https://ijp.ui.ac.ir/ Petrological Journal en daily 1 Mon, 22 Jun 2026 00:00:00 +0330 Mon, 22 Jun 2026 00:00:00 +0330 https://ijp.ui.ac.ir/article_30647.html https://ijp.ui.ac.ir/article_30457.html IntroductionThe Kushk Pb–Zn deposit in northeastern Bafq, Central Iran, is associated with Neoproterozoic–Early Cambrian magmatism related to the Proto-Tethyan continental arc system. These magmatic processes, accompanied by crustal extension and interaction between mantle-derived magmas and continental crust, played an important role in regional metallogeny. Therefore, investigating the origin and crystallization conditions of the host dacitic magma is crucial for understanding magma evolution and ore-forming processes in the Bafq district. In this study, whole-rock geochemistry together with zircon morphology and internal textures are used to evaluate the magma source, tectonic setting, and magmatic evolution. Because zircon preserves geochemical and crystallization features under different geological conditions, it is widely applied in petrogenetic studies.Regional GeologyThe Koushk Zn–Pb deposit is situated within the upper part of the Lower Cambrian volcano‑sedimentary sequences, in the central part of the Zarigan–Chahmir Basin (Figure 2). Two major stratigraphic sequences have been recognized in the area (Figure 3): (1) a mineralized sequence comprising the upper interval of the Lower Cambrian volcano‑sedimentary sequences at the base, and (2) an overlying volcano‑sedimentary sequence that includes Lower Paleozoic shales, argillaceous limestone, dolomitic units which host Fe-mineralization, as well as the rhyolitic and tuffaceous rocks (Gibbs, 1976). Rhyolitic and dacitic domes are present in the southeastern part of the deposit, adjacent to the mineralized sequence, as well as to the north and northwest of the deposit.Materials and MethodsIn this study, 65 samples were collected from the dacitic units hosting the Koushk Zn–Pb deposit. Petrographic and mineralogical investigations were carried out on 47 thin sections using an optical microscope at Shahid Beheshti University, Iran. To evaluate whole‑rock geochemistry, 27 samples of the rhyolites and rhyodacites hosting the Koushk Zn–Pb deposit were analyzed by XRF using a Philips PW 2404 instrument at Tarbiat Modares University, and a separate suite of 9 samples was processed for trace elements by ICP‑MS using a Perkin Elmer NexION 300 instrument at Zarazma Company Laboratory. Zircons were separated using a Wilfley shaking table, a Frantz magnetic separator, and heavy liquids, followed by handpicking under a binocular microscope at the Geological Survey of Iran. Zircon grains selected for CL and BSE‑SEM were mounted in epoxy resin and polished to expose their internal structures. CL images were obtained using a JEOL JXA 8900RL electron microprobe, and BSE‑SEM images were acquired using a Hitachi S3400N scanning electron microscope at Nagoya University, Japan, and Aria Electron Optics Co., Ltd.DiscussionExamination of the external and internal morphology of zircon can aid in identifying the origin of magmatic rocks, the degree of aluminum and alkali saturation (Pupin, 1980), and the temperature of the melt (Pupin and Turco, 1972). Temperature and Zr saturation are the main factors governing the relative growth of different prismatic zircon morphologies. Zircons crystallizing from alkali, water-poor, and tholeiitic melts fall within the (101) and (100) fields; those derived from peraluminous melts plot within the (101) field; and in the presence of high-water content in the melt, they occur within the (101) and (110) domains. Based on the above considerations, the examination of zircon crystals associated with the Koushk dacites indicates that they predominantly display prismatic faces (110) and (110) >> (100), along with pyramidal faces (101) and (211) >> (101). The development of prismatic forms (110) and (100) reflects a high-temperature crystallization index, whereas the dominance of the (101) pyramids suggests a high alkalinity index an interpretation that is further supported by the geochemical characteristics of the samples. Moreover, the morphological analysis reveals that some zircon crystals exhibit noticeable variations in their length-to-width ratios, indicating differences in growth dynamics during crystallization. This may be attributed to crystallization rate (Bussy and Cadoppi, 1996) or the possible presence of two zircon generations in these samples. However, based on the detrital zircon dating from the Koushk area, (Mahmoudi, 2022; Vickers-Rich et al., 2017), the presence of a single zircon generation in these samples is confirmed. Therefore, crystallization rate is likely the main factor responsible for the increased length-to-width ratio observed in these zircons.ConclusionThese crystals predominantly fall within the P2, P5, S5, and S25 fields, with fewer crystals plotting in the AB5, D, L5, P3, P4, R3, S10 and S20 domains. The minimum zircon crystallization temperatures in the studied dacites, based on zircon morphology and the temperature (I.T) and alkalinity (I.A) indices, are 740°C and 706.6°C, respectively. The temperature of the rhyolitic melt, based on zircon saturation thermometry, ranges from 703.49 to 830.74 °C (Watson and Harrison, 1983) and from 702.94 to 877.49 °C (Boehnke et al., 2013). Whole‑rock geochemical data yield a temperature range of 700 to 780 °C.The data show that rhyolitic magma was supersaturated with respect to Zr from the earliest stages of crystallization making zircon one of the first minerals to form-a temperature interval of 700 to 780 °C is inferred for zircon crystallization in the rhyolitic magma. The presence of zoning within zircon crystals likely reflects a decrease in HREE and an enrichment in LREE, U, Th, and Y in these zones. The presence of narrow and closely spaced zoning in both elongated needle‑like zircons and shorter crystals indicates that the magma remained supersaturated with respect to zircon from the earliest to the latest stages of crystallization. Internal structures of some zircon crystals reveal rounded cores with zoning patterns distinct from their rims, suggesting that these cores acted as non‑reactive mineral relics during partial melting. The zircons within the dacites also exhibit evidence of partial resorption, implying episodic intervals of zircon undersaturation in the melt. Structural and compositional characteristics, crystal growth conditions, zircon age and provenance and metamictization processes, can all contribute to reduced lattice order and, consequently, diminished or absent cathodoluminescence (CL) in zircon crystals. Based on geochemical studies, these rocks originate from crust‑derived melts, and their magmas correspond to A‑type granites, specifically the A2 subtype within the calc‑alkaline series. According to tectonic discrimination diagrams, the dacites are derived from volcanic arc granites.AcknowledgementsThe authors appreciate Shahid Beheshti University Research Council that supported this work. https://ijp.ui.ac.ir/article_30407.html IntroductionThe Hendou-Abad Cu(-Ag) deposit is located in the central part of the Urumieh-Dokhtar magmatic arc, approximately 110 km northeast of Isfahan, Iran. The deposit is hosted by upper Eocene volcanic rocks composed mainly of andesitic basalt, andesite, and subordinate trachyandesite and trachybasalt. Although copper mineralization in the area had previously been recognized, its geological controls, fluid evolution, and genetic characteristics had not been comprehensively investigated. This study integrates geological, mineralogical, geochemical, and fluid inclusion data to characterize the ore-forming processes and evaluate the relationship between the deposit and manto‑type copper systems.MethodologyField investigations, sampling, petrographic studies, XRD analyses, whole‑rock geochemistry, electron probe microanalysis (EPMA), and fluid inclusion microthermometry were conducted. Fifty‑seven representative samples were collected from mineralized and altered zones. Petrographic observations were used to determine mineral assemblages and paragenetic relationships, whereas XRD analyses identified alteration minerals. Whole‑rock geochemistry and EPMA were employed to investigate elemental distributions and ore mineral chemistry. Fluid inclusion studies on quartz, epidote, and calcite veins provided information on the evolution of temperature and salinity of the ore‑forming fluids.Geology and MineralizationThe oldest exposed rocks in the area are upper Eocene volcanic units consisting predominantly of andesitic basalt and andesite, with minor trachyandesite and trachybasalt. These rocks host the Cu(-Ag) mineralization and are intruded by mafic to intermediate dikes. Regional strike-slip fault systems, particularly the Kachomesqal and Zafarghand fault zones, acted as the principal pathways for hydrothermal fluid circulation.Mineralization occurs as veins, veinlets, stockworks, disseminations, cavity fillings, and replacement bodies. Three distinct breccia types are recognized: red, green, and white breccias. The red breccia contains rounded volcanic fragments cemented by a quartz‑calcite‑iron oxide matrix, whereas the white breccia consists of volcanic and red breccia fragments enclosed within a siliceous matrix. The green breccia is characterized by angular to sub-rounded fragments within an epidote-calcite-quartz matrix.Primary ore minerals include chalcocite, chalcopyrite, bornite, pyrite, and minor galena. Electron microprobe analyses also identified tetrahedrite, electrum, native gold, digenite, and accessory Ag‑bearing phases. Chalcocite, chalcopyrite, and bornite constitute the dominant copper sulfides. The average grades of copper and silver in mineralized samples are approximately 2.7 wt.% Cu and 62 ppm Ag, respectively.Hydrothermal alteration is closely associated with mineralization. A pervasive propylitic assemblage consisting of epidote, chlorite, calcite, tremolite-actinolite, and prehnite is particularly developed within the red breccias. In contrast, epidote-chlorite alteration is spatially associated with copper-bearing veins in the green and white breccias. Away from the mineralized zones, this alteration gradually changes into zeolite-bearing assemblages.DiscussionPetrographic observations, mineral chemistry, and fluid inclusion data indicate that mineralization developed through three successive stages. The first stage is represented by disseminated pyrite and minor chalcopyrite associated with pervasive propylitic alteration and Type I quartz within the red breccias. Fluid inclusions hosted by Type I quartz exhibit homogenization temperatures of 218–275°C and salinities ranging from 12.5 to 16.8 wt.% NaCl equivalent, indicating formation from relatively hot and moderately saline hydrothermal fluids.The second stage represents the principal Cu-Ag mineralization event and is responsible for most of the economic metal accumulation. Mineralization occurs as veins, veinlets, stockworks, and replacement bodies controlled primarily by E–W-trending structures. Ore minerals include chalcocite, bornite, chalcopyrite, tetrahedrite, electrum, native gold, and galena. This stage is associated with Type II epidote, Type II quartz, and Type II calcite. Fluid inclusion studies indicate homogenization temperatures between 95 and 237°C and salinities ranging from 2.90 to 12.96 wt.% NaCl equivalent. These lower temperatures and salinities indicate progressive cooling and dilution of hydrothermal fluids by meteoric water. Most copper and silver precipitation occurred during this stage.The third mineralization stage is characterized by low-temperature hydrothermal activity and chalcedonic quartz-calcite veinlets. This stage contributed little to the overall metal budget and is therefore economically insignificant.Whole-rock geochemical analyses reveal enrichment of Cu, Ag, Pb, Sr, and sulfur and depletion of Ba and Zn relative to host rocks. Strong positive correlations between Cu and Ag indicate a close genetic relationship between silver and copper sulfides. EPMA data show that silver is present in most copper sulfides but is preferentially concentrated in secondary sulfides. The highest silver concentrations were recorded in covellite, reaching approximately 0.7–1.08 wt.%.Supergene weathering subsequently modified the deposit and produced an enriched Cu-Ag zone. Oxidation and leaching of primary sulfides generated secondary chalcocite, covellite, Ag-bearing digenite, native copper, cuprite, tenorite, malachite, and azurite, significantly enhancing copper and silver grades.ConclusionsThe Hendou-Abad Cu(-Ag) deposit formed within upper Eocene volcanic rocks under strong structural control exerted by regional fault systems. Three successive mineralization stages are recognized, with the second stage representing the principal Cu-Ag event. Hydrothermal alteration evolved from widespread propylitic assemblages in the red breccias to epidote-chlorite alteration in the green and white breccias, grading outward into zeolite alteration. Fluid inclusion data demonstrate a progressive decrease in temperature and salinity from the first to the third stage, indicating increasing dilution by meteoric water. Chalcocite, chalcopyrite, and bornite constitute the primary copper ore minerals, whereas supergene processes generated secondary sulfides enriched in silver, particularly covellite. The geological setting, alteration characteristics, ore mineralogy, geochemical signatures, structural controls, and microthermometric data collectively indicate that the Hendou-Abad deposit shares strong similarities with manto-type copper deposits and represents an important example of volcanic-hosted Cu(-Ag) mineralization in the Urumieh-Dokhtar magmatic arc. https://ijp.ui.ac.ir/article_30326.html IntroductionUrumieh–Dokhtar Magmatic Arc (UDMA) as a part of Zagros orogeny is the most important Cenozoic magmatic belt in Iran (Alavi, 1994; Babazadeh et al., 2024). Lithostratigraphic and age dating evidence indicates that magmatic activity in this belt initiated during Late Cretaceous-Paleocene and continued to Pliocene-Quaternary, with the peak of the magmatism in the Middle-Late Eocene. This was followed by extensive Oligocene-Miocene intrusive magmatism and subsequently renewed during Pliocene–Quaternary by scattered volcanism (Moghadam et al., 2022a, b; Babazadeh et al., 2024). In the southeastern segment of the UDMA, particularly along the Jebal-e-Barez mountains, regional geology and zircon U–Pb geochronology record multiphase, extensive arc related magmaism from the Eocene to the Oligocene-Miocene, locally extending to the Pliocene–Quaternary (Nazarinia et al., 2020; Atapour and Aftabi, 2021; Moghadam et al., 2022a, b; Babazadeh et al., 2024). Peak of the magma emplacement occurred during the Oligocene–Miocene, characterized by intermediate to felsic plutons of the Jebal-e-Barez mountains (Chiu et al., 2013; Babazadeh et al., 2024). Biotite, a major Fe–Mg-bearing constituent of the Jebal-e-Barez intrusive complex, has a substantial capacity for incorporating Ti and Al, making it an effective monitor of crystallization conditions (temperature, pressure, oxygen fugacity), as well as for classification and discrimination of granite tectonic settings and their mineralization potential (Wones and Eugster, 1965; Wones, 1989; Abdel-Rahman, 1994; Henry et al., 2005; Nachit et al., 2005; Jiang et al., 2002; Uchida et al., 2007; Anderson et al., 2008; Villaseca et al., 2017). Most previous studies on the Jebal-e-Barez intrusive complex have relied on whole-rock geochemistry for petrological purposes and economic fertility assessments, whereas mineral chemistry approaches such as biotite chemistry remain sparse.GeologyThe Sarbijan–Dalfard district, located northwest of Jiroft within the Jebal‑e‑Barez mountain range, represents the southern part of the UDMA. This major volcano‑plutonic complex developed in response to prolonged subduction of the Neotethys oceanic lithosphere beneath the Central Iran block, with magmatic activity persisting from the Late Cretaceous to the Neogene. In the southeastern segment of the UDMA, a compositionally diverse suite of intermediate‑felsic plutonic rocks—including diorite, monzodiorite, quartz diorite, granodiorite, and granite—intrudes the Eocene volcanic and volcano‑sedimentary rocks (Moghadam et al., 2022a, b; Babazadeh et al., 2024). The Jebal‑e‑Barez granitoids exhibit calc‑alkaline to high‑K calc‑alkaline affinities, consistent with an active continental arc setting. Moreover, the Oligocene–Miocene magmatism has been attributed to incipient collisional processes, crustal thickening, and partial melting of the oceanic slab and metasomatized mantle wedge, with variable crustal contamination (Moghadam et al., 2022a, b; Babazadeh et al., 2024).Research MethodsRepresentative specimens from the main lithological units (monzodiorites and granodiorites) were selected for mineral chemical analyses using a JEOL 8200 electron microprobe at the Microprobe Laboratory, University of Milan, Italy. Analyses were conducted at an accelerating voltage of 30 kV, beam currents ranging from 10⁻¹² to 10⁻⁵ A, and a counting time of 80 seconds. Biotite composition was normalized to 22 oxygens, and the Fe³⁺ content was calculated following Droop (1987) assuming charge balance within the biotite structure.PetrographyThe granitoid bodies of the Sarbijan–Dalfard district show a progressive fractionated series from diorite to granite. The diorites and monzodiorites exhibit coarse‑ to medium‑grained hypidiomorphic textures, characterized by plagioclase as the dominant mineral, alongside biotite and amphibole as the primary mafic phases. Granodiorites predominantly display anhedral granular textures, where plagioclase often shows polysynthetic twinning and evidence of secondary alteration. Granites are typically coarse‑grained and anhedral granular, and show granophyric and myrmekitic textures in alkali‑feldspar‑rich varieties, representing the late‑stage simultaneous crystallization of quartz and feldspar.DiscussionBiotite geochemistry in the Sarbijan–Dalfard granitoids provides key constraints on the physicochemical conditions (P, T, fO₂) of magma generation, crystallization, and emplacement, as well as classification (I, S, A), tectonic setting , and mineralization potential. Microprobe analyses of biotites in the Sarbijan–Dalfard granitoids indicate their Mg‑rich magmatic nature, crystallized under relatively high H₂O pressure and oxidizing conditions, reflecting a calc‑alkaline (I‑type) orogenic magma within a subduction‑related continental margin environment. Fe/(Fe+Mg) ratios and Al content indicate limited crustal contribution, while Ti concentrations suggest closure temperatures of 638 to 724°C, close to the crystallization conditions of granodiorite‑granite suites (Luhr et al., 1984; Henry et al., 2005). Total Al content in biotite implies emplacement pressures of 0.98–2.56 kbar, corresponding to depths of 3‑7 km in the upper crust (Uchida et al., 2007). High Mg# contents of biotites and their coexistence with Fe‑Ti oxides further support high fO₂ conditions, consistent with subduction‑related arc magmatism and minimal post‑emplacement re‑equilibration.ConclusionBiotites of the Sarbijan–Dalfard granitoids are Mg‑rich, magmatic, and largely unaltered, recording relatively oxidizing conditions during crystallization, consistent with Fe‑Ti oxide‑bearing calc‑alkaline I‑type magmas of a subduction‑related arc setting. Thermo‑barometry estimates based on Ti and Al‑in‑biotite suggest closure temperature ranges of 630‑725 °C and pressure ranges of 1‑2.5 kbar, indicating emplacement at shallow upper crustal depths. Integration of petrography, biotite chemistry, and thermo‑barometry calculations confirms that these granitoids were generated in an oxidizing, subduction‑related environment, with significant potential for Cu mineralization.AcknowledgmentsThis study forms part of the first author’s PhD dissertation, which was financially supported by the Research Vice‑Presidency of Shahrood University of Technology (SUT). The authors gratefully acknowledge SUT, the staff of the Microprobe Laboratories at the University of Milan, and the esteemed reviewers of the Petrological Journal for their valuable guidance and constructive comments. https://ijp.ui.ac.ir/article_30439.html Introduction Ophiolitic complexes—fragments of oceanic lithosphere tectonically emplaced onto continental margins—serve as crucial archives for reconstructing the formation and evolution of ancient ocean basins. The Sabzevar ophiolite in northeastern Iran represents one of the most significant remnants of Mesozoic Neotethyan oceanic lithosphere and provides a key window into the tectonic development of the northern Neotethys branch. Previous studies have assigned this ophiolite to diverse tectonic settings, including mid‑ocean ridge, supra‑subduction zone, and back‑arc environments (Khalatbari Jafari et al., 2013a, b; Rezaei et al., 2018; Jafari and Ghasemi, 2023). Nevertheless, the co‑occurrence of contrasting magmatic signatures within its volcanic sequences points to a polyphase magmatic history in a complex geodynamic framework (Omrani et al., 2018; Moghadam et al., 2025). This study investigates the pillow lavas and sheeted dikes exposed in the Sultanabad area, in the eastern sector of the Sabzevar ophiolite. Its primary aims are to characterize the geochemistry, constrain the crystallization ages of the volcanic units via zircon U–Pb geochronology, and assess their tectonomagmatic significance for the evolution of the Sabzevar oceanic basin. Geological Setting The Sabzevar ophiolite, situated in northeastern Iran, constitutes an integral component of the tectonic structure of the Central Iranian microcontinent (Alavi, 1994). It is widely interpreted as a relict of the northern Neotethyan oceanic realm, which formed within the Central Iranian terrane between Central Iran and the Alborz belt during the Mesozoic (Agard et al., 2005). The ophiolitic succession comprises ultramafic mantle rocks, layered ultramafic–mafic cumulates, sheeted dike complexes, pillow basalts, and pelagic sedimentary cover (e.g., Shojaat et al., 2003; Khalatbari Jafari et al., 2013a, b; Moghadam et al., 2025). The Sultanabad area hosts well‑preserved volcanic units, dominated by pillow basalts intercalated with sheeted dikes and minor massive lava flows. These rocks represent the uppermost levels of the oceanic crust. Field relations indicate that the pillow lavas erupted in a submarine setting and were subsequently affected by tectonic deformation during the Neotethyan closure and obduction of the ophiolitic complex onto the continental margin. Materials and Methods Representative samples of pillow basalts and sheeted dikes were collected from the Sultanabad area. Petrographic examination was performed using optical microscopy to characterize mineral assemblages and textural features. Whole‑rock major and trace element concentrations were determined via X‑ray fluorescence (XRF) and inductively coupled plasma mass spectrometry (ICP‑MS). Zircon grains were extracted from selected samples and subjected to U–Pb isotopic dating and trace element analysis using laser ablation‑inductively coupled plasma mass spectrometry (LA‑ICP‑MS). The geochemical data served to classify magma types, constrain magma sources, and discern tectonic affinities. Zircon trace element compositions were additionally examined to offer complementary constraints on magmatic processes and crystallization conditions. Results Petrographic observations reveal that the studied volcanic rocks consist predominantly of plagioclase, clinopyroxene, and secondary alteration minerals. The pillow lavas typically exhibit porphyritic to intersertal textures, whereas the sheeted dikes show fine‑grained to subophitic textures. Whole‑rock geochemical data indicate that the studied samples fall into three main magmatic series: alkaline, calc‑alkaline, and tholeiitic varieties. The alkaline basalts are enriched in incompatible elements and display pronounced LREE enrichment relative to HREE. Their trace element patterns are akin to those of ocean island basalts (OIB). The tholeiitic basalts and sheeted dikes exhibit relatively flat REE patterns and are marked by negative Nb and Ta anomalies, characteristic of magmas generated in supra‑subduction zone settings. Calc‑alkaline basalts show intermediate geochemical signatures between these two groups. Zircon U–Pb geochronology reveals that magmatic activity in the study area took place during the Cretaceous, yielding ages between ~113 and 90 Ma. The alkaline basalts record the oldest ages (~112–110 Ma), while the tholeiitic and calc‑alkaline rocks give slightly younger but overlapping ages of ~113–91 Ma. Trace element compositions of zircon grains show HREE enrichment and LREE depletion, consistent with a magmatic origin. Variations in elemental ratios such as Th/U and Eu/Eu* point to differences in magma composition and crystallization conditions across the studied rock types. Discussion The geochemical signatures of the studied rocks point to the involvement of multiple magma sources in generating the Sultanabad volcanic sequence. The alkaline basalts most likely originated from low‑degree partial melting of a garnet‑bearing enriched mantle source, consistent with an intraplate or seamount‑related affinity. By contrast, the tholeiitic basalts and sheeted dikes appear to have been derived from higher‑degree partial melting of a depleted mantle source metasomatized by slab‑derived fluids. The calc‑alkaline basalts exhibit geochemical features characteristic of subduction‑related magmatism and probably represent melts generated in a mantle wedge modified by slab‑derived fluids. The co‑occurrence of alkaline and supra‑subduction zone magmas within the same volcanic sequence implies that the Sabzevar oceanic basin underwent a complex tectonomagmatic history, encompassing both intraplate and subduction‑related processes. The zircon U–Pb ages obtained in this study show that magmatic activity persisted over a protracted interval during the Middle to Late Cretaceous. This prolonged magmatism likely reflects the progressive evolution of a supra‑subduction zone system linked to the initiation and advancement of subduction within the northern Neotethys. Conclusions Combined whole‑rock geochemistry and zircon U–Pb geochronology provide new constraints on the petrogenesis and tectonic evolution of the volcanic units in the eastern Sabzevar ophiolite. The investigated rocks fall into alkaline, calc‑alkaline, and tholeiitic suites, reflecting the contribution of multiple mantle sources and magmatic pathways. Zircon U–Pb dating restricts magmatism to ca. 113–90 Ma, i.e., the Middle–Late Cretaceous. Geochemical fingerprints suggest that the tholeiitic basalts and sheeted dikes formed in a supra‑subduction zone setting, whereas the alkaline basalts represent within‑plate‑related magmatism subsequently incorporated into the ophiolitic succession. Collectively, the results favor a model whereby the Sabzevar ophiolite developed within a complex supra‑subduction zone system during the evolution and final closure of the northern Neotethys Ocean. https://ijp.ui.ac.ir/article_30493.html The Gishoun Pb-Zn deposit is located in the northwest of Bam, on the southwestern margin of the Lut Block, within the Cenozoic tectono-magmatic zone of Central Iran. It is associated with the Urumieh-Dokhtar magmatic arc. The Eocene volcanic rocks in the area comprise basalt, andesite, dacite, rhyolite, and pyroclastic tuffs, and are mineralogically composed mainly of plagioclase, quartz, K-feldspar, biotite, clinopyroxene, and olivine. Subvolcanic dikes of both doleritic and granitic compositions are also observed in the region. These rocks belong to the medium- to high-K calc-alkaline to shoshonitic magmatic series. The systematic decrease in CaO, MgO, FeOt, TiO₂, and P₂O₅ with increasing SiO₂ reflects the role of fractional crystallization in their magmatic evolution. Enrichment in LILE and LREE, along with negative anomalies of Nb, Ta, and Ti, are diagnostic features of these rocks. Doleritic dikes, characterized by higher Sr and Ni contents and a weaker negative Eu anomaly, served as the primary heat source and played a decisive role in the development of the Gishoun epithermal deposit, but they are not hosts to mineralization. In contrast, granitic dikes, enriched in Rb, Th, and K₂O with a more pronounced negative Eu anomaly, show no association with alteration or mineralization. The integrated petrographic and geochemical data indicate that all rock units of the Gishoun deposit formed in a continental magmatic arc setting related to the subduction of the Neotethyan oceanic slab. https://ijp.ui.ac.ir/article_30504.html The Kuh Kaput porphyry copper deposit, located north of Bam in the southern Kerman Magmatic Copper Belt, is associated with microquartz diorite intrusions emplaced within Eocene volcanic rocks. To investigate magmatic evolution and its relation to mineralization, trace and rare earth element compositions of zircon from two microquartz diorite bodies (HBQD and DPQD) and one microgranodiorite body (GD03) were analyzed using LA ICP MS. Zircon geochemical patterns, including HREE enrichment relative to LREE, positive Ce anomalies, and negative Eu anomalies, confirm their magmatic origin. Estimated zircon crystallization temperatures range from 659 to 780 °C, while ΔFMQ values indicate oxidizing magma conditions. Zircons from the microquartz diorite bodies exhibit relatively high Eu/Eu* values (>0.4), suggesting oxidized and water rich magmas and indicating fertile intrusions. Trends of constant Eu/Eu* versus Hf and increasing (Yb/Gd)ₙ versus Hf imply magma evolution dominated by amphibole and apatite fractionation. In contrast, the microgranodiorite intrusion shows lower Eu/Eu* values (<0.4), indicating a less hydrous and infertile magma, with evolution largely controlled by plagioclase fractionation. Drill core observations and lithological logging indicate that the microgranodiorite represents an earlier magmatic phase, whereas the microquartz diorite intrusions correspond to later magmatic stages. The progressive increase in zircon Eu/Eu* ratios from older to younger intrusions suggests magmatic evolution toward more hydrous conditions, which significantly enhanced the mineralization potential in northern Bam. Evidence of hydrothermal fluid exsolution from the oxidized and water rich HBQD magma indicates that this intrusion represents the principal mineralization related phase. https://ijp.ui.ac.ir/article_30515.html نتایج آنالیز شیمی کانی‌ها (EPMA) بیانگر ترکیب تورمالین‌های شورل غالب، گارنت‌های غنی از آلماندین–اسپسارتین و بیوتیت‌های سازگار با مذاب‌های حاصل از ذوب متاپلیت‌ها است. ترکیب پلاژیوکلازها در محدوده الیگوکلاز تا آندزین و زونینگ شیمیایی آن‌ها، همراه با شواهد بافتی، شرایط ناپایدار و تحول تدریجی ماگما را نشان می‌دهد. این ویژگی‌ها در مجموع بر منشأ ذوب رسوبات پلیتی و متاپسامیتی در یک محیط غنی از آلومینیوم دلالت دارد و گرانیت‌های مورد مطالعه را در زمره گرانیت‌های نوع S قرار می‌دهد. داده‌های سن‌سنجی U–Pb بیانگر جایگزینی بخش مهمی از توده‌های گرانیتی در بازه زمانی حدود ۱۶۳ تا ۱۷۳ میلیون سال پیش (ژوراسیک میانی تا پسین) همزمان با فاز اصلی دگرگونی ناحیه‌ای کمپلکس ده‌سلم است. با این حال، حضور زیرکن‌های موروثی با سن‌های قدیمی‌تر نشان‌دهنده مشارکت پی‌سنگ پرکامبرین و ثبت رویدادهای کهن‌تر پوسته‌ای در شرق ایران است. بر این اساس، گرانیت‌های شرق ده‌سلم حاصل ذوب‌بخشی پوسته‌ای در یک پهنه برخوردی فعال بوده و نقش مهمی در بازسازی و تکامل پوسته قاره‌ای حاشیه شرقی ایران ایفا کرده‌اند. https://ijp.ui.ac.ir/article_30568.html The Bajkan-Durkan complex is located in southeastern Iran, within the Makran accretionary wedge. Despite different interpretations, the origin and tectonic setting of the intrusive rocks of this complex remain unclear and controversial. The Bajakan-Dorkan complex is composed of metamorphic-sedimentary basement rocks overlain by intermediate- to acidic-intrusive rocks and carbonate deposits. Based on petrological studies, intrusive rocks have been classified into three groups: granite, diorite,, and plagiogranite. Potassium feldspar (3 mm), plagioclase (< 0.1 mm), and quartz, associated with amphibole, biotite, zircon, ilmenite, and hematite, are the main rock-forming minerals. Granular and semi-granular, micrographic and granophyric textures resulting from intergrowth of quartz and feldspar, along with traces and evidence of pertitization and replacement of biotite by chlorite, have been in most samples. The Bajkan-Durkan granitoids exhibit geochemical characteristics of A-type metaluminous granites and are of high-potassium calc-alkaline magmatic nature. The enrichment in LREE and LILE associated with Nb, P, Ba, and Ti negative anomalies in these rocks indicates a melt segregated from crustal origin. Based on discriminant tectonic diagrams, the studied granites are located in the range of volcanic arc granites (VAG) and intraplate granites (WPG). Based on geographical location and petrological and geochemical characteristics, the Bajakan-Dorkan complex is the southeastern continuation of the Sanandaj-Sirjan zone, and the granites of this complex were formed in a subduction tectonic setting with local pull-apart tensions. https://ijp.ui.ac.ir/article_30581.html The Arghash region, situated in the southern sector of the Sabzevar ophiolitic belt, represents a key area for investigating tectonomagmatic evolution and mineralization potential within paleo-oceanic settings. This study examines the geochemical characteristics, petrogenesis, and alteration signatures of the volcanic and plutonic rocks in the region, with the aim of constraining their tectonic environment of formation and assessing their relationship to submarine hydrothermal systems. The findings indicate that the pillow lavas exhibit geochemical affinities akin to E-MORB (enriched mid-ocean ridge basalt), and were derived from an enriched mantle source within an extensional regime associated with oceanic crustal spreading. In contrast, the mafic intrusive bodies and dykes display IAT (island-arc tholeiite) characteristics, implying the influence of subduction-related components during the basin’s evolutionary history. Evidence of spilitic alteration, extensive pyritization, malachite impregnation, and fossilized chimney-like structures points to the activity of a submarine hydrothermal system and the circulation of hydrothermal fluids within the basaltic crust. Despite these indicators, the absence of massive sulfide mineralization suggests that the Arghash hydrothermal system likely did not attain the stage of economic sulfide concentration. This may be attributed to incomplete system evolution, insufficient concentration of metal-bearing hydrothermal fluids, or the lack of preservation of the ore-bearing portion of the system. The results of this study demonstrate that E-MORB basalts can be associated with VMS (volcanogenic massive sulfide) systems in suitable settings; however, the formation of an economic deposit requires complete system evolution and effective focusing of ore-forming fluids. https://ijp.ui.ac.ir/article_30621.html In the southernmost part of the Sanandaj–Sirjan Zone, Mesozoic volcanic rocks crop out in the Baghat (north of Hajjiabad) and Dehsard (south of Kerman) areas. These rocks are mainly composed of basalt, andesite, and basaltic andesite, exhibiting porphyritic, trachytic microlitic, and microlitic–glassy textures. The main rock-forming minerals include plagioclase and pyroxene, with hornblende, olivine, and opaque minerals as accessory phases. The basaltic and andesitic rocks of the Baghat and Dehsard areas exhibit a tholeiitic to calc-alkaline affinity. On primitive mantle-normalized trace element diagrams, the rocks show enrichment in Cs, Ba, Pb, Th, K, and U, coupled with pronounced depletion in high field strength elements (HFSEs) such as Nb, Ti, and Zr, which are characteristic features of subduction-related magmas. Furthermore, chondrite-normalized rare earth element (REE) patterns for the Dehsard basalts and andesites display fractionated patterns with LREE enrichment relative to HREE, whereas the Baghat andesites and basalts exhibit relatively flat REE patterns. Petrogenetic modeling indicates that the majority of the andesitic and basaltic rocks from Dehsard were generated by 15–20% partial melting of an enriched mantle source with spinel–garnet lherzolite composition, whereas the Baghat rocks were derived from 15–30% partial melting of a relatively less enriched mantle source with a transitional composition from spinel lherzolite to spinel–garnet lherzolite. The formation of these rocks took place in an active continental margin volcanic arc setting, in association with the subduction of the Neotethyan slab. The extensional regime governing this magmatism is attributed to slab rollback