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Identification of geochemical anomalies is a critical task in mineral exploration targeting. Decades of research and technology have resulted in new algorithms and techniques for recognizing anomaly detection methods at various scales and sample media. However, algorithms cannot always reveal the true nature of geological processes. The mineral system concept may contribute to a better understanding of the geological processes required to form and preserve ore deposits at all spatial and temporal scales. The mineral systems concept investigates the geochemical processes occurring within mineral subsystems in soil samples from the porphyry prospect area. The Cu/(Al + Ca) index was used to compare Cu, Mo, and (Pb* Zn)/(Cu*Mo) to highlight the region of interest for mineral potential mapping and pioneer borehole drilling based on fluid-rock interaction and secondary processes (e.g., alteration, weathering, and leaching). Exploratory boreholes validate a better performing Cu/(Al + Ca) index for detecting and refining soil geochemical anomalies. [ABSTRACT FROM AUTHOR]

This research presents a case study that employs the Fuzzy Ordered Weighted Averaging (FOWA) method to develop mineral prospectivity/potential maps (MPM) for the Chahargonbad district in southeastern Iran. The primary objective of the study is to uncover intricate and concealed relationships between various evidence layers and known ore occurrences through a comprehensive analysis of multidisciplinary geospatial data. Consequently, thirteen evidence layers were meticulously derived from existing databases, encompassing geological, geochemical, geophysical, and remote sensing data, which were then integrated using the FOWA multi-criteria decision-making approach to delineate favorable zones for porphyry Cu mineralization. The FOWA methodology employs a diverse array of decision strategies to synthesize input geospatial evidence by incorporating multiple values for an alpha parameter. This parameter serves as the cornerstone of the algorithm, influencing experts' perspectives on MPM risk. The methodology generates seven mineral potential maps to identify the most suitable one(s). By considering a prediction-area plot for datadriven weight assignment to each evidence map, the hybrid FOWA outputs were scrutinized to pinpoint the most appropriate map for targeting significant Cu occurrences. The resulting synthesized evidence map indicates an ore prediction rate of 77%, with known Cu deposits primarily located within favorable zones occupying 23% of the entire district area. [ABSTRACT FROM AUTHOR]

The Urumieh-Dokhtar magmatic arc (UDMA), Iran, hosts giant to small porphyry Cu ± Au deposits associated with Miocene post-collisional magmatism. Previous studies suggested that the ore-bearing suites are derived from chalcophile element-rich juvenile lower crustal igneous rocks, and that metal contents in the magmas play an important role in the formation of porphyry Cu ± Au deposits in this region. This study investigates the whole-rock major, trace, and platinum group element (PGE) geochemistry, as well as zircon trace element geochemistry, of six porphyry Cu ± Au ore-bearing suites and three barren suites in the central and southeastern UDMA. The aim is to revisit their petrogenesis and understand the factors controlling the formation of post-collisional porphyry Cu ± Au deposits. The high Mg# and Cr and Ni contents of the most mafic variants of ore-bearing and barren rocks suggest that they are primarily derived from the mantle. However, the ore-bearing magmas from the small Dalli Cu–Au porphyry and barren magmas from central to southeastern UDMA experienced substantial crustal assimilation during evolution. The evolved ore-bearing magmas exhibit high La/Yb and Sr/Y ratios, along with concave upward chondrite-normalized REE patterns and high zircon Ce/Nd and Eu/Eu* values, suggesting that they have undergone amphibole dominant differentiation under hydrous and oxidized conditions. In contrast, the barren magmas are characterized by lower whole-rock La/Yb and Sr/Y and zircon Ce/Nd and Eu/Eu* values with flatter REE patterns, implying plagioclase dominant differentiation. The ore-bearing suites, except for the Dalli suite, have systematically higher Pd and Pt contents than barren suites with highly fractionated PGE patterns (high Pd/Ir). The chalcophile element fertility of the ore-bearing suites, as indicated by high Pd/MgO and Pd/Pt ratios, is comparable to that observed in porphyry Cu deposits found elsewhere. This similarity suggests that the Cu contents of the magma likely played acrucial role in the formation of the porphyry Cu deposits in the central and southeastern UDMA. Late sulfide saturation or small amounts of sulfide segregation may have led to the high Cu and moderate Pd contents of the ore-bearing magmas until the late stage of differentiation. In contrast, early sulfide saturation resulted in significant depletion in all PGE and Cu in the barren magma. The fractionated PGE patterns of the ore-bearing magmas could have arisen due to two potential processes. Firstly, they may have resulted from fractional crystallization of Cr-spinel in the early sulfide undersaturated differentiation. Secondly, the patterns might have been inherited from partial melting of metasomatized lithospheric mantle. The systematic geochemical differences between ore-bearing and barren suites suggest that the more hydrous and oxidized nature and higher Cu contents of the ore-bearing magmas substantially increase the porphyry Cu ore potential in the central and southeastern UDMA. [ABSTRACT FROM AUTHOR]

The study area is located 12 km south of Zahedan city in Sistan-Baluchestan province. This area includes the northern part of Sistan and Baluchestan province, which has a similar geological history as the Chagai belt beyond the Iranian border in Pakistan. The porphyry prospect south of Zahedan is located in the fertile belt of the Sistan suture zone, which includes the Janja, Siastragi, Chahuk, and Kuh-e-Lar mineral deposits, then leading to the Sindak Pakistan Molybdenum Porphyry Mine. Based on the results of the geological mapping of 1: 5,000 areas, a series of subvolcanic masses with intermediate chemical composition (related to the Zahedan granitoid) have been intruded into the sedimentary host rocks with flysch facies. The zoning of alterations occurrence in the region is concentric and with the center of phyllic and potassic alteration. Pyrite is the most abundant sulfide mineral and chalcopyrite is the main copper ore mineral. Mo and Cu mineralization in this area mainly occurred as veinlets in stockwork and disseminated texture. Based on scanning electron microscopy (SEM) studies and using EDS analysis, the presence of molybdenite, and copper sulfide minerals were detected along with electrum and gold inclusions in the collected samples. Most of the detected fluid inclusions in the study area are of the two, three, and multiphase types, including liquid, vapor, and solid. Due to the trend of salinity changes versus homogenization temperature, the effective fluid densities in the mineralization systems of the region are between 0.8 and more than 1.2 gr / cm3. Based on the salinity percentage (30 to 60 wt% NaCl equivalent) and homogenization temperature (200 to 500°C), the fluid inclusions of the region are in the porphyry range. Fluid d34S values in the study samples are in the range of 3.4 to 4.6 per thousand. Sulfur isotope analyses indicate a magmatic origin of hydrothermal fluid. In general, based on the geology, mineralization, fluid inclusion, and sulfur stable Isotope studies it can be proposed that probably the south Zahedan area is a copper, gold, and molybdenum-type porphyry deposit. [ABSTRACT FROM AUTHOR]

The Kighal porphyry Cu deposit, in the Arasbaran magmatic belt (AMB), is hosted by Late Eocene to Oligocene volcanic rocks and Miocene high–K calc–alkaline subvolcanic intrusions. The Miocene quartz monzonite stocks host porphyry–style Cu mineralization characterized by potassic, phyllic, argillic, and propylitic alteration zones and an advanced argillic lithocap. The Ar–Ar dating of secondary biotite from the potassic alteration and alunite from the lithocap yields precise ages of 20.10 ± 0.18 Ma and 19.15 ± 0.21 Ma, respectively, documenting the evolution of the hydrothermal system over ~ 1 Myr. Hydrothermal rutile occurs in the deposit from the proximal potassic to distal propylitic alteration zones, and their Ti–Fe–Cr–V–W contents can be used as a fertility indicator which suggests a decrease from the proximal zones towards the distal zones. The geochemical fingerprints of the Kighal (and in general the AMB) igneous rocks reflect a post–collisional arc setting. Their distinctly high Th/Yb and Ta/Yb ratios are typical of high–K calc–alkaline intrusions, suggesting that their parental melts were derived from an enriched upper mantle source modified by slab–derived components. Their 87Sr/86Sr(i) (0.70427 to 0.70452) and 143Nd/144Nd(i) (0.512712 to 0.512754) ratios reveal that the magmas experienced moderate crustal assimilation during their magmatic evolution, also supported by increasing Th/La and 87Sr/86Sr(i) and decreasing εNd(i) values with increasing SiO2 content. The 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb ratios of the intrusions (18.67 to 18.84, 15.60 to 15.66, and 38.83 to 39.06, respectively) reveal a crustal origin. Hence, a post–collisional arc setting is proposed for NW Iran, in which mantle–derived mafic melts underwent a MASH process and ascended into shallow magma chambers in the upper crust associated with moderate crustal contamination, which account for the formation of large–scale porphyry Cu mineralization in the AMB. [ABSTRACT FROM AUTHOR]

Kriging has some problems such as ignoring sample values in giving weights to them, reducing dependence structure to a single covariance function, and facing negative confidence bounds. In view to these problems of kriging in this study to estimate Cu in the Iju porphyry Cu deposit in Iran, we used a convex linear combination of Archimedean copulas. To delineate the spatial dependence structure of Cu, the best Frank, Gumbel, and Clayton copula models were determined at different lags to fit with higher-order polynomials. The resulting Archimedean copulas were able to describe all kinds of spatial dependence structures, including asymmetric lower and upper tails. The copula and kriging methods were compared through a split-sample cross-validation test whereby the drill-hole data were divided into modeling and validation sets. The cross-validation showed better results for geostatistical estimation through copula than through kriging in terms of accuracy and precision. The mean of the validation set, which was 0.1218%, was estimated as 0.1278% and 0.1369% by the copula and kriging methods, respectively. The correlation coefficient between the estimated and measured values was higher for the copula method than for the kriging method. With 0.0143%2 and 0.0162%2 values, the mean square error was substantially smaller for copula than for kriging. A boxplot of the results demonstrated that the copula method was better in reproducing the Cu distribution and had fewer smoothing problems. [ABSTRACT FROM AUTHOR]

The Lut Block is a potential porphyry-style mineralized region in Iran including the well-explored Shadan porphyry gold-copper deposit, which has an extensive zone of gold- and copper-bearing stockwork-like sheeted veins. The structural setting of this deposit is a key to understanding the genesis of the mineralization. Our field studies show that the mineralization occurs as steeply dipping ore bodies along NW–SE transpressional faults. The zones with a high frequency of veins and volume of veins have a NW–SE trend, which is closely related to transpressional faults. We propose that such a compressional regime inhibits focused ore-forming fluid flow to higher levels in the crust. After a local change in stress field, fluid depressurization and channeling along transpressional faults generated the sheeted veins. This indicates an important role of these transpressional faults in focusing and controlling mineralization within this porphyry deposit, which has important implications for the exploration of porphyry deposits on a regional scale. The spatial distribution of sheeted veins is used to examine gold anomalies from lithogeochemical data extracted by fractal models. The results show that a combination of high vein density and high vein volume areas with gold anomalies could result in identifying areas with greater potential at the deposit to regional scale. [ABSTRACT FROM AUTHOR]

Mineral resource classification is an important step in mineral exploration and mining engineering. In this study, copper and molybdenum resources were classified using a combination of the Turning Bands Simulation (TBSIM) and the Concentration–Volume (C–V) fractal model based on the Conditional Coefficient of Variation (CCV) for Cu realizations in the Masjed Daghi porphyry deposit, NW Iran. In this research, 100 scenarios for the local variability of copper were correspondingly simulated using the TBSIM and the CCVs were calculated for each realization. Furthermore, various populations for these CCVs were distinguished using C–V fractal modeling. The C–V log–log plots indicate a multifractal nature that shows a ring structure for the "Measured", "Indicated", and "Inferred" classes in this deposit. Then, the results obtained using this hybrid method were compared with the CCV–Tonnage graphs. Finally, the results obtained using the geostatistical and fractal simulation showed that the marginal parts of this deposit constitute inferred resources and need more information from exploration boreholes. [ABSTRACT FROM AUTHOR]

The Miocene Daralu Porphyry Copper Deposits (PCDs) is found associated with other porphyries such as Sarcheshmeh and Meiduk in the Kerman Cenozoic Magmatic Arc (KCMA), southern Iran. In this research, we provided whole-rock geochemical data, characteristics of hydrothermal fluid and sulfur isotope composition of the Daralu intrusive body, and discussed the nature, tectonic setting and fluid evolution of this deposit aiming to investigate its fertility. The Daralu porphyry shows adakites affinity, that is, high Sr/Y and La/Yb ratios and positive Eu anomalies. The REEs patterns indicate a strong fractionation ([La/Yb]n= 28.73). High La/Sm and Dy/Yb ratios suggest enrichment of amphibole and garnet as residual phases in melt source, whereas partial melting of plagioclase increases Eu and Sr in the parent magma. The presence of garnet implies a pressure equivalent to the thickness of more than 40km of crust. To elucidate the evolutionary history of fluids and the origin of the Daralu deposit, we focused on the origin and composition of the fluid through petrography, Raman spectroscopy, and microthermometry studies of fluid inclusions. The fluid inclusions have been divided into four types: vapor (type I), aqueous-vapor (type II), CO2-bearing (type III), and multiphase (type IV). The Raman shifts included 1284 and 1388 cm-1 for CO2 and 2750-3900 cm-1 for H2O. The events such as NaCl supersaturation, exhausting of CO2-rich components, high oxygen fugacity and temperature decreasing through mineralization stages were critical in controlling the fertility of the Daralu PCD. The obtained δ34S data for sulfides yielded an average of +5.5‰. Based on the observed features, it was concluded that Daralu porphyry shares formation conditions with other productive porphyries of the KCMA. [ABSTRACT FROM AUTHOR]

One of the specific features of porphyry copper (Cu) mineralization is the distinct occurrence of hydrothermal alteration zones, which can be mapped by processing various satellite images. Among free multispectral images, Landsat 8 OLI and ASTER data are known to be efficient in mapping different geological features, such as alteration zones and tectonic lineaments. This study aims to show the potential of these data types in mapping porphyry Cu mineralization by proposing a framework for employing and integrating different image processing methods. These methods include principal component analysis (PCA), spectral angle mapper (SAM), and matched filtering (MF) employed on these satellite images to map target al.teration zones. Moreover, PCA and directional filtering are applied to the ASTER dataset to enhance and map structural features. The results are evaluated and then combined to provide a potential map of Cu mineralization in the Chahargonbad area, located within the Urumieh-Dokhtar magmatic belt (UDMB) in Kerman province, Iran. The prediction-area plot and normalized density, which are data-driven methods, are used to assign the relative weight of each layer and evaluate them. Finally, using the calculated weights, data-driven multi-index overlay (DMIO) and fuzzy ordered weighted averaging (FOWA) methods are applied to combine the evidential layers. The potential mineralization maps created by the DMIO and FOWA provide a prediction rate of 80% and 82%, respectively. Furthermore, the accuracy of the integrated maps is investigated using the area under the curve (AUC) of the receiver operating characteristic (ROC) curves. The AUC scores obtained from the ROC curves of DMIO and FOWA methods are 0.85 and 0.88, respectively, representing powerful positive spatial relationships with mineralization areas. Based on the results, the proposed framework can be applied to provide a potential map of porphyry Cu mineralization, particularly in arid regions, with reasonable accuracy. [ABSTRACT FROM AUTHOR]

Detection of hydrothermal alteration zones (HAZs) associated with porphyry copper systems using remote sensing imagery is a crucial stage for discovering high potential zone of ore mineralization. Statistical model-based clustering methods have great potential for automatic and accurate detection of hydrothermal alteration minerals using hyperspectral remote sensing imagery. In this research, the Dirichlet Process based on Stick-Breaking (DPSB) model-based clustering algorithm was implemented to hyperion remote sensing imagery to discriminate HAZs associated with the Kuh-Panj porphyry copper deposit, south, Iran. The DPSB clustering algorithm was implemented and subsequently compared with the k-means algorithm, CLARA clustering, hierarchical clustering, Gaussian finite mixture model (GFMM), Gaussian model for high-dimensional (GMHD) and spectral clustering as well as spectral angle mapping (SAM). Results derived from the DPSB model-based clustering algorithm show 88.6% accuracy in distinguishing propylitic, argillic, advanced argillic, propylitic-argillic and phyllic alteration zones. The DPSB algorithm can be broadly implemented to hyperspectral remote sensing imagery for detecting alteration zones associated with porphyry systems. [ABSTRACT FROM AUTHOR]

Known to be triggered and controlled by tectonic systems, magmatism plays a significant role in the deposition and emplacement of hydrothermal mineral systems. It is, therefore, of paramount importance to recognize the tectonic processes that are genetically associated with hydrothermal mineral systems. This study seeks to address this research gap by recognizing the main tectonic processes that have controlled the distribution of porphyry copper (Cu) deposits in Dehaj Area on the Urmia-Dokhtar magmatic belt, central Iran. For this purpose, spatial associations of 31 known porphyry Copper deposits, faults, and fractures were evaluated by multiple numerical techniques including fry, fractal, (box-counting and radial-density methods), and distance-distribution analyses to investigate structural controls of the porphyry Copper mineralization. Results of the fry analysis revealed three mineralization trends, namely NS, NE, and NW, clearly following the existing fault systems in the area. Application of the fractal method demonstrated that structural controls on mineralization have operated on two different scales, regional and local scales. Distance-Distribution analysis was further used to spatially correlate known porphyry Copper deposits to fault traces, supplementing the results of fry and fractal analyses by quantitative measurements. Compiling the results of these three methods, it was shown that NW-trending faults have plausibly controlled the magmatism on a regional scale. On a local scale, however, NE- and N-trending faults have probably acted to control the channelling and emplacement of mineral-bearing fluids. [ABSTRACT FROM AUTHOR]

This study was planned with the aim of identifying the nature and circumstances of the high-graded central core and increasing trend of copper content through depth of 1000 m in Miduk PCD. Mechanisms of high-grading, refer to hypogene enrichment (HE), in PCDs poorly understood. Two main hypotheses for hypogene enrichment formation assumed addition of extra copper to the system, alternatively hypogene leaching and enrichment. In order to obtain alteration-mineralization-geochemical pattern both horizontally and vertically, all macroscopic data extracted from relogging of 6800 m' drill core along an east–west profile, compiled with microscopic observations from studying of 550 thin-polished sections and copper grades of 3400 samples analyzed by XRF and ICP-OES. Our findings proved hypogene enrichment events at deposit. HE evidences in macroscopic and microscopic scales identified almost as various replacement textures between Fe-Cu sulphides and also vein-reopening by later Cu-mineralization and new generation of disseminated or vein type mineralization. In addition, appearance of dark halo, as consuming intermediate chalcocite phase, around pyrite and chalcopyrite which gradually evolves as bornite, also extruding extra iron as fibrous hematite at the outer edge of bornite product replaced chalcopyrite, partially replacement of bornite and chalcopyrite to hypogene chalcocite and covellite-digenite in deep potassic are other HE evidences in the case study. Here, we draw on microscopic observations and SEM-BSE-EDS results, secondary hypogene genesis for some of bornite and chalcopyrite as a hypogene enrichment evidence. Observations from relogging show that potassic alteration has a relatively good preservation in the center of the deposit from depth to surface, but affected by intense overprinting of subsequent alterations towards margins. Evident function of ore-leaching at margins, also elevated copper grades in central parts of the deposit strongly suggest leaching-fixation mechanism. Where buffer potential of the rock is preserved copper fixation and where it totally eliminated almost complete leaching of copper happened. Consequently, we introduce leaching-fixation as index processes in hypogene enrichment at the case study. We suggest that identifying the nature of hypogene enrichment processes and its characterizations not only improve understanding about PCD's hydrothermal evolution, but also achieve exploration indicators, furthermore, industrial benefits in the production line. [ABSTRACT FROM AUTHOR]

The Sungun Cu-Mo porphyry deposit forms part of the Ahar–Arasbaran Magmatic Belt (AAMB). Its host Miocene porphyry stock is quartz monzonitic in composition and is cut by intermediate dykes that post-date mineralization. These dykes contain pyroxene and enclaves of ambiguous origin. Dykes of microdiorite are observed within quartz diorite dykes, whereas later diorite dykes contain three different kinds of enclaves (diorite, quartz diorite and hornfels) of sizes between 1 and 10 cm. Enclaves consist of plagioclase, hornblende and biotite, with accessory sphene, quartz and apatite. Chlorite compositions in microdiorite are within the chamosite range, whereas they are within the clinochlore range in diorite enclaves. Microprobe analyses of pyroxene indicate an augitic composition (Fs13.38-22.79Wo29.1-33.57En48.53-56.61), consistent with an igneous origin. Hornblende of the diorite enclaves formed at pressures ranging between 3 and 5.3 kilobars and temperatures between 714 and 731 °C. Average oxygen fugacity during rock formation is −14.75. Such high oxygen fugacities suggest that the diorite formed near the boundaries of a convergent margin. Amphibole compositions suggest that the diorite enclaves are sub-alkaline to mildly alkaline, consistent with reported whole-rock chemistry of the Sungun magmas. Pyroxenes were formed at pressures ranging between 11 and 15 kilobars (33–45 km) and temperatures between 1100 and 1400 °C. The amount of Fe3+ in clinopyroxene is also consistent with high oxygen fugacity within their environment of crystallization. Overall, these results have implications for our understanding of the origin of the Sungun Cu-Mo porphyry magmas and their mineral deposits in a lower-crustal setting. [ABSTRACT FROM AUTHOR]

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]

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]

Gardaneh Salavat porphyry copper system is located in the northwest of Iran. It comprises a quartz diorite to diorite porphyritic intrusion that created extensive alteration haloes in the host rocks. Despite all technical considerations, the exploration activities did not yield to ore discovery. As the matter of fact, all of the geological, geophysical, and geochemical characteristics of a porphyry Cu-Au deposit exist but there is no economic mineralization. Detailed examinations suggest that the only reasonable explanation can be related to the infertility or low metal endowment of the porphyritic intrusion. The reasons include (1) anomalous ranges of Cu, Au, and Mo rather than economic ore grades, (2) weakly development of potassic alteration, (3) probably sulfur saturation of magma that occurred before intrusion emplacement in the host rocks, and (4) probably low metal endowment in the regional scale and the lack of known porphyry copper deposits in close neighborhoods. It is tried to test the proposed hypothesis with the introduced fertility indicators based on major and trace element geochemistry. However, current fertility indicators could not prove or reject the proposed hypothesis for Gardaneh Salavat porphyritic intrusion because of the high-K calc-alkaline to shoshonitic nature of the intrusive rocks together with the unavailability of relatively fresh/unaltered samples. This case study is notable to examine because (1) it shows that characterization of fertile from barren intrusions seems to be as important as vectoring towards concealed porphyry copper deposits, especially while dealing with deep exploration targets that are associated with high financial risks, and (2) it highlights the inefficiencies and uncertainties in introduced magma fertility indicators for porphyry copper intrusions. As a result, it is of high importance to conduct an overarching investigation on other possible fertility indicators as a fundamental need for the future of the exploration industry. [ABSTRACT FROM AUTHOR]

The Kighal and Bormolk porphyry copper deposits (PCDs) are known subeconomic deposits and are ~10 km south of Sungun, the world-class copper mine in NW Iran. The deposits are located in the Azerbaijan plateau, within Alborz, Zagros, and Caucasus Mountain ranges, having undergone active tectonics, including uplift and thrust-folding from the Cimmerrian Orogeny. The sub-economic nature of the Kighal and Bormolk deposits, despite their relatively close distance and age and lithologic similarity to those of the Sungun deposit, has been discussed. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Landsat 8 Operational Land Imager (OLI) imagery were used to map alteration patterns and lineaments associated with these deposits. In order to discriminate alteration minerals of the deposits in comparison with those in the Sungun deposit, the ASTER image was processed using False Color Composite (FCC), Band Ratio (BR), Principal Component Analysis (PCA), Minimum Noise Fraction (MNF), and Mixture-Tuned Matched-Filtering (MTMF) techniques, which recognize seven alteration types in the Kighal‒Bormolk area and three types in the Sungun area, including its more intense alteration systems. The results were verified by field observations, mineralogical, and X-ray diffraction (XRD) studies. Also, lineament extraction of DEM and Landsat 8 OLI data by Envi 5.1, Geomatica, ArcGIS 10.6, and Rockworks 16, displayed a lower density of fault intersections in the Kighal‒Bormolk area. Additionally, NW‒SE trending lineaments of the Sungun deposit, which is in accordance with most of the valuable porphyry copper deposits in Iran, are taken into account. [ABSTRACT FROM AUTHOR]

Oxidation and enrichment processes as a secondary phenomenon lead to forming a vertical arrangement of leached, enriched, and hypogene mineralisation zones in porphyry copper deposits. Generating a suitable geological model of these zones can enable a more accurate resource estimation. This research introduces a multiple-point geostatistics simulation (MPS) based workflow to simulate the geological model of such mineralisation zones. The main goal of this workflow is to generate realisations in which: i) the proportions of zones, ii) the vertical arrangement of zones, iii) spatial geometry of the zones, iv) non-stationarity in local proportions are reproduced accurately. Among various MPS algorithms, single normal equation simulation (SNESIM) is used in this study. The proposed workflow includes three main steps: i) constructing an appropriate training image, ii) selecting the best values for SNESIM input parameters, iii) calculating the soft probabilities in order to control the non-stationarity of local proportions. Finally, this workflow was applied to the Ali-Abad porphyry deposit case, and one hundred realisations were generated. The validations have illustrated the acceptance of the realisations in terms of the zones' proportions, the indicator variograms, and vertical mineralogical order of zones, and the local proportion of zones. [ABSTRACT FROM AUTHOR]

Granitoid intrusions of Zagros orogenic and metallogenic belt were mainly emplaced during the Jurassic-Cretaceous and Upper Eocene – Pliocene along the Sanandaj-Sirjan Zone (SaSZ) and Urumieh-Dokhtar magmatic Arc (UDMA), respectively. The present work tried to answer the question of whether or not there are fundamental differences in magmatic systems of Mesozoic versus Cenozoic intrusions of Zagros orogen resulting in the lack of porphyry mineralization in SaSZ compared with the widespread occurrence of porphyry-bearing intrusions in the UDMA. Characterizing the geochemical features of six major granitoid intrusions in the SaSZ (Alvand, Almogholagh, Aligoodarz, Boroujerd, Dehno, and Kolah-Ghazi) show they mostly represent low to high-K calc-alkaline and peraluminous magmatic suite, which is analogous to those reported previously for the UDMA porphyry Cu intrusions. However, the SaSZ intrusions are characterized by extremely low Sr/Y contents, distinct negative Eu anomalies, and less fractioned HREE patterns with OIB signature in the less fractionated samples indicating a source dominated by melting of subcontinental lithosphere mantle. This study proposed that the inception of Cenozoic flat slab subduction followed by dehydration melting of ~ 29 Ma of metasomatized subcontinental lithospheric mantle (SCLM) during the continuous stages of continental-continental collision has a decisive role in magmatic change to a more hydrous and oxidized nature. These processes provided unique conditions for increasing metal fertility of these Miocene intrusions compared to those of older Mesozoic igneous activities in the Zagros orogenic and associated metallogenic belt. [ABSTRACT FROM AUTHOR]

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 (Th = 525–594 °C) and salinities (63–73 wt% NaClequiv), whereas vapor-rich inclusions (Type II) had lower Th (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% NaClequiv) 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. [ABSTRACT FROM AUTHOR]

The Sarcheshmeh porphyry copper deposit (PCD) is located in the southeast part of the arc‐related Urumieh‐Dokhtar volcano‐plutonic belt. This PCD was formed by intrusion of a Middle Miocene granodiorite to tonalite stock into the volcano‐sedimentary rocks that are mainly andesite exhibiting Early Tertiary thrusting and faulting. On the basis of geochemistry of intrusive rocks, they are calc‐alkalic and alkali‐calcic suites that are consistent with oxidized I‐type magmas. The Fe2O3/FeO ratio in the Sarcheshmeh PCD is 1 to 3, consistent with a high oxygen fugacity. The igneous rocks of Sarcheshmeh PCD belong to a mature arc, but related to a post‐collision arc setting. Considerable evidence supports adakitic affinities of the Sarcheshmeh rocks, including geochemical values of Sr > 300 ppm (ave., 594 ppm), high ratios of Sr/Y > 20 (ave., 75), La/Yb > 20 (ave., 30), and enrichment of LREE and LILE relative to HREE and HFSE. The adakites of Sarcheshmeh belong to high‐silica adakites (HSA) that can be formed by melting of subducting seawater‐altered oceanic plate, which interact with the mantle wedge then followed by slab break‐off with local transtension in the middle part of the Dehaj‐Sarduieh belt. In rocks of the region, the ratios of Th/Ce > 0.12 and Nb/Zr > 0.05 suggest that the subducting crust has a role in forming different groups of these rocks. Geotectonic discrimination diagrams are used to distinguish between normal arc and slab failure magmatic systems, including Nb versus Y, La/Sm versus Sm/Yb, La/Yb versus Gd/Yb, and Rb versus Nb + Y diagrams. The plutonic rocks of the Sarcheshmeh PCD have characteristics consistent with adakites derived via slab failure, which are obviously metallogenically favorable magmatic systems. Adakitic melts generated rapidly during sinking of a broken slab (into higher temperature mantle), buoyantly migrate through the subcontinental lithospheric mantle (SCLM), which is related to structural evolution of that SCLM with local extension or transpression. [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 Masjed Daghi porphyry-epithermal Cu-Au-Mo deposit in the northern Arabian-Eurasian collision zone of the Alborz Magmatic Assemblage, NW Iran, is hosted by an early Miocene quartz monzodiorite to diorite intrusion that intruded Eocene volcanic rocks. Potassic, phyllic, argillic, and propylitic alterations associated with four stages of porphyry mineralization (I to IV) are distinguished. Late high-sulfidation epithermal veins of mainly quartz or quartz-barite are enclosed in concentric zones of advanced argillic, argillic, silicic, and propylitic alterations. Poly-phase brine inclusions from the stage ΙΙ porphyry mineralization have homogenization temperatures (Th) between 305 and 600 ºC, with salinity from 30.2 to 73.9 wt% NaCl equivalent. Brines inclusions of stages ΙΙΙ and ΙV have Th from 192 to 466 ºC and salinity from 20.6 to 59.2 wt% NaCl equivalent. These brine inclusions were trapped with vapor-rich inclusions, which have Th from 122 to 318 ºC and low-moderate salinity of 0.3 to 22.3 wt% NaCl equivalent. Fluid inclusions from quartz and sphalerite in epithermal veins yielded Th ranges of 123–298 °C and 121–218 °C, and salinity ranges of 1.9–12.8 and 1.9–11.2 wt% NaCl equivalent, respectively. The δ34S values of sulfide minerals from stages ΙΙ and ΙΙΙ porphyry mineralization vary from + 0.9 to + 2.3‰, whereas the δ34S values of sulfides from the late epithermal veins range from + 1.2 to -1.1‰. These characteristics are consistent with a similar magmatic source for both the fluids of porphyry mineralization and subsequent high-sulfidation epithermal veins. The Masjed Daghi deposit that represents a telescoped porphyry-epithermal system of copper–gold mineralization in the center and peripherals of the early Miocene intrusive stocks shows both similarities and differences to other Tethyan deposits in the Alpine-Himalayan orogenic belt. [ABSTRACT FROM AUTHOR]

Copper is an essential material for electrical conductivity and is a good conductor for heat. The porphyry copper deposits (PCD) are one of the most important resources of copper, where the determination of copper grade is one of the most important issues. The finding complex relationship between copper grade and kind of rocks is a major change for modelers. This study employed the adaptive neuro-fuzzy interface system (ANFIS) and multi-layer perceptron (MLP) to estimate the copper grade in PCDs. The Henry gas solubility optimization (HGSO), weed algorithm (WA), and moth flame optimization (MFO) were applied to set the parameters of the MLP and ANFIS models. The Iju PCD, as one of the important copper deposits in the Kerman province of Iran, was chosen as a case study for predicting the copper grade. Three scenarios were used as input to the models. The first scenario used the latitude and altitude of boreholes as input and the second scenario used the longitude and altitude of boreholes as input. The third scenario used the latitude, longitude, and altitude of boreholes as input. Results of the first scenario indicated that the percent bias of the ANFIS model was 0.26, while it was 0.19, 0.22, and 0.24 for the ANFIS-HGSO, ANFIS-MFO, and ANFIS-WA models. The accuracy of models indicated that the integration of ANFIS and HGSO decreased the root mean square error (RMSE)of the ANFIS-MFO, ANFIS-WA, and ANFIS models about 14%, 21%, and 27%, respectively, in the training phase in the second scenario. The RMSE for the ANFIS-HGSO was 1.98 in the training phase, while it was 2.31, 2.45, and 2.67 for the ANFIS-MFO, ANFIS-WA, and ANFIS models, respectively, in the third scenario. The accuracy of three input scenarios was compared with that of ANFIS-HSGO. The Mean absolute error of ANFIS-HSGO for the third input scenario was 67% and 40% less than for the first and second input scenarios in the testing phase. The third scenario was the best input scenario. Uncertainty analysis for all the models showed that the least value of uncertainty belonged to the ANFIS-HGSO. This study also used an inclusive multiple model to estimate copper grade based on providing a synergy among multiple models. The utilization of an inclusive multiple model based on the outputs of the hybrid and standalone ANFIS and MLP models could increase the accuracy of individual models. The inclusive multiple model and the comprehensive uncertainty analysis are the innovations of the current study. [ABSTRACT FROM AUTHOR]

LA‐ICP‐MS analysis of molybdenite from the Sar Cheshmeh porphyry Cu‐Mo deposit (PCD), Iran, shows moderate concentration of Re (average ∼207 ppm) and low concentration of chalcogenides (average of Pb + Te + Bi, ∼31 ppm) as well as metalloids (average of As + Sb + Ge, ∼4.5 ppm). The early‐formed quartz–molybdenites associated with potassic alteration are characterized by moderately low concentration of Re (21–215 ppm with an average of 83 ppm), whereas the transitional quartz–molybdenite veins related to the sericitic stage of mineralization contain more Re (62–465 ppm, with an average of 207 ppm). In contrast, the late‐formed quartz–molybdenite veins associated with phyllic alteration show the highest concentration of Re (up to 1273 ppm with an average of 395 ppm). Gradual increase in Re content of molybdenites deposited throughout the evolution of the porphyry system is probably related to elevated ƒO2 and acidic conditions of the ore fluids governing the transitional and late stage of mineralization, when compared to the moderately low ƒO2 and basic conditions of the ore fluids precipitating the low‐Re molybdenites associated with potassic alteration. The mixed mantle/crustal source of the ore‐related magma and its fractionated composition in Sar Cheshmeh are consistent with magmatic conditions for the formation of Mo‐rich and Re‐poor PCDs in the world. [ABSTRACT FROM AUTHOR]

Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite imagery was used to identify argillic, phyllic and propylitic alteration zones and mapping geological structural features for porphyry copper exploration in the Kacho-Mesqal zone, Urumieh- Dokhtar Magmatic Arc, Iran. The image processing techniques such as specialised band ratio, Selective Principal Component Analysis (SPCA), and Spectral Angle Mapping (SAM) image processing methods were implemented to the visible and near-infrared and shortwave infrared bands of ASTER. Results indicate that the argillic alteration zone is broadly distributed in the granodiorite intrusion, andesitic rock, tuff breccia and ignimbrite. Phyllic alteration is mainly mapped associated with sandstone and some parts of andesitic lithology. Propylitic alteration zone is identified in andesite, sandstone, shale and marl, dacite to rhyodacite, andesite-basalt, tuff and andesite lava and granodiorite intrusion. The fracture density map shows that the argillic alteration is mostly abundant in the high-density fracture zone, whereas propylitic and phyllic zones are located in moderate to low-density fracture zones. Consequently, high potential zones for copper mineralisation in the study area are identified within the high to moderate fracture density zones associated with argillic and assemblage of argillic, phyllic and propylitic alteration zones in granodiorite and andesite units. [ABSTRACT FROM AUTHOR]

This study illustrates the application of a geometric average integration of aeromagnetic, radiometric and satellite imagery data over a region prone to Cu‐bearing mineralization at Chahargonbad area in Kerman province of Iran. Processing aeromagnetic, radiometric and Advanced Spaceborne Thermal Emission and Reflection Radiometer satellite data can provide exploratory insights about favourable zones in association with porphyry‐type ore occurrences, which can be synthesized through a combination of knowledge‐ and data‐driven approaches as a geometric average and be represented in a mineral prospectivity map. The existence of known deposits in a prospect region can facilitate the investigation of significant exploratory footprints extracted from airborne data by calculating each indicator layer's weight by plotting a prediction–area curve accompanied by a concentration–area fractal curve. Among various indicators, the most important ones are determined based on derived weights from the prediction–area plots to be synthesized in a single Cu favorability map. To fulfil this aim, indicator layers from airborne geophysics (magmatic bodies, magnetic lineaments and potassium radiometry) and remote‐sensing data (alterations such as argillic, phyllic, propylitic and iron oxide along with geological lineaments) were prepared and evaluated using the known porphyry Cu mineralization by the simultaneous plot of the concentration–area fractal model and the prediction–area curve to attain the ore prediction rate and the relevant occupied area of each map for weight assignment of indicators. The geometric average prospectivity model was applied to synthesize the leading indicators, and the result was compared with a multi‐class index overlay map. This study's significance lies in improvement of the performance of the mineral prospectivity/potential mapping after running a geometric average by a higher ore prediction rate of 79%, which has occupied 21% of the area as potential zones for further mining investigations. [ABSTRACT FROM AUTHOR]

An intensive study of the geochemical characteristics (including the volatile elements Cl and S) of apatite associated with porphyry deposits was undertaken to address the debate about the crust- or mantle-derivation of their copper and gold and to better understand the controls on the transport of metals in magmatic fluids in post-subduction settings. New geochemical data on apatite reveal parameters to discriminate mineralized porphyry systems across Iran and western China (Tibet and Yunnan), from coeval barren localities across this post-subduction metallogenic belt. Apatites in fertile porphyries have higher Cl and S concentrations (reflecting water-rich crystallization conditions) than those from coeval barren ones. Our new isotopic data also indicate these volatiles are likely derived from pre-enriched sub-continental lithospheric mantle, metasomatized by previous oceanic subduction. This study demonstrates that refertilization of suprasubduction lithospheric mantle during previous collision events is a prerequisite for forming post-subduction fertile porphyries, providing an evidence-based alternative to current ore-enrichment models. [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]

The Tethyan metallogenic domain (TMD), as one of the three major domains in the world, extends over 10000 km from east to west, and has developed several world-class metallogenic belts, such as the Gangdese porphyry Cu belt, the Sanjiang metallogenic belt, the Iran porphyry Cu belt, the Pakistan porphyry Cu belt, the southeastern European epithermal gold deposit belt, and the Southeast Asian Sn belt. The formation and evolution of the TMD is mainly controlled by the multi-stage subduction of Tethys oceanic slabs, the opening and closing of several small ocean basins, and continent-continent collision. The Tethys oceans include the Proto-Tethys (Cambrian-Silurian), Paleo-Tethys (Carbonaceous-Triassic) and Neo-Tethys (Jurassic to Cretaceous), which in turn are formed by rifting from the Gondwana land at different times in different micro-continents. With a series of geological processes such as oceanic opening and closing, continental collision and post-collisional reworking with intraplate deformation, various types of ore deposits are developed in the TMD, including porphyry deposits, epithermal deposits, VMS deposits, chromite deposits, Sn deposits and orogenic gold deposits. The metallogenic processes of the TMD can be categorized into three stages. (1) Oceanic subduction: With the subduction of the oceanic slab and dehydration of basalt and sediments, the asthenospheric mantle was metasomatized with preliminary enrichment in metals under oxidized condition. (2) Continental subduction: Continental collision induced partial melting of the mantle wedge enriched the metals and water in mafic melts, which ascended from subarc depths to the lower crust, locally to the shallow crust for hydrothermal mineralization. (3) Post-collisional reworking: Partial melting of the mafic intrusives in the lower crust produced felsic melts under oxidized and water-rich conditions, which underwent crystal fractionation and transferred water and metals into hydrothermal fluids for mineralization. The large-scale porphyry mineralization in the TMD mainly occurs in the Miocene, which is an important scientific issue worthy of further study in the future. How is the metal enriched in the processes of gradual maturity of the crust, and how does large-scale mineralization occur in a collisional orogen where there is no subduction and dehydration of oceanic slabs anymore to supply S and Cl? These are still important questions in the study of porphyry mineralization in the Tethyan orogen. The application of hyperspectral and mineralogical studies of alteration assemblages is beneficial for prospecting and exploration in the TMD. [ABSTRACT FROM AUTHOR]

The Bondar Hanza porphyry Cu deposit, hosted by a granitoid stock, is located 120 km south of Kerman city in the elongated NW–SE trending Urumieh‐Dokhtar magmatic arc (UDMA), Iran. The granitoid stock is a multiphase intrusive body, 2 km2 in surface area, which comprises microdiorite–microquartz diorite and granite–granodiorite. Petrological and geochemical analyses show that granitoids are peraluminous, magnesian, calcic to alkali‐calcic, and non‐adakitic intrusions characterized by negative Eu* anomalies. Thermobarometric and oxygen fugacity calculations indicate that magma emplacement occurred at 719–784°C, <100 MPa, and at a log fO2 of NNO +1.6 to +3.2. Sulphur isotopic composition of sulphide minerals (δ34S = 5.0–6.8 ‰) are similar to other porphyry Cu deposits worldwide. Molybdenite separates yield Re–Os ages of 28.22–28.03 Ma, indicating that the Cu mineralization and associated magmatism occurred during the Oligocene. The Bondar Hanza is one of the several granitoids from small porphyry Cu deposits in the UDMA that is related to island arc sub‐productive granitoids. It seems that the largest ore‐hosting porphyry systems within the UDMA are generally restricted to Miocene intrusions with adakitic affinity (e.g., Sarcheshmeh granitoids) and that the temporally discrete non‐adakitic magmatic systems are sub‐productive to barren. These data are interpreted to show that magmatism in the Bondar Hanza region was likely associated with partial melting of juvenile lower crust induced by north‐eastward subduction of the Neo‐Tethys oceanic lithosphere. [ABSTRACT FROM AUTHOR]

In this paper, the main and interaction effects of chemical reagent (collector and frother) dosages on the copper flotation performance using response surface methodology in design expert software were examined and the optimized dosage of reagents were specified. Then, in order to increase copper grade and recovery at industrial rougher flotation cells of the Miduk copper concentrator, Iran, distribution patterns of chemical reagents in suggested optimum conditions were investigated. A central composite design with three levels and five variables was employed to model and optimize the laboratory batch scale flotation process. The effect of dosages of Z11 (0–10 g/t), Flomin C4132 (14–34 g/t), A3477 (5–15 g/t) as collectors, AF65 (5–15 g/t) and MIBC (4–12 g/t) as frothers was studied. Forty-eight batch rougher flotation experiments (pH 11.5) for Miduk porphyry copper ore consisting of 0.9% Cu were conducted at different conditions using a bench scale Denver flotation cell with 3 L capacity. Second order response functions were generated for both the Cu grade and recovery models, as metallurgical indicators. These model equations were optimized using quadratic programming so as to maximize Cu grade and recovery within the experimental range studied. The main effect of all reagents dosages and the interaction of the Z11-Flomin C4132, Z11-A3477, and A3477-MIBC dosages had a significant impact on both recovery and grade. The optimum reagents dosages were found to be 5 g/t Z11, 34 g/t C4132, 5 g/t A3477, 15 g/t AF65, and 8 g/t MIBC. Maximum recovery of 91.4% and grade 8.13 were achieved under optimal conditions. Additionally, verification experiments at optimum conditions proposed by the models were carried out to specify the validity and adequacy of the predicted models. Based on the industrial rougher circuit tests results, distribution patterns of 75%-0%-25% and 50%-25%-25% were selected as the best distributions of collectors and frothers in mentioned conditions, respectively. The copper recovery and grade improved about 2% and 1.8%, respectively, via the use of optimized stage addition of reagents. [ABSTRACT FROM AUTHOR]

The main aim of this study is to investigate the applicability of a Fuzzy Inference System (FIS) approach to produce a copper mineral potential map (MPM) at the Saveh area in the Markazi province of Iran. Seven indicator layers extracted from the geological, geochemical, and geophysical data sets are casted in a geospatial database for data integration. Indicator layers are rock types, alterations, Cu concentration anomaly, main geochemical principal component anomaly, reduced-to-pole magnetic data, electrical chargeability, and electrical resistivity. A fuzzy gamma operator is used at the first phase of exploratory data integration to produce three criterium layers that are geology, geochemistry, and geophysics. Then, at the second phase, the FIS is implemented in three main stages consisting of: 1) fuzzification of input/output data, 2) designing an inference engine, and 3) defuzzification of integrated data. The mineral favourability map is prepared and reclassified into five zones through a multifractal approach at the third phase. In order to evaluate the accuracy of the FIS method, the productivity index of 18 boreholes are utilised to examine the correlation between the mineralised zones and the MPM output. Whereby the synthesised indicator layers demonstrated a Pearson's linear correlation coefficient of 0.44 in recognising copper mineralisation at depth. In addition, the eastern and central portions of the Saveh prospect were proposed as favourable potential zones for further mining operation. [ABSTRACT FROM AUTHOR]

Copper mineralization in Kahang porphyry mining district as a tectonically active region in the center of Iran, at the middle of Urmia–Dokhtar magmatic assemblage (UDMA), has been drastically controlled by structural lineaments. Determination of these footprint features is a good guide to identify the location of ore occurrences. One way to recognize lineaments is to process satellite imagery along with geophysical data. Although the visual extraction of lineaments from such data set is the most common method, automatic methods for detecting lineaments can highly reduce user errors and runtime. The most efficient automated methods in this regard are those that simultaneously take edge detection filters with lineament extraction algorithms into consideration. In this work, the CANNY algorithm was employed as an edge-detector filter at first and later Hough transform was used to extract linear features from satellite imagery and geophysical magnetometry data. The proposed methods were implemented on the high-resolution imagery data collected by QuickBird satellite along with ground-based magnetometry data to extract the shallow and deep-seated lineaments. After investigating and plotting this structural controller in a map, the dominant orientation was in the NE–SW direction perpendicular to the UDMA. Generated lineament density map also indicated that the eastern, southeast, and western portions of the area had high potential for porphyry copper mineralization. [ABSTRACT FROM AUTHOR]

This study uses remote sensing image-processing to enhance recognition of areas with mineral abundance halo, which can be associated with porphyry mineralisation of the Urumieh-Dokhtar Magmatic Belt (UDMB) in western Yazd. Granitoid intrusions of Oligocene-Miocene age in UDMB hosts the most important Porphyry Copper Deposits (PCDs) of Iran such as Darezereshk and Aliabad PCDs. Diagnostic spectral absorption features of six shortwave infrared (SWIR) and three visible and near-infrared (VNIR) bands of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data were applied to determine the alteration minerals and their abundance. In this research reflectance data from various representative alteration types throughout the study area were measured by the FieldSpec-3 spectroradiometer and applied for mapping minerals. Different remote sensing analytical techniques, including the Principal Component Analysis (PCA), band ratio, relative absorption band depth, and MTMF, were applied to enhance mapping the alteration minerals. Field works including rock sampling, petrography and field spectroradiometer followed up the alteration mapping. Field observation implies that, the vein-type mineralisation above the cupola of this porphyry system is preserved in the western part, although it was eroded in the eastern area. Consequently, PCDs potential is expected to be higher in the western area. [ABSTRACT FROM AUTHOR]

The Siah Kamar porphyry Mo deposit is the newly discovered deposit of this type in the Neo Tethys-related Urumieh–Dokhtar magmatic arc, northwest Iran. Mineralization occurs as stock-work quartz–molybdenite and mono-mineralic molybdenite veinlets within the porphyry quartz-monzonite stock and the country rocks, accompanied by locally scattered later-stage and cross-cutting quartz-chalcopyrite-pyrite veinlets in the trachy-andesite and trachy-basalt country rocks. U–Pb zircon geochronology of the porphyry stock yielded Early Oligocene dates of 32.7 ± 0.4 to 30.9 ± 0.4 Ma (at 2σ level). The Th/U ratios of the zircons range between 0.48 and 0.77, and they possess initial εHf(t) values of 3.2 to 12.1, which may suggest a dominant mantle source for the magma. Molybdenite separates yielded rhenium contents between ~10 and 41 ppm (average ~26 ppm, n = 4) and slightly younger Re–Os ages compared to the porphyry stock, ranging from 29.1 ± 0.2 to 28.1 ± 0.2 Ma (at 2σ level). The Siah Kamar porphyry Mo deposit is nearly temporally coeval with the Haft Cheshmeh porphyry Cu deposit and the vein-type Cu–Mo–Au mineralization in the Qarachilar area, corresponding to the second porphyry Cu–Mo mineralization epoch in NW Iran. However, it is younger than the majority of the porphyry Cu deposits in the southern Lesser Caucasus and only shows temporal correlation with the Paragachay and first-stage Kadjaran porphyry Cu deposits. Moreover, it is older than all the porphyry Cu–Mo systems across the central and south-eastern parts of the Urumieh–Dokhtar magmatic arc, except the Bondar Hanza deposit, which is nearly coeval with the Siah Kamar porphyry Mo deposit. All these data reveal an old to young trend along the UDMA and the porphyry Cu belt of Iran, further testifying to the diachronous and later closure of the Neo-Tethyan oceanic basin in central and SE Iran. [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 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]

Abstract This paper presents a novel gradient model for exploration of blind mineralization. The concentration gradient coefficient techniques have been proved to be very well-suited for typical mining geochemistry applications. Gradient concentration corresponds to concentration variations. Large concentration changes due to geochemical data distribution correspond to surfacing anomaly, and less concentration variations are more likely to be related to the deeper geochemical anomalies. The introduced technique is capable to distinguish the difference between the blind mineralization and zone dispersed mineralization, computationally and without exploration drilling. In this research, deep geochemical anomalies are investigated using the gradient concentration values for the porphyry–Cu deposits of the Jebal-Barez region in Iran. Based on the results obtained from the proposed gradient model, values >1.0 in G(Vz) reveal the existence of blind mineralization in the study zone. The findings based on this method suggest that SW of Jebal-Barez is a highly favourable zone for exploration of blind mineralization. The value for G(Vz) in this zone is equal to 5.04. The results obtained in this research were consistent well with the findings of the previous research in the area and the detected Kerver as the main blind mineralization in Jebal-Barez. A local exploration was carried out in this zone in four areas of Kerver using the gradient model. Highlights • New method of concentration gradient has been introduced in geochemical exploration. • This new method solves the defect of zonality method. • The cut off value was presented for detection of BM from ZDM. [ABSTRACT FROM AUTHOR]

Abstract The Sarduiyeh area in the central part of the Kerman Porphyry Copper Belt (KPCB), SE Iran, contains numerous Cu deposits and prospects. This area is bound by E-W trending major faults, which show the northern and southern borders of fault duplex. Minor faults (first, second or third orders) were identified in three trends of NW, N-S and NE. Analysis of the fault kinematics data revealed an extensional fault duplex pattern for this area. In this fault zone, Cu deposits are associated with faults that have a special trend. This proposed kinematic model for evolution of Sarduiyeh extensional fault duplex emphasizes that the main Cu deposits in the Sarduiyeh area are located within the dilatational zones related to NW-SE trending normal faults. In this study, the spatial pattern analysis conducted by Fry, Fractal, Fracture density and buffer zones methods support the conceptual model of district-scale mechanism of structural controls on final emplacement of Cu deposits. This investigation of Sarduiyeh Cu mineralization revealed that the NW-SE trending faults are effective in localization of Cu mineralization in the central part of KPCB. Graphical abstract Image 1 Highlights • This study demonstrated a fault duplex pattern in the central part of Kerman Porphyry Copper belt. • The faults Kinematic analysis indicated an extensional fault duplex pattern for this area. • In this area Cu deposits are visible on special trend that shows a high correlation with minor faults. • According to the extensional fault duplex pattern, Cu deposits in the Sarduiyeh are located within the dilatational zones that developed by NW-SE trending dilational normal faults. • The results of the spatial pattern analysis suggest that the NW-SE trending faults are effective in localizing the emplacement of porphyry copper deposits and those that trend between N090 to N120 is a key to exploration in the central part of KPCB. [ABSTRACT FROM AUTHOR]

Abstract This investigation of leached caps in Meiduk and Parkam porphyry copper deposits (PCD) in Kerman Cenozoic magmatic arc (KCMA) of SW Iran indicated that the fertility of supergene enrichment zones may be inferred from the mineralogical and geochemical characteristics of their associated leached caps. That is, the indigenous mature leached caps characterized by strong leaching of Cu, large ion lithophile elements (LILEs), and high field strength elements (HFSEs), commonly form above intrusions where supergene enrichment is strongly developed. Mineralogically, these leached caps (e.g., SE Meiduk) are characterized by abundant hematite and minor goethite (Hem:Gt ≈ 5.48), whereas immature leached caps (e.g., NW Meiduk and Parkam) are associated with poorly developed supergene enrichment zones characterized by abundant goethite (Hem:Gt ≈ 0.56 for NW Meiduk and 0.38 for Parkam), boxwork textures, secondary copper minerals and remnant pyrite. Calculated rock quality designation (RQD) from drilling cores in Meiduk deposit also revealed the relation between joint density and the extent of supergene enrichment. Moreover, increasing the rare earth elements (REEs) content in the immature and fewer REEs concentration in the mature leached caps also reflects the fertility of supergene enrichment zone in PCDs. Highlights • The fertility of supergene zone is reflected in the mineralogical and geochemical characteristics of their associated leached caps. • Calculated rock quality designation (RQD) revealed the extent of supergene enrichment. • REEs are the best geochemical indicators for supergene enrichment development. [ABSTRACT FROM AUTHOR]

Classification of mineralised zones is an important factor for the analysis of economic deposits. In this paper, the support vector machine (SVM), a supervised learning algorithm, based on subsurface data is proposed for classification of mineralised zones in the Takht-e-Gonbad porphyry Cu-deposit (SE Iran). The effects of the input features are evaluated via calculating the accuracy rates on the SVM performance. Ultimately, the SVM model, is developed based on input features namely lithology, alteration, mineralisation, the level and, radial basis function (RBF) as a kernel function. Moreover, the optimal amount of parameters λ and C, using n-fold cross-validation method, are calculated at level 0.001 and 0.01 respectively. The accuracy of this model is 0.931 for classification of mineralised zones in the Takht-e-Gonbad porphyry deposit. The results of the study confirm the efficiency of SVM method for classification the mineralised zones. [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]

[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]