma (late-stage, high-grade), within a context of a long-lived magmatism. We integrate results from the whole-rock geochemistry, the O C stable and Sr isotope systematics across the mineralised alteration zones with the available drilling data (ore element concentration) to define the ore-forming processes leading to Mo enrichment in the SKD. Our investigation shows that CO 2 bearing magmatic fluids had the major role in both early and late-stage mineralisation. The Mo shows positive correlation with SiO 2 content but a clear negative correlation with W, Cu, and S, due to a delayed precipitation of Mo during the early-stage mineralisation. The released fluids from the new acidic magmas and subsequent fluid-rock interaction in an open-system, primarily assisted by brittle fracturing, and accompanied by cooling and mixing with various amounts of meteoric water and fluid neutralisation, was responsible for the selective ore depletion and Mo-ore enhancement during carbonatisation along structurally-controlled pathways. [Display omitted] • Mo correlates positively with Si, K, Rb, and Pb but negatively with W, Cu, and S. • Two distinct stages of mineralisation (W and Mo) with different fluid conditions. • Existence of a shallow magma chamber with water-saturated acidic melts at ~29 Ma. • Structurally controlled carbonatisation and Mo ore enhancement. • Late carbonate overprinting formed columnar and planar Mo ore bodies. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Calculated log f O 2 values and FMQ buffer conditions (ΔFMQ < 2) of parental magmas of Eocene and Oligocene porphyry copper deposits in Lut block indicate never reached to ideal conditions of worldwide giant to large porphyries (Hematite-Magnetite buffer; ΔFMQ < 4). • Zircon trace element data, log f O 2 values along with the whole-rock geochemistry show slab metazomatized supra-subduction partial melted peridotite source for all primary magmas. • High parthial melting of a low water warm/hot deep steep slab subduction in a W-diredcted subduction system suggest to Eocene Cu-Au (Maher abad and Khupic) and Oligocene Cu-Mo (ChahShaljami and Dehsalm) porphyry deposits in Lut block related to the Indo-Asia and Arabian-Eurasian collision events. The small (<50 Mt) Eocene porphyry Cu-Au deposits of Maher abad and Khupic and the Oligocene Cu-Mo deposits of ChahShaljmi and DehSalam are attributed to the subduction of the Sistan ocean crust beneath the Lut block of eastern Iran. The calculated Ce4+/Ce3+ ratios of Dehsalm and ChahShaljami zircons are clustered around 10–50 and 75–155, and the values for Maher abad and Khupic are clustered around 120–300 and 50–150, respectively. The calculated log f O 2 values indicate FMQ buffer conditions for Eocene and Oligocene magmas (ΔFMQ < 2; ΔFMQ −1.8 to + 0.6 ± ∼1.5 for ChahShaljami; ΔFMQ −1.3 to −0.4 ± ∼1.5 for Dehsalm, and ΔFMQ −3.2 to −2.1 ± ∼1.5 for Maher abad; ΔFMQ −2.6 to −1.3 ± ∼1.5 for Khupic), which never reached the ideal values of the worldwide giant to large porphyries (ΔFMQ < 4; HM buffer). The 30–60% partial melting of a slab (∼10–25% garnet) can explain ChahShaljami and Dehsalm, while it is > 60% partial melting of a slab (garnet > 50%) + ∼10% of metasomatized garnet-lherzolite (∼10% garnet) for Maher abad and Khupic. High partial melting of a slab has produced magma poor in copper in the magmatic subarc of the Lut block. Our zircon data and whole-rock geochemical characteristics of the Eocene and Oligocene ore-bearing intrusions along with the kinematics studies of the subduction zones are well consistent with a west-directed subduction system in eastern Iran. In such a system, a higher subduction rate > convergence rate causes deep steep subduction and in the continuation roll-back of the slab occurs in response to the opening and closing of the back-arc basin. This event caused the thinning of the Lut continental crust, mantle delamination and hot asthenospheric upwelling. The ascent of magmas resulting from the partial melting of a hydrous slab through a hot mantle and thinned continent caused widespread volcanism, and large amounts of water, sulfur and, volatiles were released to the atmosphere in an island arc regime during the middle-upper Eocene. The poor in metal low-volume magmas resulting from the high partial melting of a low water warm/hot deepest slab slightly metasomatized the mantle that subsequently amphibole-FC process with low contamination in the MASH zones and their emplacement during the transition from the island- to normal continental arc in the upper Eocene-Oligocene formed upper Eocene high-K calc-alkaline I/A-type (ferroan) arc magmatism and lower Oligocene adakite-like high-K calc-alkaline-Shoshonitic I-type (magnesian) arc magmatism, led to the formation of small Cu-Au and Cu-Mo porphyry deposits in Lut block, respectively. These events occur in a particular tectonic condition where subduction and collision were accompanied by rotation of the block affected by both Indo-Asian and Arabian-Eurasian collisions. Our study implies that W-directed subduction systems do not have favorable conditions for the formation of large porphyry deposits such as the ideal down-dip thermal gradient of the oceanic slab, water content, depth of dehydration, degree of partial melting of oceanic slab, and thickened continental crust. [ABSTRACT FROM AUTHOR]

The Miocene Sarkuh porphyry Cu deposit is located in the southwestern part of Urumieh-Dokhtar Magmatic Arc (UDMA) in Iran. Compared with the neighboring giant Sarcheshmeh porphyry Cu deposit, this is a low-grade sub-economic porphyry Cu system (110 million tons @ 0.26 % Cu) characterized by an unusual abundance of magnetite. The present work tried to answer the question of whether or not there are differences in the hydrothermal system of Sarkuh, resulting in the lack of considerable mineralization. In this way, the mineral associations and EMPA data of magnetite were considered to distinguish the different stages of magnetite crystallization reflecting the magmatic-hydrothermal evolution of the Sarkuh deposit. They include (1) magmatic stage magnetite, including magnetite inclusions within primary silicate minerals (i.e., plagioclase and biotite), (2) pre-ore stage magnetite associated with potassic alteration assemblages, (3) main ore stage magnetite tightly associated with sulfide mineralization, and (4) late stage magnetite forming overgrowths on the sulfides. The results of EPMA analysis confirm that magnetite of these four stages differ in Mn, Fe, Ti, Mg, Al, Cr, and V concentrations. Higher V concentrations are found in the magmatic and pre-ore stages, whereas Al and Si reach the highest in the ore and late stages. Our data show that increasing fluid-rock interaction and changes in the oxygen fugacity, especially during the main ore stage extending to the late stage, are key factors controlling the trace element partitioning of magnetite. Most of ore stage magnetite formed at temperatures >500 °C and high temperatures prevailed during it. Magnetite crystallization after the main stage of sulfide mineralization accompanied by (partial) martitization indicate the increase of oxygen fugacity towards the late hydrothermal stage. This could explain why the ore and late stage magnetites show chemical similarities to those from sulfur-poor iron oxide copper‑gold (IOCG) deposits rather than porphyry deposits. • Sarkuh porphyry Cu deposit is characterized by unusual abundance of magnetite. • Four stages of magnetite crystallization could reflect the magmatic-hydrothermal evolution. • Al and Si reach the highest in the ore and late stages. • Ore and late stage magnetites show chemical similarities to sulfur-poor IOCG deposits. [ABSTRACT FROM AUTHOR]

The Iju Cu porphyry is located in the NW part of the Kerman Magmatic Copper Belt (KMCB). It is related to a ~ 9 Ma granodiorite porphyry intrusion, with three main stages of hydrothermal activity. The homogenization temperatures for the fluid inclusions are in the ranges of 200–494 °C, and their salinities vary from 4.0 to 42.8 wt% NaCl equiv., which are typical magmatic-hydrothermal fluids. The δ34S values of sulfides range from −0.4 to +3.2 ‰ (V-CDT), and the δ34S values of anhydrite samples range from +11.6 to +16.8 ‰. The δ34S values of sulfides show a narrow range, implying a homogeneous sulfur source. The oxygen isotopic composition of hydrothermal water in equilibrium with quartz samples ranges from +3.4 to +6.0 ‰ (V -SMOW) consistent with the hydrothermal fluids having a magmatic signature, but diluted with meteoric waters in the main mineralizing stage. The most important factors responsible for metal precipitation in the Iju porphyry deposit are fluid boiling, oxygen fugacity decrease and cooling followed by dilution with meteoric water. The primary fluids of the Iju Cu deposit are characterized by relatively high temperature and moderate salinity, and are CO 2 -rich, indicating a typical post-collisional porphyry system. [ABSTRACT FROM AUTHOR]

Formation of hydrothermal mineralization is related to the late stages of, or immediate following, orogenic compressional regimes that have been superimposed on arc magmatism. For instance, mineralization-related fluid flux mechanisms of porphyry Cu formation deal with how magmatic fluids are transferred from the corresponding source chambers to the environment of stock emplacement related to porphyry systems. In this paper, firstly, we review the imperative physicochemical processes of mineralizing fluid flux mechanisms, e.g., the function of intrusive, metalliferous compounds, and permeable structures, and then assemble them to translate the mechanism of forming focused fluid flux into 2D mappable criteria for mineral exploration targeting. According to the review and the ensuing knowledge and idea, we propose a simplifying approach by focusing on a geological point feature - inferred sites of strongly concentrated ore fluid flux - that represents a critical, if not the most critical, geological element in mineral exploration targeting. We demonstrate that this point feature can be derived as a mappable criterion and that there are stronger spatial and thermal relationships between the location of hydrothermal mineral deposits and this proposed point feature relative to the existing point and line features (e.g., intrusive contacts, fault density, fault intersections, and proximity to faults), which have been widely used in the procedure of prospectivity analysis for mineral exploration targeting. We illustrate the procedures of generating mineral exploration targets, proposed in this paper, using geochemical and geological data sets of porphyry Cu deposits of Iran. [Display omitted] • Function of hydrothermal mineralization-related focused fluid flux is discussed. • The function is translated into a newly-explored mappable exploration criterion. • The mappable criterion mitigates the problem of localizing hydrothermal mineralization. • Geochemical and geological data sets are applied in the modeling procedure. • Physicochemical ore-forming processes are discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Intrusive rocks as the permissive tracts for porphyry copper deposits are clustered. • Porphyry copper deposits within the permissive tracts show random distribution. • Significant structural control of faults over the spatial distribution of deposits. • Resource assessment should be applied separately for distinctly different sectors. • Predictive exploration targeting is feasible at mineralized intrusive bodies scales. The Kerman Cenozoic Magmatic Arc (KCMA, or Kerman Belt) in the southeastern part of the Urumieh–Dokhtar Magmatic Belt (UDMB) is considered as the most prospective geological province for porphyry copper deposits in Iran. Distance-based point pattern analysis methods, fractal analysis and Fry analysis are applied to porphyry copper deposits in order to gain insights into the geological controls over mineralization in the belt and suggest strategies for future exploration targeting. The results confirmed a significant structural control of strike-slip faults over the spatial distribution of deposits at the regional scale as previous structural studies defined it. The emplacement of porphyries in the Kerman Belt is likely controlled by extensional fault duplexes. The analyses further confirmed that there are two distinctly different sectors of porphyry copper mineralization in the Kerman Belt, namely, Sarduieh–Dahaj sector in the northwest and Jebal-e-Barez sector in the southeast as previous geological studies had demonstrated it. It is found that intrusive rock units, which form the permissive tracts for porphyry copper deposits in the Kerman Belt, are clustered, while the copper deposits within the permissive tracts generally show random distribution. It is recommended that predictive prospectivity modeling can be used to target mineralized intrusive bodies in the Kerman Belt; however direct detection techniques should be used to identify mineral deposits within the intrusive bodies. [ABSTRACT FROM AUTHOR]

For the purpose of multi-element geochemical modeling of stream sediment data, we investigate the use of unsupervised clustering analysis (CA). For the various reasons including straightforward implementation, fast computation, and scaling to big dataset, the K-means (KM) algorithm was implemented to cluster the geochemical data to reveal anomalous populations linked to porphyry and skarn Cu deposits in Baft district, NE Iran. However, one of the biggest disadvantages of KM method is the randomly selection of cluster centroids which may increase the systemic uncertainty in unsupervised geochemical modeling and also run time. To address this, genetic (GA) and firefly (FA) metaheuristic optimization algorithms were incorporated into the KM method (namely GKM and FKM models) for determination of cluster centroids, and then, optimal definition of geospatial patterns of anomaly-background classes using clr-transformed values of stream sediment geochemical data. To do so, sample catchment basins (SCBs) of anomalous geochemical dataset were used to spatially map the anomaly populations derived from KM, GKM and FKM methods. We have used the advantages of quantitative evaluation measures namely normalized density index (NDI) and success-rate curves to assess the effectiveness of multi-element geochemical anomaly in determining exploratory targets. The results not only affirms that CA is a useful method to decompose the geochemical anomaly-background populations, but also hybridization of clustering methods via optimization algorithms can efficiently increase the certainty of mineralized zones to be used in further exploration stages. • Sample catchment basin analysis carried out to map geochemical anomalies. • KM, GKM and FKM unsupervised clustering methods used to separate geochemical targets. • Success-rate curves and N d index were used to evaluate the efficiency of clustering methods. [ABSTRACT FROM AUTHOR]

In this contribution, we investigate the space and time distribution of the Cenozoic magmatism and the associated porphyry Cu-Mo ± Au and other hydrothermal (mostly epithermal) ore deposits along the south Caucasus-west Iranian tectono-magmatic belt. We use a comprehensive georeferenced database containing whole-rock and geochronological analyses of 3150 samples from the igneous rocks distributed in the study area. Overall, the timing of the ore deposits overlaps with the timing of the Eocene to Miocene diachronous collision between the Arabia and Eurasia plates. This is associated with a change in the geochemical fingerprints of the magmas during and after collisional thickening, with a marked increase in Sr/Y values associated with a general transition towards adakitic signatures. This is interpreted with a change towards an amphibole- (±garnet) rich residue at the arc roots. Clusters of ore mineralization are observed within areas of long-lived magmatism (lasting >10 Myr), usually located at the intersections of basement fault zones, parallel and orthogonal to the collisional boundaries and likely formed along inherited zones of crustal/lithospheric weakness. The isotopic data of the ore-forming magmas show a pronounced correlation with young (<0.7 Ga) Nd depleted mantle model ages (TDM Nd) and (87Sr/86Sr) i isotopic ratios ranging from ∼0.704 to ∼0.706. This evidence attests to post-Cadomian metal- and volatile-rich sources at crust roots, during incremental magmatic underplating. We suggest that optimum conditions to form clusters of ore deposits along the collisional zone are achieved when passive asthenosphere upwelling along slab windows (or induced by lithosphere delamination and/or slab break-off) causes the partial melting of the fertile arc roots in the amphibole ± garnet stability field. The end of mineralization along the west Iran magmatic belt is associated with crust overthickening (as evidenced by the inferred presence of a garnet-dominated residue), either as a consequence of consumption of the fertile metal-enriched sources or after the total removal/foundering of the arc roots. [Display omitted] • We present a database of magmatism and linked deposits for Armenia and west Iran. • Ore deposits mainly occur in areas of long-lived and stationary magmatism. • The diachronous collision-related crustal thickening controls timing of deposits. • Productive melts are derived from partial melting of the fertile lower crust roots. • Inherited block boundaries host prolonged magmatism, leading to ore deposition. [ABSTRACT FROM AUTHOR]

[Display omitted] • Geological domains often control the grade distribution in ore deposits. • Diagnosing the nature of geological boundaries is essential to predict grades. • Three approaches to predict grades in the presence of soft boundaries are compared. • An application to a porphyry copper deposit is presented. • Simulated grade models allow accurately assessing in-situ and recoverable resources. The incorporation of geological controls is essential for an accurate assessment of the in-situ and recoverable resources in an ore deposit, directly impacting the downstream stages of mining projects. Commonly, the mineral resources evaluation is carried out hierarchically, considering the definition of geological domains first and then predicting or simulating the metal grades within each domain. Nevertheless, this approach assumes a weak correlation between the metal grades across the domain boundaries, which could not be suitable when gradual variations of the grades are observed across these boundaries. To account for the latter scenario known as soft boundaries, we compare three approaches: (i) a hierarchical prediction of the geological domain indicators and the grade within each domain, (ii) a direct prediction of partial grades, defined as the product of the grade and a geological domain indicator, and (iii) a joint simulation of the grade and geological domain indicators. A porphyry copper deposit in which the copper grade is controlled by mineralogical and rock type domains is used as a case study. When compared with production data, the proposed approaches generate more precise predictions than the traditional approach consisting in accounting for the hard boundaries between mineralogical domains but ignoring the soft boundaries between rock types. The joint simulation approach provides more realistic grade variations across the rock type boundaries, allows for an unbiased prediction of the recoverable resources, and quantifies the uncertainty on these resources based on multiple grade outcomes. Ultimately, we emphasize that identifying the geological controls and the nature (hard or soft) of the geological boundaries, and then defining the proper approaches to account for them is necessary to accurately assess the in-situ and recoverable resources. [ABSTRACT FROM AUTHOR]

[Display omitted] • The polymetallic Chah-Mesi Cu-Pb-Zn-(Ag-Au) vein type deposit is classified as porphyry-related intermediate-sulfidation state epithermal deposit. • Tetrahedrite group minerals are the main Ag-carriers in the deposit and define a trend of increasing Sb content with increasing distance from the Meiduk porphyry deposit. • Fluid inclusions are dominated by low salinity, liquid-rich two-phase (LV) inclusions containing aqueous H 2 O-NaCl fluids with minor CO 2. The polymetallic Chah-Mesi epithermal vein deposit is located about 2.5 km south of the Meiduk porphyry Cu-(Mo-Au) deposit in the Kerman Cenozoic Magmatic Arc (Kerman Belt), representing the southeastern sector of the Urumieh-Dokhtar Magmatic Belt in Iran. The veins are N-S to NNE-SSW oriented and hosted in volcanic rocks of basaltic, andesitic to dacitic composition and pyroclastics, which were affected by intense local silicification and sericitization in proximity to mineralized veins. Propylitic, argillic, as well as potassic alteration show a more regional distribution; the latter only observed closer to the Meiduk deposit. Mineralization occurs in various types of veins (massive, banded, crustiform) and to minor extent in replacement and breccia bodies. It encompasses several stages: An early higher-sulfidation stage, characterized by pyrite, chalcopyrite, enargite/luzonite and bornite, is followed by the main intermediate-sulfidation state assemblage with pyrite, chalcopyrite, tetrahedrite group minerals and sphalerite. The late Pb-Zn rich stage with sphalerite, galena, chalcopyrite and pyrite overprints the earlier associations. Gold and silver of up to 7 g/t and 150 g/t, respectively, are associated with the main and late stages of mineralization. The main carriers of these precious metals are Ag-rich gold (electrum) and tetrahedrite; other Ag-bearing sulfosalts like pearceite are rare. The chemical composition of tetrahedrite group minerals ranges from tennantite-(Fe) to tetrahedrite-(Fe) and tetrahedrite-(Zn) exhibiting a positive correlation between Sb and Ag contents. The tetrahedrite group minerals show complex zoning and display an increase of Sb away from the Meiduk deposit. Primary fluid inclusions in sphalerite and quartz from the banded and crustiform veins are low saline aqueous H 2 O-salt inclusions with only traces of CO 2. Homogenization temperatures of two-phase LV inclusions (T h LV→L) have an average of 210 °C in sphalerite and 260 °C in quartz. Salinity values range from 1.2 to 9.9 and 2.1 to 9.2 mass% NaCl equivalent in sphalerite and quartz, respectively with an average of c. 6 mass% NaCl equiv. Low CO 2 concentrations in the vapor phase detected by Raman spectroscopy together with previously published stable isotope data indicate fluids of magmatic origin as the main fluid source that were mixed with meteoric water. Mineralization is linked to ascending hydrothermal fluids which evolved from high- to intermediate-sulfidation state due to cooling, dilution with meteoric water and progressing fluid-wallrock interaction. Similar low salinity, but higher CO 2 -bearing fluids were previously reported from the nearby Meiduk porphyry deposit. Conclusively, Chah-Mesi is classified as an intermediate-sulfidation epithermal deposit that developed in the peripheral parts of the Meiduk porphyry system. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mg-hornblende, Mg-biotite, and plagioclase were from a mantle-derived oxidized I-type magma, which is moderately to weakly contaminate by crustal materials. • The halogen contents of Mg- with F-rich magmatic biotite indicating their crystallization under similar physicochemical conditions. • The calcic- and Mg-hornblendes have crystallized under the same P-T conditions from a high f O 2 value and water-rich magmas. The Haftcheshmeh porphyry Cu–Mo deposit is located in the northwestern part of the Arasbaran Metallogenic Zone (AMZ), NW Iran. The Cu–Mo mineralization in this deposit is spatially and temporally related to late Oligocene gabbrodiorite and early Miocene granodiorite stocks. The chemistry of biotite, amphibole, and plagioclase in the ore–related granodiorite and gabbrodiorite intrusions was investigated to determine the physicochemical conditions of crystallization (temperature, pressure, oxygen fugacity, water activity, and fluorine–chlorine activity). Mg–biotite, Mg–hornblende, andesine/oligoclase and quartz are the main minerals in these rocks, associated with zircon, apatite, titanite, rutile and Fe–Ti oxides as accessory minerals; plus secondary biotite, K–feldspar, epidote, chlorite and muscovite as secondary minerals. The chemical compositions of the Mg–biotite and Mg–hornblende minerals reveal that the Oligo–Miocene magmas were most likely generated from mantle–derived oxidized I–type magma that was only weakly to moderately contaminate by crustal materials. The log(f H2O / f HF) and log(f H2O / f HCl) for the Mg–rich and relatively F–rich magmatic biotite indicate an oxidized, water– and halogen–rich melt. The halogen and water fugacities, show that the Mg–rich biotites crystallized under conditions that were similar in terms of pressure, temperature, flour, and chlorine content. Al–in–hornblende barometry and hornblende––plagioclase thermometry suggest that the Mg–hornblendes in the Haftcheshmeh granodiorite and gabbrodiorite intrusions crystallized under similar P–T conditions (from 0.11 to 0.96 kbar and 712 to 1060 °C, respectively). Oxygen fugacities obtained from the amphibole–only chemometer suggest that the gabbrodiorite and granodiorite intrusions have crystallized from oxidized (NNO + 1.82 and NNO + 2.92) magmas during amphibole crystallization. The presented method for fingerprinting magmas via trace element chemistry in biotite, amphibole and plagioclase by microprobe studies, demonstrate grouping of V, Cr, Ni and Nb concentrations in these silicates, despite the presence of large variation and zonation in other trace elements (Ba, Sr, Pb, Zn, P, Cl, F) that indicate complex petrogenetic processes. Our results show that trace elements in such silicates can be used to fingerprint of magma process. [ABSTRACT FROM AUTHOR]

[Display omitted] • In the Miduk PCD., a mature supergene process has occurred. • Geological features can influence the formation of a mature enriched ore. • Mass balance can determine how far Cu fluxed from the supergene system laterally. • Evolution of supergene ore can offer by detailed field & geostatistical studies. The present study used field geology and aimed to model the geological results by modern methods for examining the effects of geological features on the formation of an enriched ore in a mature supergene profile such as Miduk Porphyry Copper Deposit (MPCD). In addition, it aimed to discover which geologic controllers caused the fixation or conduction of Cu in supergene solutions. To this end, the anatomy of the supergene zones was examined by direct sampling and mapping. Analysis of fracture density helps uncover the role of fractures in conveyance of fluids. The results showed that MPCD endured a systematic supergene process, which resulted in the formation of a 200-meter enriched orebody on the top of the hypogene ore. Additionally, the topographic gradient was the most important controller in the migration of supergene solutions to northern side while the north–south trending fractures doubled the lateral flux. Furthermore, the mass balance analysis indicated that 181,000 tons of Cu laterally escaped from the supergene system. Considering the geochemical conditions in sources areas, this amount of metal was sufficient to form a proximal type of exotic mineralization. Further, drainages derived from the main deposit exhibited exotic mineralization, which supported the lateral movement of Cu from the main orebody. [ABSTRACT FROM AUTHOR]

[Display omitted] • Coexistence of sulphate and sulfides minerals, pore space breecia and alteration pattern arise questions. • Mixing model of previous studies has been challenged by the aforementioned evidence. • High-temperature fluid inclusions point out condensation of single-phase vapor. • H-O isotope highlighted the insignificant role of meteoric waters. • The questions justified with gas plume model. The Kahang deposit (100 Mt at 0.6% Cu) is one of the important porphyry copper deposits in the central part of Urumieh-Dokhtar Magmatic Arc (UDMA), Iran. The mineralization occurs as chalcopyrite and molybdenite in quartz and anhydrite -bearing veinlets or breccias and is closely associated with sericitic and phyllic alterations. Through comprehensive studies of the deposit's anatomy, some previously overlooked evidence raised new questions about the ore-forming process in the Kahang deposit. The coexistence of sulfate and sulfide minerals as veinlets and breccias, pore space breccias, could not be justified solely based on a previously introduced concept (i.e., mixing high temperature-high salinity magmatic water with low temperature-low salinity meteoric water). Fluid inclusions were examined in quartz veinlets of the A1, A2, and B types, anhydrite veinlets, and sphalerite of the L type veinlets. There are three types of fluid inclusions: liquid-rich (L-type), vapor-rich (V-type), and hypersaline (H-type). According to microthermometry of fluid inclusions, the fluids associated with anhydrite veinlets have relatively high temperatures (390–495 °C, mean = 455 °C) and low salinities (12.8–20.9 wt% NaCl equiv.) On the contrary, temperatures below 400 °C justified the coexistence of sulfate and sulfide minerals. The low solubility of anhydrite in high-temperature waters, on the other hand, demonstrates the gas–solid reaction of SO 2 (g) and plagioclase at such temperatures, as evidenced by fluid inclusions. Additionally, the fluid inclusions in quartz veinlets generated temperatures (290 to >600 °C) higher than those in the majority of other porphyry copper deposits. H-O isotopes indicated that magmatic fluids dominated, and meteoric waters played an insignificant role. These findings and observations supported the formation of the Kahang porphyry copper deposit as a result of a gas plume and the reactions of gas species with plagioclase to form anhydrite and sulfide minerals, as well as the formation of sericitic alteration in the host rock as a novel scenario. [ABSTRACT FROM AUTHOR]

Several machine learning approaches have been developed for the identification of geochemical populations. In these approaches, the geochemical elements are usually the sole quantitative variables used as inputs for geochemical population recognition. This means that the presence of other qualitative variables, such as geological information, is overlooked in the analysis. Hierarchical clustering, as an unsupervised machine learning method, is a common approach for dimensional reduction in the analysis of geochemical data. In this study, an alternative to this technique, known as geostatistical hierarchical clustering (GHC), is applied to identify geochemical populations in 3D in the Bondar Hanza copper porphyry deposit, Iran. In this paradigm, the qualitative geological variables can also be incorporated for geochemical population identification, in addition to qualitative geochemical elements. In this study, an innovative solution is presented to tune the weighting parameters of each variable in GHC, based on the associations that the clusters (i.e., geochemical populations) should have with the geological information. The results are compared with k-means and number–size fractal/multifractal (N–S) methods. As a result, GHC showed better agreement with alterations, rock types, and mineralization zones in this deposit. Finally, some important instructions are provided for further mineral exploration. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pyrite and chalcopyrite are the most abundant sulfides in potassic alteration zone of the Haftcheshmeh. • The sulfide minerals, especially pyrite, have been identified as principal carriers of PGEs in the Haftcheshmeh. • PGEs and other chalcophile elements were transported by exsolved high-T, saline magmatic hydrothermal fluids. The Haftcheshmeh porphyry Cu-Mo-Au deposit is located in the Arasbaran metallogenic belt, northwest Iran, with mineralization occurring mainly in gabbro-diorite and granodiorite porphyry. Pyrite and chalcopyrite are the most abundant sulfides that occur as disseminated and veinlet type ores in the potassic alteration zone. Platinum-group elements (PGEs), Au, and Cu concentrations of selected pyrite- and chalcopyrite-bearing samples were analyzed using in situ LA-ICP-MS and bulk rock Lead Fire Assay. Relatively high contents of PGEs and other precious elements are present in sulfide minerals, especially in pyrite that is the principal carrier of these elements in the deposit. Palladium is the most abundant of the PGEs in the sulfides. The contents of Pd are systematically higher than Pt in this deposit, consistent with other porphyry deposits, although Os, Rh, and Ir abundances are in general equal to or below the limits of detection in pyrite and chalcopyrite. The most important factors related to potential PGEs and chalcophile elements enrichment in the Haftcheshmeh deposit is the oxidized mafic endmember components of source magmas, i.e., high ƒ O 2 conditions, possibly with a semi-metal collector melt involved, and the high saline magmatic hydrothermal fractionation process. All these mechanisms seem to have enhanced the concentration of PGEs, Au, and other chalcophile metals. PGEs and other chalcophile elements were transported by exsolved high-T, saline magmatic hydrothermal fluids and then low T reaction and reduction to enhance saturation of sulfide phases during mineralization associated with potassic alteration. [ABSTRACT FROM AUTHOR]

Whole geochemical data are used to assess the petrogeochemical evolution and ore potentiality of different magmatic phases in the Kerman Cenozoic copper arc. There are at least five Eocene to Pliocene-Pleistocene volcano-plutonic magmatic episodes, marking the transitional from the continental arc calcalkaline, shoshonitic and adakitic to syn - to post-collisional alkaline magmatism. One of the most important episodes of the magmatism is linked to the Oligo-Miocene granodioritic-quartz monzonitic-granitic rocks of the Jebal-e-Barez type (second magmatic phase) that crosscut the first phase of Eocene volcanic rocks. The Jebal-e-Barez type granitoids mark the first phase of economic porphyry copper deposits (Sarcheshmeh and Meiduk). These granitoids and the Eocene volcanic rocks are enriched in K 2 O, LILE and LREE, indicating a high-K calcalkaline and shoshonitic magmatism of continental arc setting. The high copper contents (0.27–0.82% Cu) and low gold values (60–82 ppb) reflect the development of mineralizing systems with this continental arc setting. The Middle-Upper Miocene Kuh-e-Panj pelean dacitic (third magmatic phase) and their cogenetic granitoid rocks (fourth magmatic phase) are enriched in LILE, LREE, Sr, depleted in Y and Yb, and on Sr/Y-Y diagram illustrate a continental arc adakitic affinity. The Upper Miocene Kuh-e-Panj type porphyritic granitoids intrude into the pelean type dacitic volcanism and form the second phase of low grade (0.1–0.46% Cu) porphyry copper ores. The fifth phase of magmatism is related to the Pliocene-Pleistocene syn -to post-collisional K-rich alkaline basaltic lavas and lamprophyric dikes that formed by partial melting of the K-rich metasomatized mantle. Hydrothermally altered granitoids from different mines are depleted in Y, Yb, Zr, P, Ti and REE, thus show pseudoaffinity to the syn -post-collisional, adakitic or island arc calcalkaline-tholeiitic affinity. The low copper grade in nonproductive granitoids or weakly mineralized porphyry copper deposits may had been related to several factors; the interaction of primary garnitoid magma with organic-rich sedimentary basement host rocks that led to the low oxygen fugacity (below FMQ), Ca-enriched meteoric waters of low salinity, low fracture density in the porphyry stock and vapour transport of hydrothermal copper complexes to the distal part of the porphyry system. [Display omitted] • The Kerman Cenozoic porphyry copper arc includes five magmatic phases. • The arc displays calcalkaline, shohonitic and adakitic magmatism. • Eocene volcanism has no link to porphyry Cu ores. • Jebal-e-Barez granitoids host the economic porphyry ores. • Kuh-e-Panj granitoids link to weakly mineralized porphyry ores. [ABSTRACT FROM AUTHOR]

[Display omitted] • Astarghan deposit includes skarn, porphyry and epithermal mineralizations (Cu–Au). • Epithermal mineralization of Au in Astarghan shows low-sulfidation characteristics. • Tetrahedrite and stibnite are the main hosts for gold in the Astarghan deposit. • Native gold also occurs in epithermal quartz veins as tiny particles of 50–200 μm. • The δ34S values of pyrites in all mineralization zones show magmatic origin. The Astarghan area in northwest Iran (~50 km north of Tabriz) represents an excellent example of coexisting and associated skarn, porphyry and epithermal mineralizations of copper and gold. This contribution aims to study the geology, alteration and mineralization in these deposits, as well as the occurrence of gold and its host minerals, and present the physico-chemical characteristics of ore-forming fluids and the sulfur origin, in order to get a better understanding of development and evolution of these mineralizations. The Astarghan porphyry stock (Oligo–Miocene) intruded the upper Cretaceous flysch-type sedimentary sequence (calcareous sandstone and limestone with intercalations of siltstone, shale and marl) and brought about metamorphism and metasomatism along the contact. The Cu–Au mineralization in the Astarghan area occurred mainly in three forms: (1) skarn patches along the contact (Zone A), (2) stockwork-type and disseminated porphyry mineralization within the potassic (at Kaghdara and Boiokwari areas) and phyllic (at Sildirimdara area) alteration zones (Zone B), and (3) native gold-bearing low-sulfidation epithermal veins within the argillic alteration zone at Nowrozkala area (Zone C). The micro-thermometric studies on the porphyry-type Kaghdara potassic alteration zone showed that homogenization temperatures for liquid-rich and vapor-rich 2-phase, as well as halite-bearing multiphase inclusions range about 160–420 °C, 220–460 °C, and 320–580 °C, respectively. Salinities of the 2-phase and multiphase inclusions have ranges of 5–25 and 40–70 wt% NaCl eq. , respectively. However, fluid inclusions present in the epithermal veins of Nowrozkala are mainly liquid-rich 2-phase, and their homogenization temperature and salinity values lie within the ranges of 118–325 °C and 0.6–7.4 wt% NaCl eq. , respectively. The approximate estimated depth of the sulfide and gold mineralization in the porphyry system ranges from 1.6 to 2.5 km, and in the epithermal system is < 0.9 km. The sulfur isotopic analysis of pyrite from the porphyry and epithermal mineralizations in the potassic alteration zone at Kaghdara and argillic alteration zone at Nowrozkala indicate that the δ34S values (–0.1 to –0.3 and –0.5 to –1.1‰, respectively) are close to the range of magmatic sources. Finally, electron probe micro-analyses indicate that besides independent particles of 50–200 μm in the epithermal veins, gold is mainly hosted by tetrahedrite within the porphyry-related phyllic alteration zone, but especially stibnite within the epithermal veins; these minerals, as well as epithermal polyhedral pyrites contain native gold inclusions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Porphyry Cu deposits in the UDMB occur along the magnetic structures in high magnetic blocks. • Pb-Zn deposits in Central Iran mostly occur at boundaries between high magnetic blocks. • Most deposits in Central Iran occur in regions with thickened crust. • Newly identified hidden structures in Central Iran have potential for further exploration. Regional-scale magnetic and gravity data have been enhanced to identify major structures and distinguish geophysical blocks in order to evaluate the distribution of major mineral deposits and prospects in Central Iran. Major structures and coherent magnetic blocks have been defined from magnetic data enhanced using a combination of upward continuation and edge enhancement filters. Broad-scale regional structural architecture and coherent density blocks have been defined from gravity data enhanced using the tilt angle. Crustal thickness was calculated from Bouguer gravity data. Integration of the structures, magnetic, density and depth characteristics derived from the complementary geophysical techniques have been used to correlate and interpret the regional distribution of mineral deposits and occurrences to assist future exploration. Porphyry Cu deposits in the Kerman metallogenic zone are shown to be closely associated with major structures in high magnetic and gravity blocks that are coincident with the Tertiary volcanic units, and in areas where the crustal zone was interpreted to be more than 50 km thick. Pb–Zn deposits in Central Iranian Microcontinent are shown to be spatially associated with major structures, predominantly outside of the high magnetic response blocks, and commonly overlay the low gravity and thick crustal zones. In the north of the study area, one group of Fe deposits display a close correlation to blocks with both a high magnetic and high gravity response. Along strike to the southeast, a second group cluster is seen in an area with a moderate magnetic and a low gravity response. [ABSTRACT FROM AUTHOR]