Primary Fluid Research Articles

Quantifying heat losses from experimental setup and their effect on annular channel heat flux using CFD

An advanced experimental setup in the form of a double-pipe heat exchanger has been developed to investigate various flow and heat transfer regimes in an annular channel. The experimental setup is designed for heat transfer measurements and flow visualization in a transparent annular channel with temperature-controlled heating of the inner tube. It allows measurements in both, single-phase and two-phase (boiling) flow regimes. The transparent annular channel is connected at the front and rear end by specially designed inlet and outlet headers, which ensure a uniform velocity field of the coolant (primary fluid) in the annular channel. The heating water (secondary fluid) heats the inner tube made of copper, which contains unique turbulators positioned equidistantly. These are designed to enhance the heat transfer on the inner side of the copper tube and to accommodate the thermocouples measuring the surface temperature of the tube.The main purpose of this study is to assess as accurately as possible the influence of heat losses in the experimental setup on the heat fluxes in the transparent annular channel. Therefore, it is necessary to accurately estimate the heat losses at the inlet and outlet header, upstream and downstream of the annular section. To this end, a detailed three-dimensional conjugate heat transfer CFD model has been developed and validated with a series of single-phase measurements, including the measured temperatures in both headers and the temperature profile along the heated inner copper tube. The simulated velocity and temperature fields have been used to quantify the heat flux distribution in the experimental setup. This study clearly demonstrates that properly validated numerical simulations can provide missing experimental information and significantly improve the interpretation of complex experimental results.

Age of Carlin-type gold mineralization in the Youjiang basin, South China: Constraint from hydrothermal zircon geochronology in the Badu dolerite-hosted gold deposit

Selecting a robust chronometer is crucial to determine the primary mineralization age of the deposits that have witnessed multiple hydrothermal events. The Youjiang basin of South China hosts the world’s second-largest Carlin-type gold province. However, the age of the Carlin-type gold mineralization remains highly debated, partly due to the presence of multiple hydrothermal events that may have disturbed the primary isotopic system with low durability. Hydrothermal zircon is a robust chronometer that can survive multiple hydrothermal events. To this end, in this study, we report in-situ secondary ion mass spectrometry (SIMS) and laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) U–Pb dating results of hydrothermal zircon identified in carbonate–sericite–sulfide–altered dolerite from the Badu Carlin-type gold deposit to constrain the timing of gold mineralization.The hydrothermal zircons exhibit subhedral to anhedral morphologies, sector cathodoluminescence zonings, and contain gold-related mineral assemblages of arsenian pyrite, quartz, sericite, and carbonate. Primary two-phase fluid inclusions also commonly occur in the hydrothermal zircons. Compositionally, these zircons feature relatively flat light rare-earth element (REE) patterns, high La contents, low (Sm/La)N values, and small Eu and Ce anomalies, which are different from the magmatic counterparts of the Badu pluton but consistent with those of hydrothermal zircons reported worldwide. These features indicate that the hydrothermal zircons are probably paragenetically associated with the gold mineralization. Consequently, the U–Pb ages of ca. 140 Ma of these zircons, which are much younger than those of the magmatic zircon in the fresh dolerite, can represent the timing of primary gold mineralization of Badu. Our new data suggests that there truly was an episode of gold mineralization during the Early Cretaceous in the Youjiang basin, which may have been driven by large-scale lithospheric extension in the interior of South China. This study demonstrates that hydrothermal zircon could be a robust clock for investigating the timing of magmatic rock-hosted Carlin-type gold deposits.

Fluid Regime of Crystallization of the Calcite–Quartz Carbonatitoids of the Murun Massif

Abstract —Primary melt and fluid inclusions in quartz and dalyite of calcite–quartz carbonatitoids of the Murun massif have been studied. They contain CO2, N2, CH4, C2H6, C3H8, H2, and H2S as well as sulfates and hydrocarbonates as solid daughter phases. The inclusion solutions contain HS- and chlorides. In addition, disordered carbon and bitumen are present. It is concluded that the magmatic fluid phase that was in equilibrium with quartz was characterized by a predominantly H2O–CO2–H2S composition and a reduced state. This explains the appearance of sulfides at the magmatic stage of crystallization of calcite–quartz carbonatitoids of the Murun massif. We substantiate the hypothesis that the sulfates, hydrocarbons, and H2 detected in the inclusions form at decreasing temperature as a result of shift of the redox equilibrium.

Fracturing timing of Jurassic reservoirs in the Dibei-Tuziluoke gas field, Kuqa foreland basin: Evidence from petrography, fluid inclusions, and clumped isotopes

Determining the timing of fracturing is crucial for understanding reservoir evolution and hydrocarbon accumulation in foreland basins. Using fracturing data from cores, borehole images, and outcrops, combined with the clumped isotope (Δ47) and fluid inclusion analyses of carbonate minerals filled in pores and fractures, this study ascertained the fracturing timing of the Jurassic reservoirs in the Dibei-Tuziluoke Gas Field, Kuqa Foreland Basin. Data from outcrops and borehole images show two dominant fracture sets in the study area: W-E and NE-SW striking fractures. Some W-E striking fractures are carbonate-filled, while NE-SW striking fractures lack mineral fillings. Bitumen veins, not easy to be identified in borehole images, are prevalent in cores. The petrographic analysis reveals that these bitumen veins formed before the calcite cementation in pores and display high viscosity and low maturity. Homogenization temperatures (Th) from primary fluid inclusion assemblages in two representative calcite vein samples were notably lower than TΔ47 values from corresponding samples. This suggests the Δ47 signature underwent alteration due to partial reordering during burial. Thus, Δ47-derived temperatures (apparent temperatures) may not faithfully represent the mineral precipitation temperatures. When plotting these apparent temperatures vs. the burial history, only the possible latest ages of fracturing emerged. These ages were further refined by considering petroleum charging, tectonic evolution, and stress orientation. Bitumen-filled fractures likely resulted from the Late Cretaceous uplift, marking the migration of low-maturity hydrocarbons in the study area. Carbonate-filled E-W striking fractures emerged during the late Miocene (∼13–6.5 Ma) alongside fold development. NE-striking fractures that crosscut W-E ones possibly formed recently due to stress reorientation.

Multiphase-solid fluid inclusions in HP-LT eclogite facies rock (Zavkhan Terrane, Western Mongolia): evidence for the evolution from saline to hypersaline fluids during metamorphism in subduction zone

Fluid inclusions in high- and ultrahigh-pressure metamorphic rocks provide direct information on the composition of the fluids that evolved during metamorphism and fluid-rock interactions in deep subduction zones. We investigate the fluid inclusions in the Khungui eclogite of the Zavkhan Terrane, Central Asian Orogenic Belt. Fluid inclusions are observed in garnet and quartz in the eclogite samples that underwent metamorphism during subduction. The primary fluid inclusions in quartz are composed of liquid and vapor with high salinities (15.7–16.4 wt.% NaCl eq.), whereas the secondary fluid inclusions in quartz are classified as: relatively high salinity (Type I:12.5–16.3 wt.% NaCl eq.) and low salinity (Type II:6.7–10.6 wt.% NaCl eq.). The garnet shows compositional zoning from Ca-poor cores to Ca-rich rims, and the rims that grew during the eclogite-stage metamorphism (2.1–2.2 GPa at 580–610 °C) preferentially contain numerous primary fluid inclusions. The primary fluid inclusions in garnet are commonly bi-phases (liquid and vapor); however, some are multiphase-solid fluid inclusions composed of fluids (liquid and vapor) and combinations of several minerals (halite, quartz, apatite, calcite, biotite, chlorite, and actinolite). Bi-phase fluid inclusions preferentially occur in the inner parts of the Ca-rich garnet rim, whereas multiphase-solid fluid inclusions occur along the margins of the Ca-rich rim. We hypothesize that the multiphase-solid fluid inclusions are formed via interactions between trapped fluids, trapped minerals, and the host garnet during exhumation. By combination of FIB–SEM and synchrotron X-ray CT analyses, the detailed occurrences, volumes, and compositions of the solid phases in the fluid inclusion was analyzed. We then conduct mass balance analysis to reconstruct accurate fluid compositions using data from the FIB–SEM and synchrotron X-ray CT images of the multiphase-solid fluid inclusion. The results of these analyses reveal that (1) fluid changed from an H2O-dominated saline fluid (13–16 wt. % NaCl eq.) at the prograde to the earlier eclogite stage to H2O–CO2-dominated hypersaline fluid at later eclogite stage (~ 32 wt. % NaCl eq., 7.3 wt. % CO2 and ~ 19 molal dissolved cations); (2) a variety of mineral assemblages in multiphase-solid fluid inclusions are produced by post-entrapment reactions between the trapped hypersaline fluid, trapped minerals and the fluid host mineral. The evolution of fluids from saline to hypersaline during the eclogite facies stage is probably caused by the formation of hydrous minerals (i.e., barroisite) under a near-closed system.

An efficient 3D cell-based discrete fracture-matrix flow model for digitally captured fracture networks.

Complex hydraulic fracture networks are critical for enhancing permeability in unconventional reservoirs and mining industries. However, accurately simulating the fluid flow in realistic fracture networks (compared to the statistical fracture networks) is still challenging due to the fracture complexity and computational burden. This work proposes a simple yet efficient numerical framework for the flow simulation in fractured porous media obtained by 3D high-resolution images, aiming at both computational accuracy and efficiency. The fractured rock with complex fracture geometries is numerically constructed with a cell-based discrete fracture-matrix model (DFM) having implicit fracture apertures. The flow in the complex fractured porous media (including matrix flow, fracture flow, as well as exchange flow) is simulated with a pipe-based cell-centered finite volume method. The performance of this model is validated against analytical/numerical solutions. Then a lab-scale true triaxial hydraulically fractured shale sample is reconstructed, and the fluid flow in this realistic fracture network is simulated. Results suggest that the proposed method achieves a good balance between computational efficiency and accuracy. The complex fracture networks control the fluid flow process, and the opened natural fractures behave as primary fluid pathways. Heterogeneous and anisotropic features of fluid flow are well captured with the present model.

Ore Mineralogy, Fluid Inclusion Geochemistry, and Zircon U-Pb Geochronology of the Nanmingshui Gold Deposit in East Junggar, Xinjiang, Northwest China: Implications for Ore Genesis

The Nanmingshui gold deposit, located in the eastern segment of the Kalamaili gold belt (KGB), is hosted by the sub-greenschist facies rocks of the Lower Carboniferous Jiangbasitao Formation. The genesis of this deposit, however, has been debated for decades because of controversial constraints on the P-T-X conditions and origins of hydrothermal fluid and mineralization age. In this study, we present gold-bearing sulfide compositions, fluid inclusions, H-O isotopes, and the results of hydrothermal zircon U-Pb dating to provide new insights into the genesis of the gold deposit. Three gold mineralization stages are recognized: quartz–pyrite–minor native gold veins (early), quartz–tourmaline–arsenopyrite–pyrite–gold–polymetallic sulfide veins (middle), and quartz–calcite veinlets (late). Gold predominantly occurs as native gold with high fineness ranging from 941 to 944 in sulfides and quartz, and some as solid solutions (Au+) within the lattice of pyrite and arsenopyrite. Three types of primary fluid inclusions are identified in hydrothermal quartz: CO2-H2O (C-type), aqueous (W-type), and pure CO2 (PC-type) inclusions. The early-stage quartz mainly contains C-type and minor W-type inclusions, with total homogenization temperatures (Th) of 220–339 °C, salinities of 0.4–3.7 wt.% NaCl eqv., and bulk densities of 0.66–1.01 g/cm3. All three types of inclusions are observed in the middle-stage quartz, of which the C- and W-type inclusions yield Th values of 190–361 °C, with salinities of 0.4–6.0 wt.% NaCl eqv. and bulk densities of 0.69–0.99 g/cm3. The late-stage quartz contains only W-type inclusions that have lower Th values of 172–287 °C, higher salinities of 1.4–6.9 wt.% NaCl eqv., and bulk densities of 0.79–0.95 g/cm3. Trapping pressures estimated from C-type inclusions in the early and middle stages cluster at 280–340 MPa and 220–310 MPa, respectively, corresponding to metallogenic depths of 10–13 km and 8–11 km. The H-O isotopic compositions (δ18Owater = 1.8–10.9‰, δD = −99 to −62.9‰) and microthermometric data indicate that the ore-forming fluids belong to medium–high-temperature, low-salinity, medium-density, and CO2-rich-H2O-NaCl ± CH4 ± N2 systems, probably originating from metamorphic water. Fluid immiscibility is a crucial mechanism for gold precipitation. Additionally, the U-Pb dating of hydrothermal zircons, from the auriferous quartz–tourmaline vein, yield a weighted mean 206Pb/238U age of 314.6 ± 9.6 Ma. Taking all of the above, the Nanmingshui deposit can be reasonably classed as a typical mesozonal orogenic gold deposit in the KGB, which was formed in a Late Carboniferous tectonic transition from syn-collision between the Jiangjunmiao accretionary complex and Yemaquan arc to post-collision in the East Junggar Orogen. Our results serve to better understand the gold mineralization and genesis of the Late Paleozoic orogenic system in the Kalamaili area, Xinjiang.

Healthcare-Associated Ventriculitis in Children during COVID-19 Pandemic: Clinical Characteristics and Outcome of a First Infection.

During the COVID-19 pandemic, patients in need of neurosurgical care suffered. Elective procedures were postponed, and emergency care visits decreased. Healthcare-associated ventriculitis (HAV) is a serious problem in children, with poor outcomes and frequent relapses. Our objective was to describe the clinical characteristics and the factors associated with a first HAV in children during two years of the pandemic. A retrospective cross-sectional study was performed from January 2021 to December 2022. The inclusion criteria were patients who developed a first HAV after a primary cerebrospinal fluid diversion procedure. The controls included patients without a first infection. Intraoperative and clinical data were extracted from medical records. A total of 199 CSF diversion surgeries were registered. A first infection occurred in 17 patients (8.5%), including 10 with external ventricular drain (EVD) and 6 with ventricular shunts. Gram-positive cocci were identified in 70.6%. Six patients recovered uneventfully, eight had relapse or superinfections, and three eventually died. Twenty patients were included as controls. Factors associated with a first infection were a younger age (median 9 vs. 102 months, p < 0.01), malnutrition (23.5% vs. 0%, p = 0.03), and an EVD placement (58.8% vs. 10%, p = 0.03). None of the intraoperative factors showed statistically significant differences. The rate of HAV was high. Most cases presented in children <1 year and with an EVD.

It’s a trap!: Modern and ancient halite as Lagerstätten

ABSTRACT Chemical sediments, such as bedded halite (NaCl), are strongly influenced by environmental conditions during deposition and, if unaltered, may preserve microorganisms, microfossils, and organic compounds for hundreds of millions of years. Recent studies show that halite is an excellent repository for organic materials, as well as a variety of environmental data. Halite is a perfect trap. Due to its rapid growth, parent brine, gas, crystals of other minerals, and any organic material are encased within primary fluid inclusions or as solid inclusions along growth bands. These inclusions function as “snapshot” repositories of the hydrosphere, atmosphere, lithosphere, and biosphere. However, organic material in halite is still relatively unknown in the sedimentological and paleontological communities. Here, we present highlights of preservation in halite to showcase the diversity of life that has been documented within it. We also discuss: 1) the properties of halite that give it such excellent preservation potential, 2) the challenges to and strategies for studying organic material in halite, 3) preservation in other salt minerals such as gypsum, and 4) implications for astrobiological research. Recommendations for the future study of organic material in halite include collaboration amongst chemical sedimentologists, paleontologists, and microbiologists.

Role of evaporites in sodium metasomatism and formation of albite-rich rocks in IOCG provinces

Hydrothermal Iron-oxide-Cu-Au (IOCG) deposits are important exploration targets for a number of metals of economic importance. Voluminous sodium metasomatism is ubiquitous in most IOCG provinces. The origin of the metasomatic fluid responsible for the formation of albite-rich rocks in such terranes is contentious; both evaporite-derived fluid and magmatic fluid have been advocated. The Singhbhum IOCG province in India is known for hosting several polymetallic deposits from which U, Cu, and apatite-magnetite are mined as principal commodities together with Ni, Au, Ag, Se, Te, Mo, and low-Ti magnetite as by-products. Voluminous albite-rich rocks occur at several sites along the mineralized belt. Metasomatic albite schist comprising predominantly albite and quartz at Pathargora contains tourmaline intricately associated with albite. Based on textures and mineralogical associations, tourmaline is classified as: tur1: coarse nodular tourmaline ± albite ± magnetite aggregate; tur2: disseminated fine-grained tourmaline in a schistose matrix; and tur3: tourmaline + biotite + magnetite + apatite clots. All tourmaline belongs to the alkali group and most to the dravite sub-group. Very low concentrations of Li (avg 3.8 ppm), Zn (avg 6 ppm) and Mn (avg 21 ppm) but high V (avg 2130 ppm) and Ni (avg 306.5 ppm) in tur1 core (tur1c) co-genetic with albite contrast with what is reported in magmatic/magmatic-hydrothermal tourmaline of granitic affinity. The δ11B values of tourmaline are mostly positive, ranging between –4.0 and 9.2 ‰ (avg 4.0 ± 3.0; n = 79); values of tur1 cores are 4.9–9.2 ‰. Previous fluid inclusion studies described the presence of halite and barite daughter crystals in primary fluid inclusions and demonstrated the involvement of a high-temperature (≥450 °C) and high-salinity (≥50 wt% NaCl equivalent) brine in the formation of cores of tur1. Calculated δ11B values of the hydrothermal fluid in equilibrium with tur1c range from 7.3 to 11.5 ‰ (for a crystallization temperature of 450 °C). Based on the textural setting of the tur1c-albite assemblage, geochemical and boron isotope composition of tur1c, and evidence of a high saline brine, we propose that the albite schist is the product of Na-metasomatism by brines that derived major constituents from the dissolution of marine evaporite. The inferred paleo-latitude and geological environment of sedimentation related to the host lithologies are consistent with the evaporitic model. We further suggest that a similar mechanism might have played an important role in the formation of albite-rich rocks in other IOCG provinces where the involvement of evaporite-derived fluids in mineralization/alteration have been demonstrated. Similar major element, trace element and positive boron isotope (1.5–6.3 ‰) composition of tur3 suggest similar source of fluid as that of tur1c, and tur3 formed either during the same alteration event or during a separate fluid pulse. On the other hand, the mode of occurrence, very low trace element concentration and weakly negative to positive δ11B (−4 to 2.3 ‰) value of tur2 suggest their metamorphic origin.

Geology, geochemistry, fluid inclusion microthermometry and depositional environment of the Early Cretaceous Meymeh sub-seafloor replacement sideritic-ankeritic iron deposit, Malayer-Esfahan Metallogenic Belt, Iran

Meymeh sideritic-ankeritic iron deposit in the eastern part of Malayer-Esfahan Metallogenic Belt (MEMB) is formed in the sedimentary-volcanic rocks of the Early Cretaceous sequence. Ore mineralization in the study area based on stratigraphic location and type of host rocks divided in two ore horizons. Lower ore horizon located in the dolomitic-sandy limestone (Kc3) unit, which upper ore horizon is formed in thin-bedded limestone (Km) rocks. Petrographic studies indicates that mineralization comprises three ore facies: stockwork, bedded and massive ore facies. The most important primary minerals are siderite, ankerite, ferroan-dolomite, pyrite, pyrolusite, barite and minor chalcopyrite. The most frequent textures in the ore zones include laminae, replacement, vein-veinlet, massive and banded. Dolomitization and silicification are the main wall rock alteration styles; alteration intensity increases towards the ore zones. Based on relationships between ore minerals and rock forming minerals, ore mineralization (hypogene and supergene) in the Meymeh deposit formed during three main stages: fine-grained Fe-carbonate bands are intricately interlayered with dolomite beds. Sideritic-ankeritic bands exhibit classic sedimentary textures, such as laminations and bedding, indicative of a syn-sedimentary to early diagenesis origin. Coarser-grained stage two siderites and ankerites show breccia and vein-veinlet textures, and are considered to have formed by replacement during burial diagenetic sub-seafloor fluid flow. In stage three, siderite and ankerite were converted to secondary iron oxides such as oxide/hydroxide Fe minerals during meteoric water flow through the inverted normal and thrust faults and uplift. The primary two-phase fluid inclusions in the quartz-2 and ankerite-2 minerals that have been investigated from the ore mineralization section of the Meymeh deposit are homogenized at temperatures between 110.3 to 226.9 °C. Salinities of the primary fluid inclusions range from 3.39 wt.% to 14.77 % NaCl eq. This finding suggests that hydrothermal brine fluid mixing with seawater could be the primary mechanism that prompted ore formation. The similarity of REE patterns between siderite and ankerite in different ore facies and host rock carbonates indicates their derivation from the same ore fluids. The Meymeh deposit is considered a typical case of sedimentary hydrothermal diagenetic sideritic-ankeritic mineralization, in which minerals deposited when hydrothermal fluid was released from anoxic to suboxic water columns.

Electrodialysis membrane desalination with diagonal membrane spacers: a review.

Electrodialysis desalination uses ion exchange membranes, membrane spacers, and conductors to remove salt from water. Membrane spacers, made of polymeric strands, reduce concentration polarization. These spacers have properties such as porosity and filament shape that affect their performance. One important property is the spacer-bulk attack angle. This study systematically reviews the characteristics of a 45° attack angle of spacers and its effects on concentration polarization and fluid dynamics. Membrane spacers in a channel create distinct flow fields and concentration profiles. When set at a 45° attack angle, spacers provide greater turbulence and mass-heat transfer than traditional spacers. This is because both the transverse and longitudinal filaments become diagonal in relation to the bulk flow direction. A lower attack angle (<45°) results in a lower pressure drop coupled with a decline in wakes and stream disruption because when the filaments are more parallel to the primary fluid direction, the poorer their affect. This research concludes that membrane spacers with a 45° spacer-bulk attack angle function optimally compared to other angles.

Formation of hydrothermal ferromanganese oxides from the Daigo-Kume Knoll in the middle Okinawa Trough, Japan

Many active hydrothermal sites resulting from active volcanism have been recognized in the Okinawa Trough, a nascent back-arc basin. Despite its importance for understanding whole hydrothermal circulation, low-temperature (LT) hydrothermal activity, which precipitates ferromanganese (Fe–Mn) oxides, has not been actively studied compared to high-temperature (HT) hydrothermal activity, which forms sulfide deposits. Therefore, in this study, we investigated the origin and formation of Fe–Mn oxides obtained from the outer rim of the Daigo-Kume Knoll caldera in the middle Okinawa Trough based on their chemical and mineral compositions. Composed of birnessite and todorokite, the Fe–Mn oxide samples contain low levels of trace elements, indicating their precipitation from LT hydrothermal fluids. This is the first report of hydrothermal activity at the Daigo-Kume Knoll. Based on an independent component analysis of elemental mapping data, it was determined that the hydrothermal activity consisted of two stages: a primary hotter LT hydrothermal fluid (roughly 30 °C–150 °C) that altered silicate debris and precipitated mainly Fe oxides, and a secondary colder LT hydrothermal fluid (roughly 30 °C) that precipitated mainly Mn oxides without alteration. The growth rate, estimated from the chemical composition, and the thickness of the Fe–Mn oxide samples indicated that the duration of the hydrothermal activity was about 17.7–29.5 kyr. In contrast to their LT hydrothermal origin, the high Mo/Mn ratio of the Fe–Mn oxide samples suggested that the LT hydrothermal fluids that precipitated the Fe–Mn oxide samples might be originally produced by HT water–rock interactions.

Hydrothermal circulation at 1.8 Ga in the Kiruna area, northern Sweden, as revealed by apatite geochemical systematics

The Kiruna area in northern Sweden hosts the classic Kiruna iron-oxide-apatite (IOA) deposit. The area has experienced complex tectonic processes, including basin formation, inversion, and hydraulic fracturing events from ∼1.9 Ga and possibly down to ∼1.5 Ga. However, the nature, timing and links of hydrothermal events related to this tectono-thermal evolution are unclear, impairing our full understanding of IOA formation processes. Here, we use multiple analytical methods to study apatite from the Kiirunavaara orebody. Electron microscopy, cathodoluminescence images, and rare earth element contents of the studied apatite indicate alteration by hydrothermal fluids. U-Pb Tera-Wasserburg lower intercept age of the altered apatite is 1800 ± 36 Ma, indicating a contemporaneous hydrothermal event in the central Kiruna area during coeval basin inversion. Sr isotopes obtained in these altered apatites, ranging from 0.709 to 0.713, may represent intermediate Sr isotope values between primary apatite and secondary fluid resetting. The relatively high but scattered 87Sr/86Sr ratios suggest that country rocks of the IOA deposits and other regional intermediate-felsic igneous rocks with old or enriched components are most likely the source of the fluids. Previous studies have revealed two hydrothermal events in the IOA ores at roughly 1.73 Ga and 1.63 Ga. Thus, fluids sourced from the host rocks of the regional IOA deposits and regional granitoids have circulated episodically at 1.80 Ga, 1.73 Ga, 1.63 Ga and possibly 1.5 Ga in the Kiruna area and have partly redistributed rare earth elements formed during the primary 1.88 Ga IOA formation event.

The Prognostic and Predictive Value of Human Gastrointestinal Microbiome and Exosomal mRNA Expression of PD-L1 and IFNγ for Immune Checkpoint Inhibitors Response in Metastatic Melanoma Patients: PROTOCOL TRIAL.

Immunotherapy has been successful in treating advanced melanoma, but a large proportion of patients do not respond to the treatment with immune checkpoint inhibitors (ICIs). Preclinical and small cohort studies suggest gastrointestinal microbiome composition and exosomal mRNA expression of PD-L1 and IFNγ from the primary tumor, stool and body fluids as potential biomarkers for response. Patients treated with immune checkpoint inhibitors as a first line treatment for metastatic melanoma are recruted to this prospective study. Stool samples are submitted before the start of treatment, at the 12th (+/-2) week and 28th (+/-2) week, and at the occurrence of event (suspected disease progression/hyperprogression, immune-related adverse event (irAE), deterioration). Peripheral venous blood samples are taken additionally at the same time points for cytologic and molecular tests. Histological material from the tumor tissue is obtained before the start of immunotherapy treatment. Primary objectives are to determine whether the human gastrointestinal microbiome (bacterial and viral) and the exosomal mRNA expression of PD-L1 and IFNγ and its dynamics predicts the response to treatment with PD-1 and CTLA-4 inhibitors and its association with the occurrence of irAE. The response is evaluated radiologically with imaging methods in accordance with the irRECIST criteria. This is the first study to combine and investigate multiple potential predictive and prognostic biomarkers and their dynamics in first line ICI in metastatic melanoma patients.

Using pyrite composition to track the multi-stage fluids superimposed on a porphyry Cu system

Abstract The Yulekenhalasu porphyry Cu-Mo deposit (0.2 Mt Cu at 1.04 wt% and 0.012 Mt Mo at 0.06 wt%) is located in the Devonian Halasu copper belt, East Junggar block, northwest China. At Yulekenhalasu, Cu and Mo mineralization commonly occurs as disseminated sulfides or veinlets in porphyry-related alteration zones. Five alteration stages have been identified, including porphyry-type alteration, i.e., sodic-calcic (stage I), potassic (stage IIa), propylitic (stage IIb), and phyllic (stage III) alteration, and widespread late Cu sulfide-bearing veins (stage IV) cross-cutting porphyry-type alteration, plus a post-ore fault-controlled argillic alteration (stage V). Stages IV and V have overprinted porphyry-type alteration (stages I–III). Anomalous concentrations of trace elements in stage IIb pyrite (e.g., Ti, Zr, Gd, and Hf) are due to the presence of micro-inclusions (e.g., zircon and rutile) in the low-temperature (~200 °C) propylitic zone. Cu, Ag, Co, and Mn, occurring as stoichiometric substitutions or as tetrahedrite inclusions in overprinting stage IV pyrite, were sourced directly from the primary hydrothermal fluid. The enrichment of distal pathfinder elements (e.g., Cr, Au, and Tl) in overprinting stage V pyrite was caused by a low-temperature (~160 °C) hydrothermal event related to regional orogenic Au mineralization. The spatial variation of Se/S in pyrite among various paragenetic stages were influenced by changes in the hydrothermal fluid composition and temperature, with the latter having the effect of decreasing pyrite Se/S. Lower Se concentrations in pyrite of stages IIb and III close to the orebody are explained by relatively higher temperatures in the locus of mineralization. This may provide a potential vectoring tool to mineralization using pyrite geochemistry in porphyry deposits. Systematic thermodynamic calibrations were applied to pyrite compositions to fingerprint the corresponding Se/S and Co/Ni ratios of fluids and further to develop a complete metallogenic model for Yulekenhalasu. The Devonian diorite porphyry generated fluids that produced the early porphyry-type alteration. High Co/Fe (average ~1 × 10–4) and Ni/Fe (average ~3 × 10–6) ratios of fluid for late Cu sulfide-bearing veins, combined with higher Se/S (average ~6 × 10–7) than orogenic Au deposits (average ~3 × 10–8), indicate that the fluids possibly derived from a Late Devonian-Carboniferous mafic intrusion. Argillic alteration assemblages forming at ca. 280 Ma host pyrite relatively enriched in Au (average 0.1 ppm, with native gold inclusions). Therefore it is likely related to a regional orogenic gold mineralizing event in the Early Permian that overprinted Devonian mineralization. Although spatially contiguous, hydrothermal alteration and hypogene mineralizing stages identified herein represent discrete episodes of hydrothermal activities at Yulekenhalasu. The multi-stage alteration features observed at Yulekenhalasu may provide insights into the complete evolutionary history of Paleozoic porphyry Cu deposit systems in the Central Asian orogenic belt. This study contributes to a better understanding of the metallogenic and exploration models of porphyry Cu deposits overprinted by multi-stage hydrothermal events, which is economically important in Phanerozoic orogenic belts.

Irreversibility analysis of hydromagnetic nanofluid flow past a horizontal surface via Koo-Kleinstreuer-Li (KKL) model

The goal of this research is to investigate the effects of Ohmic heating, heat generation, and viscous dissipative flow on magneto (MHD) boundary-layer heat transmission flowing of Jeffrey nanofluid across a stretchable surface using the Koo-Kleinstreuer-Li (KKL) model. Engine oil serves as the primary fluid and is suspended with copper oxide nanomolecules. The governing equations that regulate the flowing and heat transmission fields are partial-differential equations (PDEs) that are then converted to a model of non-linear ordinary differential equations (ODEs) via similarity transformation. The resultant ODEs are numerically resolved using a Keller box technique via MATLAB software that is suggested. Diagrams and tables are used to express the effects of various normal liquids, nanomolecule sizes, magneto parameters, Prandtl, Deborah, and Eckert numbers on the velocity field and temperature field. The outcomes display that the copper oxide-engine oil nanofluid has a lower velocity, drag force, and Nusselt number than the plain liquid, although the introduction of nanoparticles raises the heat. The heat transference rate is reduced by Eckert number, size of nanomolecules, and magneto parameter rising. Whilst, Deborah number is shown to enhance both the drag-force factor and the heat transfer rate. Furthermore, the discoveries reported are advantageous to upgrading incandescent lighting bulbs, heating, and cooling equipment, filament-generating light, energy generation, multiple heating devices, and other similar devices.

A Mars-analog sulfate mineral, mirabilite, preserves biosignatures

Abstract Various sulfate minerals exist on Mars; except for gypsum, they are understudied on Earth. Extremophiles have been documented in modern gypsum and halite and ancient halite, but other chemical sediments have not been evaluated for biosignatures. Here, we present the first observations and analysis of microorganisms and organic compounds in primary fluid inclusions in the Mars-analog mineral mirabilite, Na2SO4·10H2O, from Great Salt Lake, Utah, USA. Microscopy by transmitted light and ultraviolet-visible (UV-vis) light, and Raman spectroscopy, show abundant bacteria and/or Archaea, algae, fungi, diatoms, protozoa, and organic compounds such as beta-carotene. This discovery expands our current knowledge of biological materials trapped in salt and aids the search for life on Mars, both for sample selection by rover and for analyses of return samples on Earth.

3D Raman mapping combined with FIB‐SEM on multiphase fluid inclusions: A tool to unravel complex phase assemblages

AbstractIn this study, we performed high resolution 3D Raman mapping on primary multiphase fluid inclusions from a granulite and an eclogite of the Cabo Ortegal Complex (NW Spain), the latter representing a former subduction zone environment. Several microns‐sized inclusions are great targets to test the advantages and limitations of 3D Raman mapping. We show how optical and Raman scattering properties of the phases inside the inclusions can affect the veracity of both 2D and 3D Raman maps. As an independent control, 3D Raman models were compared with focused ion beam‐scanning electron microscopy submicron‐scale slicing of three previously 3D Raman mapped inclusions, allowing us to optimize Raman spectroscopy data evaluation and provide volume proportion calculations. We found that a non‐optimized evaluation procedure might result in even an order of magnitude over‐ or underestimation of phase volume properties. We propose that correcting the Raman maps even with empirically determined Raman cross sections of the phases inside the inclusions can vastly improve the quality of the maps. The results provide valuable input data for thermodynamic modeling and draw implications for fluid/rock interactions.

Physico-chemical conditions of Sodmein fluorite deposit, Central Eastern Desert, Egypt

This study aimed to spot more light on the nature of fluorite mineralized fluids and conditions of fluorite formation of these fluorites using the fluid inclusion studies. Fluorite vein-type mineralization at Egypt exists predominantly along faults, dissecting younger granitic plutons in the Arabian-Nubian shield (ANS). In Wadi Sodmein area fluorite hosted in pegmatitic veins dissecting the schists and metavolcanics. These veins are trending NE-SW and NW-SE in conformity with the general trend of faults dissecting the pegmatitic veins. The petrography of the fluid inclusions revealed primary and secondary fluid inclusions. Microthermometric investigation on the two-phase primary fluid inclusions specifies that the studied fluorites of Sodmein area were possibly deposited from low salinity (1.57–3.39 wt % NaCl eq.) aqueous fluids due to boiling processes and density ranging from 0.836 to 0.941 g/cm3. The trapping conditions of fluid inclusions in Sodmein fluorites estimated at temperatures between 140 °C and 240 °C, and pressures between 18 and 85 bars.