Search

Sensor-based particulate ore sorting is a pre-concentration technique that sorts particles based on measurable physical properties, resulting in reduced energy consumption by removing waste prior to grinding. This study presents an integrated methodology to determine the potential for ore sorting based on intrinsic particle properties. The methodology first considers the intrinsic sortability based on perfect separation. Only intrinsically sortable ore is further assessed by determining the sensor-based sortability. The methodology is demonstrated using a case study based on a typical copper porphyry comminution circuit. The sorting duty identified for the case study was the removal of low-grade waste material from the pebble crusher stream at a suitable Cu cut-off grade. It was found that the ore had the potential to be sorted based on the intrinsic and ideal laboratory sensor sortability results but showed no potential to be sorted using industrial-scale sensors. The ideal laboratory XRF sensor results showed that around 40% of mass could be rejected as waste at copper recoveries above 80%. An economic analysis of the sortability tests showed that, at optimum separation conditions, the intrinsic, ideal sensor and industrial sensor sortability would result in an additional annual profit of ~$30 million, $21 million and $−7 million (loss), respectively. [ABSTRACT FROM AUTHOR]

The Zhunsujihua porphyry Mo-Cu deposit is located in the Erenhot–East Ujimqin metallogenic belt in northeastern China. Granodioritic intrusions in the mining area are dominated by granodiorite and granodiorite porphyry, but the Mo mineralization is limited within the granodiorite. Zircon LA-ICP-MS U-Pb dating yields crystallization ages of 301.5 ± 3.0 Ma for granodiorite and 296.0 ± 3.0 Ma for granodiorite porphyry. These ages constrain the magmatic activity at the Zhunsujihua deposit that took place during the subduction of the Paleo-Asian oceanic plate. Whole-rock geochemical data suggest that the granodioritic intrusions belong to calc-alkaline and high-K calc-alkaline series, and are characterized by enrichment in K, Rb, U, Th, and Pb, and depletion in Nb, Ta, Ti, and P. The negative Eu, Ba, and Sr anomalies suggest that they have experienced extensive fractionation of plagioclase. Trace element compositions of zircons from the Zhunsujihua deposit provide constraints on the oxygen fugacity (ƒO2) of the magma, which is shown to high values with ∆FMQ = +0.5 to +5.6. The wide range of zircon εHf (t) (+1.3~+9.4) values, positive whole-rock εNd (t) (+2.5~+3.9) values, and relatively low initial (87Sr/86Sr)i (0.70367~0.70561) ratios indicate that the magmas mainly originated from a juvenile lower crust source derived from depleted mantle, but mixed with pre-existing crustal components. Moreover, the juvenile lower crust represents the main source of Mo for the Zhunsujihua deposit. A high magmatic oxygen fugacity and fractional crystallization played key roles in forming the Zhunsujihua deposit. [ABSTRACT FROM AUTHOR]

The paper reviews and summarizes data on the physicochemical parameters and chemical features of mineralizing fluids at porphyry deposits of the Cu–Mo–Au system. The calculated average values and ranges of parameters of the fluids in mineral-hosted fluid inclusions at porphyry deposits are as follows: temperature 90–957 °C, average 388 °C; salinity 0.1–88.0 wt % equiv. NaCl, average 29.4 wt % equiv. NaCl; and density 0.38–1.85 g/cm3, average 0.93 g/cm3. The highest average temperature and the highest maximum homogenization temperatures of the fluids were detected at deposits of the Cu (Au) type, with both values systematically decreasing with the transition to the Cu, Mo (Au), and then to Mo and Au types of porphyry deposits. The situations with the average and maximum salinity values of the fluids and their density are analogous. The data in the literature on the concentrations of some elements are still insufficient to reliably characterize variations in these concentrations at all of the discussed types of porphyry deposits. The highest Cu and Fe concentrations were found in the highest temperature fluids at deposits of the Cu (Au) type. The maximum Mo concentrations were detected in fluids at porphyry Mo deposits, and the highest Ag concentrations occurred at porphyry Au deposits. The chemical composition of the mineralizing fluids is, thus, strongly correlated with the types of the porphyry deposits. The hypothesis is discussed: the geochemical specifics of mineralizing fluids at various types of porphyry deposits of the Cu–Mo–Au system are related to the depths at which fluid separated from the magmatic melt. A scenario is proposed for the separation of mineralizing fluids from granite melt at various depths for fluids that form different types of porphyry deposits. [ABSTRACT FROM AUTHOR]

The study of lithic raw material quality has become one of the major interpretive tools to investigate the raw material selection behaviour and its influence to the knapping technology. In order to make objective assessments of raw material quality, we need to measure their mechanical properties (e.g., fracture resistance, hardness, modulus of elasticity). However, such comprehensive investigations are lacking for the Palaeolithic of Kazakhstan. In this work, we investigate geological and archaeological lithic raw material samples of chert, porphyry, and shale collected from the Inner Asian Mountain Corridor (henceforth IAMC). Selected samples of aforementioned rocks were tested by means of Vickers and Knoop indentation methods to determine the main aspect of their mechanical properties: their indentation fracture resistance (a value closely related to fracture toughness). These tests were complemented by traditional petrographic studies to characterise the mineralogical composition and evaluate the level of impurities that could have potentially affected the mechanical properties. The results show that materials, such as porphyry possess fracture toughness values that can be compared to those of chert. Previously, porphyry was thought to be of lower quality due to the anisotropic composition and coarse feldspar and quartz phenocrysts embedded in a silica rich matrix. However, our analysis suggests that different raw materials are not different in terms of indentation fracture resistance. This work also offers first insight into the quality of archaeological porphyry that was utilised as a primary raw material at various Upper Palaeolithic sites in the Inner Asian Mountain Corridor from 47–21 ka cal BP. [ABSTRACT FROM AUTHOR]

Compared with the porphyry Cu-epithermal Au mineralization system, detailed studies on the porphyry Mo-epithermal Pb–Zn–Ag–Au mineralization are rare due to limited exposures. The Shipingchuan polymetallic deposit, located in the South China Mo Province (SCMP) represents a typical example containing both porphyry Mo and epithermal Pb–Zn–Ag mineralization. The Mo mineralization mainly occurs as molybdenite-quartz veins in veinlets or as disseminated molybdenite within the potassic, silicic, and sericitic syenogranite. The Pb–Zn–Ag mineralization is characterized by veinlet-type sphalerite–galena–pyrite–quartz–calcite vein within the volcanic rocks accompanied with silicification and propylitization. Five molybdenite samples yield a Re–Os isochron age of 104.7 ± 0.7 Ma that is consistent with the zircon age (107.5 ± 2.1 Ma) of the ore-bearing syenogranite within errors. Together with previous reported Ar–Ar ages (106.6–121.8 Ma) of Pb–Zn–Ag related volcanic rocks, the Mo and Pb–Zn–Ag mineralization belong to a magmatic-hydrothermal event in the Early Cretaceous. Meanwhile, the total Re contents of molybednite range from 1.28 to 45.55 ppm, indicating the ore-forming materials were from a mixture between the mantle and crustal material. Moreover, previous sulfur isotopic values (3.7–4.3‰) of the pyrites from the porphyry Mo mineralization were consistent with the reported range of 4.0–6.1‰ of the sphalerites from the Pb–Zn–Ag mineralization, implying that the sulfur of two-types of mineralization was derived from magma. The above-mentioned spatial, temporal, and isotopic lines of evidence suggest that the Mo and Pb–Zn–Ag mineralization of the Shipingchuan deposit was formed from the same metallogenic system. In consideration of regional tectonic evolution history, we propose that the porphyry Mo-epithermal Pb–Zn–Ag mineralization formed in an extensional tectonic setting caused by the continued rollback and the eventual slab break-off of the subducting Paleo-Pacific plate. [ABSTRACT FROM AUTHOR]

South China can be divided into four metallogenic belts: The Middle-Lower Yangtze Metallogenic Belt (MLYB), Qinzhou-Hangzhou Metallogenic Belt (QHMB), Nanling Metallogenic Belt (NLMB), and Wuyi Metallogenic Belt (WYMB). The major mineralization in the four metallogenic belts is granite-related Cu–Au–Mo and porphyrite Fe-apatite, porphyry Cu (Au), and epithermal Pb–Zn–Ag, hydrothermal Cu–Au–Pb–Zn–Ag, and granite-related skarn-type and quartz-veins W–Sn, respectively. Low-temperature thermochronology, including fission-track and U-Th/He dating, has been widely used to constrain tectonic thermal evolution and ore deposits preservation. Understanding fission-track annealing and He diffusion kinetics in accessory minerals, such as zircon and apatite, is essential for dating and applications. In this study, previous zircon fission-track (ZFT) and apatite fission-track (AFT) ages in South China were collected. The result shows that the ZFT ages are mainly concentrated at 140–90 Ma, and the AFT ages are mainly distributed at 70–40 Ma. The age distribution and inversion temperature–time paths reveal heterogeneous exhumation histories in South China. The MLYB experienced Late Cretaceous-Cenozoic extremely slow exhumation after rapid cooling in the Early Cretaceous. The northern QHMB (i.e. from southern Anhui province to the Hangzhou Bay) had a relatively faster rate of uplifting and denudation than the southern QHMB in the Cretaceous. Subsequently, the northern QHMB rapidly exhumed, while the continuously slow exhumation operated the southern QHMB in the Cenozoic. The southern NLMB had a more rapid cooling rate than the northern NLMB during the Cretaceous time, and the whole NLMB experienced rapid cooling in the Cenozoic, except that the southern Hunan province had the most rapid cooling rate. The WYMB possibly had experienced slow exhumation since the Late Cretaceous. The exhumation thickness of the four metallogenic belts since 90 Ma is approximately calculated as follows: the MLYB ≤ 3.5 km, the northern QHMB concentrated at 3.5–5.5 km, and the southern QHMB usually less than 3.5 km, the NLMB 4.5–6.5 km and the WYMB < 3.5 km. The exhumation thickness of the NLMB is corresponding to the occurrence of the world-class W deposits, which were emplaced into a deeper depth of 1.5–8 km. As such, we infer that the uplifting and denudation processes of the four metallogenic belts have also played an important role in dominated ore deposits. [ABSTRACT FROM AUTHOR]

Porphyry Cu deposits (PCDs) are major global exploration targets for Cu, Mo, and Au, and mainly formed in accretionary orogens. This study integrates the whole-rock geochemical and Nd isotopic mapping based on ca. 5000 intermediate to felsic magmatic rocks to characterize the crustal structure and metallogeny of PCDs in the Central Asian Orogenic Belt (CAOB), the world's largest Phanerozoic accretionary orogen. The Nd isotopic maps image clearly the extent of cratons, microcontinents, and juvenile crustal blocks, with the PCDs intimately associated with juvenile crust that is consistent with the conclusions drawn by study in other orogens such as Himalayan–Tibetan. More importantly, PCDs are mainly distributed in the juvenile crust's margin adjacent to cratons or microcontinents, indicating that the external magmatic arcs are favorable sites for PCDs. The ore-forming intrusions of Cu-Au deposits are isotopically more depleted than those of Cu-Mo deposits, implying more input of mantle or juvenile crust materials into magmatic sources of Cu-Au deposits. Crustal thickness proxy mapping shows that Cu-Au deposits formed in thinner crust than Cu-Mo deposits, which could be used to target favorable sites for mineral exploration. The crustal thickness proxy and εNd(t) define a negative linear relationship, which quantifies the contributions of juvenile materials to PCDs in response to the changing crustal thickness, from which a newly proposed crustal maturity index was derived to distinguish the Cu-Au and Cu-Mo PCDs. The structure of the crust plays an important role in localizing PCDs; therefore, the integrated mapping of Nd isotopes and crustal thickness proxy could provide mappable exploration targets of PCDs at the orogen scale. [ABSTRACT FROM AUTHOR]

The Qulong deposit in Tibet is one of the largest porphyry copper‐molybdenum deposits in China. We used short‐wave infrared (SWIR) spectroscopy to examine the spectral characteristics of the extensively developed chlorite in this deposit. X‐ray diffraction and electron microprobe analyses were used for phase identification and to obtain the chemical composition, ion substitution relationships, and formation environment of the chlorite. SWIR spectral parameters were applied to detect the hydrothermal centers. The results indicate that the wavelength of the absorption feature for Qulong chlorite Fe‐OH (Pos2250) range from 2240 to 2268.4 nm; the chlorite substitution relationships are dominated by Mg‐Fe substitution at the octahedral sites together with AlIV‐Si substitution at the tetrahedral sites; the chlorite formation temperatures range within the medium‐low temperature hydrothermal alteration range from 164 to 281°C, with an average value of 264°C; the wavelength of the chlorite peak position for Fe‐OH (2250 nm) absorption and its chemical composition are positively correlated with AlVI, Fe + AlVI, Fe/(Fe + Mg), Fe, and Fe + AlIV but negatively correlated with Mg and Mg/(Fe + Mg); and the wavelength associated with the chlorite Fe‐OH (2250 nm) absorption feature is positively correlated with the temperature at which the chlorite formed. These correlations indicate that more Fe and AlVI ions and fewer Mg ions at the octahedral sites of chlorite lead to a longer the wavelength of the chlorite Fe‐OH (2250 nm) absorption feature and a higher chlorite formation temperature. The wavelength of the Qulong chlorite Fe‐OH (2250 nm) absorption feature (>2252 nm) can thus serve as an exploration indicator to guide the detection of hydrothermal centers in porphyry copper deposits. The results of the study indicate that the mineralogical and SWIR spectral characteristics of chlorite are significant indicators for locating hydrothermal centers within porphyry deposits. [ABSTRACT FROM AUTHOR]

This special issue grew out of a small conference The Known & the Unknown: Exploring Twelfth-Century Philosophy , which was funded by the Carlsberg Foundation, hosted by the Saxo Institute, and held at the University of Copenhagen in April 2018. Its central topic was the many, mostly unexplored, commentaries on Aristotle, Boethius, and Porphyry that constitute the key textual evidence for a fascinating phenomenon that, although it played a pivotal role in the philosophical revival of Western Europe, remains frustratingly underexplored to this day: the logical schools of the twelfth century. The present introduction has two parts. In the first part, John Marenbon lays out the background to this special issue of Vivarium as a whole, explaining both what the philosophical project pursued by twelfth-century logicians was and how, and how far, the historical project of understanding it has progressed over the last two hundred years. In the second part, Heine Hansen briefly presents the issue and its contents. [ABSTRACT FROM AUTHOR]

Mount Hagen is a mid-Pleistocene stratovolcano located in the Papua New Guinea Highlands. It was selected for this study because of (1) its close location to several giant Cu–Au porphyry deposits in the region; (2) its high-K calc-alkaline character (absarokite–shoshonite) and (3) its wide compositional range (2 to 12 wt % MgO). Whole-rock geochemistry, petrography and QEMSCAN observations are consistent with fractional crystallisation of the evolving magma being controlled by the phases now represented by the megacrysts in the lavas: olivine and clinopyroxene at high MgO and hornblende and plagioclase at low MgO. However, the role of plagioclase is enigmatic. Although it is an abundant megacryst phase in the low-MgO samples, plagioclase has little or no influence on fractional crystallisation, suggesting that it may be an antecryst. The appearance of plagioclase megacrysts does not slow the rate of increase in Al2O3 or Sr with decreasing sample MgO and the low-MgO samples do not have Eu anomalies. At ~5.5 wt % MgO, there are significant changes in the system that are inconsistent with simple fractional crystallisation. These changes include hornblende and plagioclase replacing olivine and clinopyroxene as the principal megacryst phases, a sharp rise in platinum-group elements (PGE) concentrations, the brief reappearance of high Fo olivine megacrysts and reversed zoning in the plagioclase megacrysts. These changes are interpreted to have resulted from a new pulse of magma entering the system, with higher water, MgO, SiO2 and PGE concentrations than the original parent magma. Scatter in the PGE data is attributed to the presence of micronuggets in all samples, including the most mafic samples. We conclude that the magma system became sulphide saturated during an early stage in its fractionation history, probably before leaving the crust to deep crustal magma chamber, and then became undersaturated as a consequence of decreasing pressure as magma ascended into a mid-crustal magma chamber. The early saturation episode had a pronounced influence on PGE concentration but had little affect Cu and Au, due to their lower partition coefficient into sulphides. The magma became sulphide saturated again in the crustal magma chamber at ~8.5 wt % MgO, this time affecting all chalcophile elements. Given the early episodes of sulphide saturation, depletion in Au in the Mount Hagen magma system and the absence of a known porphyry system, it is unlikely that Mount Hagen produced economic porphyry mineralisation. [ABSTRACT FROM AUTHOR]

The Tonggou deposit is a porphyry Cu and vein-type Cu-Zn mineralization system located in the Bogda Orogenic Belt, north of Eastern Tianshan. Systematic fluid inclusion analyses were performed on granular quartz from the magnetite–quartz stage and pyrite–chalcopyrite–quartz stage from the porphyry Cu mineralization. During the early stage of porphyry Cu mineralization, the ore-forming fluids were at high temperatures (450–501 °C) and high salinity (51.2–55.2 wt.% NaCl equiv.) H2O-NaCl hydrothermal fluids with fluid boiling. These fluids evolved to high temperature (412–450 °C) and intermediate to low salinity (8.3–14.2 wt.% NaCl equiv.) H2O-NaCl hydrothermal fluids during the pyrite–chalcopyrite–quartz stage. In addition, magnetite from the Tonggou deposit was studied as a marker for the ore-forming process evolution of porphyry and vein-type mineralization. Sampled magnetite can be divided into MagI (allotriomorphic magnetite from altered granodiorite), MagII (magnetite from altered granodiorite found in veinlets or as granular aggregates), MagIII (from the magnetite–quartz stage of porphyry mineralization), and MagIV (from the polymetallic sulfide–epidote–quartz stage of vein-type mineralization). Magnetite LA-ICP-MS data indicate a hydrothermal origin. The contents of Ti, Si, Al, and Ta are controlled by temperature, and these elements gradually decrease from MagI to MagIV. Moreover, fO2 has considerable influence on the substitution of Sn, V, and Mn in magnetite, and the contents of these elements generally decrease from MagI to MagIII—increasing only in MagIV. Indeed, high fO2 in the polymetallic sulfide–epidote–quartz stage (MagIV) of vein-type mineralization is shown by the presence of a replacement texture in ilmenite grains within hydrothermal magnetite. On the other hand, magnetite samples from the Tonggou deposit have relatively low Ti + V contents compared to other porphyry Cu deposits—plotting in the skarn field of the (Ti + V) vs. (Ca + Al + Mn) diagram—and shows negative correlations in the (Ti + V) vs. Sn diagram. These data indicate that the porphyry Cu mineralization at Tonggou formed at relatively lower fO2 conditions than the Tonggou vein-type mineralization and other typical porphyry Cu deposits. Finally, porphyry and vein-type mineralization at Tonggou are both sourced from the porphyry system, as a result of ore-forming fluid transfer to a different location. [ABSTRACT FROM AUTHOR]

This study tests the hypothesis of Cretaceous Turn of Geological Evolution (CTGE). It uses the large dataset on mineral deposits of NE Asia compiled by the US Geological Survey in collaboration with Russian, Mongolian, Korean, and Japanese geological institutions. As predicted, the Triassic–Early Jurassic and Late Cretaceous–Paleogene geodynamic activities in NE Asia were simple, producing a relatively small amount of mineral deposits (94 and 132, respectively). In contrast, the greatly increased geodynamic activity around CTGE produced a huge amount of mineral deposits (288). The Jurassic–Early Cretaceous superplume-related melts were injected into accretionary wedges that formed along the Pacific–Eurasian margins, whereas adakitic and granitic magmas derived from the shallow slab and lower crust were intruded into the huge intracontinental region. The characteristic mineral deposits are represented by the unique Jurassic–Early Cretaceous plume-related Ti-Fe-V (+P + Cr-PGE + Au + diamond) ores. Other CTGE representatives are the porphyry Cu-Mo and Au (+Ag)-vein deposits, which formation, however, continued into the Late Cretaceous–Paleogene epoch. These deposits were generated by the slab- and crust-derived adakitic and granitic melts formed under influence of the expiring superplume and intensifying subduction. The Late Cretaceous–Paleogene epoch is indicated by a decreasing metallogenic activity in general, and an increasing role of subduction-related deposits in particular. [ABSTRACT FROM AUTHOR]

The Duobaoshan Cu (Mo) deposit is one of the oldest super large porphyry deposits in the eastern part of the Central Asian orogenic belt. Although ore-forming processes have been extensively concerned, the post-mineralization ore preservation state was poorly focused on. In order to improve the ability of prospecting forecast, it is necessary to consider both deposit formation and deposit preservation. Here, we reported apatite fission track (AFT) data for the Duobaoshan porphyry copper deposits in the belt to reveal the cooling and exhumation history and evaluate ore preservation. The results show that the rapid cooling of the ore-hosting rock body occurred later than the surrounding rock body. The rapid cooling of the surrounding granodiorite occurred between 82 and 72 Ma, with the exhumation depth of 2.33–3.11 km and the exhumation rate of 0.25 mm/a, whereas the ore-hosting granodiorite porphyry was rapid cooling between 71.8 and 50.2 Ma, with the exhumation depth of 2.99–3.86 km and the exhumation rate of 0.22 mm/a. This differential exhumation and cooling event provide favorable geological conditions for the preservation of the ore body. [ABSTRACT FROM AUTHOR]

The Chaqiabeishan area of the Quanji Massif in NW China is characterized by extensive Li‐rich pegmatites and granites of various ages. In this study, the major and trace element compositions, U–Pb zircon ages, and zircon Hf isotopic compositions of the granites were investigated, including the Garideng porphyritic monzogranite, the Gongkaxiuma monzogranite, and the Narong granitic porphyry. Precise U–Pb zircon dating revealed that these three granites were emplaced at approximately 468, 444, and 245 Ma, respectively. The geologic and geochemical data indicate that the Garideng porphyritic monzogranite and the Narong granitic porphyry are two I‐type granites, and the Gongkaxiuma monzogranite is an A2‐type granite. Based on the Hf isotopes and geochemical data, the Garideng porphyritic monzogranite and the Narong granitic porphyry were derived from partial melting of the relatively deep and relatively shallow juvenile mantle‐derived mafic lower crust, respectively, while the Gongkaxiuma monzogranite was derived from partial melting of the granulitic metamorphic basement. Moreover, tectonically, the Garideng porphyritic monzogranite represents the northward subduction of the South Qilian oceanic plate from 500 to 440 Ma. The Gongkaxiuma monzogranite represents the closure of the South Qilian Ocean by ~440 Ma, and the Narong granitic porphyry represents the Late Permian to Middle Triassic southward subduction of the Zongwulong oceanic plate under the Quanji Massif. [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]

Huangmeijian composite pluton is a uranium-bearing A-type granite in Middle-lower Yangtze River valley metallogenic belt. Huangmeijian composite pluton can be divided into four emplacement stages from earliest to latest, including stage Ⅰ biotite quartz syenite, stage Ⅱ syenite porphyry, stage Ⅲ quartz syenite and stage Ⅳ alkali feldspar granite. The vein-type uranium mineralization predominantly occurs along the contacts between the stage Ⅰ biotite quartz syenite and the clastic rocks. The study on the micro-textures, REE characteristics and U-Pb dating of zircons in Huangmeijian composite pluton was carried out. The results show that the zircons of biotite quartz syenite, syenite porphyry and quartz syenite are of magmatic genesis, and yield zircon U-Pb ages of(131.8±1.1),(129.7±1.6),(124.7±1.6)Ma, respectively. The cores of zircons in alkali feldspar granite are of magmatic genesis and undergo metamictization, while the rims of zircons in alkali feldspar granite are altered by hydrothermal fluid, and probably undergo recrystallization. The zircon U-Pb dating of alkali feldspar granite yields the crystallization age of(111.5±1.3)Ma and the hydrothermal activity age of(107.6±2.1)Ma. Based on the previous geochronological studies, the A-type granites in Middle-lower Yangtze River valley metallogenic belt can be divided into three periods. The early period is represented by biotite quartz syenite and syenite porphyry with crystallization age of 132-129 Ma; the main period is represented by quartz syenite and syenogranite with crystallization age of 128-124 Ma; the late period is represented by alkali feldspar granite with crystallization age of 115-110 Ma. The crystallization ages of alkali feldspar granite and hydrothermal activity time are close to the uranium mineralization ages; combining with the stable isotope studies, it probably indicates that stage Ⅳ alkali feldspar granite of Huangmeijian composite pluton has provided the ore-forming fluid and heat for the uranium mineralization. [ABSTRACT FROM AUTHOR]

The Zhaiping Ag–Pb–Zn vein deposit in the Coastal Volcanic Belt of southeastern China, which resulted from subduction of the paleo-Pacific oceanic lithosphere beneath the South China Block, is hosted by Early Cretaceous sub-volcanic rocks (rhyolite porphyry) and younger granite porphyry and quartz porphyry. Three generations of veins have been recognized: (i) pre-ore quartz + pyrite, (ii) syn-ore silver + pyrite + pyrrhotite + base metal sulfides + quartz + sericite, and (iii) post-ore quartz + calcite + fluorite veins. Rubidium–Sr dating of syn-ore pyrite yielded an isochron age of 132.2 ± 2.1 Ma (2σ, MSWD = 2.0, n = 4), which is roughly coincidental with the age of the granite porphyry and quartz porphyry (zircon U–Pb age: ca. 133 Ma). The age data, together with Pb, S, H, and O isotopic compositions, indicate a close temporal and possibly genetic relationship between mineralization and porphyry magmatism at Zhaiping. Geochemical and isotope data demonstrate that the Zhaiping sub-volcanic rocks were derived from partial melting of Proterozoic crustal sources and underwent fractionation of feldspars, monazite, and/or allanite. The 87Sr/86Sr ratios of pre-ore (Aph1) and syn-ore (Aph2) stage apatite are in the ranges of 0.71350 to 0.71441 and 0.71260 to 0.71328, respectively, which are distinct from those of the sub-volcanic intrusive rocks (0.7119–0.7125). The Sr isotope signature, together with lower fluid temperatures (< 360 °C) relative to typical magmatic fluid, points at addition of an external fluid. It is suggested that the sub-volcanic intrusion acted as a heat source that drove the dehydration of, and subsequent fluid circulation within, the host rocks. Lower 87Sr/86Sr ratio but higher Sr content of Aph2 relative to Aph1 possibly indicates continuous fluid–rock interaction and progressive decomposition of feldspar in the host rocks, thus supplying large amounts of Sr and probably Pb to the ore fluid. [ABSTRACT FROM AUTHOR]

Dabie-type porphyry Mo deposits have recently been identified as a new subtype of porphyry Mo deposits, but several questions remain about the role of ore-related magmas in the formation of this type of deposit, as well as distinctions in genetic processes with the well-studied Climax-type porphyry Mo deposits. Here, mineral and melt inclusions from the giant Qian'echong deposit, Dabie orogen, central-eastern China, were studied in order to improve our understanding of the nature and the role of ore-related magmas in the genesis of Dabie-type porphyry Mo deposits. The magmatic and hydrothermal evolution of the system was reconstructed based primarily on the analysis of quartz-hosted silicate melt and mineral inclusions, in concert with field and petrographic relations as well as previously published U–Pb and Re-Os geochronology. Ore-related magmas at Qian'echong include, from early to late, quartz porphyry dikes, rhyolite porphyry dikes, granite porphyries (stock and dikes) and a newly discovered, deep-seated monzogranite porphyry stock. Based on TitaniQ thermobarometry, these lithologies were sourced from a ~16–19-km deep (500–600 MPa) magma chamber and underwent nearly isothermal decompression to ~7 km (200 MPa), at temperatures ranging from 720°C to 690°C. According to the trace element composition of melt inclusions, in combination with published whole-rock Nd isotopic compositions, the early magma evolved from quartz porphyry to rhyolite porphyry through fractionation crystallization and thus became a crystal mush. This viscous crystal mush was subsequently re-melted to produce the granite porphyries and was injected with melts from a different source to generate the monzogranite porphyry. At Qian'echong, all melt inclusions have low concentrations of Mo (2–8 ppm), >5 wt. % H2O, and little to no F (≤0.26 wt. %), arguing against the requirement for ore-related magmas to be enriched in Mo to form large porphyry Mo deposits. Rayleigh fractionation modeling shows that the concentration of Mo in the quartz and granite porphyries increased through fractionation of quartz, feldspars, biotite, magnetite, and ilmenite and that Mo was subsequently depleted in the melt through fluid exsolution, exclusively in the rhyolite and monzogranite porphyries, as a result of magma ascent and decompression. This suggests that, in addition to ore-related granite porphyry, both the rhyolite and the monzogranite porphyries also contributed to the hydrothermal mineralization. This study confirms that the formation of porphyry Mo deposits does not rely on abnormally high concentrations of Mo in ore-related magmas but instead requires efficient extraction of Mo from large volumes of magmas, with normal concentrations of Mo. Unlike the Climax-type deposits where multiple pulses of ore-forming fluids are delivered from convecting shallow magma chambers, Mo mineralization in Dabie-type deposits was achieved by the assembling of ore-forming fluids from successively emplaced, relatively deep intrusions. Although the Dabie- and Climax-type Mo deposits are respectively associated with I-type and A-type granitoids in the Dabie orogen, it is suggested that both types of magmas are derived from the partial melting of subducted Yangtze continental crust and that it is the tectonic transition from compressional to extensional settings that controlled the different styles of porphyry Mo mineralization in this orogen. [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]

The essential sources and processes required for the formation of Cu–(Au)-porphyry deposits have been part of a long-standing debate. In this study we investigate one of the youngest and best-preserved world-class Cu–(Au)-porphyry systems in order to learn more about melt sources and what geochemical tracers in zircon and apatite might be useful to identify ore-forming intrusions within porphyry systems. Combined, in-situ Hf, O, and Nd isotope analyses in zircon and apatite imply that the Tampakan magmas were derived from depleted mantle sources. Hence, we suggest that older crustal components or metasomatized mantle are not required for the production of metallogenically fertile magmas in island arc settings. Based on the compositions of apatite and zircon, we confirm that previously established fertility-indicator signatures of these minerals are useful to identify fertile porphyry systems. Our data show that intrusions directly associated with mineralization events contain apatite with elevated Cl and S concentrations compared to pre- and post- mineralization igneous events. [ABSTRACT FROM AUTHOR]

The eastern part of the North China Craton suffered significant lithospheric thinning since the Mesozoic, and petrogenesis of the Dagushan adakitic diorite porphyries provides an excellent opportunity to investigate the lithospheric thinning mechanism and geodynamic setting. The zircon LA-ICP-MS U–Pb geochronology reveals that the representative Dagushan adakitic porphyry was formed at 120.5 ± 0.5 Ma. The Dagushan diorite porphyries are characterized by the relatively high contents of SiO2 (64.25–65.70 wt%), Al2O3 (15.00–15.38 wt%), Sr (333–491 ppm), low contents of Y (6.50–10.3 ppm), and Yb (0.57–0.85 ppm), and resultant high Sr/Y (47–57) and La/Yb (37–55) ratios, exhibiting geochemical characteristics of typical adakites. Moreover, the relatively high MgO contents (MgO = 2.23–2.29 wt%) and Mg numbers (Mg# = 54–56) of the Dagushan adakitic rocks imply that the pristine adakitic magma interacted with mantle peridotite. However, the zircon Hf isotopic signatures (εHf(t) = − 19.0 to − 28.0; TDM2 = 2378–2944 Ma) suggest an ancient lower crustal source. Therefore, it is proposed that the Dagushan adakitic rock was probably generated by partial melting of delaminated lower crust which was triggered by the Tan-Lu Fault Zone, and the interaction of pristine adakitic magma with mantle peridotite during the ascent finally generated the Dagushan high Mg# adakitic rocks. It is suggested that delamination was an important mechanism for lithospheric thinning of the NCC. [ABSTRACT FROM AUTHOR]

The origin of hypogene alteration and mineralization features in the Escondida porphyry Cu deposit resulted from intense overprinting related to three main hydrothermal stages. The beginning of each stage is recorded by deposition of bright quartz crystals on vein walls that precipitated from high-temperature fluids. In the deepest zones of the deposit, the earliest stage started with exsolution of intermediate-density fluids, which transported high concentrations of Cu, whereas Mo was not detected. However, in the shallow zones, the early stage began with depressurization and unmixing of intermediate-density fluids, which generated both a hypersaline and vapour-rich fluid phase, producing an important geochemical segregation between both phases. The transitional stage also started with circulation of intermediate-density fluids but never experienced unmixing. These fluids transported the highest Mo concentrations in the deposit; however, Cu displays lower concentrations relative to intermediate-density fluids from the early stage. The beginning of the late stage was also associated with intermediate-density fluids; however, Cu and Mo were below the detection limits in most of the analysed fluids. During the evolution of the three stages, the fluids experienced gradual cooling, which promoted the precipitation of euhedral and zoned quartz crystals that overgrew the early high-luminescence quartz generations. Sometimes, sulfide minerals display euhedral crystal boundaries with zoned quartz, suggesting that mineralization started during these phases. The latest events detected in each main stage are linked to cooler and low-salinity fluids, from which dark quartz and hypogene sulfides precipitated along microfractures and interstitial spaces developed in the earlier quartz generations. [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]

In order to understand how the metallogenic process of porphyry deposit specifically and directly respond to regional uplifting and exhumation, we compiled previous fluid inclusion data of 32 porphyry deposits in China by recalculating the fluid trapping depths and trapping depth reduction magnitude from early to late mineralization stage veins. The data reveal that the average trapping pressure ratio (Ave TPE/TPL) between early‐ and late‐stage veins of the these deposits are 1.2–18.4, mainly in the range of 1.35–5.83, with average trapping pressure reduction (1–Ave TPL/TPE) from early‐ to late‐ stage veins are 17%–95%, and mainly in the range of 25%–83%. The fluid trapping pressure based mineralization depths most of the porphyry deposits in China had decreased from early to late vein stages by at least 450 m (900–5800 m predominant), or greater than 950 m when take the average depth reduction value, which is greater than the current gap between early‐ and late‐ stage veins of each deposit. We propose that the apparently greater mineralization depth reduction magnitude than the current elevation gaps between early and late veins are likely a consequence of syn‐mineralization uplifting and exhumation process that often occurs in porphyry systems. [ABSTRACT FROM AUTHOR]

Producing an accurate and valid mineral prospectivity map is one of the most significant parts of mineral exploration studies. For this purpose, it is needed to obtain valid evidential layers and integrate them with an accurate methodology. Knowledge and data‐driven methods are two primary techniques applied to combine various evidential layers for mineral prospectivity mapping, of which each of them includes a variety of analytical techniques. In this study, in the first step, satellite data, aeromagnetic and airborne radiometric data, stream sediment geochemical data and geological data were applied to create valid remote sensing, geophysical, geochemical, lineaments and lithological evidential layers of the study area that are an essential factor in recognition porphyry copper mineralization, then in the second step, based on the known mineralization occurrences data, the evidential layers were weighted. Finally, these layers were integrated using fuzzy logic and index overlay methods in a combination of knowledge and data‐driven way. Validation of each layer was done using available data in the second step. The final mineral prospectivity map was evaluated, and the confirmation of this layer detected that the final mineral prospectivity map obtained from data‐driven multi‐index overlay method has a higher ore prediction rate of 76%, which identifies 24% of the area as potential zones for further exploration. [ABSTRACT FROM AUTHOR]

Arc magmas globally are H2O-Cl-S-rich and moderately oxidized (ΔFMQ = +1 to +2) relative to most other mantle-derived magmas (ΔFMQ = 0). Their relatively high oxidation state limits the extent to which sulfide phases separate from the magma, which would otherwise tend to deplete the melt in chalcophile elements such as Cu (highly siderophile elements such as Au and especially platinum-group elements are depleted by even small amounts of sulfide segregation). As these magmas rise into the crust and begin to crystallize, they will reach volatile saturation, and a hydrous, saline, S-rich, moderately oxidized fluid is released, into which chalcophile and any remaining siderophile metals (as well as many other water-soluble elements) will strongly partition. This magmatichydrothermal fluid phase has the potential to form ore deposits (most commonly porphyry Cu ± Mo ± Au deposits) if its metal load is precipitated in economic concentrations, but there are many steps along the way that must be successfully negotiated before this can occur. This paper seeks to identify the main steps along the path from magma genesis to hydrothermal mineral precipitation that affect the chances of forming an ore deposit (defined as an economically mineable resource) and attempts to estimate the probability of achieving each step. The cumulative probability of forming a large porphyry Cu deposit at any given time in an arc magmatic system (i.e., a single batholith-linked volcanoplutonic complex) is estimated to be ~0.001%, and less than 1/10 of these deposits will be uplifted and exposed at shallow enough depths to mine economically (0.0001%). Continued uplift and erosion in active convergent tectonic regimes rapidly remove these upper-crustal deposits from the geological record, such that the probability of finding them in older arc systems decreases further with age, to the point that porphyry Cu deposits are almost nonexistent in Precambrian rocks. A key finding of this paper is that most volcanoplutonic arcs above subduction zones are prospective for porphyry ore formation, with probabilities only falling to low values at late stages of magmatic-hydrothermal fluid exsolution, focusing, and metal deposition. This is in part because of the high threshold required in terms of grade and tonnage for a deposit to be considered economic. Thus, the probability of forming a porphyry-type system in any given arc segment is relatively high, but the probability that it will be a large economic deposit is low, dictated to a large extent by mineral economics and metal prices. [ABSTRACT FROM AUTHOR]

Post-collisional K-rich magmatic rocks of the Qinghai–Tibet Plateau provide important information for understanding the continental collision and uplift of this plateau during the Cenozoic. However, the source of these K-rich rocks is still debated, and limited investigations have been conducted in the western Kunlun Mountains (WKM) in the northwestern margin of the plateau. In this paper, we present geochemical, geochronological, and Sr–Nd–Hf isotope data for Quanshuigou post-collisional K-rich igneous rocks from the WKM. Geochronological results show that these rocks were emplaced during two stages: (1) ca. 5.3 Ma, as an intrusive suite of granite porphyries; and (2) ca. 4.8 Ma, as a suite of shoshonites. These rocks are enriched in light rare earth elements (LREEs) and large-ion lithophile elements (LILEs), and depleted in heavy rare earth elements (HREEs) and high-field-strength elements (HFSEs). Compositions of the granite porphyries classify these rocks as high-K calc-alkaline peraluminous A-type granites. Combining the negative zircon εHf(t) values (−6.9 to −1.1) with Hf crustal model ages (TDM2) of 1.16–1.53 Ga and negative εNd(t) values (−5.31 to −4.96) with two-stage Nd model ages (TDM2) of 1.22–1.46 Ga, these signatures suggest that the granite porphyries most probably originated from partial melting of thickened lower crust with limited input of mantle-derived magmas. In contrast, the shoshonites have low SiO2 contents (50.84–53.94 wt.%), relatively high Mg# values (50–57), and εNd (t) values ranging from −6.18 to −5.34, with single-stage Nd model ages (TDM1) of 0.97–1.02 Ga. Our analyses show that the parental magma of the shoshonites probably formed by partial melting of EMII-type lithospheric mantle, with the addition of subducted and recycled oceanic sediments. Hence, we conclude that these granite porphyries and shoshonites formed in a post-collisional, extension-related geodynamic setting and that the melting was probably triggered by motion on the Altyn Tagh strike-slip fault system. [ABSTRACT FROM AUTHOR]

Crustal growth is commonly associated with porphyry deposit formation whether in continental arcs or collisional orogens. The Miocene high-K calc-alkaline granitoids in the Gangdese belt in southern Tibet, associated with porphyry copper deposits, are derived from the juvenile lower crust with input from lithospheric mantle trachytic magmas, and are characterized by adakitic affinity with high-Sr/Y and La/Yb ratios as well as high Mg# and more evolved isotopic ratios. Researchers have argued, lower crust with metal fertilization was mainly formed by previous subduction-related modification. The issue is that the arc is composed of three stages of magmatism including Jurassic, Cretaceous, and Paleocene--Eocene, with peaks of activity at 200 Ma, 90 Ma, and ca. 50 Ma, respectively. All three stages of arc growth are essentially similar in terms of their whole-rock geochemistry and Sr-Nd-Hf isotopic compositions, making it difficult to distinguish Miocene magma sources. This study is based on ~430 bulk-rock Sr-Nd isotope data and ~270 zircon Lu-Hf isotope data and >800 whole-rock geochemistry analyses in a 900-km-long section of the Gangdese belt. We found large scale variations along the length of the arc where the Nd-Hf isotopic ratios of the Jurassic, Cretaceous, and Paleocene--Eocene arc rocks change differently from east to west. A significant feature is that the spatial distribution of Nd-Hf isotopic values of the Paleocene--Eocene arc magmas and the Miocene granitoids, including metallogenic ones, are "bell-shaped" from east to west, with a peak of εNd(t) and εHf(t) at ~91°E. In contrast, the Jurassic and Cretaceous arc magmas have different isotopic distribution patterns as a function of longitude. The isotopic spatial similarity of the Paleocene--Eocene and Miocene suites suggests that the lower crust source of the metallogenic Miocene magmas is composed dominantly of the Paleocene--Eocene arc rocks. This is further supported by abundant inherited zircons dominated by Paleocene--Eocene ages in the Miocene rocks. Another important discovery from the large data set is that the Miocene magmatic rocks have higher Mg# and more evolved Sr-Nd-Hf isotopic compositions than all preceding magmatic arcs. These characteristics indicate that the involvement of another different source was required to form the Miocene magmatic rocks. Hybridization of the isotopically unevolved primary magmas with isotopically evolved, lithospheric mantle-derived trachytic magmas is consistent with the geochemical, xenolith, and seismic evidence and is essential for the Miocene crustal growth and porphyry deposit formation. We recognize that the crustal growth in the collisional orogen is a two-step process, the first is the subduction stage dominated by typical magmatic arc processes leading to lower crust fertilization, the second is the collisional stage dominated by partial melting of a subduction-modified lower crust and mixing with a lithospheric mantle-derived melt at the source depth. [ABSTRACT FROM AUTHOR]

The nature and source of magmatism associated with large igneous provinces (LIPs) remain disputed. Here we investigate the role of recycled materials that contributed to mantle heterogeneity in the Tarim Large Igneous Province (TLIP) in China through integrated Zn-Mg-Sr-Nd isotopes of a rare tephritic rock suite. The Sr--Nd isotopes [(87Sr/86Sr)i = 0.70368-0.70629; εNd(t) = -0.25-4.64] and δ26Mg values (-0.23‰ to -0.34‰) of the tephritic porphyries are consistent with a normal mantle origin. In contrast, the whole rock and pyroxene phenocrysts yield δ66Zn values of +0.28‰ to +0.46‰ and +0.30‰ to +0.39‰, which are slightly heavier than those of the terrestrial mantle (+0.16 ± 0.06‰) and mid-oceanic-ridge basalts (MORBs) (+0.27 ± 0.05‰). We exclude the possibility that the heavy Zn isotopes of the Wajilitag tephritic porphyries are caused by magmatic processes such as fractional crystallization and partial melting and correlate the isotopic features to the role of altered oceanic crust along with magnesite in the mantle source. The Wajilitag tephritic porphyry displays trace-element patterns similar to those of the melts from natural hornblendite, especially those of hornblendite + peridotite. Additionally, the geochemical characteristics such as enrichment in Nb and Ta, depletion in K, high TiO2, and constant Na2O/K2O ratios also suggest that the tephritic porphyries were derived from an amphibole-bearing source contributed by altered oceanic crust along with sedimentary carbonates. Our study provides insight into the contribution of subducted materials to the mantle heterogeneity beneath the TLIP and highlights the role of subduction in the deep carbon cycle and subducted slab-lithosphere-plume interaction in the generation of LIPs. [ABSTRACT FROM AUTHOR]

Tourmaline is widespread at the Bilihe porphyry gold deposit in Inner Mongolia, China. Five types of tourmaline are recognized based on their occurring locations and microscopic structures: (1) Tur-A in quartz–magnetite ± K-feldspar veins and related potassic-altered rocks, (2) Tur-B in auriferous quartz veinlets, (3) Tur-C in the intermediate argillic shell, (4) Tur-D in late quartz–carbonate–tourmaline–pyrite veins, and (5) Tur-HB in hydrothermal breccia pipes, consisting of three sub-generations (Tur-HB1, -HB2, and -HB3). Almost all these tourmalines have a schorlitic–dravitic composition and belong to the alkali group. Most of the tourmalines contain high Al contents, which may suggest that the fluids are Al-enriched, and that (□Al)(NaFe)-1 and (AlO)(R2+)-1(OH)-1 exchanges have dominated their elemental substitutions. Tur-A and -B yield similar REE patterns with no strong fractionation of LREE and HREE, whereas LREE-enrichment and HREE-depletion characterize Tur-C and Tur-D; Tur-HB1 and -HB2 have flat REE patterns. Tourmalines in hydrothermal veins always show negative Eu anomalies, whereas the ones replacing plagioclase in the altered rocks yield positive Eu anomalies. The mineral precipitation and assimilation of host rocks probably both contributed to the variable compositions of Bilihe tourmaline. Tur-A−D from the main orebody all yield positive δ11B values ranging from +0.7 to +6.3‰, whereas Tur-HB1−HB3 from the hydrothermal breccia pipe show negative δ11B values of −8.8 to −3.5‰. Magmatic hydrothermal fluids enriched in isotopically light boron could have dominated the formation of Tur-HB. In contrast, the heavy boron in Tur-A−D was probably leached from the widespread marine carbonates around the deposit. Systematic contrasts in the trace element compositions of tourmaline from different mineralization types and granitic rocks suggest that (Sn + Li) vs. (Ni + V + Zn), (∑REE + Y + Zr) vs. (Ni + V + Zn) and V vs. Zn are potential elemental groups for distinguishing tourmaline from different environments. [ABSTRACT FROM AUTHOR]

We performed experiments to determine the solubility of Au and Pd in magmatic aqueous fluids as a function of oxygen fugacity (ƒO 2), temperature (T), pH and total chloride concentration (Cl total). Experiments were conducted at 800–1000 °C and 200 MPa in an externally-heated rapid-quench Molybdenum-Hafnium Carbide (MHC) cold-seal pressure vessel assembly. We employed a synthetic fluid inclusion (SFI) technique to entrap equilibrated, hydrothermal fluids in response to in situ fracturing of quartz cylinders at experimental run conditions. The solubility of Au and Pd both have positive relationships with ƒO 2 , temperature, acidity and chlorinity. Concentrated aqueous brines containing 63 wt.% NaCl can dissolve wt.% levels of Au (∼1.2 wt.%) and Pd (∼1.7 wt.%) at metal saturation in relatively oxidized conditions, 1.44 log units above the Ni-NiO oxygen buffer (NNO+1.44), and mildly acidic pH at 900 °C and 200 MPa. Thermodynamic modeling of experimental results suggests that Au is mainly transported as AuCl (aq) at high pH and low Cl total conditions, whereas HAuCl 2(aq) and potentially AuCl 2(aq) − predominates at low pH and high Cl total conditions. Results from thermodynamic modeling also suggest Pd is mobilized in significant contributions by both PdCl 2(aq) and PdCl 3(aq) − with the latter gaining predominance in response to increasing Cl total. Calculated fluid/melt partition coefficients for Au and Pd in low-density, magmatic vapors at 1000 °C and 200 MPa suggest that Pd may experience fractionation from Au in porphyry Au-Cu (±Pd, Pt) systems due to the restricted compatibility of Pd in the fluid phase (requiring strongly acidic and substantially high ƒO 2 conditions). Moreover, high-density, concentrated aqueous brines facilitate the compatibility of Pd in the fluid phase which may be important with respect to the formation of platinum-group element (PGE)-enriched horizons in layered mafic intrusions (e.g., J-M Reef, Stillwater Complex, U.S.A.). The potential for magmatic, near-neutral pH, high-salinity brines to dissolve significant amounts of Pd as Pd(II)-chloride complexes (∼400 to ∼900 µg/g) well below the NNO buffer suggests that such fluids may be responsible for late-stage hydrothermal remobilization of Pd within mafic-ultramafic igneous environments (e.g., Cu-Ni-PGE footwall deposits and low-sulfide PGE deposits in the Sudbury Igneous Complex, Canada). [ABSTRACT FROM AUTHOR]

The infrastructures of the Sungun copper mine are located inside the ultimate extraction limits where blasting operation is carried out in their proximity. In such cases, investigating blast-induced phenomena is at most important to reduce their adverse impacts on the mine and surrounding environments. The main objective of this study is to analyze and improve the most critical adverse outcomes of over 100 cases of blasting in different zones of Sungun mine to make it feasible from an operational viewpoint. Hence, the blasting operation and its adverse outcomes recorded in the mine were first studied. Moreover, the important factors that resulted in blast-induced phenomena were investigated. These investigations were in the form of observation, acquisition, and complete field studies at the site. Then, the technical problems and weaknesses of the blasting operation resulted in undesirable outcomes, and their negative impacts on the mine and surrounding environment were extracted and analyzed using checklists, specification forms, and recorded observations. Given the results of the qualitative and quantitative analysis of operation based on a trial blasting strategy, an improved blasting scheme was discussed to enhance the current conditions and reduce the undesirable outcomes down to the permissible limits. The present study could provide a practical framework to identify, analyze, and reduce the critical adverse blast-induced phenomena in metallic open-pit mines. [ABSTRACT FROM AUTHOR]

Glacial erratics, whose petrographic composition ranges from limestone to porphyry, granite and gneiss, are found in the northern part of Mantua province (Italy) on the moraine hills of Lake Garda end-moraine Complex. They are polyhedral in shape and their maximum size attains 1.80 m. Glacial erratics are natural assets of great geological and landscape interest and should be adequately preserved by public authorities. [ABSTRACT FROM AUTHOR]

This paper considers the imagery of the Lindisfarne gospels (and to a lesser extent the Book of Kells) in light of pagan views of Christianity, preserved through the writings of late antiquity as well as the living memory of Insular pagans. It argues that the production of this gospel manuscript—down to minute visual details—was still being shaped by the persuasive methods of late-antique Christian fathers’ attempts to defend their faith against criticism. As a result, the book’s effort to persuade the viewer bears the scars of a drawn-out debate between figures such as St Augustine and earlier anti-Christians such as Porphyry. This resemblance is one that draws the intellectual world of the third- to fifth-century Roman empire close to the eighth-century Anglo-Saxon kingdoms. [ABSTRACT FROM AUTHOR]

This commentary reflects on Radcliffe Edmonds' remarkable Ancient Magic, Theurgy, and Philosophy , focusing specifically on his study of the interface between theurgy and magic in late antiquity. Edmonds explores the striking similarities of theurgy and magic. After demonstrating a keen understanding of how theurgy worked for Iamblichus and the later Platonists, he compares its metaphysics and theory to the magical papyri. Although magicians were far less "theoretically inclined" than Platonic theurgists, Edmonds argues that they implement theurgical principles in their practices. He finds remarkable parallels and makes a strong case, but I argue that in one significant respect the magician and theurgist were profoundly different, a difference defined by the fact that Platonists like Iamblichus had passed through the withering catharsis of Platonic mystagogy, something that was not required or evident among magicians. [ABSTRACT FROM AUTHOR]

Aim. The aim of this study was to trace the scenarios of theatrical adaptations of the novel Crime and Punishment, directed by both Andrzej Wajda and Waldemar Śmigasiewicz, as well as to indicate the similarities and differences between the works studied. Methods. Two separate theatrical scenarios were analysed and compared scene by scene in order to show, and then discuss, the similarities and differences in the construction of the play in terms of the translation of a literary work into a stage work. Results. Analysis revealed that both scenarios are based on three alternating dialogues between Raskolnikov and Porphyry and Raskolnikov and Sonya. Both theatrical adaptations focus on the criminal's mental condition immediately after the crime committed, and on the question: why did Raskolnikov kill? The differences in scenarios are due, firstly, to the directors' choice of supporting characters. Secondly, because of the episodes that occur between the dialogues of Raskolnikov with Porphyry and Raskolnikov with Sonya. Conclusions. In this study, only similarities and differences in the construction of the textual layer of the adaptations in question were taken into account, in order to understand which ideas and symbols of Crime and Punishment Wajda and Śmigasiewicz wanted to convey to the audience. Stage solutions such as acting, set design, costumes, lights, music and other means of expression were not covered by the study. [ABSTRACT FROM AUTHOR]

Airborne magnetic and radiometric data of parts of Zamfara, North West Nigeria, were analysed to delineate the structural complexity, emplacement of porphyry intrusives and hydrothermal alteration zones with a view to deducing optimum areas of mineralisation. These mineral indicators were achieved with the Centre for Exploration Targeting (CET) grid, CET porphyry analysis, and radiometric ratio maps. The result indicated that the structures within the study area trend in the NE–SW, WNW–ESE, ENE–WSW, NW–SE and E–W directions. Areas with high structural complexity have a high occurrence of porphyry features indicating a strong probability for further ore deposition. The porphyry features and hydrothermally altered zones from the K/eTh ratio map showed more structural relationships that aided the migration of hydrothermal fluids that react with rock formation for subsequent alteration. Mineral indicators from the various methods were integrated to proffer promising areas of mineralisation within the study area. [ABSTRACT FROM AUTHOR]

Melt inclusion (MI) homogenization experiments are essential for determining the pressure-volume-temperature-composition (P-V-T-X) parameters of magma systems. The hydrothermal diamond-anvil cell (HDAC) is currently the only equipment that can exert external pressure on MIs while allowing in situ observation of MI phase changes during heating. The HDAC's pressure potentially prevents the MI diffusion that, under heating at one atmosphere, produces artificially elevated measurements of phase transition temperatures. It is important to compare the phase transition temperatures measured using HDAC at elevated external pressure with those obtained using conventional equipment at one atmosphere. Such a comparison not only helps assess the reliability of HDAC phase transition temperatures but also helps determine phase transition temperatures that are naturally occurring in MI during the natural history of cooling. In this study, we homogenized MIs hosted in quartz from the granitic porphyry in the Yixingzhai Au deposit, China, using HDAC at an elevated pressure of ~(140–230) MPa. We compared our experimental results with published data measured using a Linkam TS1500 stage at one atmosphere. The experiments show that the initial melting temperature (TIniM), total melting temperature (TTotM), and total homogenization temperature (ThTot) of the MIs are 695 ± 20, 780 ± 15, and 833 ± 17 °C, respectively. These phase transition temperatures are as much as 374 °C lower than the corresponding values measured at one atmosphere using the Linkam stage. Moreover, the temperatures measured using HDAC agree with actual values estimated using the linear extrapolation method based on correlations of MI size with phase transition temperatures measured using the Linkam stage. Based on the experimental HDAC results, we estimate that MIs in the Yixingzhai Au deposit were trapped at ~140 Ma and contained ~2 wt% H2O. These values are consistent with previously estimated emplacement pressures and H2O contents of granitic magmas in granitic porphyry-type Cu-Au deposits. Our results demonstrate that MI-homogenization experiments using HDAC at suitably elevated pressures can yield reliable naturally occurring phase transition temperatures in MI during the melt cooling process. [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]

The Grasberg Cu—Au—(Mo) deposit comprises the shallower Main Grasberg porphyry Cu—Au and the deeper Gajah Tidur (GT) porphyry Cu—Mo—(Au) systems. The GT porphyry preserves various types of white mica whose geochemical variations provide insights into the white mica‐dominated alteration of porphyry systems. The white mica assemblages within the GT porphyry system comprise: (1) muscovite‐anhydrite‐chlorite (MAC), (2) muscovite‐chlorite‐anhydrite (MCA), and (3) muscovite‐quartz ± pyrophyllite (MQP). These assemblages display zonation from central and deep parts of the system to its shallower and peripheral parts. The MAC alteration white micas are characterized by high Na, Fe, Ti, and V concentrations, and with short‐wave infrared Al—OH absorption wavelengths of 2203–2208 nm. The MCA white micas have higher Mg content than the other two GT white mica assemblages but similar Al—OH absorption wavelengths to the MAC white micas. The MQP alteration white micas have low Na, Fe, Mg, and Ti, but relatively high Si, Al, and F, and Al—OH absorption wavelengths are largely shorter than 2202 nm. We interpret that the high Fe and Ti content of the MAC white micas is due to inheritance of these elements from mafic minerals they replaced. The higher Fe content of these white micas explain their longer wavelength Al—OH absorption positions relative to the MQP white micas. In contrast, lower Fe content and shorter Al—OH wavelengths of the MQP white micas are caused by their higher Si and Al content, which reduces iron occupancy in the white mica crystal structure. White micas in this assemblage formed at lower temperature and probable lower pH condition that may have led to a replacement of Fe by Al. The short‐wave infrared Al—OH position of white mica together with the associated hydrothermal assemblage can be used as a proximitor for porphyry Cu hydrothermal centres. White mica associated with chlorite, anhydrite, and chalcopyrite, which commonly occur overprinting or adjacent to the potassic alteration center, are characterized by Al—OH absorption positions at 2200–2215 nm. By contrast, white mica associated with quartz‐pyrite are characterized by Al—OH wavelengths shorter than 2202 nm. In the distal part of porphyry Cu system, white micas may be associated with chlorite and have Al—OH absorption positions longer than 2204 nm. [ABSTRACT FROM AUTHOR]

An indication of high‐sulfidation epithermal–porphyry transition was observed in the Kumbokarno prospect, East Java, Indonesia. The prospect is composed of two Middle Miocene intrusions with tonalitic and dioritic compositions. Tonalite, the main host‐rock was subjected to argillic, advanced argillic, and vuggy quartz alteration, whereas the juxtaposing diorite was subjected to peripheral propylitic alteration. Three types of vein exist in the research area, which are massive quartz, comb quartz, and stockwork vein. In addition, supergene alteration represented by goethite and hematite pervasively superimposed both the hydrothermal alteration and mineralization. Fluid inclusion petrography and microthermometry analysis on three types of quartz veins distinguished primary fluid inclusions into two groups, that is, V30 group composed of vapor (30 vol%)–liquid (70 vol%), and the second group V30H group composed of vapor (30 vol%)–halite (30 vol%)–liquid (40 vol%). The homogenization temperatures of both the groups show a similar range of ca. 350–480°C, but the V30H group has significantly higher salinity (35–50 wt% NaCl eq.) compared to the V30 group (10–20 wt% NaCl eq.). In terms of the vein types, the massive quartz vein has the highest homogenization temperatures, followed by the comb quartz vein and lastly the stockwork veins. The presence of alunite and its sulfur isotope compositions, δ34S = 19.6 (σ = 2.1‰), indicate acidic pH and presence of SO42− in the hydrothermal fluids. The prospect is an intrusion‐centered magmatic‐hydrothermal system reflecting the porphyry‐epithermal transition. The fluid inclusions with high homogenization temperatures up to 480°C and high salinity up to 50 wt% NaCl eq. also support the transition of porphyry to high‐sulfidation epithermal mineralization. The presence of two different types of primary fluid inclusions suggests that boiling process occurred and separated the original magmatic fluid into the liquid and vapor phases. More, this fluid underwent dilution and mixing with meteoric waters. The migration of both the fluids were likely unrelated to the formation of the advanced argillic–argillic alteration halo because the quartz veins cut across this alteration. The prospect was later subjected to intensive weathering process that altered most of the sulfides into iron oxides and hydroxides. Small amounts of copper and minor gold were detected, especially in the iron oxides and hydroxides ones with colloform and bladed textures. The Kumbokarno prospect evidences the potential for high‐sulfidation to porphyry deposits at the Southern Mountain Arc, Indonesia. [ABSTRACT FROM AUTHOR]

The Baishan molybdenum deposit is located in the central part of the Eastern Tianshan‐Beishan tectonic belt, NW China. The deposit is hosted in early Carboniferous Gandun Formation biotite‐rich hornfels and is genetically related to unexposed granodiorite porphyry beneath the orebodies. The molybdenite occurs in three different types from early to late stage: Molybdenite ‐ Fe‐Cu‐sulfides ‐ K‐feldspar ‐ quartz veins (Group 1); Molybdenite ‐ Fe‐Cu‐sulfides ‐ quartz veins (Group 2); and disseminated molybdenite in the wall rock (Group 3). Rhenium concentrations in the molybdenite grains range from 108 to 277 ppm in Group 1, 69–121 ppm in Group 2 and 46–135 ppm in Group 3. The Re concentrations of molybdenite in the Baishan Mo deposit decrease from early to late and from the center to periphery, and molybdenite types vary from the 2H1 poly‐type in Groups 1 and 2 to the 2H1 + 3R2H1 poly‐type in Group 3, based on X‐ray diffraction results. The Re‐enriched molybdenite probably formed from an oxidized magmatic fluid that separated from a highly oxidized and H2O‐ and volatile‐enriched adakitic intrusion generated in the lower crust. [ABSTRACT FROM AUTHOR]

The Maricunga metallogenic belt, herein defined to encompass the region from 25° S to 28° S along the Cordillera Frontal of northern Chile, is known for hosting a series of gold-copper and lesser copper-molybdenum porphyries and gold-silver epithermal systems that are hosted in a segment of the late Oligocene-Miocene Andean calc-alkaline magmatic arc. Based on an up-to-date geochronological database, four episodes of magmatism and related hydrothermal deposits are proposed to characterize intensity and style of volcanism and hypabyssal intrusive rocks over time. The late Oligocene episode (26-21 Ma) is characterized by stratovolcanoes, dome complexes, pyroclastic sequences, and hypabyssal intrusives of andesitic to dacitic composition that host gold-rich porphyry systems such as Caspiche, Maricunga, and La Pepa. The early Miocene episode (21–17 Ma) has similar rock types but is volumetrically reduced, hosting epithermal and porphyry deposits like La Coipa and Caserones, respectively. A reinvigoration of volcanism occurred during the third stage between 17 and 11 Ma, giving rise to large volcanic complexes and intra-to extra-caldera ignimbritic deposits that host several gold-rich porphyry deposits such as Lobo-Marte, Luciano, and Cerro Casale; as well as epithermal deposits such as Fenix. Some of the 17 to 11 Ma and younger igneous rock belong to the high-K calc-alkaline series, showing a higher alkali content compared to previous periods. The last magmatic episode, from 11 to 5 Ma, coincides with the shallowing of the subduction angle and is characterized by an eastward migration of volcanism, and more heterogeneous rocks including trachytic compositions. During this period mineralization was emplaced at the Salares Norte epithermal deposit and El Volcan porphyry Au–Cu deposit. Porphyry and epithermal systems formed throughout the evolution of the Maricunga belt. Overprint of advanced argillic alteration on porphyry style alteration is widespread albeit commonly devoid of significant addition of epithermal Au–Ag mineralization. The Au-rich nature of the majority of the porphyry systems is attributed to the shallow crustal depths of emplacement compared to Cu- and Mo-rich porphyry systems. Conversely, high-sulfidation epithermal Au–Ag deposits such as La Coipa and Nueva Esperanza are not known to be telescoped on coeval porphyry gold deposits. The location of the mineralized centers was favored by crustal weaknesses expressed by intersection of oblique- and parallel-to arc structures, the former inherited from the construction of the continent before to the formation of the Andean range. The arc oblique structures also segment the Maricunga belt into domains with unique magmatic and hydrothermal styles. • This is an updated compilation of the distribution of magmatism and related mineralization within the Maricunga belt. • The belt is segmented by major cross-strike structural corridors which control the styles of mineralization for each segment. • Mineralization events that defined the Maricunga belt covered a more extensive area from original models. [ABSTRACT FROM AUTHOR]

Tourmaline is an effective indicator mineral for porphyry Cu-Au-Mo exploration because the compositional and morphological features of tourmaline in such systems are distinct from those found in non-mineralized environments. The texture and chemistry of detrital tourmaline was investigated using local stream sediment samples in the vicinity of the Casino calc-alkalic porphyry Cu-Au-Mo deposit (Yukon, Canada) to identify prospective grains by comparing them to grains in bedrock samples from the deposit. Bulk stream sediment samples were collected up to 18 km downstream of the Casino deposit and as far as 30 km away in a drainage basin that does not contain any known porphyry Cu mineralization. Overall, a method combining the physical and chemical characteristics is effective in discriminating detrital tourmaline, including morphology (i.e., grain clusters), inclusion populations (i.e., lack of inclusions), crystal chemistry (i.e., Na-dominant X -site, Mg/Fe dominant Y -site, and OH−/O2− dominant W -site), and trace-element compositions (i.e., high Sr/Pb values and relatively low Zn/Cu values). Detrital tourmaline was evaluated on the basis of these parameters. Detrital grains are light brown to brown, sub- to euhedral, and range in texture from individual isolated grains to clusters of radiating aggregates. Tourmaline in the Casino deposit compositionally ranges from Fe-rich; 0.03–2.54 apfu , avg. 0.61 to Mg-rich, avg. 2.00 apfu , with a minor povondraite (Fe3+) component. Detrital tourmaline is similar in composition with Fe-rich; 0.03–3.73 apfu, avg. 1.04 to Mg-rich, 0.14–2.93 apfu , avg. 1.83 to tourmaline in bedrock at Casino. In both bedrock and detrital tourmaline, alkali- and alkaline-earth element concentrations are similar with Na > Ca > vacancy. The most relevant distinctions between tourmaline groups comes from grain morphology (i.e., clustered versus individual grains) and trace-element chemistry. A significant abundance of prospective porphyry Cu tourmaline grains (14 % of total recovered tourmaline in one sample) can be observed up to 18 km downstream from the Casino deposit (the current limit of sampling), while in drainages where there are no known porphyry Cu systems, tourmaline fitting these criteria is absent and reflect grains sourced from other geologic environments (e.g., pegmatitic, granitic, and metamorphic). This method provides a new addition to the indicator mineral toolbox for the exploration of porphyry Cu systems. • Detrital tourmaline from porphyry Cu systems can be distinguished from background grains. • Textures, major, and trace-element chemistry are required for effective classification. • Tourmaline morphology and inclusions can be just as effective as trace-elements for determining source. [ABSTRACT FROM AUTHOR]

[Display omitted] • Determination of tilting of crystalline bodies by low-T thermochronology tools. • The methodology applied to determine tilting is crucial for the exploration of PCDs. • Halilaga deposit exhumed by the coupling effects of Aegean extension and westward propagation of the North Anatolian Fault. • Aegean back-arc extension initiated at ∼ 24 Ma in the north of Western Anatolia. • Westward propagation of the North Anatolian Fault occurred no earlier than 2 Ma. Because most crystalline bodies lack intrinsic paleo-horizontal information, their tilting cannot be measured directly. Their vertical movement, however, may be tracked by low-T thermochronology (LTT) tools. Because tilting is caused by differential vertical movements, it can be understood if the rate of differential movements is determined. In this regard, here we apply a new LTT-based approach to calculate the orientation of a tilted crystalline body, the Halilaga Cu-Au deposit, in NW Anatolia. Orientation is consistent with the one calculated from a drillhole-based 3D model of the deposit. This reveals the significance of tilting calculations for the exploration of porphyry Cu deposits. On the other hand, and more importantly, it emphasizes the importance of tilting calculations for geological applications such as LTT-based exhumation histories of samples taken from vertical profiles, and paleomagnetic studies. AHe data from the Halilaga deposit reveals the earliest response to the Aegean back-arc extension at ∼ 24 Ma in the north of Western Anatolia. Lastly, thermal models, the new complementary datasets for the tectonic evolution of the region, show that the Halilaga deposit was exhumed to the surface by the coupling effects of Aegean extension and westward propagation of the North Anatolian Fault, which occurred not earlier than 2 Ma. [ABSTRACT FROM AUTHOR]

The numerical simulation framework for modeling porphyry magma cooling and crystallization. [Display omitted] • A hybrid numerical approach has been proposed for modeling magma dynamics. • This hybrid method combines numerical modeling and thermodynamics calculation. • Moderate initial magma temperature is favorable for porphyry mineralization. • Slow boundary heat transfer is beneficial for metal enrichment in porphyry magma. The ore-forming metals (such as Cu, Mo, and Au) and hydrothermal fluids necessary for the formation of porphyry copper deposits (PCDs) are separated and precipitated from the felsic magma during its cooling and crystallization process, due to changes in physical and chemical conditions triggered by magma ascending and emplacement. Magma cooling and crystallization process is influenced by various factors, mainly including the initial cooling temperature of magma, the startup speed of magma chamber circulation inherited from the pulsations of deep-seated magma, and the cooling rate caused by the contact between magma chamber and surrounding rocks. However, the precise mechanisms of these factors triggering the evolution of porphyry magma in the shallow crust and their role in controlling ore-forming during this process are still not clearly understood. Therefore, this study proposes to use multiphysics numerical modeling in conjunction with thermodynamic calculations to investigate porphyry magma cooling and crystallization control of mineralization. Firstly, based on the whole-rock geochemical data of porphyry intrusions in the world's famous Bingham Canyon cooper deposit, we utilized MELTS to calculate the thermodynamic properties including density, melt fraction, thermal conductivity and heat capacity of porphyry magma. Then, we established the finite element numerical model coupled heat transfer and fluid flow that employed these four thermodynamic properties to simulate the dynamic processes of porphyry magma cooling and crystallization. Finally, we conducted numerical modeling experiments by varying the three parameters, including the initial temperature and startup cycling speed of magma, as well as heat transfer coefficient at the up boundary of magma chamber, to investigate their controls on magma evolution and mineralization of PCDs via calculating and analyzing temporal and spatial variations of the magma temperature, crystallinity, velocity, and metal (i.e. copper) concentration. The results show that the evolution of a porphyry magma chamber is primarily controlled by its initial temperature and the heat transfer coefficient of its upper boundary. 900 °C is the most favorable initial cooling temperature for forming both porphyry magma plumes with high metal endowment, and connected tunnels for volatile to rapidly migrate upward and concentrate to apical parts of the magma chamber. A lower heat transfer coefficient, indicating a magma chamber in a relatively closed tectonic environment, is more beneficial for forming metal migration tunnels within the magma chamber. The startup cycling speed significantly influences the early circulation and convective patterns within the magma chamber, may leading to heterogeneous mixing of magmas with different properties inside the chamber. [ABSTRACT FROM AUTHOR]

[Display omitted] • Lengjia monzogranite and Mo deposit were formed in 113 Ma. • High f O 2 enhanced porphyry Mo formation in Weidshanian suites. • Mesozoic granitoids formed by the drifting and subduction of Pacific and Izanagi plates. Oxygen fugacity is a key factor in controlling the formation of porphyry molybdenum deposits. We present new data on Lengjia monzogranite and compile the Mesozoic magmatism data of the Jiaodong Peninsula to elucidate the correlation between magma oxygen fugacity and porphyry Mo mineralization. Zircon U-Pb geochronology indicates that the formation of the Lengjia monzogranite occurred at 113.7 Ma, while molybdenite Re-Os geochronology shows that the Lengjia Mo deposit was formed at 113.5 ± 3.0 Ma. The Lengjia monzogranite, characterized by low Sr/Y ratios (12.28 ∼ 20.16), low Sr, and high Yb and Y concentrations, can be classified as a non-adakite I-type granite. It had low zircon ε Hf (t) values (–23.8 ∼ -13.8) and ancient T DM2 (Hf) (2047–2680 Ma) with variable zircon O isotopic compositions (5.82 ‰ ∼ 7.38 ‰). The Lengjia monzogranite was formed by partial melting of the Paleoproterozoic crustal source and mantle components metasomatized by slab-derived melt. The zircon trace element calculation revealed that the Weideshan suite had higher ΔFMQ values (0.32 ∼ 4.47, average is 2.27) compared to the Guojialing suite (-0.91 ∼ 2.88, average is 0.82) and Linglong suite (-1.81 ∼ 2.76, average is 0.37). The oxidized Weideshan suite resulted from the increased involvement of mantle metasomatized by slab-derived melt. The elevated oxygen fugacity promoted the porphyry Mo-metallogenic potential of the Weidshanian suite. We propose that the Linglong suite was related to the northwestward flat-slab (subhorizontal) subduction of the Izanagi plate (Paleo-Pacific plate), the Guojialing suite was formed by low-angle northwestward subduction of the Izanagi plate, and the Weideshan suite was related to the northwestward subduction and major slab rollback of the Pacific plate. [ABSTRACT FROM AUTHOR]

To reveal the hydrothermal evolution from porphyry Mo to vein-style Zn-Pb mineralization, the Chalukou deposit in NE China with these two typical mineralization overprinted is selected for detailed research. From early to late hydrothermal veins, the quartz cathodoluminescence intensities change from bright to dark and the textures also evolve. The Ti concentrations of quartz in these veins change from high to moderate and then to low values. The fluid inclusion petrography, microthermometry and stable isotope analyses indicate intermediate-density magma-derived fluids (δ18Owater = +4.7 to + 6.2‰, δD = −132 to −136‰) exsolved at high temperatures (560° to 600 °C) with low to moderate salinity (2.4 to 8.0 wt% NaCl equiv) containing minor CO 2 (<5.7 mol %). Early minor molybdenite occurred under lithostatic conditions at high temperatures (540° to 580 °C) during fluids pH change and early magnetite precipitation. Later main molybdenite precipitation at moderate temperatures (350° to 430 °C), result from fluid cooling and involving of meteoric water under the transition from lithostatic to hydrostatic conditions. The precipitation of pyrite in transitional veins at moderate temperatures (330° to 420 °C), and the late sphalerite-galena from a lower-temperature fluid (180° to 300 °C) is consistent with the cooling of magmatic fluid, and gradually dilution with meteoric water under hydrostatic conditions. It is deduced the transition from porphyry Mo to vein-style Zn-Pb mineralization is likely driven by progressive decrease in temperature of the magmatic fluids and the increasing influx of meteoric water. [ABSTRACT FROM AUTHOR]

Mercury (Hg) isotopes display unique mass-independent isotope fractionation (MIF, reported as Δ199Hg), which is primarily generated via Hg photochemical processes in the land-ocean-atmosphere system. Magmatic and hydrothermal processes do not trigger MIF of Hg isotopes, therefore, Hg-MIF signals detected in deep reservoirs (mantle and crust) are theoretically sourced from recycled surface materials. Here, we observed positive Δ199Hg signals (0.10 ± 0.07‰, SD) in Mesozoic porphyry Mo deposits of NE China. These values correspond to the recently reported Δ199Hg signature of Mesozoic epithermal Au Ag systems in NE China (Δ199Hg: 0.11 ± 0.07‰, SD), suggesting that both mineral systems receive large amounts of Hg from subducted marine materials, given that marine Hg has positive Δ199Hg composition. Our study thus provides novel geochemical evidence on the linkage between oceanic plate subduction and metallogeny of various hydrothermal systems at convergent margins. Subduction contributes large amounts of volatiles to arc magmas, which then release metal-rich magmatic-hydrothermal fluids of the porphyry to epithermal ore deposit spectrum. [ABSTRACT FROM AUTHOR]