Fluid Source Research Articles

Evaluation of Noopept Effect on the Neurotransmitter Amino Acids in the Hippocampus in Alcohol Drinking Rats Using in Vivo Microdialysis

The aim of the present work was to study the dynamics of neurotransmitter amino acids after acute Noopept (a dipeptide analogue of piracetam used in clinical practice as a nootropic agent) administration in intact and long-term ethanol (ETOH) exposed rats. Albino male rats were given 10% (vol/vol) ETOH solution as the only source of fluid 24 h / 7 days per week (n = 5). Also we used intact rats of the same age which had no access to ethanol (n = 5). The excitatory and inhibitory amino acids in the extracellular space of the dorsal hippocampus region in freely moving intact and ETOH-exposed rats during prolonged alcohol deprivation were measured using the intracerebral microdialysis method followed by HPLC/ED. There were no significant differences in the level of neurotransmitter amino acids between ETOH-exposed and intact animals. For the first time, in vivo experiments the effect of Noopept (1.5 mg/kg, i.p.) on the level of excitatory amino acids (an increase in ASP by 2.38 times and GLU by 2.28 times) along with an increase in the level of the inhibitory amino acid GLI by 3.13 times only in intact rats was shown. Thus, in ETOH-exposed rats under the adaptive rearrangements in prolonged ethanol withdrawal, the neurochemical mechanisms of the hippocampus seem to be characterized by insensitivity to an acute Noopept administration. Animal neurochemical studies of changes in the mediator amino acids due to the long-term effect of alcohol on the CNS may be of practical importance for the development of optimal strategies and pharmacotherapy.

Gauge invariant perturbations of static spatially compact LRS II spacetimes

Abstract We present a framework to describe completely general first-order perturbations of static, spatially compact, and locally rotationally symmetric class II spacetimes within the theory of general relativity. The perturbation variables are by construction covariant and identification gauge invariant and encompass the geometry and the thermodynamics of the fluid sources. The new equations are then applied to the study of isotropic, adiabatic perturbations. We discuss how the choice of frame in which perturbations are described can significantly simplify the mathematical analysis of the problem and show that it is possible to change frames directly from the linear level equations. We find explicitly that the case of isotropic, adiabatic perturbations can be reduced to a singular Sturm–Liouville eigenvalue problem, and lower bounds for the values of the eigenfrequencies can be derived. These results lay the theoretical groundwork to analytically describe linear, isotropic, and adiabatic perturbations of static, spherically symmetric spacetimes.

Visualizing the obscure- Chromophore-assisted retinal break detection.

Finding a retinal break which is responsible for retinal detachment is a critical step in the surgical treatment of this condition. In spite of improvement in visualization systems in pars plana vitrectomy, identifying the break which is the source of subretinal fluid (SRF) could pose a challenge, especially in complex retinal detachments or re-detachments with extensive laser scars. The current technique of break identification involves direct detection of the break via peripheral indentation or using perfluorocarbon liquid (PFCL) to displace SRF from the posterior retina to the periphery and visualizing the proteinaceous SRF egress from the retinal break. In retinal detachments, if no peripheral breaks are visualized, surgeons tend to make a posterior draining retinotomy and drain SRF, the necessity of which can be confirmed after subretinal brilliant blue green (BBG) dye injection. In addition, in already vitrectomized eyes where it can be difficult to identify SRF egressing via the break, subretinal BBG dye provides a color contrast that enhances break visualization. A method to identify these occult breaks was required, which is described in this video. Hence, the idea of BBG dye injection into the subretinal space with a 41G subretinal needle was thought of. PFCL would be placed over the posterior pole, which would displace the dye to the periphery, and this would disperse out into the vitreous cavity into a blue plume via the break, thereby leading to its identification. Subretinal dye injection is useful for occult retinal break detection as it provides a color contrast. A posterior draining retinotomy can be avoided. It is also useful in recurrent retinal detachments. We describe the use of BBG, which is the least toxic dye available, and report the use of this technique in Indian eyes. https://youtu.be/JGXQjNV9asw.

Magmatic and rock-leaching contributions to the metal load in hydrothermal fluids at þeistareykir, Iceland

Magmatic-hydrothermal systems are key environments to study the transfer of elements from the deep Earth to the surface and the mobilization and re-distribution of elements within the crust. These systems have been recognized as potential active analogue sites for ore deposition. The source of fluids and their metal load is split between the relative contributions from degassing of underlying magma and interactions between the hydrothermal fluid and the host rock. Here, we combine analyses of noble gases and volatile metals in fluids and rocks from the þeistareykir geothermal field (NE Iceland) to provide constraints on the relative contribution of these two sources. Helium isotope data suggest 80–85% originated from magma degassing. The 3He/4He ratio, corrected for atmospheric contamination (Rc/Ra) correlates with volatile metal abundances in surface fluids and indicates that Bi and Hg are predominantly derived from magma degassing. It is also shown that the deep geothermal reservoir fluid is dominated by magmatic input, except for Mn, Fe, Co, Cu, Ti and V, using the elemental signature of magmatic degassing and water-rock interaction. The spatial variations in Rc/Ra and surface fluid volatile metal contents among the wells suggest an impact of the local and regional structures on the fluid's pathway from depth to surface.

Substantial in situ Ti isotope variations in rutile record source and fluid evolution of porphyry copper mineralization systems

Titanium (Ti) and its stable isotopes have been widely used as tracers for magmatic processes. However, our understanding of Ti isotope behavior in magmatic-hydrothermal systems remains limited. Hence, the in situ Ti isotope composition (δ49Ti) of magmatic titanite and hydrothermal rutile associated with magnetite and chalcopyrite mineralization was determined for the first time in four well-characterized porphyry copper deposits in southern Tibet. The rutile formed through the alteration of primary Ti-rich minerals during fluid-rock interaction in the early high-temperature magnetite and later moderate-temperature chalcopyrite stages of mineralization. Hydrothermal rutile, altered from magmatic titanite, exhibits δ49Ti values similar to those of residual magmatic titanite. This suggests that hydrothermal rutile inherited the Ti isotope composition of magmatic titanite. The average δ49Ti values of rutile are negatively correlated with whole-rock εNd(t) and zircon εHf(t) data, and positively correlated with whole-rock (87Sr/86Sr)i values, which suggests that the initial Ti isotope compositions of hydrothermal rutile in porphyry copper deposits primarily reflect their source. Rutile from the Qulong deposit sometimes exhibits fractionation of δ49Ti at levels exceeding 0.5‰, displaying a negative correlation with Zr and FeO, which may be attributed to the formation of magnetite and rutile at an early potassic alteration stage. Isotopically light Ti is preferentially incorporated into magnetite and rutile. Thus, the rutile associated with sulfide mineralization that formed from the remaining fluids during a later stage of phyllic alteration is enriched in heavy δ49Ti. These findings contribute to the understanding of how rutile fractionates Ti isotopes in hydrothermal systems related to porphyry copper deposits. In local contexts, the substantial crystallization of magnetite, along with the preferential incorporation of isotopically light Ti during the early stages, leads to a decrease in oxygen fugacity within the ore-bearing fluid. This, in turn, facilitates the formation of sulfides during later stages. The results of this study demonstrate the efficacy of in situ Ti isotope analysis as a powerful tool for tracking fluid and metal sources, and can be used to help interpret ore precipitation throughout different stages of magmatic-to-hydrothermal ore-forming processes.

Geochemistry and Mineralogy of Phlogopite and Its Implications for Serpentinization of Jian Forsterite Jade in Southern Jilin Province, China

Mica is a kind of important rock-forming mineral in the lithosphere of Earth, which can be a superior tool used to trace the origin and late evolution of rock. The Jian forsterite jade (a kind of geological skarn) is an emerging kind of gemstone in China with a beautiful color and luster, discovered in Ji’an County, Jilin Province, Northeast China. It is mainly composed of rare Mg-rich forsterite (Mg# (Mg/(Mg+Fe2+) up to 99), serpentine and brucite. The source of hydrothermal fluid triggering the late metamorphism (the serpentinization of forsterite) of forsterite jade deposits remains unclear. We report a series of phlogopites with a regular range of mineral compositions in the forsterite jade deposit. Micrographs show that the phlogopites are associated with forsterite and coexist with serpentine in forsterite jade, tourmaline and tremolite in the contact zone, and plagioclase in pegmatite, and the related replacement of phlogopite seems to have not occurred. The phlogopites that occurred as single grains or veinlets in forsterite jade named type I are characterized by high XMg, ranging from ~0.98 to ~0.95, and the phlogopites that occurred in the contact zone of forsterite jade and pegmatite named type II are rich in Fe, with a range of XMg from ~0.82 to ~0.66. Additionally, the type II phlogopites are also rich in Ti, Mn, Cl, Li, Rb, Zn, V, Co, Nb and Ta but poor in Na, Sr and F compared to the type I phlogopite. Petrological and mineralogical characteristics and geochemical compositions suggest that the phlogopites are crystallized from the corresponding fluid component by hydrothermal metasomatism. The abundant Mg of the fluid phase is produced during the serpentinization of forsterite, triggered by pegmatitic hydrothermal fluid, and other main materials like K, Al, Si and H2O are provided by the intrusive pegmatite. With the occurrence of and regular compositional variation in phlogopites in the forsterite jade deposit, we suppose that the hydrothermal fluid triggering the serpentinization of the Jian forsterite jade is produced by the intrusive pegmatite.

Detection and interpretation of central type structures within the territory of southeastern Transbaikalia for prediction of ore-forming systems

Extremely little attention is paid to the issues of detecting and interpreting of central type structures (CTS) when conducting remote structural-geological and structural-geomorphological studies. At the same time, in the 70–80s of the 20th century, the important role of CTSs in the localization of deposits and ore fields was proven. The position of these structures must necessarily be taken into account when solving problems of searching for and predicting mineral resources in the context of metallogenic analysis and reconstruction of the geological history of development of the studied areas. The almost absence of results of mass detecting and interpreting of CTSs can be explained by the still poorly developed methodology for identifying and analyzing this type of structure. In the present study for the territory of southeastern Transbaikalia, based on modern geoinformation technologies, the use of remote sensing data (radar topographic survey) of high resolution, the creation of a digital elevation model and the application of an integrated structural-spatial analysis, an author’s approach to detection and interpretation of the CTSs is presented, including in connection with the localization of ore objects of various geological-industrial (geological-genetic) types within the framework of the concept of the formation of mineral systems. A statistical analysis of the CTSs identified in the area was carried out, which made it possible to establish a smooth increase in the number of structures with a decrease in their diameter. It is shown that the spatial maxima of ore mineralization extent within the territory are concentrated on the periphery of large CTSs and in their immediate vicinity. Most of the known large ore objects are confined to the internal areas of structures less than 10 km in diameter. Based on the approach of constructing model sections, it was possible to reconstruct the deep position of magma chambers associated with the identified CTSs, and, thereby, to determine the probable sources of metal-bearing fluids. A close spatial relationship between the identified magma chambers and deep faults has been established. To determine the most favorable sites for the deposition of ore mineralization, based on structural-spatial criteria, which include not only structural elements of the CTSs, but also segments of known fault structures, weight of evidence models of the territory have been created. The accuracy of the complex model is 89%. Thus, in accordance with the concept of mineral systems, the sources, migration pathways and sites of the most probable deposition of ore mineralization have been reconstructed.

The Sources of Ore-Forming Materials and Fluids for the Jinqingding Gold Deposit in the Mouping–Rushan Metallogenic Belt, Jiaodong Peninsula: Evidence from S-H-O Isotopes and Trace Elements in Pyrite

The Jinqingding gold deposit, characterized as an extra-large quartz-vein-type deposit, is located in the middle of the Mouping–Rushan metallogenic belt in the Jiaodong Peninsula, and there is still controversy over its sources of ore-forming materials and fluids. This paper divides the mineralization of Jinqinding gold deposits into four stages, based on a field geological investigation and indoor petrographic observations: (1) coarse-grained pyrite–quartz stage, (2) quartz–fine-grained pyrite stage, (3) quartz–polymetallic sulfide stage, and (4) quartz–carbonate stage. The quartz fluid inclusions showed δD values of −96.0 to −81.8‰ and δOV-SMOW values of 0.70 to 6.32‰, indicating that the ore-forming fluids were mainly magmatic water, with some metamorphic water and atmospheric precipitation. The in situ δ34S values in different subzones of the pyrites of the Jinqingding gold deposit range from 6.69 to 10.86‰. The δ34S value range of the Jinqingding gold deposit is basically consistent with the contemporaneous intermediate–basic dikes in the region, suggesting a shared material source. In situ LA-ICP-MS geochemical analyses of the pyrites show large variations of Co/Ni ratios (0.21 to 99.5), which suggest a hydrothermal origin for the gold deposit. We infer that the ore-forming fluid of the Jinqingding gold deposit originated from the magma from the upper mantle and the mantle–crust transition zone.

The role of gas emissions (He, Rn, and CO2) from fault zones in understanding fault and seismic activity

Active fault zones are critical pathways for the migration of deep fluids to the Earth’s surface, carrying gases such as He, Rn, and CO2 that provide evidence for the physical and chemical dynamics of the Earth’s interior. This review examines the geochemical characteristics of fault zone gases and their implications for understanding fault activity and seismic events. Fault zones with high activity levels exhibit significant gas release, and variations in soil and hot spring gas concentrations can serve as indicators of seismic activity. Changes in gas concentrations and isotopic ratios, particularly before and after earthquakes, reflect the dynamic interplay between deep-sourced and shallow-sourced fluids. Seismic-induced stress alterations enhance gas release along fault zones, leading to observable anomalies that can aid in earthquake monitoring and prediction. The study underscores the importance of isotope tracing in deciphering fluid sources, migration pathways, and the evolution of fault zones, providing valuable information for assessing tectonic activity and mitigating seismic risks.

Source of Ore-Forming Fluids and Ore Genesis of the Batailing Au Deposit, Central Jilin Province, Northeast China: Constraints from Fluid Inclusions and H-O-C-S-Pb Isotopes

The Batailing Au deposit is a vein-type deposit in central Jilin Province, situated in the southern sector of the Lesser Xing’an–Zhangguangcai Range within the eastern Central Asian Orogenic Belt. NE-trending fault-controlled orebodies occur in the Upper Permian Yangjiagou Formation and quartz diorite–porphyrite. The mineralisation process was delineated into three stages: (I) quartz–arsenopyrite–pyrite, (II) quartz–polymetallic sulphides (main Au mineralisation stage), and (III) quartz–pyrite–carbonate. Fluid inclusions (FIs) in quartz were identified as four types: PC-type (pure CO2), C1-type (CO2-bearing), C2-type (CO2-rich), and W-type (aqueous two-phase). Raman spectroscopy analysis revealed that the vapor components of the FIs predominantly comprised CO2 with minor quantities of CH4 in stages I–II. Stages I and II encompassed four types of FIs with homogenisation temperature ranging from 264 to 332 °C and 213 to 292 °C and salinity spanning from 4.7 to 11.2 wt% and 1.8 to 11.6 wt%, respectively. Stage III exclusively contained W-type FIs with homogenisation temperature ranging from 152 to 215 °C and salinity spanning from 1.4 to 6.4 wt%. H-O isotopic values (δD = −84 to −79.6‰, δ18OH2O = 6.2 to 6.4‰ in stage I and δD = −96.4 to −90.4‰, δ18OH2O = 2.8 to 4.4‰ in stage II) and microthermometric data indicated that the ore-forming fluids are initially from a magmatic source, with later meteoric water input. Low C isotopic data from CO2 in FIs in quartz (−24.4 to −24.3‰ in stage I and −23.7 to −22.6‰ in stage II) indicated an organic carbon source. Ore precipitation is mainly attributable to fluid immiscibility. S-Pb isotopic data (δ34S = −3.5 to −1.6‰; 206Pb/204Pb = 18.325–18.362, 207Pb/204Pb = 15.523–5.562, 208Pb/204Pb = 38.064–38.221) revealed that ore metals primarily originated from magma. Based on this research, the origin of the Batailing Au deposit is of the mesothermal magmatic–hydrothermal lode type.

Differences in the Genesis and Sources of Hydrocarbon Gas Fluid from the Eastern and Western Kuqa Depression

The Kuqa Depression is rich in oil and gas resources and serves as a key production area in the Tarim Basin. However, controversy persists over the genesis of oil and gas in the various structural zones of the Kuqa Depression. This study employs natural gas composition analysis, gas carbon isotope analysis and gold pipe thermal simulation experiments, to comprehensively analyze the differences in the genesis and sources of hydrocarbon gas fluid from the eastern and western Kuqa Depression. The results show that the Kuqa Depression is dominated by alkane gas, with an average gas drying coefficient of 95.6, with nitrogen and carbon dioxide as the primary non-hydrocarbon gases. The average of δ13C1, δ13C2 and δ13C3 values in natural gas are −27.70‰, −20.43‰ and −21.75‰, respectively. Based on comprehensive natural gas geochemical maps, the CO2 in the natural gas from the Tudong and Dabei areas, as well as the KT-1 well of the Kuqa Depression, is thought to be of organic origin. Additionally, natural gas formation in the Tudong area is relatively simple, consisting entirely of thermally generated coal gas derived from the initial cracking of kerogen. The natural gas in the KT-1 well and the Dabei area are mixed gasses, formed by the initial cracking of kerogen from highly evolved lacustrine and coal-bearing source rocks, exhibiting characteristics resembling those of crude oil cracking gas. The methane (CH4) content of natural gas in the Dabei area is high and the carbon isotopes are unusually heavy. Considering the regional geological background, potential source rock characteristics and geochemical features may be related to the large-scale invasion of dry gas contributed by CH4 from highly evolved, underlying coal-bearing source rocks. Consequently, the CH4 content in the mixed gas is generally high (Ln (C1/C2) can reach up to 5.38), while the relative content of heavy components is low, though remains relatively unchanged. Thus, the map of the relative content of heavy components still reflects the characteristics of the original gas genesis (initial cracking of kerogen). Mixed-source gas was analyzed using thermal simulation experiments and natural gas composition ratio diagrams. The contributions of natural gas from deep, highly evolved coal-bearing source rocks in the KT-1 well and the Dabei area accounted for more than 90% and approximately 60%, respectively. This analysis provides theoretical guidance for natural gas exploration in the research area.

Marine clay maturation induces systematic silicon isotope decrease in authigenic clays and pore fluids

Marine silicate alteration exerts a major influence on marine carbon and cation cycles, but has proven difficult to quantify. In this context, silicon isotopes of marine pore fluids became an important tracer. However, poorly constrained silicon isotope signatures of precipitates produced during silicate alteration (i.e. authigenic clays) remain a major source of uncertainty. Here we present in situ silicon isotope analyses of marine authigenic clays (intergrown iron-smectites and iron-glauconites) occurring within recent sediments from the Oregon margin, eastern North Pacific. We identify a trend to lower silicon isotopes (from −2.24‰ to −3.17‰), accompanied by decreasing aluminum/silicon ratios and increasing potassium oxide contents, which we interpret as an isotopic shift caused by progressive clay maturation via dissolution-reprecipitation reactions. Our modelling suggests that this clay maturation pathway, together with mixing of other fluid sources, may induce pore fluid silicon isotope shifts of up to −1.7‰, if sufficient newly precipitated clays are re-dissolved. This could potentially produce silicon isotopes values significantly lower than seawater and implies that conventional isotope-based approaches underestimate the prevalence of marine silicate alteration. Our findings highlight that clay maturation must be considered when interpreting silicon isotope signatures in terms of marine silicate alteration and upscaling to global element cycles.

Sedimentary exhalative Pb-Zn deposit model of the Ban Lin – Phia Dam ore range, Vietnam

Purpose. The aim of this study is to construct a typical ore model for Pb-Zn ore range in Ban Lin – Phia Dam and to compare it with the existing ones. The model is constructed based on three main elements of the mineral generation process, such as formation environment, generated-ore fluid source, and deposited-ore mechanism. The obtained results are aimed at determining and predicting the resource of sedimentary exhalative (SEDEX) Pb-Zn ore deposit in Vietnam. Methods. To comprehend the characteristics of the SEDEX Pb-Zn ore deposits in the Ban Lin – Phia Dam area, we employ a combination of approaches that include mineralography to determine the composition and tectonic structure of rocks and ore, inclusion analysis to determine the temperature and inclusion composition, Pb isotopic analysis and stable S isotopic analysis to explore the environment and sources of ore-forming materials. Findings. The sedimentary exhalative (SEDEX) Pb-Zn ore deposit arises from the dissolution of metal-rich salt deposits due to heating at shallow depths (several kilometers). Subsequently, this fluid migrates through faults and fractures to preferred locations where galena and sphalerite precipitate alongside sedimentary basin deposition. Originality. SEDEX ore deposits have been extensively studied in various regions of the world. Although there are multiple theories regarding their origin, including explosion, biological debris accumulation, and surface replacement, each model has its own distinct advantages and limitations in explaining the genesis and development of SEDEX ore deposits. Practical implications. The acquired findings are intended to identify and predict the resources of sedimentary exhalative Pb-Zn ore deposits in Vietnam.

Genesis studies of Li–Rb deposits in pegmatites from Bailongshan, western China: Evidence from chronology, fluid inclusions, and H–O isotope analysis

The Bailongshan Pegmatite deposit, located in the West Kunlun Orogenic Belt, Northwest China, is a newly discovered, super-large Li–Rb (Be–Ta–Nb) rare-metal deposit. Since complex magmatic-hydrothermal processes are responsible for the mineralization of such rare-element pegmatites, it is desirable to study the evolution and sources of ore-forming fluids to analyze the genesis of ore deposits. In this study, the 40Ar/39Ar plateau ages of muscovite and biotite were determined to be 171.36 ± 1.87 and 172.39 ± 1.66 Ma, respectively, indicating that the duration of hydrothermal mineralization was approximately 170 Ma. Based on the zonal nature of the mineral assemblage, the Bailongshan area was divided into four zones and stages (I–IV), namely the albite–quartz–lithium tourmaline (AQT, stage I), albite–quartz-bearing mica (AQM, stage II), albite–quartz–spodumene (AQS, stage Ⅲ), and spodumene–quartz (SQ, stage IV) zones. Among these, AQS and SQ were the main ore-bearing areas. In terms of the fluid inclusions found in quartz and spodumene, the different types include a gas-rich phase (V-type), a liquid-rich phase (L-type), a daughter mineral-bearing three-phase (S-type), and a carbon dioxide-bearing phase (C-type). In stage I, the homogeneous temperatures of the V- and S-type fluid inclusions varied from 365 to 415 °C, while their corresponding salinities were 8.5–12.9 and 44.8–47.2 wt% NaCl equiv., respectively. In stage II, the homogeneous temperature and salinity of the L-type inclusions were 315–365 °C and 9.9–13.3 wt% NaCl equiv., respectively, while in stages Ⅲ and IV, the homogeneous temperatures of the L- and S-type fluid inclusions were between 235 and 335 °C, while their salinities were 7.2–12.3 and 32.1–37.0 wt% NaCl equiv., respectively. Furthermore, for the C-type inclusions, the homogeneous temperature and salinity were 235–320 °C and 4.9–10.6 wt% NaCl equiv., respectively. The laser Raman results showed that the fluid in the metallogenic stage was an H2O–NaCl–CO2–CH4 system. Based on the homogeneous temperature and salinity results, the fluid capture pressure from stage III to stage IV was calculated to be 280–150 MPa, and the depth of the capture was >6 km. Moreover, the H–O isotope results suggested that the early ore-forming fluids are mainly magmatic hydrothermal fluids, whereas the later (stage IV) mineralizing fluids may be mixed with a small amount of meteoric water. The subsequent immiscibility of the fluid may be one of the factors responsible for the discharge and precipitation of minerals.

Metabolic landscaping of extracellular vesicles from body fluids by phosphatidylserine imprinted polymer enrichment and mass spectrometry analysis

Extracellular vesicles (EVs) are emerging as new source of biomarkers discovery in liquid biopsy due to their stabilization in body fluids, protected by phospholipid bilayers. However, the metabolomics study of EVs is very little reported due to the lack of efficient and high-throughput isolation methods for clinical samples. In this study, phosphatidylserine imprinted polymers were employed for rapid and efficient EVs isolation from five human body fluids, including plasma, urine, amniotic fluid, cerebrospinal fluid, and saliva. The isolated EVs were subsequently analyzed for metabolomic studies by high-resolution mass spectrometry. Metabolic landscaping was conducted between the body fluids and their EVs, indicating EVs contain a large number of metabolites that are completely specific to the body fluid source. Finally, quantitative metabolomic analysis of EVs was carried out with plasma samples of hepatocellular carcinoma. Several differentially expressed exosomal metabolites were revealed including the upregulation of sphingosine (d18:1), taurochenodeoxycholic acid (TCDCA), pipecolic acid (PA), and 4-hydroxynonenal (4-HNE) and down-regulation of piperine, caffeine, and indole. We believe the proposed methodology will provide a deeper understanding of the molecular composition and functions of EVs as an alternative source for biomarker discovery.

Titanite from the NYF-type pegmatites of Szklarska Poręba Huta quarry, Karkonosze granite massif, SW Poland

Titanite, an accessory mineral of pegmatite related to aplogranite, was identified in the Szklarska Poręba Huta quarry within the Karkonosze granite massif in Lower Silesia, Poland. It formed during pegmatitic to hydrothermal stages. Besides the isovalent substitution Sn → Ti, the chemical composition of the mineral is characterized by three coupled substitutions: (1) (Al, Fe, Sc)3+ + (OH, F)- → YTi + ZO, (2) XREE3+ + Y(Al, Fe, Sc)3+ →X)Ca2+ + YTi4+, and (3) (Al, Fe, Sc)3+ + (Nb, Ta)5+ → 2YTi. These substitutions are strongly dependent on the composition of the magma in terms of its Al2O3/TiO2 activity ratio, with the first one also influenced by the H2O/HF fugacity ratio. Fluorine, which induced the most common substitution (1), had its source in high-temperature F-bearing fluids released from rocks of the metamorphic envelope adjacent to the intruding granite. These fluids mobilized and transported various rock components (Sc, REE, Nb, Ta, etc.) among others in the form of fluoride complexes, enriching the aplogranite magma with some metallic elements. The substitution of Sn for Ti developed with decreasing temperature to the extent that in thin ore-mineralized quartz veins cutting aplogranite, titanite reaches Sn-bearing compositions up to the prevalence of Sn corresponding to malayaite.

Quantifying element mass transfer in the Jiling Na-metasomatic hydrothermal uranium deposit, Northwest China

The Na-metasomatic hydrothermal uranium deposits are relatively widespread, low in grade (less than 1 % U3O8) but high in tonnage. Although it has been considered that this type of deposit was formed due to hydrothermal alteration unrelated to magmatic activity, the detailed evolution of fluids and ore-forming process are still not well understood. Through element-mass-balance calculation and geochemical mapping of regional rocks, we investigated the Jiling uranium deposit in northwestern China and evaluated the composition and source of fluids and element-transfer behavior through Na-metasomatism and uranium mineralization. The findings show that, in the early Na-metasomatism stage, the Na-, HFSE- and REE-rich late-magmatic hydrothermal fluids caused Na-metasomatism of wall rocks, enriching Na2O (>53 %) while removing K2O (<-78 %), depleting SiO2 (30 % in granite and 3 % in diorite), and massively mass-transferring Fe, Ti, P and some incompatible elements. With increased rock permeability and the formation of partial Fe2+-bearing minerals, the Na-metasomatic alteration produced reducing agents and migration channels for ore-forming fluids, as well as the creation of ∼ 15 vol% porosity in the altered granite for metallogenic space. In the late uranium mineralization stage, CO2-rich fluids extracted uranium and HREEs, converted Fe2+ to Fe3+, and subsequently precipitated uranium to form pitchblende with apatite, calcite and chlorite. Thus, the Na-metasomatic alteration caused by late-magmatic hydrothermal fluids is critical for the production of large Na-metasomatic hydrothermal uranium deposits. Our new geochemical mapping reveals that the mass-concentration changes of Na, K and Si are more credible to defining Na-metasomatic alteration, while Fe, Ti, P, ∑(Zr-Hf-Nb-Ta) and ∑LREE/∑HREE vary strikingly during the uranium mineralization process.

Origin of the Narenwula quartz vein-type W deposit, Inner Mongolia, China: Insights from geochemistry of hosting granites, fluid inclusions, H-O-S isotopes, and wolframite trace elements

Wolframite that coexists with quartz is common hydrothermal mineral in tungsten deposits, and its geochemical features can be used to constrain the tungsten mineralization. Here we show that the Narenwula deposit is a typical quartz vein-type W deposit on the northern margin of the North China Craton, Northeast China, and temporally and spatially associated with Early Cretaceous granitoids, provides an opportunity to decipher the W mineralization process. All the orebodies are composed of a series of northeast- trending wolframite-polymetallic sulfides bearing quartz veins accompanied by intense alterations, mainly hosted in the Early Cretaceous monzogranite and porphyraceous monzogranite. Three paragenetic stages were identified: (I) quartz-wolframite, (II) quartz-wolframite-sulfide, and (III) quartz-fluorite-calcite. LA−ICP−MS trace element analyses revealed that both wolframite (I) and (II) have similar trace elements, REEN patterns, and overall consistent Nb/Ta and Y/Ho ratios, indicate a single fluid source and evolution in the W mineralization of the Narenwula deposit. Fluid inclusions microthermometry of quartz and wolframite, coupled with H-O isotopes suggest that the early ore-forming fluids of the Narenwula deposit are mainly magmatic water with relatively moderate-to-high temperature and salinity, while the late ore-forming fluids are mixed with meteoric water, with medium-to low temperature and low salinity. The δ34S values of pyrite (4.63–6.65 ‰, average = 5.44 ‰) further support a magmatic origin for the sulfides. The metallogenic mechanisms at the Narenwula deposit include fluid boiling and fluid-rock interactions were the two major factors controlling the deposition of wolframite and sulfide, while simple cooling and fluid mixing may have also promoted wolframite precipitation.

Deformation and fluid flow history of a fractured basement hydrocarbon reservoir below the Sab'atayn Basin, Habban Field, Yemen

Fractured crystalline basement reservoirs are of increasing economic interest for oil and gas exploration and subsurface fluid storage. The successful characterization of these reservoirs is commonly challenged by their structural heterogeneity, complexity in fracture distribution and flow properties at multiple scales, and the difficulty of imaging fractures in exploration seismic. We analyzed the fracture geometry and fracture diagenetic attributes in two oriented cores from the Habban Field in the Late Jurassic Sab'atayn Basin (Yemen) to evaluate the multi-phase deformation history and fracture flow pathway evolution for (hydrothermal) fluids and hydrocarbons. Analyses included petrographic and fluid inclusion analysis of fracture-filling cements, and stable sulfur isotope analyses of fracture-filling pyrite.The Paleoproterozoic basement consists of amphibolite-facies metamorphic ortho- and paragneiss cut by several phases of Neoproterozoic granitoid intrusions. The investigated lithologies in the drill cores comprise (1) epidote quartzite, (2) amphibolite, (3) monzogranite, (4) meta-arkose, and (5) quartz-feldspar porphyry. These lithologies show an inhomogeneous fracture network that is partially cemented. Ediacaran brittle-ductile deformation (D1) recognized only within a Pan-African monzogranite lead to cataclasis and porosity generating alteration. Late Jurassic – Early Cretaceous extension (D2) related to the break-up of Gondwanaland and the formation of the Sab'atayn Basin is found in all lithologies and likely resulted in pervasive quartz cementation. Late Jurassic fractures parallel to the NW-SE trending long axis of the Sab'atayn Basin are best recognized in a strongly foliated amphibolites. Cenozoic extensional fracturing (D3) reactivated older structures, which probably formed during activity of the Neoproterozoic Najd Fault System and caused multi-phased (pyrite-(saddle) dolomite-calcite) fracture cementations. The sulfur isotope compositions of pyrite with δ34S values ranging between −17.4 and + 26.4‰ vs. V-CDT reflects the variability of the fluid source during sulphide mineral formation from hydrocarbon-rich hydrothermal solutions. Fluid inclusions indicate that cementation reactions occurred in a relatively narrow temperature field between 120 °C and 140 °C, ideal for hydrocarbon maturation. Our results demonstrate the potentially complex charge history of basement reservoirs, involving multiple phases of fracture formation and cementation, and fluid charge episodes.

The Carboniferous Wuzunbulake orogenic gold deposit in South Tianshan Orogen (NW China): Sericite Rb[sbnd]Sr geochronology, pyrite geochemistry, and metallogeny

The Kumishi area is located in the eastern part of the South Tianshan Orogen, which hosts several gold deposits and has substantial gold discovery potential. The timing of gold mineralization at Kumishi, however, has been poorly constrained owing to the absence of suitable dating minerals. Hydrothermal activity at Wuzunbulake is divided into the pre-ore stage 1 pyrite-quartz, syn-ore stage 2 quartz(-sulfide) and post-ore stage 3 quartz-calcite alteration/mineralization. Three types of pyrite have been recognized, i.e., Py1 (stage 1), Py2 (stage 2), and PyWR (from wallrock). Our in-situ RbSr dating on stage 2 sericite yielded an isochron age of 351.0 ± 17.4 Ma, indicating Early Carboniferous gold mineralization. Py1 and Py2 have δ34SΣS = 8.28–15.97 ‰ (avg. 12.88 ‰) and 6.92–8.70 ‰ (avg. 7.67 ‰), respectively, indicating that the sulfur in Py1 was metamorphic fluid sourced, while that of Py2 may have a mixed metamorphic fluid and wallrock source (0.84–3.27 ‰; avg. 2.31 ‰). For Py1, its contents of Au, As, Ag, Bi, Co, Cu, Mn, Ni, Pb, Sb, Tl are the lowest. Py2 has significantly higher Au-As-Ag, slightly higher Co-Cu-Ni-Sb-Tl, but lower Bi-Mn-Pb contents than those in PyWR. Considering also the sulfur isotope features, we considered that Py1 was primarily originated from the initial ore-forming fluid, and Py2 was derived from both the ore fluid and PyWR, with the former being more important and represents the source of gold. Based on that Py2 was formed by metasomatism on the PyWR margin and the element spatial coupling characteristics shown in EPMA geochemical maps, we inferred that the Au enrichment and precipitation are associated with fluid-rock reactions. The initial ore fluid is likely featured by the enrichments in Au, As, Ag, Co, Cu, Ni, Sb, Tl, and depletions in Bi, Mn, and Pb. The Wuzunbulake is best classified as an orogenic gold deposit based on its tectonic background, wallrock alteration style, and the ore-fluid source and characteristics.