Fluid Source Research Articles

Case Report: Cryptococcal Infection in Renal Transplant Patient

A significant portion of all invasive fungal infections in solid organ transplants are due to cryptococcus. It can be a debilitating infection and affects the quality of life in transplant patients. We report a case of a 57-year-old male patient with recent kidney transplant, who presented with cryptococcal meningitis, after exposure to birds during a trip to Mexico 1 week ago. In addition to a two-day history of generalized weakness, dizziness, intermittent fever, and lightheadedness, the patient presented with on and off headaches, increased sinus pressure, neck stiffness, clogged ear sensation, confusion, and night sweats. The patient was initially treated empirically with fluconazole. Lumber punctuation showed elevated opening pressure, increased WBC, with neutrophil predominance. Cryptococcal antigen tests were positive in both serum and cerebrospinal fluid sources. After confirmation from CSF analysis, he was administered liposomal amphotericin B and flucytosine. Patient’s symptoms rapidly improved. Due to his immunocompromised state, the patient will require lifelong fluconazole maintenance therapy. Even though kidney transplant recipients have a positive outcome in terms of longevity, they are at increased risk of post-transplant infection, such as zoonotic infections. Therefore, in any recent kidney transplant patient with meningitis symptoms, cryptococcal meningitis should always be considered. We report the appropriate criteria, procedures, and tests that allow for a cryptococcal meningitis diagnosis in immunocompromised patients.

Genesis of the Tangshang Au Deposit in Southeast Yunnan Province, China: Constraints from In Situ Chemical and S-Sr Isotope Analyses

The Yunnan–Guizhou–Guangxi district (also known as the Dian–Qian–Gui “Golden Triangle”) in southwestern China contains numerous Carlin-type Au deposits (CTGDs). However, the sources of Au and Au-bearing fluids in these deposits remain controversial. The Tangshang Au deposit is a middle-sized CTGD in southeastern Yunnan Province. This study involved in situ chemical and S isotope analyses of sulfides and in situ trace elemental and Sr isotope analyses of ore-related calcite; these data were used to trace the sources of fluids and Au, as well as the genesis of this deposit. Four pyrite types (Py1, Py2, Py3, and Py4) and two arsenopyrite types (Apy1 and Apy2) were identified based on their textural characteristics. It was found that Py1 contains relatively lower Au, Sb, Cu, and Tl contents than those of Py2, Py3, and Py4. Py1 is wrapped by rim-Py2 and Py3, which indicates an early-ore-stage genesis. The Carlin-type mineralization elements are elevated in the pyrites (Au = 3.04–38.1 ppm; As = 40,932–65,833 ppm; Tl = 0 to 3.3 ppm; Sb = 1.2 to 343 ppm; and Cu = 10 to 102 ppm), and the average Co/Ni ratio is 0.54. Additionally, Au has a positive correlation with Tl and Cu. The high concentrations of As and Au in all types of pyrite indicate that the ore-forming fluids are rich in both elements. The sulfides in the ores were shown to produce similar S isotope ratios, which are obviously higher than the S isotope value of sulfide (~0‰) in Emeishan basalt; therefore, the integration of these and elemental composition data indicated that all pyrites (Py1, Py2, Py3, and Py4) form during the ore stage. These results also demonstrate that the δ34S values of the Au-bearing fluids are higher than those of basalt wall rocks. The flat chondrite-normalized REEs pattern and positive Eu anomaly of the calcite were similar to those obtained from Emeishan basalt, which suggests a reducing characteristic of hydrothermal fluids. The 87Sr/86Sr ratios (0.70557–0.70622) of calcite were also comparable to the range obtained from Emeishan basalt. Some slightly higher 87Sr/86Sr ratios, which ranged between those obtained from Emeishan basalt and limestone from the Maokou Formation, indicated that the Sr isotope ratios of the Au-bearing fluids are higher than those of Emeishan basalt. Based on data generated in the present study and the regional geology of this area, a genetic model involving a metamorphic fluid system was proposed for the Tangshang gold deposit, and a gold mineralization event related to metamorphic fluid in the south of the Dian–Qian–Gui “Golden Triangle” was indicated.

Metasomatized mantle lithosphere and altered ocean crust as a fluid source for orogenic gold deposits

Whether auriferous hydrothermal fluid is generated during crustal metamorphism or by subcrustal processes to form orogenic gold deposits is hotly debated. Noble gas isotope and halogen abundance ratios can provide important constraints to help resolve this controversy. The Danba gold deposit is a rare example of a Jurassic age hypozonal orogenic gold deposit on the western margin of the Yangtze Craton, China. It is characterized by thick barren quartz veins with fractures infilled by thin auriferous quartz veinlets. The syn-gold quartz veinlets are associated with plagioclase and pyrrhotite and are distinguished from the barren quartz vein hosts on the basis of cathodoluminescence, trace-element content and Raman spectroscopy and microthermometry of fluid inclusions. The dominant fluid inclusions in the gold-bearing quartz and plagioclase are H2O–CH4 with vapor fill of ∼ 15–45 vol% and high pressure-corrected trapping temperatures of ∼ 500 °C, low salinities (<4 wt% NaCl equiv.) and high Mg/Fe ratios. Crushing syn-gold quartz and plagioclase released fluid inclusions with 40Ar/36Ar ratios of between 490 and 710, molar Br/Cl ratios of (0.3–0.7) × 10−3 and molar I/Cl ratios of (18–60) × 10−6. Crushing syn-gold pyrrhotite released fluid inclusions with 3He/4He ratios of 0.21–0.38 Ra (Ra = air value, 1.39 × 10−6) that are higher than typical crustal values of < 0.1 Ra, and 40Ar/36Ar of 330–640 that are similar to the gold-related quartz-hosted inclusions. The combined noble gas and halogen data do not favor an auriferous fluid derived from K- and U-rich Proterozoic granitic basement, which is expected to have radiogenic 40Ar/36Ar and 3He/4He ratios. Instead, the data are more consistent with a fluid source from underlying mantle lithosphere containing a high proportion of altered ocean crust (AOC). The auriferous fluid that formed the Danba gold deposit is thus considered to have been derived from a source comprising both metasomatized mantle lithosphere that had been fertilized in a Neoproterozoic subduction event and a portion of relict AOC beneath the western margin of the Yangtze Craton. In contrast with syn-gold fluid inclusions, those in pre-gold barren quartz are H2O–CO2 dominated. Crushing pre-gold quartz released fluid inclusions with 40Ar/36Ar ratios of 2410–5450, Br/Cl ratios of (1.2–1.5) × 10−3 and I/Cl ratios of (60–80) × 10−6 that are distinctly different to the gold-ore stage. The higher 40Ar/36Ar ratios of the pre-gold fluids are consistent with a source for the barren host quartz veins from prograde greenschist- to amphibolite-facies metamorphism of the Proterozoic granitic basement.

The Gold–Palladium Ozernoe Occurrence (Polar Urals, Russia): Mineralogy, Conditions of Formation, Sources of Ore Matter and Fluid

We studied the mineralization and sulfur isotopic composition of sulfides of gold–palladium ores in olivine clinopyroxenites from the Dzelyatyshor massif made up of a continuous layered series of rocks: olivine-free clinopyroxenite–olivine clinopyroxenite–wehrlite. The primary igneous layering of rocks, manifested as different quantitative ratios of clinopyroxene and olivine in them, controls the local trends of variability in the chemistry of mineral-forming medium and the concentrations of ore components, including noble metals, and sulfur in each separate layer during its cooling. The replacement of primary rock-forming minerals by secondary minerals, when the temperature decreases, is a characteristic trend for pyroxenites: (a) olivine → serpentine, secondary magnetite, and (b) clinopyroxene → amphibole, secondary magnetite → chlorite. The deposition of native gold in parageneses with PGM and sulfides at the Ozernoe occurrence took place during the replacement of earlier rock-forming minerals by chlorite. This process completed mineral formation at the deposit and took place at temperatures 150–250 °C and at the high activity of S, Te, Sb, and As of fluid. The variability of mineral formation conditions during chloritization is reflected in the change of native-sulfide forms of Pd by arsenide-antimonide forms and the sulfur isotopic composition of sulfides. The Pd content in native gold increases in the series—Au-Ag solid solution (&lt;1.5 wt.% Pd)—Au-Cu intermetallides (to 6 wt.% Pd)—Cu-Au-Pd solid solutions (16.2–16.9 wt.% Pd). The sulfur isotopic composition of pyrite, chalcopyrite, and bornite varies from −2.1 to −2.9‰. It is assumed that a deep-seated magmatic basic melt was the source of fluid, ore components, and sulfur.

Parametric approach to promote a divergence-free flow in the image-based motion estimation with application to bioirrigation

Flow fields are determined from image sequences obtained in an experiment in which benthic macrofauna, Arenicola marina, causes water flow and the images depict the distribution of a tracer that is carried with the flow. The experimental setup is such that flow is largely two-dimensional, with a localised region where the Arenicola resides, from which flow originates. Here, we propose a novel parametric framework that quantifies such flow that is dominant along the image plane. We adopt a Bayesian framework so that we can impart certain physical constraints on parameters into the estimation process via prior distribution. The primary aim is to approximate the mean of the posterior distribution to present the parameter estimate via Markov Chain Monte Carlo. We demonstrate that the results obtained from the proposed method provide more realistic flows (in terms of divergence magnitude) than those computed from classical approaches such as the multi-resolution Horn–Schunk method. This highlights the usefulness of our approach if motion is largely constrained to the image plane with localised fluid sources.

Saliva Diagnostics.

Cancer remains one of the leading causes of death, and early detection of this disease is crucial for increasing survival rates. Although cancer can be diagnosed following tissue biopsy, the biopsy procedure is invasive; liquid biopsy provides an alternative that is more comfortable for the patient. While blood, urine, and cerebral spinal fluid can all be used as a source of liquid biopsy, saliva is an ideal source of body fluid that is readily available and easily collected in the most noninvasive manner. Characterization of salivary constituents in the disease setting provides critical data for understanding pathophysiology and the evaluation of diagnostic potential. The aim of saliva diagnostics is therefore to develop a rapid and noninvasive detection of oral and systemic diseases that could be used together with compact analysis systems in the clinic to facilitate point-of-care diagnostics.

In-situ monazite Nd and pyrite S isotopes as fingerprints for the source of ore-forming fluids in the Jiaodong gold province

The giant Jiaodong gold province has attracted a large amount of research on its geological features, ore-forming processes and genesis. Uncertainties as to the primary sources of ore-forming fluids, and whether host rocks contribute materials to gold mineralization, are still subject to intense debate. Here, we present comprehensive in-situ sulfur isotopic studies of pyrite from the Qujia and Xincheng gold deposits, and neodymium isotopic studies of monazite from the Xiadian, Zhuangzi, Hushan, Daliuhang, and Muping gold deposits, whose timing of gold mineralization has been constrained to ca. 120 ± 5 Ma using in-situ monazite U-Pb dating. The δ34S values among Py1 (+9.0 to +9.9‰), Py2 (+8.4 to +10.7‰) and Py3 (+6.9 to +12.3‰) are similar, showing consistence with that of other deposits in the Jiaodong gold province. It indicates that these gold deposits share the same dominant sources of sulfur and/or ore-forming fluids, potentially being exsolved from the contemporaneous magmas. Slightly wide range of δ34S for Py3 is likely due to the partially closed deposition spaces and intensive fluid-rock interaction. Hydrothermal monazite is intergrown with pyrite in the orebodies, suggesting that they were precipitated simultaneously from the same fluids. Our newly published Sm-Nd isotopic studies on monazite yielded inconsistent values of εNd (t = 120 Ma) among the Zhuangzi (−25.5 to –22.6), Xiadian (–23.3 to −20.2), Hushan (−20.6 to −18.4), Muping (−20.5 to −17.3) and Daliuhang (−13.7 to −11.6) gold deposits. These in-situ monazite Nd isotopes overlap with whole-rock Nd isotopes of their corresponding host rocks, indicating the material contribution of host rocks to the gold mineralization. This study provides robust evidences showing that the ore-forming fluids of the Jiaodong gold deposits share the same primary origin, but incorporate nonnegligible abundance of materials (REE, and potentially ore-related elements, such as Au, As, Fe) from the host rocks upon ascending, due to intensive fluid-rock interaction.

The Ulug-Sair Gold Occurrence (Western Tuva, Russia): Mineralogy, Ore Genesis, and S-O Isotope Systematics

Ulug-Sair Au-Bi-Te-Se mineralization is one prospect for native Au in the Western Tuva, and its origin remains debated. Mineralization consists of gold–sulfide–quartz veins in the host sedimentary rocks (conglomerates, siltstones, shales), quartz–tourmaline, and quartz–carbonate–sericite–altered rocks. To determine its origin, we examined the mineralogical–geochemical features, formation conditions, and fluid sources of the Ulug-Sair ore. A mineralogical–geochemical investigation outlines two substages with Au: an early gold–sulfide–quartz with pyrite, chalcopyrite, galena, gold, and electrum; and a late gold–telluride–sulfide–quartz, characterized by the presence of Bi-bearing minerals (AgBiTe, Bi2Te2Se, Cu3BiS3, Bi), tellurides (Au and Ag), Se-tellurides (Ag and Bi), and selenides (Au, Ag, and Hg). The paragenesis of Au–Ag tellurides, and fluid inclusion study data (microthermometry, Raman spectroscopy, LA-ICP-MS, and crush leach analysis (gas and ion chromatography, ICP-MS) in quartz showed that quartz–tourmaline-altered rocks were formed by an aqueous Mg–Na–K-chloride fluid with a salinity of 8–10 wt % NaCl eq. at 325–370 °C, whereas the host quartz–carbonate–sericite-altered rocks were formed from CO2–H2O fluid containing CH4 and N2, with a salinity of 0.18–6.1 wt % NaCl eq. at 200–400 °C. Gold-bearing mineral assemblages were formed at P ~ 0.75–1.0 kbar (~2.3–3 km) due to CO2–H2O chloride (Na–K ± Fe, Mg) fluid with CH4, Na2SO4, and Na2B2O5, and salinities 1.7–12.5 wt % NaCl eq. at temperatures decreasing from 360 up to 115 °C (gold–sulfide–quartz veins—360–130 °C, and gold–telluride–sulfide–quartz veins—330–115 °C), and variable fO2, fS2, fSe2, and fTe2. Results of the investigation of the isotope composition of S in pyrites indicates the magmatic origin of the fluid (δ18SH2S fluid from −0.4 to +2.5‰). The stable O isotope data in quartz indicates that, at an early substage, the formation of ore involved a fluid of magmatic and metamorphic origin (from +8.2 to +11.6‰), and, in the later substage, multiple sources of hydrothermal fluids (from +3.1 to +10.4‰), including magmatic-derived, metamorphic-derived, and meteoric waters. These data, in conjunction with structurally controlled mineralization, point towards similarities of the Ulug-Sair ore system with orogenic gold deposits.

Iron and sulfur isotope fractionation during pyrite dissolution-reprecipitation revealed by in-situ isotopic analyses in the Muping gold deposit (Jiaodong, China)

Pyrite is an excellent archive for understanding geochemical behaviors of elements and isotopes in the course of ore formation. Here we present a combined textural-geochemical characterization of gold-related pyrites from the Muping deposit of Jiaodong gold province. Element mapping reveals core-rim texture, with the core being enriched in Pb, Ag, Cu, and Sn, whereas the rims in Au and As. Electron backscattered diffraction analysis shows consistent crystallographic orientation for both core and rim in pyrite. Simultaneous in-situ isotopic measurements unravel a coupled variation in Fe-S isotopes during pyrite growth and modification. We interpret the core-rim texture as an indication of coupled dissolution-reprecipitation, where the cores precipitated from an initial fluid, and then dissolved and overgrown in response to cooling and oxidizing conditions. During this process, Pb, Ag, Cu, and Sn migrated out from the rims. Instead, Au were locked in the rims with the aid of As in the fluids. It is supposed that a variation of temperature and oxygen fugacity led to the disparity of Fe-S isotope of pyrite cores. Kinetic fractionation might account for the dispersion of Fe-S isotopic compositions of rims. The rims have relatively homogeneous S isotope composition. However, the variation of the Fe isotope of the rims was derived from different degrees of isotope exchange, suggesting that Fe isotope did not equilibrate with the mineralizing fluid. The different fractionation behavior of Fe-S isotopes in pyrite during fluid modification has a significant implication for reconstructing precipitation environment and tracing sources of ore-forming fluid and mineralization process.

Geochemical Characteristics and Geological Significance of Cassiterite in the Dalong Tin Deposit, Baoshan Block, SW China

The Dalong tin deposit, located in the Luziyuan polymetallic ore field of the southern Baoshan block, Southwest China, is composed of lenticular and bedded orebodies hosted in a Cambrian slate-marble sequence. As the only tin deposit in the orefield, the genesis of the Dalong deposit is of great significance to the understanding of regional metallogenic regularity. Based on a systematic field survey and petrographic observation, EPMA and LA-ICP-MS major/trace element analyses of cassiterite were carried out in this study. The enrichment of Fe, W, and Ti in cassiterite, as well as the depletion of Nb, Ta, and Mn, reveal cassiterite’s features in granitic magmatic-hydrothermal deposits. The Dalong deposit can be categorized as a magmatic-hydrothermal vein-type deposit because of its sulfur isotopic properties, and the main sources of ore-forming fluid and minerals are thought to be buried intermediate-acid intrusions in the mining area’s depths.

Crustal Electrical Structure and Deep Metallogenic Potential in Northern Wuyi Area (South China), based on Magnetotelluric Data

AbstractThe northern Wuyi area, which is located in the northern Wuyi metallogenic belt, has superior mineralization conditions. The Pingxiang–Guangfeng–Jiangshan–Shaoxing fault (PSF) extends across the whole region regardless of whether or how the PSF relates to the near‐surface mineralization. We carried out an MT survey in the region and obtained a reliable 2D model of the crustal electrical structure to a depth of 30 km. In the resistivity model, we inferred that a continuous high conductivity belt that ranges from the shallow to deep crust is a part of the PSF. Then, we estimated the fluid content and pressure gradient to identify the deep sources of fluid as well as its pattern of motion pattern. Finally, we proposed a model for the deep metallogenic migration processes that combines geological data, fluid content data, pressure gradient data, and the subsurface resistivity model. The model analysis showed that the Jiangnan orogenic belt and the Cathaysia block formed the PSF during the process of com. The deep fluid migrated upward through the PSF to the shallow crust. Therefore, we believe that the PSF is an ore‐forming fluid migration channel and that it laid the material basis for large‐scale mineralization in the shallow crust.

Fluid sources and mineralizing processes in greenstone belts: a stable isotope (O, H) comparison between the weakly mineralized Moly-Desgagné–Guercheville system and Val-d’Or orogenic gold deposits, Canada

In orogenic gold systems, the source of the fluids and the processes leading to mobilization, transport, and deposition of gold remain debated. Most studies focus on endowed rather than on gold-poor orogenic systems to unravel the “key” parameters of gold mineralizing processes. Here, we present stable isotope (O, H) data from the Moly-Desgagné–Guercheville fault system (gold-free to low gold endowment) in the Chibougamau area, Abitibi greenstone belt, Canada. The gold-free Moly-Desgagné showing and nearby poorly endowed Hazeur showing and Monster Lake deposit share similar features typical of orogenic systems. The stable isotope compositions of tourmaline and quartz from the Moly-Desgagné–Guercheville fault system also display similar characteristics, such as (1) temperature of vein formation of 345 ± 86 °C (1σ); (2) fluid mixing between an upper crustal reservoir (low T – high δD – low δ18O) and a metamorphic water reservoir (high T – low δD – high δ18O); and (3) positive δDfluid values consistent with multiple boiling-condensation cycles related to fault-valve processes. These characteristics are similar to those from the gold-endowed Val-d’Or vein field. The difference in gold endowment between the Moly-Desgagné–Guercheville and Val-d’Or vein fields may be related to the nature of the fault system (i.e., terrane-bounding or “intragreenstone belt”) and the volume and (or) composition (i.e., gold, its ligands, CO2) of the fluid source rocks.

The Origin of Synchysite-(Ce) and Sources of Rare Earth Elements in the Rožná Uranium Deposit, Czech Republic

Synchysite was identified in the Rožná uranium deposit in a quartz–carbonate–sulfide vein, which is a part of the late (post-uranium and, post-Variscan) stage of the development of the hydrothermal system. The synchysite forms needles or lamellae, which are almost exclusively bound to the quartz filling of the veins. The structure of the quartz vein-filling, i.e., the preserved tubular syneresis crack pattern, Liesegang bands formed by hematite, chaotic grain size distribution of quartz grains, and ribbons of fibrous SiO2 grains, indicate that the synchysite crystallized in a silica gel. Its formation may be explained by the reaction of hydrothermal acid fluids rich in Fe2+ and rare earth elements (REEs) with alkaline Ca2+ HCO3− and F-rich fluids expelled from the gel during syneresis, or by its ageing. The subsequent recrystallization of the gel to form euhedral quartz grains was accompanied by the deformation of previously formed Liesegang rings, and the development of quartz rosettes. The study of fluid inclusions indicated that the silica gel originated at a very low temperature. The temperatures of the homogenization of two-phase inclusions in carbonate and quartz vein-filling varied between 38 and 74 °C, and the salinity ranged between 4 and 10 wt.% NaCl equiv. The δ13C carbonate values (from −4.65 to −5.21‰, PDB) indicate the deep-seated source of CO2, and δ18O values (from 14.76 to 18.22‰, SMOW) show that the source of the hydrothermal fluids was mainly surface water, with a possible admixture of fossil saline brines. The main sources of REEs are thought to have predominantly been uranium minerals (coffinitized uraninite and coffinite) that form a part of the breccia fragments embedded in the vein filling. The results illustrate the significant mobility of REEs in the late, low-temperature hydrothermal system, and they indicate the multiple remobilizations of REEs in the uranium deposits in general.

Open–closed–open palaeofluid system conditions recorded in the tectonic vein networks of the Parmelan anticline (Bornes Massif, France)

Fluid sources and migration pathways can dramatically change during the multiphase tectonic evolution of thrust wedges. We present a multidisciplinary study of syntectonic calcite cements in the Lower Cretaceous carbonates of the external Bornes (SE France), which underwent subaerial exposure during flexural bulging, layer-parallel shortening, folding and post-folding oblique contraction. Based on stable and radiogenic isotopes, trace elements, fluid inclusions and clumped isotope thermometry, we identified two main palaeofluid types. The older iron-rich calcite cements, associated with the pre-folding and early syn-folding stages, precipitated from an 18 O-enriched fluid ( δ 18 O = +8.6 – +11.6‰ VSMOW) at temperatures between 90 and 115°C. The younger calcite cements, associated with the late syn-folding and post-folding oblique contraction stages, have low iron content and precipitated from an 18 O-depleted ( δ 18 O = −7.5 – −4.3‰ VSMOW) meteoric fluid at temperatures between 40 and 80°C. The older fluid reached thermal equilibrium with the host rock at the maximum burial conditions, whereas the second one was probably heated in the inner sector of the belt before migrating towards the foreland. 87 Sr/ 86 Sr ratios exclude any contribution from basement-derived ascending fluids, pointing to the migration of meteoric fluids within the laterally continuous fractured Cretaceous units. Supplementary material: Details of the sampling sites and a complete dataset are available at https://doi.org/10.6084/m9.figshare.c.5882212

Dynamic simulation model with virtual interfaces of supercritical working fluid heat exchanger based on moving boundary method

The supercritical cycle has a better variable-temperature match between the working fluid and heat source, potentially providing higher efficiency. Accurate simulation of the transient performance of supercritical heat exchangers is significant in advanced thermal system control. This paper proposes a dynamic model of supercritical heat exchangers based on the moving boundary method. The model redefines the concept of “interface” in the traditional moving boundary model. The new interfaces are determined by the thermophysical properties of the working fluid, called “virtual interfaces”. A control-volume separation method is proposed based on the virtual interface. Additionally, the specific enthalpy is selected as the switching criterion for the configuration of the control volumes, so the model can dynamically adjust the number of control volumes. The integrity check results show that the simulation accuracy is at least equivalent to the finite volume model with 20 control volumes; however, the time cost is approximately 1/5 of that of the finite volume model with the same precision. An experimental study on the convective heat transfer of supercritical n-decane in an electrically heated vertical tube was conducted. The maximum absolute error of the steady-state outlet temperature is ±1.5 K, and the relative error is ±3% under different pressures.

Spatio‐Temporal Complexity of Aftershocks in the Apennines Controlled by Permeability Dynamics and Decarbonization

AbstractIn 2016, a series of large normal faulting earthquakes in the Apennines filled the seismic gap between the 1997 Colfiorito and 2009 L’Aquila earthquakes. These earthquakes, known as the Amatrice‐Visso‐Norcia (AVN) sequence, spawned hundreds of thousand of aftershocks in the first year, extending about 60 km along strike. The Colfiorito and L’Aquila aftershocks showed a significant high fluid‐pressure component in their aftershock genesis, and here we show evidence that the AVN aftershocks also include a significant high pressure CO2 component. This CO2 is both deeply‐derived, and internally generated by thermal decomposition. Using a simple model of non‐linear diffusion with a source term, we compare model results with the observed cumulative number of aftershocks, and also spatial comparisons between the calculated fluid pressure and the hypocenters of about 35,000 well‐located events. The good comparisons between model and observations provide evidence that the AVN sequence includes a contribution (additional fluid source) from co‐seismic decarbonization. Our results suggest that internal fluid generation through devolitization or decarbonization is responsible for non‐Omori type aftershock behavior such as observed for the AVN sequence and for the 2011 Mw 9.1 Tohoku (Japan) and the 2014 Iquique (Chile) Mw 8.2 megathrust subduction zone earthquakes.

Research on Metallogenic System and Deposit Genesis: With Zhacun Goldmine in Weishan County of Yunnan as an Example

This paper mainly takes Zhacun goldmine as the research object and carries out research on the metallogenic system and genesis of the deposit in the area. The research methods are as follows: according to the geological characteristics of the metallogenic mining area in the Zhacun goldmine, combined with the comparative analysis of the metallogenic age, alteration characteristics and lithology between the Zhacun goldmine and the Lianhuashan alkali rich rock mass, and the analysis of the isotopic data in the Zhacun goldmine, this paper demonstrates that the magmatic activity of the Lianhuashan quartz monzonite porphyry plays an important role in the mineralization of this area, which is both an important ore source and fluid source. It is also the main heat source driving the circulation of ore-forming fluid. On this basis, through the analysis of the metallogenic elements in the area, the metallogenic system model of Zhacun goldmine is constructed. It is considered that under the action of long-term horizontal compressive stress, the atmospheric precipitation infiltrated into the formation continued to penetrate along the fractures and fissures to deep crust and finally mixed with the magmatic water sealed in the thick formation. During this period, a series of shallow and ultrashallow porphyry mass intruded, providing heat source and part of the ore-forming materials and resulting in incomplete homogenization under high temperature and high pressure, which formed highly mineralized mixed water. Under the combined action of long-term compressive stress and various deep thermal dynamics, these mineral fluids migrated along the buried deep faults near the core of the duplex anticline to the upper part of the crust. When the metal elements in these ore fluids migrated over long distances to the nappe fault zone of the gold-bearing fracture zone, the gold began to precipitate, and the native gold and the coarse-grained pyrite and quartz formed at the same time or earlier started to fill the fracture zone along the fissures and accumulate into minerals. Then, through the analysis of metallogenic conditions, gold mineralization process, and genetic mechanism of the deposit, it is proposed that the genetic type of the ore deposit in this area is magmatic mesothermal-epithermal gold deposit. The establishment of metallogenic system model in Zhacun goldmine will provide theoretical and practical guidance for deep and peripheral prospecting prediction in the area, carry out targeted and reasonable prediction, and improve prospecting effectiveness.

Legal Interpreting and Translanguaging: Contested Spaces in the Centre-Periphery Dynamic

Community or public-service interpreting is often institutionally perceived by service providers as being based on an ideological framing of languages as monolingual bounded resources, and the interpreting act as a bridge between two centric and separate linguistic regimes (LB – LA). However, this monolingualism is an ideological construct rather than a linguistic reality, the product of an historic, one nation one language myth, that is increasingly challenged by post-modern, superdiverse societies and their consequent multilingual realities on the ground. In particular, in today’s world the superdiversity of people within nation states, with multiple linguistic resources, has given rise to the increasingly visible phenomenon of ‘translanguaging’, a creative, dynamic and fluid sourcing of diverse linguistic repertoires in synchronic discourse. What was once only considered to be at the periphery has begun to challenge monolingual hegemony and establish its own centrality in public and private speech.&#x0D; Translanguaging is ‘multilingualism from below’ (Pennycook &amp; Otsuji 2015), coming as it almost inevitably always does from the peripheral end of the spectrum, typically in urban spaces where language practices are part and parcel of getting things done. But when this emerges in a legal context, in a court of law, how should legal interpreters respond? Drawing on preliminary research involving a cohort of court /legal interpreters in the UK[1], this article explores the problems this presents to monolingual bridging approaches and proposes potential future developments for the interpreting profession. A cohort of 6 professional public-service interpreters in the UK. The research drew on questionnaires and personal correspondence over a 6-month period.

Tungsten mineralization process and oxygen fugacity evolution in the Weijia W deposit, South China: Constraints from the microstructures, geochemistry, and oxygen isotopes of scheelite, garnet, and calcite

Scheelite is a major (W)-bearing mineral enriched in rare earth elements (REEs) and is widely used to investigate the mineralization process, fluid source and redox environment of W deposits. In the Weijia skarn-type W deposit in South China, scheelite was formed during the greisen, retrograde skarn, oxidation, and sulfide-quartz vein stages. Various characteristics of cathodoluminescence (CL) images of scheelite grains (e.g., light to dark color, core-rim texture and oscillatory zonation) have recorded their detailed crystallization process. Scheelite grains formed in the greisen and retrograde skarn stages have similar LREE patterns, and the gradual fractionation in HREEs may be a result of the precipitation of garnet (And38-70Gr29-52Pr1-3) in the prograde skarn stage. In addition, the similar REE patterns of scheelite from the greisen stage and the granite porphyry pluton suggest a genetic relationship. The oxygen isotopic compositions of scheelite and quartz are all plotted near the edge of the magmatic fluid field, confirming their derivation from the same magmatic hydrothermal fluid. Elemental mapping and spot analyses using an electron probe microanalyzer indicated that extensive isomorphic substitution of W by molybdenum (Mo) occurs in scheelite, and the darker color in the CL images corresponds to a higher Mo content and lower W content. The Mo content of scheelite gradually increased from the greisen stage (mean = 0.46%), through the retrograde stage (mean = 2.89%), to the oxidation stage (mean = 19.8%), and then dropped sharply in the sulfide-quartz vein stage (mean = 0.20%), indicating a change in oxygen fugacity. Moreover, scheelite formed in the sulfide-quartz vein stage has an oscillating Mo content, thus implying a slight or periodical change in oxygen fugacity during the same mineralization stage.

Mass Bias Corrections for Hydrogen and Oxygen Isotope Analysis of Tourmaline by Secondary Ion Mass Spectrometry

ABSTRACT Hydrogen (δ2H) and oxygen (δ18O) stable isotopes are used to trace fluid sources, metals, and contaminants in the environment and Earth's subsurface. Tourmaline-supergroup minerals provide an opportunity to quantify both δ2H and δ18O from the same grain using in situ analytical techniques (e.g., Secondary Ion Mass Spectrometry – SIMS). These minerals occur in a wide variety of geological environments and have a wide range of chemical compositions. However, large differences in chemical composition are problematic during SIMS analysis, as instrumental mass fractionation (IMF) often varies with the chemical composition of the mineral. Therefore, calibration models derived by analyzing tourmalines of different chemical composition must be developed for accurate analysis by SIMS. Hydrogen and oxygen isotope analysis was done on six reference tourmaline samples using a CAMECA 7f SIMS instrument operating at extreme energy filtering. Spot-to-spot repeatability for tourmalines was in the range 4–5‰ and 0.6–1.0‰ for δ2H and δ18O, respectively. There is a strong correlation between IMF and several elements (B, Si, Ca, Fe, and Fe#). Iron content is the most robust predictor of IMF, and we report two calibration curves for the correction of δ2H and δ18O measured by SIMS using reference tourmaline crystals with different Fe contents, ranging from 0.00 to 14.00 wt.% Fe. This is the first calibration curve used to correct for the fractionation of hydrogen isotope ratios in tourmaline as measured by SIMS. Tourmaline-supergroup minerals require a suite of at least three, with a range of Fe content, to ensure accurate and precise H and O analysis by SIMS. Crystallographic orientation effects were not observed for these tourmalines.