Palaeogene syn-collisional basins of the Sava Suture Zone (SSZ) record the sedimentary response to the continental collision between the Adria plate and the Tisza Mega-Unit. This study presents a preliminary investigation of polymict conglomerates from selected localities from Zrinska Gora and Požeška Gora mountains, combining petrography, whole-rock geochemistry and zircon geochronology to constrain sediment provenance and basin evolution.Petrographic analyses reveal a diverse assemblage of pebble lithotypes, including granitoid, volcanic, and metamorphic clasts, reflecting multiple source rocks. Petrographic characteristics provide initial indications that certain pebble lithologies may correlate with nearby inselberg sources, but these interpretations remain tentative and must be further evaluated through whole-rock geochemistry and constrained by zircon U–Pb geochronology. The presence of granitoids and volcanics indicates a significant contribution from magmatic units of the SSZ, while metamorphic pebbles suggest additional input from the pre-Eocene metamorphic basement.Preliminary whole-rock geochemical data from selected pebbles indicate A-type granite affinities and alkaline magmatic signatures, consistent with previously documented SSZ magmatism. Ongoing geochronological analyses of zircons separated from representative pebbles aim to provide more robust age constraints on source lithologies. These data will enable direct correlation between sedimentary components and their parental magmatic and metamorphic units, offering critical temporal constraints on sediment supply and tectono-magmatic evolution.The integration of petrographic, geochemical, and geochronological datasets provides new insights into sediment routing systems and provenance evolution in Palaeogene syn-collisional settings of the western branch of the SSZ. This work contributes to a broader understanding of the interplay between subduction, collision, and basin development within the Alpine-Mediterranean orogenic system. The presented work is supported by the Croatian Science Foundation Project SECret (HRZZ IPS-2023-02-2683).

We have investigated the major- and trace-element composition of hydrothermal pyrite, magnetite, and Ti-magnetite, and of the principal Cu-minerals chalcopyrite and chalcocite, to constrain ore-forming processes in the northeastern Saveh district (central Urumieh-Dokhtar magmatic arc, Iran). Our data provide new constraints on the magmatic-hydrothermal evolution and subsequent hydrothermal-supergene modification of the ore system. Ti-magnetites hosted in monzodioritic intrusions are enriched in Ti-V-Al, plot below the magnetite-ulvospinel join and record high crystallization temperatures (<500 degrees C) under relatively low oxygen fugacity. By contrast, magnetite from silica-rich hydrothermal veins is Fe-rich with very low TiO2; it formed at intermediate temperatures (similar to 200-300 degrees C) under higher fO(2) and is markedly depleted in Ti and V compared with the intrusive oxides. Textures and oxide systematics (Al + Mn vs. Ti + V; V/Ti-Fe) document repeated hydrothermal pulses, Fe2+ leaching and element redistribution during cooling and fluid-rock interaction. Geochemical trends indicate progressive evolution from a magmatic fluid to later meteoric water overprint, with increasing As contents reflecting cooling and mixing with meteoric waters. Vertical elemental zoning suggests that most samples represent mid- to deep-level sections of the epithermal system. Elevated Cu contents (up to 0.95 wt.%) highlight pyrite as a significant Cu host. Co/Ni ratios between 1 and 10 further corroborate a magmatic-hydrothermal origin. Chalcopyrite is the principal economic Cu carrier at Northeast Saveh. Replacement follows a temperature- and fluid-controlled pathway (chalcopyrite -> covellite -> chalcocite). At lower temperatures (

Abstract We investigate the relationships between monazite Th-U-Pb ages, chemical domains, and monazite-xenotime immiscibility gap thermometry from two Indosinian orthogneisses from the Khanom Core Complex (Southern Thailand), with the aim of better understanding the relationships of these systems and their possible implications for petrochronology. Our data reveal that direct dating of chemical domains in monazite and temperature estimates can be ambiguous. On one side, U, Si, and Ca contents do not influence the Th-U-Pb ages or monazite-xenotime immiscibility gap temperatures, reinforcing the geological reliability of these age and thermometric data. However, the variability in REE enrichment and depletion and the underlying mechanisms remain poorly understood, with post-magmatic processes likely playing a major role in these geochemical modifications. Principal component analysis shows that monazite chemistry is the primary driver of data variation, with age and temperature estimates largely decoupled from chemical signatures, further underscoring the complexity of monazite petrochronology. Pseudosection modeling then suggests a protracted history of monazite growth and recrystallization, spanning approximately 40 million years. These findings challenge previous petrochronological postulations about coupled substitution mechanisms and highlight the necessity of using integrated analytical approaches to decipher complex metamorphic histories in monazite-bearing rocks. The study emphasizes the importance of considering the multifaceted nature of monazite systems when interpreting their petrochronological data.

The morphologies and compositional zoning of tourmaline-group minerals can provide insight into the evolution of pegmatite-forming melts. We present a dataset of major element compositions of the pegmatite-hosted tourmalines from six localities in the Boroujerd region, Lorestan (western Iran), to document the origin of tourmaline and its genetic implications. All tourmalines from the Boroujerd pegmatites belong to the alkali group and the schorl (NaFe2+ 3Al6(Si6O18)(BO3)3(OH)3(OH))-foitite(square(Fe2+ 2Al)Al6(Si6O18)(BO3)3(OH)3(OH)) solid-solution series. The compositional variations of these tourmalines can thus be expressed by the substitution square Al(NaMg)-1, AlFe-1 and MgFe-1. The data presented here suggest that the distinct major-element zoning observed in tourmaline from pegmatites can best be explained in terms of processes occurring during tourmaline growth and evolution of pegmatite-forming melts. Morphological and geochemical characteristics indicate that two different types of tourmalines have been recognised in the Boroujerd pegmatites, including primary (magmatic) and intermediate (magmatic-hydrothermal). This study, and others like it, demonstrate that tourmaline composition can serve as a useful proxy for deciphering the petrogenesis of granitic pegmatites and trace the magmatic-hydrothermal transition.

This paper focuses on delineating and charactering of the magma crystallization conditions of the post-collision Lavarab Alkaline Basaltic Lavas in East Iran. The lavas consist mainly of alkali basalt and basanite, with subordinate trachybasalt. Olivine mostly shows forsterite, chrysolite and hyalo-siderite compositions. Clinopyroxenes are diopside and augite, belonging to peralkaline to subalkaline magmatic series within post-collisional tectonic settings. Estimates of temperature and pressure obtained from single clinopyroxene thermobarometers suggest that crystallization temperatures vary between approximately 1110 and 1260 °C, with pressures ranging from about 0.05 to 1.35 GPa, which correspond to depths of roughly 2 to 51 km at high oxygen fugacity in both the lower and upper continental crust. Olivine-liquid thermometry yields temperatures of ~1385 to ~1393 °C for basanites and ~1275 to ~1339 °C for alkali basalts, assuming a constant pressure of 1.4 GPa. The chemical compositions of phenocrysts in the studied basaltic lavas provide evidence of magma recharge, occurring through multiple pulses of new magma injected into the existing reservoir prior to eruptions. Petrographic evidence, including absorption features, rounded crystal morphologies, patchy zones in olivine, and sieve textures in clinopyroxene, support this interpretation. Additionally, microprobe analyses reveal oscillatory variations in crystal composition from core to rim, confirming the hypothesis of dynamic magma replenishment.

We have investigated the major- and trace-element composition of hydrothermal pyrite, magnetite, and titanomagnetite, and of the principal Cu-minerals chalcopy-rite and chalcocite, to constrain ore-forming processes in the northeastern Saveh district (central Urumieh–Dokhtar magmatic arc, Iran). Our data provide new con-straints on the magmatic–hydrothermal evolution and subsequent hydrothermal–supergene modification of the ore system. Titanomagnetites hosted in shallow monzo-dioritic intrusions are enriched in Ti–V–Al, plot below the magnetite–ulvöspinel join and record high crystallization temperatures (< ~500 °C) under rela-tively low oxygen fugacity. By contrast, magnetites from silica-rich hydrothermal veins are relatively Fe-rich, have very low TiO₂, formed at intermediate tempera-tures (~200–300 °C) under higher fO₂, and show pronounced depletion in Ti and V relative to monzo-dioritic oxides. Textures and oxide systematics (Al+Mn vs Ti+V; V/Ti–Fe) document repeated hydrothermal pulses, Fe²⁺ leaching and element redis-tribution during cooling and fluid–rock interaction. Geochemical trends indicate progressive evolution from a magmatic fluid to later meteoric water overprint, with decreasing As contents reflecting mixing with oxidizing meteoric waters. Vertical elemental zoning suggests that most samples represent mid- to deep-level sections of the epithermal system. Elevated Cu contents (up to 0.95 wt.%) highlight pyrite as a significant Cu host. Co/Ni ratios between 1 and 10 further corroborate a magmatic–hydrothermal origin. Chalcopyrite is the principal economic Cu carrier at Northeast Saveh. Replacement follows a temperature- and fluid-controlled pathway (chalco-pyrite → covellite → chalcocite/digenite). At lower temperatures (< ~200 °C) re-placement proceeds more slowly, producing chalcocite/digenite under prolonged reaction conditions. Chalcocite commonly occurs as thin replacement rims and fracture fills that concentrate remobilized copper. Collectively, the investigated oxide and sulfide proxies provide robust discriminants for separating magmatic versus hydrothermal domains and for vectoring toward higher-temperature feeders and zones of remobilized copper.

The magmatic arcs in the north-west region of Pakistan comprises of numerous volcanic and plutonic bodies of different ages and compositions evolved during the subduction of the Neo- Tethys Ocean under the Eurasian supercontinent. This study focusses on the examination of the granitoids of the Kohistan batholith (a part of Kohistan-Ladakh Island Arc; KLIA) and the Khunjerab pluton, concentrating on their petrological traits, mineral chemistry, in-situ zircon U-Pb geochronology, and whole-rock major and trace element geochemistry. According to zircon U-Pb dating, the Kohistan batholith granitoid was emplaced around 91.7 +/- 0.3 Ma, while zircons of the Khunjerab pluton yield ages of 106.4 +/- 0.4 Ma and 106.4 +/- 1.0 Ma. All the samples from both magmatic units have calcic to calc-alkaline (Na2O + K2O: 3.6-10.6 wt.% and SiO2: 60-73 wt.%), metaluminous to peraluminous properties (Aluminum Saturation Index (ASI): 0.9- 1.2). Notably, Nb, Ta, and Ti show depletion, while large ion lithophile elements like Cs, Rb, and K have been enriched. Additionally, we find that SiO2 and P2O5 have a negative correlation while Rb and Th have a positive correlation, which confirm an I-type arc magmatism. Together with the published literature, TEM analysis, and thermal modelling, our zircon U-Pb results point to a period of continuous magmatic activity from the Late Jurassic to the Late Cretaceous (between 150 Ma and 91 Ma) in the Kohistan Island arc region while the Khunjerab pluton (part of Karakorum block/Eurasian plate) experienced widespread magmatism around 120 Ma to 106 Ma. With SiO2 concentrations ranging from 67.5-73.3 wt.% and 60- 71.4 wt.% and relatively low alkali (Na2O + K2O) contents between 3.6-10.6 wt.% and 5.1-7.4 wt.% in the Kohistan batholith and Khunjerab pluton respectively, showing clear signs of acidity. The whole rock as well as the mineral geochemical analysis and the elevated water contents (8-10 wt.% and 3.1-3.5 wt.%) inferred from amphibole and biotite chemistry respectively, indicates that the Kohistan batholith was most likely formed through partial melting of a (hydrous) magma originating from a more or less altered metasomatized mantle wedge. Likewise, the Khunjerab pluton whole rock geochemistry also indicates its origin through partial melting of magma originating from an altered metasomatized mantle wedge. This study also shows that both units are not only different in terms of the nature of magmatism but also in terms of their ages i.e., continental arc magmatism occurred in the Khunjerab (Karakoram) block in the middle Cretaceous (106 Ma) while island arc magmatism occurred on the Kohistan side in the late

The major and trace element content in hydrothermal pyrite was analyzed, as the most abundant sulfide mineral associated with quartz veins, to reveal ore-forming processes in the Mamuniyeh deposite, central Urumieh-Dokhtar Magmatic Arc. The Co–Ni–As signatures in pyrite is closely linked to the genetic model and geological processes of the deposits. Cobalt, nickel, and arsenic data from the Mamuniyeh pyrites indicate a predominance towards the cobalt region, consistent with hydrothermal and epithermal magmatic ore deposits. Data shows fluid evolution from primary magmatic water to later meteoric waters, with magmatic water dominating the early stages and meteoric waters added later. The reduction in arsenic content in pyrites, due to the mixing of the ore-forming fluid with oxygen-rich meteoric waters, leads to an increase in arsenic concentration in the system. Under oxidizing conditions, arsenic with an oxidation state of As¹⁻ substitutes for sulfur, and in combination with Fe²⁺, it incorporates into the pyrite structure as As³⁺ and As⁵⁺. Vertical zoning of elements in epithermal systems suggests that most Mamuniyeh samples exhibit characteristics of the middle part of the mineralization system and somewhat deeper zones. Copper contents in the Mamuniyeh pyrites, up to 1.1 wt.%, indicate pyrite can act as a significant copper absorber. Nickel contents in the Mamuniyeh pyrites (up to 0.34 wt.%) are higher than continental crust nickel, indicating a mantle origin of them. Variations in Ni/Co ratios in pyrite for classifying hydrothermal deposit origins show a dominant range between 1 and 10, consistent with magmatic-hydrothermal origin, likely formed by fluid-rock interactions between magmatic-hydrothermal fluids and volcanic host rocks. Introduction Pyrite as the most common sulfide mineral in the Earth's crust, widely exists in magmatic-hydrothermal systems (Reich et al., 2013; Deditius et al., 2014; Dubosq et al., 2018). The rare element content in pyrite can reflect the conditions of the mineralizing fluid, such as temperature, pH, and oxygen fugacity, as well as the mechanisms of element formation and deposition during fluid evolution and ore formation (Agangi et al., 2014; Sykora et al., 2018). Pyrite commonly plays a vital role in determining the distribution of rare elements and heavy metals in these systems and can effectively control the distribution of economically valuable elements such as silver, arsenic, gold, and heavy metals (Large et al., 2009; Cook et al., 2013; Agangi et al., 2014). Given pyrite's ubiquity and its capacity to host many rare elements (e.g., Co, Ni, Cu, As, Se, Ag, Sb, Te, Pb, Bi, and Au), its chemistry has been successfully used to trace the physicochemical evolution of hydrothermal fluids and to reveal formation processes in various mineral deposits (e.g., Carlin-type gold, Cline, 2001; Large et al., 2009; epithermal gold, Deditius et al., 2008; Kouhestani et al., 2017; orogenic gold, Wu et al., 2019; volcanogenic massive sulfide, Martin et al., 2022; porphyry copper (gold), Reich et al., 2013, Keith et al., 2022). The aim of this studyis to analyze chemistry of pyrite in the low-sulfidation epithermal copper mineralization system in southern Mamuniyeh. The findings will enhance the understanding of the epithermal mineralization processes and magmatic evolution in this region. The results provide insights into the fluid evolution and ore formation processes within the epithermal system, contributing to a broader understanding of mineral deposit formation. Geology and Petrography Mamuniyeh epithermal system includes significant rock outcrops composed of intrusive rocks such as gabbro, diorite, and monzodiorite, along with a series of acidic to basic volcanic rocks. These include andesite tuff, pyroxene andesite-andesite porphyry, dacite-rhyodacite tuff, acidic lava, basaltic andesite, diabase, and basalt-diabase (Goudarzi et al., 2024a). According to the 1:100,000 scale geological map of Zaviyeh (Amidi et al., 2004), the volcanic and pyroclastic units are of Eocene age, while the intrusive units likely intruded during the Oligocene to Early Miocene periods. Geochemical characteristics show that these magmatic series are calc-alkaline, significantly influenced by mantle metasomatism (Rezaei Kahkhaei et al., 2014). Features like LILE enrichment over HFSE, negative Nb and Ti anomalies, and highly positive lead anomalies indicate calc-alkaline magmatism associated with a subduction zone, with crustal contamination during the ascent of the parent magma in this region (Goudarzi et al., 2024a). Mineralization and Mineralography The main copper mineralization in the Mamuniyeh epithermal system features veins and veinlets aligned with regional structures. Primary mineralization includes quartz with sulfide minerals like chalcopyrite, pyrite, and bornite, and oxide minerals such as specularite. Pyrite, the most abundant sulfide, appears in two generations. The first generation consists of framboidal and semi-euhedral pyrite, which can be fine- to coarse-grained and sometimes altered to hematite and goethite (Goudarzi et al., 2024c). The second-generation forms vein and veinlet fillings and occasionally include inclusions within chalcopyrite. Pyrite occurs in various assemblages: quartz + pyrite (Qz+Py); quartz + chalcopyrite + pyrite (Qz+Ccp+Py); quartz + specular hematite + pyrite (Qz+Py+Hem); and quartz + chalcopyrite + specular hematite ± pyrite ± bornite (Qz+Ccp+Hem±Py±Bn), found in replacement, breccia, disseminated, and colloform textures. Vein/Veinlet Pyrite Quartz + Pyrite (Qz+Py): Oldest veins, 1-20 mm thick, with coarse, euhedral pyrite grains Quartz + Chalcopyrite + Pyrite (Qz+Ccp+Py): Veins contain chalcopyrite (50%), pyrite (30%), and quartz (20%), 1 mm to 5 cm thick Quartz + Chalcopyrite + Specular Hematite ± Pyrite ± Bornite (Qz+Ccp+Hem±Py±Bor): Most common, 0.5-5 cm thick, with chalcopyrite (40%), specular hematite (30%), pyrite (10%), bornite (5%), and quartz (15%) Quartz + Specular Hematite + Pyrite (Qz+Py+Hem): Veins, 0.5-10 cm thick, contain specular hematite (60%), pyrite (10%), and quartz (20%) Other types of Pyrite mineralization Disseminated type: Euhedral to anhedral pyrite crystals spread within intrusive and volcanic rocks and quartz veins Colloform type: Rapid, low-temperature quartz deposition in shallow epithermal systems, forming alternating ore-bearing and ore-free bands Crustiform type: Periodic temperature fluctuations and fluid changes during boiling, forming colloform banding with iron oxides, hematite, pyrite, and secondary copper minerals Hydrothermal Breccia Mineralization: Hydraulic fracturing from fluid pressure increases, creating breccia with ore mineral fragments like pyrite, indicative of boiling processes Research Methodology After thorough field examinations of surface outcrops and drill cores, 70 polished sections from mineralized zones and veins containing sulfide and oxide minerals were collected for ore and mineralogical studies. Suitable sulfide samples from 8 polished sections were re-examined using an electron microscope and BSE images. Following carbon coating, the samples were analysed using a CAMECA SX Five Electron Microprobe equipped with a field emission cathode and energy-dispersive X-ray (EDX) system. This setup, with a 20 kV accelerating potential, 25 nA probe current, and 60 µm beam diameter, enabled rapid semi-quantitative elemental analysis in the Department of Lithospheric Research laboratory at the University of Vienna. Results and Discussion EPMA analysis on 58 points in pyrite shows no gold presence and very low silver concentration, up to 0.05 wt.%. Maximum concentrations of elements measured are arsenic (0.20 wt.%), lead (0.26 wt.%), copper (0.95 wt.%), antimony (0.23 wt.%), tin (0.04 wt.%), zinc (0.018 wt.%), nickel (0.34 wt.%), and cobalt (1.12 wt.%). Strong element correlations in pyrite include tin with zinc, arsenic with lead, manganese with zinc, and manganese with silver. BSE images show pyrite in oxide-sulfide veins as individual grains, often with chalcopyrite at the edges or as inclusions within chalcopyrite. Element variation diagrams for the Mamuniyeh pyrites indicate no significant changes in iron and sulfur with increasing arsenic. Cobalt content increases, while copper decreases with more iron. Cobalt and nickel show a stable relationship. Copper increases with zinc, while silver decreases with increasing arsenic and antimony but increases with tin. Previous studies indicate that the composition of trace elements in sulfides is controlled by the physicochemical conditions of hydrothermal fluids, such as temperature, pH, and redox conditions, revealing ore-forming processes in hydrothermal environments (Reich et al., 2013; Large et al., 2014; Gregory et al., 2016; Sykora et al., 2018; Saravanan Chinnasamy et al., 2021). For example, Te content in pyrite is mainly influenced by oxygen fugacity and pH, whereas As and Se are likely controlled by temperature (Huston et al., 1995; Deditius et al., 2008; Keith et al., 2018). The Co–Ni–As ratio in pyrite correlates closely with the deposit's genetic model and geological processes (Loftus-Hills and Solomon, 1967; Yan et al., 2012). Co, Ni, and As data plots for the Mamuniyeh pyrites indicate samples skewed towards the cobalt region, typical of magmatic-hydrothermal and epithermal deposits (Yan et al., 2012; Niu et al., 2016) (Fig. 7A). S-As substitution degree in pyrite is a temperature indicator, showing arsenic enrichment at lower temperatures (Kusebauch et al., 2018). Co and Ni are mantle-derived elements; Ni is usually concentrated in early-stage magmatic minerals, decreasing gradually with magmatic evolution, while Co increases (Kusebauch et al., 2018; Niu et al., 2016). Arsenic content depends on meteoric and magmatic water ratios, with higher arsenic content indicating a meteoric water role. If magmatic water predominates, samples plot towards Co; with meteoric water dominance, samples plot closer to arsenic (Yan et al., 2012). The plotted data suggests fluid evolution from initial magmatic water to later meteoric water. Reduction of arsenic content in pyrites, due to the mixing of hydrothermal vein fluid with high-oxygen-fugacity meteoric water, may increase arsenic content. Under oxidizing conditions, arsenic content decreases as arsenic replaces S in the pyrite structure (Cook and Chryssoulis, 1990; Liang et al., 2013). Geochemical studies have shown vertical zoning in epithermal systems (Boyle, 1979), with As, Sb, Hg, Ba, and Ag dominant in the upper parts; Cu, Pb, Zn, and Bi in the middle parts; and Co, Ni, Ti, and Cr in deeper parts. Mamuniyeh's system mainly shows middle to deep characteristics. Studies indicate that copper can significantly incorporate into pyrite's structure, sometimes reaching notable weight percentages (Einaudi, 1968; Clark, 1970; Pacevski et al., 2008). In Mamuniyeh, copper concentrations in pyrite reach up to 1.1 wt.%, showing pyrite as a substantial copper host. Due to large ionic size, lead rarely enters pyrite's lattice and typically deposits as galena (Huerta-Diaz and Morse, 1992; Koglin et al., 2010). Pyrite can also trap elements like silver, antimony, and tin when remobilized, though their contents in the Mamuniyeh pyrites are minimal (0.05 wt.%, 0.02 wt.%, and 0.002 wt.%, respectively). Nickel, easily incorporated into pyrite, remains even during recrystallization (Huerta-Diaz and Morse, 1992). High nickel content in the Mamuniyeh pyrites (0.34 wt.%) suggests a mafic-ultramafic mantle source (Palme and O'Neill, 2003; Zhao et al., 2011), exceeding continental crust levels (Rudnick and Gao, 2014). Nickel’s solubility limit is around 10 mol% NiS2 in pyrite while cobalt can fully mix into pyrite at temperatures above 700 °C (Abraitis et al., 2004), making Co concentration in pyrite a useful geothermometer (Zhao et al., 2011). Co/Ni ratios in pyrite, unaffected by slight differences in Co and Ni affinities for chloride ligands, reflect hydrothermal deposit conditions (Bralia et al., 1979; Bajwah et al., 1987). In Mamuniyeh, Co/Ni ratios between 1 and 10 indicate a magmatic-hydrothermal origin (Reich et al., 2016), consistent with previously defined characteristics.

Boiling is one of the common processes that lead to the formation and enrichment of precious metal deposits. The investigation of the spatial relations between fluid boiling and deposition of precious metals is a valuable tool in exploration of epithermal deposits. Fluid boiling, isothermal mixing and surface dilution of fluids processes are important factors for the instability of chloride and sulphide complexes, which lead to the simultaneous deposition of Fe-Cu and then deposition of sulphide phases in the final stages of mineralization which are caused by a sudden decrease in pressure in the fractures. To investigate evidence of boiling and its role in mineralization we have studied fluid inclusions and quartz textures in the Mamouniyeh Cu deposite in the middle part of Urumieh-Dokhtar magmatic arc in Iran. Evidence for fluid boiling, such as different liquid-vapor ratios of fluid inclusions, the coexistence of fluid inclusions with different salinities and co-existing liquid single-phase fluid inclusions with vapor single-phase fluid inclusions and breccia, crustiform and colloform textures of quartz indicate that boiling process occurred during the formation and growth of minerals. The study of 138 fluid inclusions in ore-bearing silica veins shows the similar density values from 0.8 to 1 g/cm3 for quartz with pyrite + chalcopyrite, chalcopyrite and chalcopyrite + specularite ± pyrite ± chalcocite mineralization systems. Adjacency of multiphase fluids with vapor-rich fluid inclusions indicates that fluids are trapped at the boiling point, that is, in the state where the vapor is in equilibrium with the liquid. As a result of this boiling part of the Cu in the fluids was deposited as chalcopyrite. Evidence shows this process probably occurred at a depth of about 700 meters below the water table and lithostatic pressure of about 16 MPa. In the case study area, boiling, mixing of magmatic fluids with meteoric fluids and cooling process by oxide and sulphide complexes, that this mixing process has reduced the temperature and salinity in the system and caused oxide-sulphide mineralization include chalcopyrite, pyrite, bornite, specularite, and secondary ore minerals include chalcocite, covellite, azurite, malachite, chrysocolla, goethite, and limonite which related to granodiorite, monzonite and gabbro-diorite intrusive rocks.

The Sepid-Sarve copper deposit is part of an Eocene volcano-sedimentary sequence located in the southern Sabzevar Zone. The copper mineralization occurs at the contact between pyroclastic and lava units with various limestone layers (including marly, Nummulitic, sandy, and clastic limestones). The ore minerals consist of malachite, azurite, chalcocite, digenite, cuprite, tenorite, covellite, and occasionally native copper. The associated hydrothermal fluids show moderate to high salinities, ranging from 3.08 to 13.38 wt.% NaCl equivalent, with homogenization temperatures between 90 and 356 °C, indicating fluid mixing during ore formation. Chalcocite is rarely accompanied by quartz, suggesting low silica content in the ore-forming fluids. The δ34S values of sulfide samples from the Sepid-Sarve deposit range from −23.9 ± 0.3‰ to −2.9 ± 0.2‰, while δ34S values of hydrothermal H2S range from −24.1 ± 0.3‰ to −21.0 ± 0.3‰. The δ18O values of hydrothermal fluids associated with mineralization fall within the range of basaltic rocks, meteoric waters, and sedimentary rocks. Geochemical variations in major and trace elements suggest the involvement of continental crustal contamination in the magmatic evolution. The studied volcanic rocks fall within the calc-alkaline to shoshonitic fields, formed in a continental arc setting, and are derived from an enriched mantle source influenced by subduction-related fluids. These rocks are characterized by HREE depletion, moderate LREE enrichment, and a weak negative Eu anomaly. Based on the results, the Sepid-Sarve deposit is classified as a stratabound (Manto-type) copper sulfide deposit, formed in a volcano-sedimentary setting associated with a subduction-related magmatic arc environment.

ABSTRACT The Yaoundé Group is one of numerous Pan‐African basins located north of the Congo Craton in central Africa. One of the main characteristics of this basin is the presence of high‐grade gneisses and granulites which have been considered the root of the collision between the Central Africa Fold Belt and the Congo Craton. Interpretation of these high‐grade rocks is mainly based on studies (petrology metamorphism, geochronology) carried out in the southern part of the WSW–ENE trending Yaoundé basin. The northeastern part of the basin (Belabo area) was filled by detritus of magmatic rocks (Sm/Nd = 0.182) of Rhyacian (2263 Ma) to Statherian (1677–1757 Ma) eras, of the southern Adamawa domain, and which have been later transformed by in situ partial melting into metatexitic to diatexitic migmatites (with a melt fraction less than 85%). Whole‐rock chemical analyses show that the melanosome portion (sample EB1) is enriched in refractory elements with respect to the leucosome (sample EB3). This high‐grade paroxysmal episode of metamorphism is characterised by a Sil–Kfsp–Pl–Bt–Grt assemblage and took place between 724 and 620 Ma ( 206 Pb/ 238 U zircon apparent ages). Few metamorphic transformations took place, especially Bt + Sil + Qtz = Grt + Kfsp + melt and Bt + Grt = Pl + Opq + melt. The evolution of the Yaoundé sedimentary basin was diachronic, starting earlier in the northeastern part (Ebaka region) with respect to the southwestern part (Yaoundé region).

Changes in the grain size distribution of river sediment have environmental, ecological and social implications. This study investigated the variation of the grain size of bulk samples, detrital zircons and rutiles from the mainstream and major tributaries of the Yangtze River. The mean size of bulk samples from the upper reaches is significantly higher than the mid-lower reaches. The Equivalent Spherical Diameter (ESD) of most zircons (from previous work) and rutile grains fall within the range of 32-250 μm with dominant size of 63-125 μm. Coarse-sized zircons and rutiles with ESD of 125-250 μm are found in higher proportions in the upper reaches than in the mid-lower reaches, and a significant grain size decrease is observed downstream of the Three Gorges Dam. The significantly decreasing in coarse grains downstream of the dam indicates that the massive sediment contributed by the Three Gorges Dam (TGD), especially coarse-sized sediment. Our study demonstrates that a complex sediment routing system like the Yangtze River is interrupted by the Three Gorges Dam. The problem of grain-size bias caused by human activities on age-data acquisition and interpretation of detrital minerals (rutile and zircon) from large rivers is not negligible and deserves more attention when using single grain geochronology to constrain sediment provenance and tectonic evolution.

The low-sulfidation epithermal copper mineralization in the Mamouniyeh area occurs as silica-sulfide-oxide veins hosted by monzonitic, gabbroic intrusions, and andesite. Magnetite and titanomagnetite are the primary hypogene oxide ore minerals in this system, present as titanomagnetite in intrusions and mainly as magnetite in silica veins. The chemical composition of Mamouniyeh magnetites in the FeO-Fe2O3-TiO2 system indicates a tendency towards wüstite (FeO). Increased Al2O3 and TiO2 content in silica vein magnetites compared to monzonitic intrusions is characteristic of hydrothermal magnetites. The decreased Cr2O3 and V2O3 content in re-equilibrated silica vein magnetites suggests their formation at higher oxygen fugacity than monzonitic titanomagnetites. The Al+Mn vs. Ti+V diagram shows that intrusive titanomagnetites formed at temperatures above 500°C, while silica vein magnetites formed at 200-300°C. The temperature drops in the system, influenced by atmospheric fluid mixing during hydrothermal fluid intrusion, led to magnetite deposition in silica veins at lower temperatures. The Ti vs. Mg+Al+Si diagram indicates the crystallization of intrusive titanomagnetites under conditions of limited hydrothermal fluid-wall rock interaction. An increase in oxygen fugacity from the parent magma towards the mineralized veins is observed, with intrusive magnetites forming at higher temperatures and lower ƒO2. ntroduction Iron oxides are present in many magmatic-hydrothermal mineral deposits, either as primary minerals (e.g., IOCG deposits and banded iron formations) or as secondary minerals (e.g., massive sulphide deposits). The chemical composition of magnetite provides insights into the characteristics of ore-forming fluids during magmatic or hydrothermal processes. Unique features of magnetite, such as its formation under various geological conditions and its ability to host numerous trace elements, have led to its use as an important petrogenetic indicator in recent years. This study investigates the composition of magnetite - titanomagnetite as the main hypogene oxide minerals associated with the low-sulfidation epithermal copper mineralization system in southern Mamuniyeh, within the central part of the Urumieh-Dokhtar magmatic arc (UDMA). The findings offer a better understanding of the evolution of the epithermal mineralization system and magmatic evolution in this area for the first-time using magnetite-titanomagnetite compositions. Despite numerous signs of ancient mining, mineral indices, and copper-gold-silver deposits associated with Eocene magmatism in this region, it has received less attention from researchers compared to other areas of the UDMA. Petrography, Mineralogy and Mineralization The study area features a series of intrusive and volcanic rocks ranging from acidic to basic, including andesite tuff, pyroxene andesite-porphyritic andesite, dacitic-rhyodacitic tuff, acidic lava, basaltic andesite, diabase, gabbro, diorite, monzonite, granodiorite, monzodiorite, and basalt-diabase. Geochemical characteristics show calc-alkaline magmatism related to a subduction zone, with crustal contamination during magma ascent (Goudarzi et al., 2024a). Copper mineralization appears as veins, primarily aligned NW and N40W. Six main types of veins/veinlets exist: quartz + pyrite (Qz+Py); quartz + chalcopyrite + pyrite (Qz+Ccp+Py); quartz + chalcopyrite (Qz+Ccp); quartz + specular hematite + pyrite (Qz+Py+Hem); quartz + chalcopyrite + specular hematite ± pyrite ± bornite (Qz+Ccp+Hem±Py±Bor), and quartz + secondary copper minerals, with magnetite ± titanomagnetite as minor accessory minerals (Fig. 2). During main mineralization, quartz formed with sulfides like chalcopyrite, pyrite, and bornite, and oxides like magnetite-titanomagnetite and specularite (Goudarzi et al., 2024c). In the supergene stage, chalcocite, covellite, minor native copper, and limited magnetite were observed. The oxidation stage saw minerals like malachite, cuprite, azurite, chrysocolla, hematite, goethite, and limonite forming. Syngenetic iron oxide ores include magnetite, titanomagnetite, specular hematite, and ilmenite exsolution lamellae. Magnetite and titanomagnetite, as primary hypogene oxide ores, are found in hypabyssal monzodioritic bodies and silica veins, sometimes associated with copper sulfides. Magnetite occurs as scattered grains, while titanomagnetite forms micro-grains in mineralized veins. Some titanomagnetite crystals intergrow with ilmenite, and hematite blades form during final cooling stages. The transformation of magnetite to hematite due to Fe2+ leaching in acidic environments results in martitic textures. The association of iron and titanium oxides suggests non-equilibrium conditions. Replacement of magnetite and titanomagnetite by hematite indicates alteration under higher oxygen fugacity, likely due to weathering or hydrothermal alteration (Klein, 2005; Makvandi et al., 2016; Riegler et al., 2014). Research methodology After detailed field examinations, 70 polished sections from various ore-bearing sections and veins were prepared for mineralogical studies. The study of oxide minerals in 8 polished sections was conducted using an electronic microscope and SEM-BSE analyses. The samples were analyzed using the CAMECA SX Five Electron Microprobe at the University of Vienna. The analysis was performed on 48 points of primary titanomagnetite-magnetite in intrusive units and 45 points of magnetite associated with mineralized veins. Results and discussion The results show that the FeO and TiO2 contents vary significantly. In intrusive rocks Fe2O3 ranges from 60 to 80 wt.% and TiO2 from 0 to 16.57 wt.%. In mineralized veins Fe2O3 ranges from 80.6 to 91.4 wt.% and TiO2 from 0 to 0.12 wt.%. Al2O3 and TiO2 contents decrease towards siliceous veins, indicating minimal spinel formation, characteristic of hydrothermal magnetites. Fe2O3 in intrusive masses correlates with Cr2O3 and V2O3, whereas in mineralized veins it correlates with MnO and Cr2O3. TiO2 in intrusive masses correlates with Al2O3, V2O3, and MnO, but not in mineralized veins. SiO2 content is generally less than 1 wt.%. Variation diagrams show that in intrusive samples, Al, Cr, and V oxides increase with TiO2, while Fe and Mg decrease. In mineralized veins, Al and Fe oxides decrease with TiO2, while Cr increases slightly, and V, Mn, and Mg initially increase then decrease. Chemical Composition Titanomagnetite (TixFe3-xO4) is a significant Fe-Ti phase in orthomagmatic rocks and oxide deposits (Spencer and Lindsley, 1981). It can undergo reduction or oxidation (O’Reilly, 1984), forming ilmenite lamellae or intergrowths (Saito et al., 2004). Ideal titanomagnetite forms through deuteric oxidation along the magnetite-ulvospinel line. Mamouniyeh titanomagnetites trend towards wüstite (FeO) (Fig. 9). Martitic hematites indicate final oxidation stages with decreasing temperature and increasing oxygen fugacity (Mondal and Baidya, 2015). With rising temperatures, titanomagnetite separates into ulvospinel and magnetite, forming a Widmanstätten texture (Mondal and Baidya, 2015). Ilmenite forms upon cooling and ulvospinel instability, reacting with oxygen and TiO2. Thick ilmenite blades are formed under advanced oxidation conditions and thin ilmenite blades are formed under early oxidation conditions. Martitization intensity varies, with high oxygen fugacity leading to heavily martitized crystals. Hematite lamellae in ilmenites may result from final oxidation and cooling. Petrographic analysis shows disrupted cubic structures in titanomagnetite, with thin lamellae forming due to oxidation and titanium enrichment, and thicker lamellae forming under advanced oxidation (Pasteris, 1985). Origin Comparing magnetite-titanomagnetites from intrusive rocks and mineralized zones reveals element redistribution during iron oxide transformation. Intrusive bodies are enriched in Ti, Al, and V, while mineralized veins are depleted. Higher V and Cr in magnetite from intrusive bodies align with the mafic nature of host rocks (Curtis, 1964). Reduced Cr and V in mineralized veins indicate high oxygen fugacity during formation. In Mamuniyeh, vanadium oxide content in titanomagnetites of intrusive rocks ranges from 0.016 to 1.28 wt.% (average 0.88 wt.%) and in magnetites of mineralized veins from 0.012 to 0.39 wt.% (average 0.12 wt.%). Vanadium content in magnetite reflects oxygen fugacity conditions of the environment, with higher oxygen fugacity leading to less vanadium in magnetite (Canil and Lacourse, 2020). V3+ incorporates into magnetite under low oxygen fugacity, while V5+ is incompatible with iron oxide structures at higher oxygen fugacity. Titanium content in magnetite is temperature dependent, with higher crystallization temperatures resulting in higher titanium contents (Tian et al., 2021). Magnetite appears in primary, secondary replacement, and solid solution forms. Primary magnetite shows no elemental substitution in fractures. Hematite replaces magnetite in fractures, starting from cracks and spreading across the crystal. Magnetite forms solid solutions with ilmenite, indicating limited Ti solubility at low temperatures. In tholeiitic magma, high-temperature liquidus minerals form first, while in calc-alkaline magma, elevated oxygen fugacity leads to earlier crystallization of iron oxide minerals (Mason and Moore, 1966). As magma approaches the surface, increased oxygen fugacity results in fine-grained magnetite and titanomagnetite crystals, with titanomagnetite forming first, followed by magnetite and ilmenite (Wechsler et al., 1984). In Mamuniyeh samples, ilmenite as a solid solution with magnetite indicates similar formation conditions. The V/Ti ratio in magmatic magnetite is generally 1 (Dupuis and Beaudoin, 2011). Vanadium is mobile in low-temperature hydrothermal fluids, while Ti is immobile (Oliver et al., 2004). A V/Ti vs. Fe diagram is used to study re-equilibration in magnetite (Wen et al., 2017). EPMA analysis shows magmatic magnetite in intrusive rocks and re-equilibrated magnetite in mineralized veins, indicating hydrothermal fluid influence during crystallization and re-equilibration. Temperature and Oxygen Fugacity Titanomagnetites formed in high-temperature intrusive bodies, while magnetites in siliceous veins formed at moderate temperatures (200-300°C), consistent with fluid inclusion data in quartz veins. This indicates a temperature decrease due to atmospheric equilibrated meteoric fluid mixing during hydrothermal fluid intrusion and magnetite deposition at lower temperatures. The Ti vs. Mg+Al+Si diagram shows that titanomagnetites in Mamunieh intrusions crystallized under limited hydrothermal fluid-wall rock reaction, while magnetites formed under extensive reaction conditions. Petrographic evidence shows primary magnetites in intrusive bodies have a magmatic origin, partially replacing primary crystallized sulfides and silicates. A Ti vs. V diagram distinguishes hydrothermal from magmatic magnetites, showing clear separation between titanomagnetite-magnetite crystals in intrusive bodies and mineralized veins. Magnetites from semi-deep rocks are found at temperatures above 500°C, while those from siliceous veins are at 200-300°C. Sun et al. (2017) showed magnetite in the early retrograde stage has high levels of cobalt, vanadium, titanium, aluminium, and manganese, indicating low oxygen pressure (ƒO2) and high temperature. High TiO2 and V2O3 levels in intrusive magnetites indicate high temperature and relatively low ƒO2 magma. According to Toplis and Corgne (2002), increased vanadium in magnetite indicates reduced oxygen fugacity. Wang et al. (2018) showed changes in vanadium content reflect changes in fluid oxygen fugacity during metallogenic processes. V2O3 oxide content indicates increasing oxygen fugacity from the parent magma to mineralized veins, with higher oxygen fugacity in siliceous veins. It appears crustal contamination occurred with decreasing temperature, evolving magnetite composition from porphyry to skarn-porphyry type.

Cenozoic plutonic rocks in northeast Saveh, part of the central Urumieh–Dokhtar Magmatic Arc (UDMA) in Iran, comprise monzonite, monzodiorite, gabbro, and gabbrodiorite. Geochemical, zircon U-Pb geochronology, and Hf isotopic data reveal that these plutonic rocks belong to a medium-K calc-alkaline, metaluminous series with arc-related signatures. Zircon U-Pb ages (ca. 60 to 3 Ma) indicate prolonged magmatic evolution from the Middle Paleocene to the Middle Pliocene. Contrary to earlier reports of a 15 Ma period of reduced magmatic activity (ca. 72–57 Ma), our data indicate a shorter interval (ca. 10–12 Ma) during which magmatic activity decreased significantly. Key magmatic pulses occurred during the Late Eocene (ca. 40–47 Ma), Early Miocene (ca. 23–18 Ma), and Late Miocene–Pliocene (ca. 11–5.2 Ma), with geochemical data indicating a subduction-related origin. The most recent magmatic pulses in the central UDMA, potentially extending across the entire UDMA, are dated between 5 and 2.5 Ma, identified in a cluster of zircons from gabbroic rocks, which could correspond to the concluding stages of slab steepening related to continental subduction. Zircon εHf(t) values (−11.43 to 12.5) and geochemical data suggest fractional crystallization, crustal assimilation, and mantle-derived melts. The clinopyroxene crystallization temperatures (1150–1200 °C) and supporting geochemical data imply that magma was produced in a metasomatized spinel–lherzolite mantle at depths <80 km. This generation is associated with asthenospheric upwelling and slab rollback, which, in turn, triggered the partial melting of the lithosphere and fueled the region’s magmatic activity.

The Lut-Sistan region, eastern Iran has an extensive record of Eocene-Oligocene magmatism the origin of which is not fully understood. In this study, we analyze a set of volcanic rocks in the Jonob-e-Sechangi area of the Lut block. U-Pb zircon analyses demonstrate that magmatism can be divided into two age groups. Group 1 formed at similar to 45 Ma and involved different felsic (calc-alkaline rhyolitic to dacitic) and intermediate (high-K calc-alkaline andesitic) rocks. All samples from Group 1 display nearly identical initial 87Sr/86Sr values (Sr-87/(86)Sri = 0.7045-0.7056). However, the felsic rocks show higher epsilon Nd-t (+2.21 to +2.73) and lower T-DM (0.51-0.61 Ga). In contrast, intermediate rocks have epsilon Nd-t values of +1.27 to +2.23 and T-DM values between 0.63 and 0.74 Ga. Additional geochemical variations suggest that the felsic and intermediate rocks of Group 1 are not co-genetic. The felsic extrusive rocks in the Jonob-e-Sechangi area likely formed from the partial melting of the amphibolitic arc crust. In contrast, the high-K calc-alkaline andesitic rocks of Group 1 may have originated from low-degree partial melting of a spinel-peridotite mantle source. Group 2 formed basaltic andesite to andesitic rocks at 37-40 Ma, showing high-K calc-alkaline to shoshonitic compositions, relatively high Sr-87/(86)Sri (0.7047- 0.7076) and relatively low epsilon Nd-t (0.48 to -5.86). These geochemical features require magma derivation from a mantle source that is not only elementally but also isotopically enriched, followed by variable fractionation and crustal contamination. The enriched mantle source was most likely resided in the lithosphere and formed by metasomatism by continental crust-derived materials. Clinopyroxene trace elements compositions display marked variations between different magmatic rocks. Clinopyroxene in dacitic samples of Group 1 shows relatively high contents of Sr, Rb, and Ba whereas that in Group 2 rocks has relatively high contents of Sc, V, Ga, Nb, Zr, Hf, Y and rare earth elements (REE). The findings of this study show that the intricate interactions between the lithosphere and asthenosphere, stemming from post-collisional delamination processes following the closure of the Sistan Ocean and the collision of the Lut-Afghan blocks, led to differing levels of partial melting in the region's heterogeneous metasomatized mantle. This phenomenon explains the diverse range of volcanic rocks found not just in the Jonob-e-Sechangi area but also in other regions of the Lut Block.

The products of Cenozoic continental arc magmatism in Iran provide an outstanding natural laboratory for investigating subduction-related processes. Here we present whole rock, SrNd isotopic, zircon U-Pb-Hf age, and mineral composition data for Cenozoic intrusive rocks from the Natanz area, central Urumieh-Dokhtar magmatic arc (UDMA), with a view to re-evaluate spatial-temporal variations in arc magmatism, magma petrogenesis and mantle source characteristics. The suite investigated in this study ranges from less evolved (gabbro) to highly evolved (granite) rocks with calc-alkaline affinity and an age range from 23.2 to 19.7 Ma. Their epsilon Nd-(t) values vary from -0.32 to 2.73, initial Sr-87/Sr-86 values range from 0.7049 to 0.7075, and zircon epsilon Hf-(t) values range from -2.2 to +8.9. Combined modelling of trace element and isotopic data suggests that the most mafic Natanz magmas could have formed through similar to 5% melting of a source comprising 99% depleted mantle +1% sediment, with the melts modified subsequently by similar to 3% contamination by Cadomian upper crustal components. We postulate that Natanz magmatism originated during a flare-up event instigated by retreat of the subducted slab prior to or in conjunction with the collision between the Arabian and Eurasian plates. The spatial-temporal associations in central UDMA (i.e., 33 degrees 30 ' N to 34 degrees N) mirror three distinct flare-up episodes that occurred between 57 and 36 Ma, 26-15 Ma, and < 10 Ma; these events have not been reported previously from the northwestern and southeastern portions of the UDMA. Our results argue against any lull in magmatic activity in central UDMA during Eocene to Miocene times.

The Tangal-e-Sefid Fe-Cu mineralization forms syngenetic stratiform deposit in the Late Neoproterozoic volcano sedimentary sequence from the Central Iran. Early Cambrian metamorphic rocks are associated ore-bearing geologic units. The mineralization includes early oxide phase as a magnetite-rich bodies that are overprinted by a pyrite-chalcopyrite-rich sulfide phase. The most current alteration zone includes propylitic-carbonate, chlorite, sericite and silicic with a well-developed distribution of chloritization, especially in the layered part. Magnetite, pyrite and chalcopyrite comprise the primary main mineral assemblage, which is accompanied by malachite, covellite, hematite and goethite as the secondary minerals associated with epidote, chlorite, quartz and calcite minerals. Magnetite chemistry reveals the hydrothermal evolution of mineralization, and all the examined magnetite fall within fields of magnetite from VMS deposits. Fluid inclusion analysis of quartz and calcite coexisting with magnetite represent homogenization temperature range of 198 degrees C and 357 degrees C with a cooling trend from the massive toward the layered parts. The measured fluid salinity identifies two distinct medium-salinity fluids with mean values corresponding to 15 and 22 wt% NaCl. There is no significant difference in terms of temperature and salinity measured in calcite and quartz minerals. However, the average measured temperature values of fluids trapped in calcite (189-336 degrees C) are slightly lower than quartz (227-357 degrees C). Since the ore deposit distribution is spatially associated with actinolite schist, thermometric data of actinolite show temperature fluctuations of 310-315 degrees C and mineral formation pressures of 2.5-3 Kbar, which are correlated with the low-grade metamorphism. Primary hydrothermal fluids derived from submarine magmatism in an extensional system of seafloor were enriched in Fe and Cu (+/- Zn and possibly Pb) and it is the responsible for the first stage of magnetite formation and following the overprinting pyrite and chalcopyrite mineralization. The ore deposit geometries associated with magnetite mineralization and sulfide replacement styles; reveals that in the second stage of mineralization, hydrothermal fluid is mixed with oceanic water and eventually metal sulfides are deposited. The mineralizaton zone associated with the volcano-sedimentary sequence is affected by low-grade regional metamorphism related to Pan-African orogeny and represent the green schist territory as the VMS deposits related to Archean.