Fluid Source Research Articles

The Origin and Evolution of Rare Earth Element Mineralization in the Muluozhai Deposit (Sichuan, China): Insights from Mineralogical, Trace Element, and Sr-Nd-Pb-C-O-Ca Isotope Data

Abstract Carbonatite complexes are globally significant sources of rare earth elements (REEs); however, mechanisms governing REE deposition in various tectono-lithologic settings, encompassing host rocks, wall rocks, ore-controlling structures, and metasomatism, remain inadequately understood. The Zhengjialiangzi mining camp, situated within the extensive Muluozhai deposit (containing 0.45 million metric tons [Mt] at 4.0 wt % REE2O3) in the northern segment of the Mianning-Dechang belt, Sichuan (southwestern China), is characterized by a complex vein system that evolved within metamorphosed supracrustal rocks of the Yangxin and Mount Emei Formations. The mineralization is coeval with Oligocene intrusions of carbonatite and nordmarkite at ~27 Ma. The major gangue minerals include fluorite, barite (transitional to celestine), and calcite, with bastnäsite serving as the primary host for REEs in all analyzed orebodies. Several other accessory to minor minerals were identified in the ore veins, including some that had not previously been known to occur in the Muluozhai deposits (e.g., thorite and pyrochlore). The stable isotopic (C-O-Ca) and trace element compositions of calcite, along with whole-rock data, suggest that carbonate material was derived from the mantle and subsequently reequilibrated with the Yangxin marbles. The radiogenic isotope (Sr-Nd-Pb) compositions of vein material remained unaffected by wall-rock contamination and suggest a mantle source influenced by crustal recycling, consistent with other REE deposits hosted by carbonatite and nordmarkite in the region. The combined petrographic and geochemical evidence suggests derivation of Muluozhai mineralization from a carbonatitic source and interaction of carbonatite-derived fluids with wall rocks, xenoliths, and early-crystallizing mineral phases, particularly barite.

Sources of organic matter elucidated through Pyr-CG-MS, and relation to basin scale events in the Pimienta Formation (Central Mexico)

The study of organic matter is essential for understanding the sedimentary and diagenetic processes that have occurred in a certain area. Sediments rich in organic matter with a vocation for producing hydrocarbons are of particular importance. Studies of organic matter in these environments help not only to determine their potential as hydrocarbon generators, but also contribute to the understanding of the processes that have occurred in the basin over time. In this study, the use of pyrolysis-gas chromatography-mass spectrometry (Pyr-GC-MS) is proposed to analyse the diversity of organic molecules contained in the sediments of the Pimienta Formation. This technique is versatile and, although destructive, allows rapid analysis of organic matter, in addition to the minimal quantities required for the study. Pyr-GC-MS allows functional groups to be determined; in this study 34 different moieties were identified. The use of this technique is perfectly complemented by Rock-Eval-pyrolysis and fluid inclusion studies, which allows greater detail of the origin of the molecules. The results of the Rock Eval Pyrolysis suggested that there were two types of kerogen: continental (Type III) and marine (Type II)]. Some samples contained organic matter of continental origin , while others contained organic matter of marine origin. Analysis of fluid inclusions suggested sedimentary-diagenetic and meteoric sources for fluids, as well as different types of interaction between them and the surrounding rocks.

Genesis of a sediment-hosted vein-type Cu deposit in the Lanping Basin, SW China: New insights from geology and LA–ICP–MS analysis of fluid inclusions

Sediment-hosted Cu deposits, including stratiform and epigenetic vein-type Cu deposits, are the second largest source of Cu worldwide. However, many facets of these vein-type Cu deposits, such as the nature and origin of ore fluids and geodynamic mechanisms that produced these fluids, remain controversial, limiting our interpretations of the ore genesis and hampering the selection of exploration strategies. Numerous sediment-hosted vein-type Cu deposits are present in the Lanping Basin, SW China, of which the Jinman deposit is the largest. Copper orebodies at Jinman consist of Cu-sulfide–quartz–carbonate veins and altered wall-rocks hosted mainly in faults and fracture zones in metamorphosed and deformed clastic rocks. The deposit was formed in three stages, pre-, syn- and post-ore, with the first two stages producing hydrothermal veins. The veins in pre-ore stage consist of quartz + ankerite ± sericite ± pyrite, whereas those in syn-ore stage consist of Cu-sulfides + quartz + carbonate ± sericite. During the syn-ore stage, tennantite, quartz, and ankerite crystallized early, then bornite was precipitated, followed by chalcopyrite and chalcocite and finally calcite. Only minor sericite was formed during the post-ore stage. Two major types of fluid inclusions—CO2-rich and aqueous inclusions—are present in both pre- and syn-ore quartz, whereas only aqueous inclusions are present in syn-ore calcite. In pre- and syn-ore quartz and calcite, CO2-rich inclusions have higher homogenization temperatures (275–323 °C) and pressures (307–3495 bar) and lower salinities (0.22–2.7 wt% NaCl eqv.) than aqueous inclusions (164–299 °C, 6.5–80.4 bar and 3.7–20.9 wt% NaCl eqv.). However, the small variations in Cs/Na and Cs/(Na + K) ratios [log Cs/Na = –3.3 ∼ –1.9, log Cs/(Na + K) = –3.3 ∼ –2.1] of the fluid inclusions suggest a same source for the ore fluids. We propose that during both stages, CO2-rich inclusions resulted from unmixing of initial deep-seated, single-phase CO2-rich fluids, whereas aqueous inclusions likely represent the fluids that evolved from these unmixed fluids by extensive CO2 degassing. This interpretation, combined with microthermometric results of CO2-rich inclusions, suggests a mesothermal, low-salinity H2O–NaCl–CO2 ore fluid system. The fluid inclusions from Jinman have similar compositions to those of metamorphic fluids, suggesting a metamorphic origin for the ore-forming fluids. The evolution of fluid compositions suggests that fluid degassing likely acted as a major mechanism for Cu precipitation. We propose that the ore fluids were generated through metamorphic devolatilization of basement of the Lanping Basin in the Biluoxueshan–Chongshan metamorphic zone under a compressional or transpressional regime caused by Cenozoic India–Asia collision. The Jinman deposit has many similarities to orogenic gold deposits worldwide and thus can be thought of as an orogenic deposit. Based on a compilation of the geological characteristics of global sediment-hosted epigenetic vein-type Cu deposits, we suggest that other sediment-hosted epigenetic vein-type Cu deposits with similar genesis to the Jinman deposit are likely present in other regions worldwide. This highlights the exploration potential of this type of deposit in these regions and the need for further research.

Sulfide mineralization in orogenic eclogites of the North Muya block (northeastern Transbaikalia): genesis and the first data on the isotopic composition of sulfur

Subduction processes are accompanied by the sites of hydrothermal activity including large deposits of gold and transitional metals of island-arc or back-arc origin, whereas volcanic arcs host most part of the worldwide resources of metallic minerals. However, the role of suprasubduction metal transfer and the associated role of redox processes in their formation are still ambiguous and require direct studies of sulfide mineralization in high-pressure rocks, as well as their formation stages and sulfide preservation during progressive and peak metamorphism. In order to describe the behavior of chalcophile elements in the paleozones of continental subduction we performed preliminary mineralogical (SEM-EDX) and isotope (S) studies of sulfides in the North Muya block eclogites (northeastern Transbaikalia). Sulfide mineralization of pyrite-chalcopyrite-pyrrhotite composition has a metasomatic origin associated with the retrograde fluid transformation of initially “dry” eclogite assemblages during exhumation to lower- or mid-crust levels after or synchronously to the decompression and formation of plagioclase-diopside±amphibole symplectites (below 10-12 kbar). Extremely heterogeneous isotopic composition of pyrite sulfur (δ34SVCDT) was caused by various sources of fluids of presumably metasedimentary origin (from -8.2 to -6 %) in the paragneiss segments of the North Muya block. But they also could be predominantly buffered by hydrothermally altered metabasites (from +0.7 to +7.1 %). An alternative mechanism could be the participation of a single predominantly oxidized (sulfate-containing) fluid with the significant isotopic fractionation (up to ~15–20 %).

Typomorphic and Technological Characteristics of Quartz of the Mica-Pegmatite Formation on the Example of the Berkutinskaya Vein (South Urals)

Abstract ––Understanding the origin of quartz veins of the mica-pegmatite formation is of great importance for deciphering the emplacement conditions for the of commercially prospective quartz targets. On the example of the Berkutinskaya vein, which is the typical metamorphogenic quartz deposit of the mica-pegmatite formation of the South Urals, we study the source and origin of the mineral-forming fluid, temperatures of quartz formation, the structure of intergranular boundaries, their morphometric feature, the fractal dimension of quartz grains and commercial characteristics of quartz grit. An integrated approach to the study of the typomorphic features of quartz allowed us to assess their impact on the technological characteristics of quartz concentrates. Comparison of data on the content of impurity elements in the Berkutinskaya quartz vein with quartz of the vein No. 175 of OOO Russian Quartz and IOTA-std (Sibelco) showed that the Berkutinskaya quartz vein is promising for commercial development.

In-Situ Geochemical and Rb–Sr Dating Analysis of Sulfides from a Gold Deposit Offshore of Northern Sanshandao, Jiaodong Peninsula, North China: Implications for Gold Mineralization

The gold deposit offshore of Northern Sanshandao is an ultra-large-scale gold deposit discovered in the Jiaodong ore area in recent years. This deposit is a fractured-zone altered-rock-type gold deposit; however, its ore genesis and precise mineralization processes are still highly controversial. Based on petrographical observation, the trace elements, sulfur isotopes, and rubidium–strontium isotopes of the gold-bearing pyrite were analyzed using LA-MC-ICP-MS to obtain the source of the ore-forming fluids and ore genesis. The results show that Au has a good positive correlation with Ag, As, and Cu. It is speculated that the As in the pyrite of the gold deposit offshore of Northern Sanshandao is in the form of As−, replacing S− and entering the pyrite, causing its lattice defects, and thus promoting the entry of Au+ into the gold-bearing pyrite. The Co/Ni ratios mainly range between 0.1 and 10, indicating that the mineralization process has experienced different forms of hydrothermal evolution and the mixing of different fluids. The results of the in-situ sulfur isotope analysis show that pyrite δ34S in the mineralization period is characterized by a high sulfur value. The authors of this study believe that the initial sulfur isotope composition has mantle-derived components. The large-scale, deep cutting, and high degree of fragmentation in the Sanshandao fault zone are conducive to the interaction between fluids and rocks, as well as the mixing and addition of seawater, resulting in the characteristic high δ34S value. The Sr isotopic compositions indicate a crust–mantle mixing attribute of the mineralized material source. The Rb–Sr isochron age of the pyrite is 118.5 ± 0.65 Ma, which represents the age of gold mineralization. According to the characteristics of the trace elements and sulfur isotopes, it is inferred that the gold deposit minerals offshore of Northern Sanshandao originated from deep magmatic-hydrothermal reservoirs, and the mixing of seawater and Au–As-rich hydrothermal fluids was the formation mechanism of huge amounts of gold precipitation.

Primary microfossiliferous chert in the Aptian Barra Velha Formation

ABSTRACTThe Barra Velha Formation and other Aptian pre‐salt deposits record the history of the proto‐Atlantic basin and the rifting of Gondwana. Studies have sought to characterize the depositional environment of the basin with a focus on carbonate fabrics and magnesium silicate clays. However, the water chemistry and fluid sources in the basin, the silica cycle, and how the basin evolved over time are not fully constrained. Additionally, current understanding of the microbiota that inhabited this basin is incomplete because microfossils have rarely been identified in pre‐salt deposits, especially on the Brazilian margin. This study describes authigenic chert in the Barra Velha Formation that preserves distinct, organic‐rich structures and textures. The petrographic relationships between the chert and carbonate suggest that both formed as authigenic phases, but their formation was temporally decoupled. These relationships and δ30Si and δ18O data suggest that chert post‐dates the formation and subsequent dissolution of the carbonates, and may have formed from a different fluid. By characterizing the chert–carbonate paragenesis and mechanism of chert formation, this study provides new insights into the fluid sources and complexity of the basin. Together, the results of this research suggest that the chert precipitated as primary, authigenic phases after karstification of the carbonate from a newly introduced, low temperature, freshwater fluid that was chemically distinct from the lake water. The chert preserves organic matter that is compositionally and texturally distinct from the void‐filling bitumen associated with the classically studied carbonate facies. Based on the composition and morphologies of organic structures, this is likely primary organic matter and a morphologically diverse microfossil assemblage preserved in place at the time of chert formation. Thus, this early chert provides new insights into the water chemistry, fluid sources and silica cycle in the basin, and represents a unique taphonomic window that helps us characterize the pre‐salt basin microbiota.

A new conceptual model of the Travale (Italy) enhanced geothermal system: Insights from electromagnetic geothermometry

The paper presents an electromagnetic geothermometer-based two-dimensional temperature model for the Travale (Italy) enhanced geothermal system derived from magnetotelluric and temperature data. Joint analysis of the temperature and electrical resistivity models made feasible a new self-consistent conceptual model of this site, which agrees with available geological data and previous geophysical results. It explains the nature of seismic reflection horizons detected in 1978 and unusual seismicity distribution in depth which could not be properly addressed earlier without temperature predicting beyond boreholes. It is concluded that the heat source feeding this system may be a granitic intrusion located at a depth below 4 km, which corresponds to the isotherm of 600 °C. A sharp temperature gradient above this intrusion forms a contact thermo-metamorphic halo in the depth range of 3–4 km. Assessment of the released fluid volume fraction from the electrical resistivity model indicates that the general amount of thermo-metamorphic and magmatic fluids in the rock-dominated Travale geothermal system is negligible. It is concluded that meteoric waters are the main source of fluids penetrating along normal faults up to 3 km. Despite some supercritical fluids of thermo-metamorphic origin could circulate in the system below this depth, their amount is hardly sufficient for economically justified exploration drilling. The results of the study indicate that building the temperature model of the geothermal area is crucially important for the exploration of enhanced geothermal systems.

Mineralogical evidence for the role of deep magmatic fluids in beryllium enrichment in magmatic-hydrothermal systems

Vein-type and greisen-type beryllium (Be) mineralization is closely associated with the magmatic-hydrothermal evolution in highly fractionated granites. However, the source of ore-forming fluids and their role in the migration and enrichment of Be is poorly understood. Although whole rock Ba-Rb isotope researches highlight that even deep magmatic fluids beneath the shallow magmatic-hydrothermal systems could provide rare metals and promote mineralization, it is still challenging to determine the influences of such fluids via using conventional geochemical indicators. Here we present zircon-monazite-xenotime-wolframite U-Pb ages, whole-rock geochemistry, monazite Nd isotopes, as well as muscovite and beryl geochemistry for the Zhujiayingzi quartz vein-type Be mineralization in the southern Great Xing’an Range (SGXR), Northeast (NE) China, and introduce the neighboring Nasigatu gresien-type Be mineralization for comparison. Geochronological results reveal that the Zhujiayingzi beryl-wolframite-bearing quartz veins formed in the Early Cretaceous (149–147 Ma), much younger than the host Permian (270–267 Ma) crystal tuffs, but coeval with the Nasigatu highly fractionated alkali-feldspar granite (144–139 Ma). Similar muscovite-beryl compositions and monazite Nd isotopes, combining with their close temporal-spatial relationships indicate that the Zhujiayingzi and Nasigatu Be mineralization have consistent hydrothermal assemblages and enrichment processes. Higher silica, K, and lower Al contents of muscovites from Be-rich veins (M2) and greisens (M4) than those recorded in barren crystal tuffs (M1) and alkali-feldspar granite samples (M3) at both Zhujiayingzi and Nasigatu are consistent with the evolution of the Early Cretaceous granitic magma, proving the involvement of shallow magmatic fluids exsolved from the Nasigatu-like highly evolved granitic melts. However, ore-related M2 and M4 samples have higher Mg (>1 wt%) and Ti contents than those of M1 and M3 samples, which violates the conventional hydrothermal evolution trend. Trace element compositions as well as K/Rb, K/Cs, and Rb/Sr ratios of four-type muscovites, together with the core-rim geochemical variations of muscovites at Zhujiayingzi and beryls at Nasigatu, indicate the existence of deep magmatic fluids rather than fluid-rock interaction to account for the anomalous mineralogical evidence. Such deep magmatic fluids were exsolved from large silicic magmatic reservoirs beneath the shallow magmatic-hydrothermal system, and thus likely display low evolution degrees and high Mg-Ti contents. They can not only provide heat and promote fluid-mineral interactions, but also can efficiently extract and transport Be enriched in deep crystal mushes at different depths. Thus we invoke that the Early Cretaceous Be mineralization in the SGXR was achieved under the combined action of both shallow and deep magmatic fluids derived from the crystal mush-dominated transcrustal magmatic system.

Lawsonite and Garnet Oxygen Isotope Record of Fluid‐Rock Interaction During Subduction

AbstractDuring the subduction of an oceanic plate, fluids are released from metabasaltic crust, metasediment, and serpentinite under high‐pressure/low‐temperature conditions. Although some fluids may eventually leave the slab, some participate in metamorphic reactions within the slab during subduction and exhumation. To identify fluid sources and other controls influencing mineral composition, we report the in situ‐measured δ18O of lawsonite and garnet in blueschist‐ to eclogite‐facies rocks from 10 subduction zones that represent various field settings, including mélanges, structurally coherent terranes, and an eclogite xenolith derived from a subducted plate. Lawsonite records distinct δ18O depending on the host rock type and other rock types that were fluid sources during lawsonite growth. In general, lawsonite in metabasalt (7.6 ± 0.2–14.8 ± 1.1‰) is isotopically lighter than in metasediment (20.6 ± 1.4–24.1 ± 1.3‰) but heavier than in metagabbro (4.0 ± 0.4–7.9 ± 0.3‰). The extent of δ18O fractionation was evaluated for lawsonite–fluid and lawsonite–garnet pairs as a function of temperature (T). Results demonstrate that variations of >1.7‰ in lawsonite and >0.9‰ in garnet are not related to changing T. More likely, the relative contributions of fluids derived from isotopically heavier lithologies (e.g., sediments) versus lighter lithologies (e.g., ultramafic rocks) are the major control. Monte Carlo simulations were performed to investigate the sources of metasomatic fluids and the water/rock ratio that formed lawsonite‐bearing metasomatite. Results indicate that δ18OLws and δ18OGrt record interactions with fluids sourced from diverse lithologies (sediment, serpentinite), further supporting that δ18OLws is a useful indicator of subduction fluid‐rock interactions.

Metallogenic model of the Amensif Zn-Pb-Cu-Ag±Au-Bi carbonate replacement deposit (Western High Atlas, Morocco): New litho-structural and mineralogical data

Purpose. In this paper, we discuss the genetic model and emphasize many pending issues on the carbonate replacement textures of the Amensif Zn-Pb-Cu-Ag±Au-Bi deposit (the Western High Atlas, Morocco), the source of metal and the possible contribution of the Azegour granite to this ore genesis. Methods. This study is based on geological mapping, drill core and petrography analysis in combination with ICP-AES, XRD, and SEM data. Findings. The detailed mineralogy consists mainly of sulfides and sulfosalts. The main ore minerals include arsenopyrite, pyrite, sphalerite, chalcopyrite, galena and bismuthinite. Mineral inclusions related to isomorphic sulfosalts are found in galena and/or chalcopyrite. They include matildite, galenobismutite, pavonite, cosalite, schirmerite, krupkaite, ramdohrite, wittichenite, emplectite, luzonite, gustavite, hedleyite, krennerite, wittite, freibergite, tetrahedrite, tennantite and native bismuth. The supergene minerals are anglesite, covellite, malachite, azurite and goethite. In addition, specific replacements are observed between dolomites and sulfides, indicating an interaction between hydrothermal fluid and host rocks. Four ore stages have been identified based on the relationship between mineral phases and ore-forming conditions. The results of this study indicate that Ag and Au precipitation is controlled by the Bi-Te-Pb-S system, while enrichment in Bi, Te and Se sulfosalts and Bi-telluride indicates a magmatic source of the ore-forming fluid. Originality. The study delves into the genetic model of the Amensif Zn-Pb-Cu-Ag±Au-Bi deposit in the Western High Atlas, Moroc-co, with a focus on carbonate replacement textures, while also exploring its classification as either a carbonate replacement deposit or a skarn deposit. Practical implications.Mineral textures are indicators of the replacement process in the Amensif Zn-Pb-Cu-Bi-Ag±Au carbonate replacement deposit (the Western High Atlas, Morocco). The results obtained from this research paper can be used as a powerful tool in mineral exploration of the Western High Atlas.

Comparing endpoint and real-time PCR for forensic body fluid identification

ABSTRACT Identifying the body fluid source of stains can give an indication of activities, prioritize samples for DNA profiling, and provide probative evidence when the presence of DNA alone does not. Messenger RNA profiling assays using endpoint reverse-transcription polymerase-chain reaction (RT-PCR), were developed to address the issues with conventional body fluid identification and have since been used in forensic casework. However, endpoint RT-PCR has a narrow linear dynamic range (LDR), and there is currently no specific method for mRNA quantification to direct case strategy and optimize input template. Real-time reverse-transcription quantitative PCR (RT-qPCR) collects data during the amplification phase which reflects the starting quantity. The application of RT-qPCR assays as a quantification precursor to endpoint RT-PCR was investigated using previously described assays for circulatory blood, saliva, menstrual fluid, spermatozoa, seminal fluid, and vaginal material. While blood marker SLC4A1 and vaginal marker CYP2B7P showed a strong relationship, the remaining body fluid markers lacked a robust predictive relationship, likely due to differences in LDR. CYP2B7P and SLC4A1 showed high sensitivity when compared with other markers – resulting in a greater number of data points for estimation of the linear relationship. Compared with endpoint, the RT-qPCR assays had higher precision, LDR, and sensitivity.

Abstract 229: Molecular-genomic characterization of metastatic gastric cancer organoids and establishment of organoid-immune cell co-culture model

Abstract Advanced gastric cancer (AGC) showed marked molecular heterogeneity with aggressive behavior and treatment resistance, especially AGC with ascites from peritoneal metastasis. Tumor organoids are valuable in vitro model for mimicking organ characteristics and are used for developing therapeutic strategies. Therefore, we aimed to understand the characteristics of organoids established from AGC patient-derived fluids. Also, we are in progress of setting up an organoid-immune cell co-culture model for drug screening of immune checkpoint inhibitors (ICI) for AGC. All established organoids from peritoneal and pleural fluid of AGC patients were authenticated through short tandem repeat (STR) profiling, comparing with their matched PBMCs. We compared the morphological characteristics using Operetta High Content Imaging (Perkin Elmer). Also, the in house targeted sequencing and RNA sequencing data were obtained from the genome database of the Song-Dang Institute for Cancer Research and it was verified using molecular methods. Then, we co-cultured organoids with healthy donor PBMCs that were pre-activated using anti-human CD3/CD28 Dynabeads (Gibco). 3D spheroids, rather than single cells, and the PBMCs were co-cultured in matrigel (Corning Inc.) for more than 3 days. The overall success rate of the organoid establishment was 53.8% (78/145), with different sources of peritoneal (54%, 61/113) and pleural fluids (53.1%, 17/32). The organoid success rate was various as in EBV positive (66.7%, 2/3) and dMMR (0%, 0/4). Based on the analysis of 91 patients eligible for histopathology, the success rate of HER2-negative (57.5%, 46/80) is higher than that of HER2-positive (36.4%, 4/11). The organoids were observed in a variety of morphologies categorized in 3 groups such as grape-like, compact and glandular structure. Based on genomic data of 31 organoids, we could subgrouping for TCGA subtypes and EMT subtype. RTKs were amplified in 10 organoids, including the amplification of ERBB2 (n=2), MET (n=4) and FGFR (n=4). And KRAS alterations including amplification (n=2) and G12A/D (n=2) mutation were also detected. Then, we established the condition for organoid-immune co-culture model with PBMCs with Dynabead activation for 3-10 days. We confirmed that higher dose of PBMCs killed the tumor cells with reduction of organoid size and partial disintegration. We established the proper PBMC dose and characterization to maintain the organoids co-culture for further drug (ICI) sensitivity testing. In conclusion, we evaluated phenotypic and molecular characteristics of gastric cancer organoids established from malignant peritoneal and pleural effusion. The established organoid-immune cell co-culture models can be utilized to evaluate a variety of drug screenings, including ICI and various combinations, helping in the selection of drugs for individual patient. Citation Format: Han Byeol Mun, juin Park, Jinsoo Jang, Jingmin Che, Tae Soo Kim, Woo Sun Kwon, Hyun Cheol Chung, Sun Young Rha. Molecular-genomic characterization of metastatic gastric cancer organoids and establishment of organoid-immune cell co-culture model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 229.

Contrasting fluids and implications for ore genesis in the Jiawula-Chaganbulagen Porphyry Mo-epithermal Pb[sbnd]Zn metallogenetic system: Evidence from fluid inclusions and H-O-He-Ar isotopes

The Jiawula-Chaganbulagen (Jia-Cha) ore field is located in the part of the southern Erguna Block of Northeast China and has significant mineralization potential. It comprises three deposits: The Chaganbulagen hydrothermal vein-type PbZn (Ag) deposit in the southeast, the Jiawula hydrothermal vein-type PbZn (Ag) deposit in the northwest, and the blind porphyry Mo mineralization in between. Previous geochronological dates, including molybdenite ReOs, zircon UPb, sulfide RbSr, and sericite ArAr, indicate that the formation of hydrothermal molybdenite and the PbZn mineralization were coeval and that they originated from a porphyry-epithermal metallogenetic system that was related to Early Cretaceous magmatism. However, our comprehensive analysis of fluid inclusions and H-O-He-Ar isotopes reveals dissimilarities in the features and sources of the fluids that form three different deposits. Both the Jiawula deposit and porphyry Mo mineralization have three distinct types of fluid inclusions, which comprise liquid-rich two-phase aqueous inclusions (L-type), vapor-rich two-phase inclusions (V-type), and daughter mineral-bearing three-phase inclusions (S-type). The HeAr (3He/4He = 1.32–1.51 Ra; 40Ar/36Ar = 300 to 324) and HO (δ18OH2O = − 13.4 ‰ to 4.1 ‰; δD= − 155.1 ‰ to −129.9 ‰) isotope analysis results suggest that the trap fluids originated from an H2O-NaCl magmatic fluid system, which experienced Mo mineralization with high-temperature transformed into medium-temperature fluids that were primarily of meteoric water in the late-stage (Jiawula PbZn (Ag) deposit). The Chaganbulagen PbZn (Ag) deposit features L-type and V-type inclusions, along with aqueous‑carbonic inclusions (C-type). The results of Laser Raman analysis reveal that the gas phases of the fluid inclusions present in Chaganbulagen contain three different compositions: H2O, CO2, and CH4. The HO isotope compositions (δ18OH2O = −18.8 ‰ to −11.6 ‰; δD = −166 ‰ to −131 ‰) and HeAr (3He/4He = 0.034–0.041 Ra; 40Ar/36Ar = 296–298) in quartz of the Chaganbulagen PbZn (Ag) deposit indicate that the crustal fluids (MASW) were the main source of the ore-forming fluids, and belonged to a H2O-NaCl-CO2-CH4 system, which had low-temperature and low-salinity characteristics. By combining previously published geochronological dates, we proposed a model to explain the difference in the evolution of the fluids.

Re-distribution and upgrade of metals induced by the superimposition of later magmatic fluids in the Archean Hongtoushan VMS deposit, NE China

The Hongtoushan copper-zinc deposit is a highly metamorphosed Archean volcanogenic massive sulfide deposit (VMS) in China. After metamorphism, the deposit underwent later fluid superimposition, which is of significance for the re-distribution of metals and upgrading ores. However, the hydrothermal modification mechanism and fluid source remain unclear due to the difficulties in accurately recognizing the mineral textures and assemblages formed by hydrothermal modification. In this study, the mineral texture was investigated to identify the modification mechanism of later fluid and in situ sulfur isotope and trace elements of chalcopyrite were tested to track the source of later fluid and metals. The dominant assemblage formed by superimposed fluid consisted of pyrite, chalcopyrite, sphalerite, minor galena, magnetite, calcite, anhydrite, and hydrothermal alteration minerals, i.e. sericite and chlorite. These minerals infilled the fractures in early pyrite porphyroblasts or precipitated along the grain boundary. Additionally, the pre-existing sulfides were corroded by these minerals. They exhibited replacement and porous textures, indicating that the superimposed fluids resulted in a dissolution-reprecipitation process and formed new sulfides. The hydrothermal metasomatism produced the sericitization of plagioclase and chlorization of biotite, which concurrently liberated silica to form silicification. These interactions suggested that the hydrothermal fluid is acid fluid. The chlorite geothermometer defined the formation temperature of 226–279°C, implying that the superimposed fluid has a moderate temperature. The chalcopyrite precipitated from superimposed fluid either coexisted with pyrite (Ccp 2a) or magnetite (Ccp 2b). The sulfur isotope of Ccp 2a defined a closing zero range (0.75–2.41‰), demonstrating the superimposed fluids were derived from magmatic fluids. In contrast, the Ccp 2b enriched heavy sulfur with a δ34S range of 4.10–8.63‰, which was attributed to the oxidation of fluids. Partial ferrous ions were oxidized to ferric iron, and ferrous and ferric iron precipitated as magnetite. The mineral assemblage changed from chalcopyrite + pyrite, followed by magnetite + chalcopyrite + pyrite, to magnetite + pyrrhotite, representing the local increase of the oxidation state of hydrothermal systems. During the oxidation process, the oxygen fugacity of the superimposed fluid decreased, whereas the pH increased. These results provide crucial evidence on the re-distribution pattern of metals and the post-hydrothermal modification process in the Hongtoushan Cu-Zn deposit.

Dehydration‐driven deformation of eclogite: Interplay between fluid discharge and rheology

AbstractAqueous fluids released during dehydration of a subducting slab have a large effect on the rheology of the subduction interface. While high‐pressure experiments and natural‐case studies link deformation with critical dehydration reactions during eclogitization, the exact interplay between these processes remains ambiguous. To investigate fluid–rock interaction and associated deformation at high‐pressure, we studied a suite of eclogites from the Tsäkkok Lens of the Scandinavian Caledonides that record prograde metamorphism within an Early Palaeozoic cold subduction zone. Our results show that in‐situ dehydration during the blueschist to eclogite facies transition produces fluid fluxes leading to rheological weakening and densification, consequently promoting ductile‐brittle deformation. Petrographic evidence, supported by thermodynamic modelling and thermobarometry, attest to a prograde passage from lawsonite‐blueschist to peak eclogite facies of ~2.5 GPa and ~620°C. Phengite‐bearing eclogites imply interaction with an externally‐derived fluid, whereas rare phengite‐free, kyanite‐eclogites only record internally‐derived fluid production. Models predict that prograde breakdown of chlorite, lawsonite and amphibole between 500 and 610°C lead to progressive dehydration and release of up to 4.6 wt.% of aqueous fluid. Microstructural data reveal elongated shapes of highly strained omphacite porphyroblasts, displaying minor yet gradual changes in misorientation towards the grain boundaries. Occasionally, these intragranular structures form subgrain cells that have similar sizes to those of neoblasts in the rock matrix. These observations point to the potential onset of dynamic recrystallization processes via dislocation creep. Moreover, the omphacite neoblasts and rutile show non‐random crystallographic preferred orientations (CPOs), which are characterized by the subparallel alignment of point‐like maxima in rutile [001] and [100] axes to those of [001] and (010) of omphacite neoblasts, respectively. Additionally, the [001] axes of these minerals are also subparallel to the weak stretching mineral lineation, and the (100) of rutile and the (010) of omphacite neoblasts are distributed in the plane of the foliation. This suggests that the development of their CPOs was coeval and structurally controlled. Garnet microfractures normal to the foliation are dilated and sealed predominantly by omphacite. The lack of obliquity between CPO and foliation plane, as well as the systematic orientation of garnet microfracture orientations, are consistent with coaxial deformation at peak‐pressure conditions. Unlike other studies, we show that neither an external fluid source nor channelized fluid flow is needed to facilitate a ductile‐brittle deformation of eclogite in a subduction setting.

Precipitation of Ag-Pb-Zn ores of the Poshan vein deposit in the Qinling orogen (central China) by dilution of magmatic hydrothermal fluids

Abstract Constraints on the source, nature, and evolution of ore-forming fluids are crucial for better understanding the ore genesis and mechanisms that lead to metal precipitation. Here, we present results of in situ analysis for quartz oxygen isotopes and sulfide sulfur isotopes, combined with apatite U-Pb age and fluid inclusion data, to provide insights into the source and evolution of ore fluids of the Poshan Ag-Pb-Zn vein deposit in the Qinling orogen, central China. Quartz-carbonate-sulfide veins at Poshan are hosted in lower Paleozoic metavolcanic-sedimentary rocks and structurally controlled by fracture zones associated with the Heqianzhuang anticline. The Ag-Pb-Zn mineralization consists of three stages, which are represented by quartz-pyrite-arsenopyrite (stage I), quartz-carbonate-sulfide-silver minerals (stage II), and quartz-calcite ± native silver (stage III). Apatite texturally associated with galena from stage II has a U-Pb age of 125 ± 14 Ma (2σ; mean square of weighted deviates [MSWD] = 0.9), which suggests that the Poshan deposit formed in the Early Cretaceous and thus significantly postdated the Paleozoic and early Mesozoic orogenic deformation of the Qinling orogen. Aqueous-carbonic fluid inclusions from stages I and II have similar total homogenization temperatures of 263–347 °C and calculated salinities of 1.2–5.1 wt% NaCl equivalent, whereas the values for liquid-dominated aqueous inclusions from stage III are 211–245 °C and 0.5–3.0 wt% NaCl equivalent. Five quartz generations are recognized from the three paragenetic stages, including Qz-1 and Qz-2 from stage I, Qz-3 and Qz-4 from stage II, and Qz-5 from stage III. Based on in situ secondary ion mass spectrometry oxygen isotopic analysis of the five quartz generations (Qz-1 to Qz-5), the calculated δ18Ofluid values for the ore fluids are 7.8‰ to 9.2‰ (mean 8.3‰), −3.2‰ to 8.7‰ (mean 5.6‰), −3.5‰ to 7.4‰ (mean 4.6‰), −4.5‰ to 7.6‰ (mean −0.2‰), and −6.4‰ to 1.4‰ (mean −3.8‰). The oxygen isotopic data and trend among the five quartz generations are best interpreted to represent magmatically derived ore fluid being diluted by modified meteoric water to cause mineralization. Fluid mixing is considered to be the principal mechanism that led to Ag-Pb-Zn precipitation at Poshan. Sulfides coexisting with the quartz generations have δ34SV-CDT values of −1.7‰ to 4.4‰, with no systematic variations among different paragenetic stages. These data, combined with apatite U-Pb age and geologic relations, provide additional evidence for a magmatic origin of the Poshan Ag-Pb-Zn deposit, as inferred from the oxygen isotopes. This study highlights the role of fluid dilution in triggering Ag-Pb-Zn deposition, and sheds light on the origin of silver-polymetallic deposits in orogenic belts.

Timing and Mechanism of Ore Precipitation in Porphyry Cu Systems: Insight from LA-ICP-MS Analysis of Fluid Inclusions and In Situ Oxygen Isotope Analysis of Hydrothermal Quartz at Zhunuo Porphyry Cu Deposit, China

Abstract The timing and mechanism of ore precipitation in porphyry copper systems are hot topics and remain controversial. The large Miocene collision-related Zhunuo porphyry Cu deposit in the Gangdese belt of southern Tibet, China, was produced by multistage quartz veining and hydrothermal alteration, accompanied by Cu sulfide precipitation. In this study, we have combined cathodoluminescence (CL) petrography with in situ oxygen isotope analysis and fluid inclusion microthermometry and laser ablation-inductively coupled plasma-mass spectrometer microanalysis to constrain the growth history of individual quartz veins, the source and evolution of the hydrothermal fluids, and the timing and mechanism of ore precipitation at Zhunuo. Early quartz A veins associated with potassic alteration are composed of quartz, K-feldspar, biotite, Cu-Fe sulfides, and pyrite. Quartz B veins are composed of quartz, Cu-Fe sulfides, molybdenite, and pyrite. CL imaging shows that quartz grains in the A and B veins consist of abundant early generation of bright-luminescent quartz (QA and QB) with volumetrically minor later generation of dull-luminescent quartz (QA-crack and QB-crack) occurring in the voids or at the margins of the QA and QB veins with embayed contacts. Cu-Fe sulfides are generally in contact with the dull-luminescent quartz and locally in contact with the bright-luminescent quartz and K-feldspar in the A and B veins or occur as disseminations in the potassic-altered porphyries that have been overprinted by chlorite ± muscovite alteration. QA and QB contain single-phase intermediate-density inclusions and abundant brine and vapor-rich inclusions. A boiling assemblage in QA has a homogenization temperature of ~560°C and trapping pressure of ~530 bar. Two boiling assemblages in QB have homogenization temperatures of ~440°C with trapping pressures of ~230 and ~250 bar, indicating a transition from lithostatic to hydrostatic conditions at a paleodepth of ~2.0 to 2.5 km. QA-crack and QB-crack contain aqueous inclusions with lower homogenization temperatures of 340° to 400°C and salinities of 6 to 12 wt % NaCl equiv. In situ oxygen isotopes indicate that QA and QB have δ18O values of 7.6 to 11.4‰, whereas QA-crack and QB-crack have δ18O values of –7.2 to 6.7‰. Combined with fluid inclusion compositions, we propose that condensation of vapors into brines and mixing with 25 to 60% meteoric water can produce the salinity and oxygen isotopes of fluids that caused the dissolution of the early bright-luminescent quartz and the precipitation of the later dull-luminescent quartz. Zhunuo Cu-Fe sulfides are in contact with the bright-luminescent quartz and cut the growth bands. The dull-luminescent quartz in contact with the Cu-Fe sulfides has oscillatory growth banding. In addition, Cu-Fe sulfides in the A and B veins or in the potassic-altered rocks coexist with chlorite ± muscovite alteration minerals. These geologic observations, together with evidence that there is an abrupt drop in the Cu/(Na + K) ratio by more than one order of magnitude in the aqueous fluids within the dull-luminescent quartz compared to the brines within the bright-luminescent quartz, indicate that precipitation of Cu-Fe sulfides occurred after the potassic alteration stage and during the chlorite ± muscovite alteration stage. Ore precipitation was associated with mixing of magmatic fluids (brines + vapors) with meteoric water, accompanied by fluid cooling, salinity decrease, and retrograde quartz solubility as the rocks transitioned from lithostatic to hydrostatic conditions. During continued cooling in the latest stage, the hydrothermal fluids precipitated D veins that contain abundant pyrite with minor quartz. Quartz in the D veins (QD) contains aqueous inclusions with much lower temperatures and Cu/(Na + K) ratios, indicating that most of the Cu-Fe sulfides have been precipitated during this stage.

Vertical transmission of microbiomes into embryo culture media and its association with assisted reproductive outcomes

Research Question: Can microbes vertically transmit from semen and follicular fluids to embryo culture media during assisted reproductive technology (ART) treatments?Design: Spent embryo culture media (SECM) were collected along with seminal fluid and follicular fluid samples from 61 infertility couples undergoing ART treatment at the Prince of Wales Hospital, Hong Kong SAR, China. Metagenomic analysis was conducted to identify the source of microbes in SECM, the correlation between semen microbiomes and male infertility, and the correlation between follicular fluid microbiome and female infertility.Results: Microbial vertical transmission into SECM was reported in 82.5% of the cases, and semen was the main source of contamination in c-IVF cases. The increased abundances of Staphylococcus and Streptococcus anginosus in semen showed statistically negative impacts on sperm count and total motility, respectively (p <0.001). We observed significant increases in the abundances of Prophyromonas, Neisseria, and Facklamia in follicular fluid in women with anovulation, uterine factor infertility, and unexplained infertility, respectively (p <0.01). Finally, there was no significant correlation between the bacteria identified in all sample types with ART outcomes including fertilization rates, embryo development, the number of available embryos, and clinical pregnancy rates.Conclusion: Embryo culture media can be contaminated during ART treatment, not only by seminal microbes but also by follicular fluid and other sources of microbes. There were strong correlations between specific microbial taxa in semen and sperm quality as well as between follicular fluid microbiomes and the etiology of female infertility. However, the microbiome of SECM, semen, and follicular fluid showed no significant association with ART treatment outcomes.

Lithospheric mantle as a metal storage reservoir for orogenic gold deposits in active continental margins: Evidence from Hg isotopes

Abstract The subcontinental lithospheric mantle (SCLM) is now suggested by many workers to play a role in the formation of orogenic gold deposits in active continental margins, given that the gold and volatiles may be introduced into the SCLM during plate subduction. The giant Cretaceous Jiaodong gold province within the North China block occurs in a convergent margin setting where there is no terrane accretion, thus eliminating from consideration the commonly accepted metal and fluid source reservoir for orogenic gold—the metamorphosed upper crust of an active orogenic belt. Thus, the auriferous fluids were released below the high-grade Archean cratonic rocks from either enriched SCLM or directly from the subducted oceanic slab. Mercury (Hg) isotopes allow fingerprinting of isotopically distinct reservoirs, discriminating between the two possibilities. We present Hg isotope data for a set of pyrite grains, native gold, and lamprophyres from six main gold districts in the Jiaodong gold province. These samples dominantly yielded near-zero Δ199Hg (0‰ ± 0.1‰), within uncertainty of the mantle Δ199Hg value. The results provide novel evidence that the SCLM predominantly controlled the Hg budget of the Jiaodong gold deposits, implying that the SCLM acted as a buffer for the crustal mass-independent fractionation Hg signatures and a storage reservoir for gold and volatiles. Consequently, during slab subduction, gold and volatiles were recycled and stored within the SCLM and were later released from the mantle during uplift and relaxation of compressional tectonics.