NaCl Fluid Research Articles

Genesis of the Proterozoic Mangabeira tin–indium mineralization, Central Brazil: Evidence from geology, petrology, fluid inclusion and stable isotope data

The Mangabeira deposit is the only known Brazilian tin mineralization with indium. It is hosted in the Paleo- to Mesoproterozoic Mangabeira within-plate granitic massif, which has geochemical characteristics of NYF fertile granites. The granitic massif is hosted in Archean to Paleoproterozoic metasedimentary rocks (Ticunzal formation), Paleoproterozoic peraluminous granites (Aurumina suite) and a granite–gneiss complex. The mineralized area comprises evolved Li-siderophyllite granite, topaz–albite granite, Li–F-rich mica greisens and a quartz–topaz rock, similar to topazite. Two types of greisens are recognized in the mineralized area: zinnwaldite greisen and Li-rich muscovite greisen, formed by metasomatism of topaz–albite granite and Li-siderophyllite granite, respectively. Cassiterite occurs in the quartz–topaz rock and in the greisens. Indium minerals, such as roquesite (CuInS2), yanomamite (InAsO4·2H2O) and dzhalindite (In(OH3)), and In-rich cassiterite, sphalerite, stannite group minerals and scorodite are more abundant in the quartz–topaz rock, and are also recognized in albitized biotite granite and in Li-rich muscovite greisen. The host rocks and mineralized zones were subsequently overprinted by the Brasiliano orogenic event.Primary widespread two-phase aqueous and rare coeval aqueous-carbonic fluid inclusions are preserved in quartz from the topaz–albite granite, in quartz and topaz from the quartz–topaz rock and in cassiterite from the Li-rich muscovite greisen. Eutectic temperatures are −25°C to −23°C, allowing modeling of the aqueous fluids in the system H2O–NaCl(–KCl). Rare three-phase H2O–NaCl fluid inclusions (45–50wt.% NaCl equiv.) are restricted to the topaz–albite granite. Salinities and homogenization temperatures of the aqueous and aqueous-carbonic fluid inclusions decrease from the topaz–albite granite (15–20wt.% NaCl equiv.; 400°C–450°C), to the quartz–topaz rock (10–15wt.% NaCl equiv.; 250°C–350°C) and to the greisen (0–5wt.% NaCl equiv.; 200°C–250°C). Secondary fluid inclusions have the same range of salinities as the primary fluid inclusions, and homogenize between 150 and 210°C.The estimated equilibrium temperatures based on δ18O of quartz–mica pairs are 610–680°C for the topaz–albite granite and 285–370°C for the Li-rich muscovite greisens. These data are coherent with measured fluid inclusion homogenization temperatures. Temperatures estimated using arsenopyrite geothermometry yield crystallization temperatures of 490–530°C for the quartz–topaz rock and 415–505°C for the zinnwaldite greisens. The fluids in equilibrium with the topaz–albite granite have calculated δ18O and δD values of 5.6–7.5‰ and −67 to −58‰, respectively. Estimated δ18O and δD values are mainly 4.8–7.9‰ and −60 to −30‰, respectively, for the fluids in equilibrium with the quartz–topaz rock and zinnwaldite greisen; and 3.4–3.9‰ and −25 to −17‰, respectively, for the Li-rich muscovite greisen fluid. δ34S data on arsenopyrite from the quartz–topaz rock vary from −1.74 to −0.74‰, consistent with a magmatic origin for the sulfur. The integration of fluid inclusion with oxygen isotopic data allows for estimation of the minimum crystallization pressure at ca. 770bar for the host topaz–albite granite, which is consistent with its evolved signature.Based on petrological, fluid inclusion and isotope data it is proposed that the greisens and related Mangabeira Sn–In mineralization had a similar hydrothermal genesis, which involved exsolution of F-rich, Sn–In-bearing magmatic fluids from the topaz–albite granite, early formation of the quartz–topaz rock and zinnwaldite greisen, progressive cooling and Li-rich muscovite greisen formation due to interaction with meteoric water. The quartz–topaz rock is considered to have formed in the magmatic-hydrothermal transition. The mineralizing saline and CO2-bearing fluids are interpreted to be of magmatic origin, based on the isotopic data and paragenesis, which has been documented as characteristic of the tin mineralization genetically related to Proterozoic within-plate granitic magmatism in the Goias Tin Province, Central Brazil.

Fluid Inclusion Study of the Higher Himalayan Quartzitic Pelites, Garhwal Himalaya, India: Implications for Recrystallization History of Metasediments

Abstract Quartzitic pelites forms a part of Higher Himalayan Crystalline of higher geotectonic zone in Garhwal Himalaya. Quartzitic pelites (locally known as Pandukeshwar Quartzite) in Garhwal Himalaya is sandwiched between high grade metamorphic rocks of Central Crystallines and Badrinath Formation. Fluid inclusion studies are carried out on the detrital, and recrystallized quartz grains of quartzitic pelites to know about the fluid phases present during recrystallization processes at the time of maximum depth of burial. The quartzitic pelite (Pandukeshwar Quartzite) essentially consists of recrystallised quartz with accessory minerals like mica and feldspar. Fluid microthermometry study reveals the presence of three types of fluids: (i) high-salinity brine, (ii) CO2- H2O and (iii) H2O-NaCl. These fluids were trapped during the development of grain and recrystallization processes. The high saline brine inclusions and CO2- H2O fluid with the density of 0.90 to 0.97 gm/cm3 are remnants of provenance area. CO2 density in detrital quartz grains characterise the protolith of the sandstone as granite or metamorphic rock. The H2O–NaCl fluids involved in the recrystallization processes at temperature-pressure of 430-350°C; 4.8 to 0.5 Kbars as constrained by fluid isochores of CO2- H2O and H2O–NaCl inclusions and bulging and sub- grain development during recrystallization processes. The re-equilibration of the primary fluid due to elevated internal and confining pressure is evident from features like ‘C’ shaped cavities, stretching of the inclusions, their migration and decrepitation clusters. The observed inclusion morphology revealed that the rocks were exhumed along an isothermal decompression path.

Extended defects in natural diamonds: An Atomic Force Microscopy investigation

Surfaces of natural diamonds etched in high-pressure experiments in H2O, CO2 and H2O–NaCl fluids were investigated using Atomic Force Microscopy. Partial dissolution of the crystals produced several types of surface features including the well-known trigons and hillocks and revealed several new types of defects. The most remarkable ones are assigned to twins of several types. The observation of abundant microtwins, ordering of hillocks, and presence of defects presumably related to knots of branched dislocations suggests importance of post-growth deformation events on formation of diamond microstructure. This work confirms previous reports of ordering of extended defects in some deformed diamonds. In addition, the current study shows that natural diamonds deform not only by slip, but also by mechanical twinning. The dominant mechanism should depend on pressure–temperature–stress conditions during diamond transport from the formation domain to the Earth surface.

Reactions between basalt and CO2-rich seawater at 250 and 350 °C, 500 bars: Implications for the CO2 sequestration into the modern oceanic crust and the composition of hydrothermal vent fluid in the CO2-rich early ocean

This study aims to understand how basaltic rocks absorb CO2 in high-temperature alteration zones in the subseafloor, and to reconstruct hydrothermal alteration processes such as carbonatization of Archean greenstones. To this end, we conducted two laboratory experiments, simulating hydrothermal reactions between basalt (synthesized under quartz–fayalite–magnetite oxygen fugacity) and CO2-rich NaCl fluid (pH=6.5 at 25°C) at high temperature and pressure. As the water/rock reactions progressed at 250°C and 350°C, 500bars, total carbonic acid concentration (ΣCO2) reduced from its initial 400mmol/kg to near 0 and 100mmol/kg, respectively, meanwhile calcite was formed in the basalt as an alteration mineral. This indicates that calcite destabilizes as temperature increases in the H2O–CO2–basalt system and that crustal basalts can absorb almost all CO2 in the fluid as calcite, at least at temperatures and initial CO2 concentrations below 250°C and 400mmol/kg, respectively. Although the second aim was realized in the experiments, minerals such as sericite, dolomite, ankerite, and siderite present in Archean greenstones were not identified in the alteration products, possibly because K, Mg, and Fe were lacking in the initial solutions. Steady-state concentrations of SiO2, Mg, and K in the fluids during water/rock reactions were similar to those of high-temperature fluids (>250°C) in modern basalt-hosted hydrothermal systems. However, the final experimental pHin-situ was 6.6 and 7.2 at 250°C and 350°C, respectively, higher than that in modern hydrothermal fluids (approximately 5) and higher than the neutral pH (5.5–5.6) at 250–350°C, 500bars. The results suggest that the presence of abundant CO2 in the initial fluid induced carbonatization of basalt; consequently, pH was buffered by precipitation and dissolution of calcite. Because pHin-situ was elevated, the dissolved Fe and Mn concentrations in the fluid were two to three orders of magnitude lower than those of modern hydrothermal fluids. In modern oceans, high-temperature hydrothermal vent fluids are the second-largest iron source (after riverine input). However, because alkaline, metal-poor hydrothermal fluids are generated in CO2-rich systems, CO2-rich seafloor hydrothermal systems may have behaved as iron sinks in early oceans.

Metallogenesis at the Carris W–Mo–Sn deposit (Gerês, Portugal): Constraints from fluid inclusions, mineral geochemistry, Re–Os and He–Ar isotopes

The Carris orebody consists of two partially exploited W–Mo–Sn quartz veins formed during successive shear stages and multipulse fluid fillings. They cut the Variscan post-D3 Gerês I-type granite. The most important ore minerals are wolframite, scheelite, molybdenite and cassiterite. There are two generations of wolframite. The earlier generation of wolframite is rare and has the highest WO4Mn content (91 mol%) and the most common wolframite contains 26–57 mol% WO4Mn. Re–Os dating of molybdenite from the ore quartz veins and surrounding granite yields ages of 279 ± 1.2 Ma and 280.3 ± 1.2 Ma, respectively which are in very good agreement with the previous ID-TIMS U–Pb zircon age for the Carris granite (280 ± 5 Ma). 3He/4He ratio of pyrite ranging between 0.73 and 2.71 Ra (1 Ra = 1.39 × 10− 6) and high 3He/36Ar (0.8–5 × 10− 3) indicate a mixture of a crustal radiogenic helium fluid with a mantle derived-fluid. The fluid inclusion studies on quartz intergrown with wolframite and scheelite, beryl and fluorite reveal that two distinct fluid types were involved in the genesis of this deposit. The first was a low to medium salinity aqueous carbonic fluid (CO2 between 4 and 14 mol%) with less than 1.95 mol% N2, which was only found in quartz associated with wolframite. The other was a low salinity aqueous fluid found in all the four minerals. The homogenization temperatures indicate minimum entrapment temperatures of 226–310 °C (average 280 °C) for the H2O–CO2–N2–NaCl fluid and average temperatures of 266 °C for scheelite and 242 °C, 190 °C and 160 °C for the last generations of beryl, fluorite and quartz, respectively. It was estimated that wolframite was deposited ~ 7 km depth, assuming a lithostatic pressure, probably due to strong pressure fluctuation caused by seismic events triggered by brittle tectonics during the exhumation event. Precipitation of scheelite and sulphides took place later, at the same depth, but under a hydrostatic or suprahydrostatic pressure regime, and probably caused by mixing between the magmatic–hydrothermal fluid and meteoric waters that deeply penetrated the basement during post-Variscan decompression.

Geology and geochemistry of the Qiaoxiahala Fe–Cu–Au deposit, Junggar region, northwest China

The Qiaoxiahala Fe–Cu–Au deposit located in Fuyun County at the northern margin of Junggar Terrane in China is hosted by Middle Devonian tuffaceous sandstones, marbles, tuffs, basalts, and andesites of the Beitashan Formation. The Cu and most Fe orebodies are stratiform, podiform, or lenticular, and are spatially and temporally related to diorite porphyry dykes in the ore district. The deposit is associated with epidote, chlorite, garnet, diopside, K-feldspar, quartz, and carbonate wall-rock alteration. On the basis of field evidence and petrographic analysis, three stages of mineralization can be distinguished: (1) a prograde skarn stage; (2) a retrograde stage associated with the development of Fe mineralization; and (3) a quartz–sulfide–carbonate stage associated with Cu–Au mineralization. H2O–NaCl and H2O–CO2–(±CH4/N2)–NaCl fluids are present in fluid inclusions in quartz and calcite. These fluids show peak Th of 200–320°C and salinities of 1.23–13.72wt.% NaCl equiv. Stable isotope analysis of quartz and calcite yielded values of −141‰ to −93‰δD, 8.1‰ to 15.8‰δ18OSMOW, −0.7‰ to 9.6‰δ18Ofluid, and −3.9‰ to −2.7‰δ13CPDB, indicating that the ore-forming fluids were mainly magmatic fluids, with some contributions from meteoric water. The δ34S values of pyrite and chalcopyrite range from −4.3‰ to 2.9‰, indicating that the sulfur in the deposit was probably derived from deep-seated magmas. Zircon U–Pb dating (206Pb/238U) of the diorite porphyry yielded a weighted mean age of 377.6±1.4Ma (MSWD=0.20), whereas the molybdenite yielded a Re–Os isochron age of 375.2±2.6Ma (MSWD=1.4). These geochronological data suggest that the mineralization-related diorite porphyry was emplaced during the Late Devonian, coincident with the timing of mineralization within the Qiaoxiahala Fe–Cu–Au deposit. The geological and geochemical evidence presented here suggests that the Qiaoxiahala Fe–Cu–Au deposit is related to late-stage magmatic–hydrothermal activity of the diorite porphyry, and shares a number of similarities with the IOCG deposits.

Fluid circulation and deformational gradient in north-Pyrenean flyschs: Example from the Saint-Jean-de-Luz basin (France)

Abstract The relationships between fluid circulation and deformation are one of the issues of the sedimentary basin study. In the Cretaceous flysch of the Saint-Jean-de-Luz basin, the evolution of folds geometry and the increasing volume of calcite-filled fractures and veins evidence a northward deformational gradient along the French Basque coast. A combined approach is proposed to assess the corresponding physical and chemical conditions: the microthermometric study of fluid inclusions in calcite sampled in different generations of veins and fractures and the X-ray diffraction analysis of clay minerals from adjacent marl layers. Salinity of the trapped H2O–CaCl2–NaCl fluids increases with depth in the series, in good agreement with salinity gradients reported in sedimentary basins. Dispersion of the data also increases with depth from 0.3 to 1.3 wt.% NaCl eq. in the shallowest formation (Haizabia flysch) to 9.1 to 23.0 wt.% NaCl eq. in the deepest formation (Guethary flysch). Minimal trapping temperatures of the fluids in the Haizabia and Socoa flyschs (79 and 102 °C, respectively) are consistent with the temperatures estimated from the depth of burial, which did not exceed 5 km, in good agreement with the stability of the smectite–illite–kaolinite assemblage found in marls. In addition, the kaolinite proportion significantly decreases with depth in the series, as a potential consequence of climate changes and diagenetic transformations, whereas the increasing dispersion of illite crystallinity data might indicate fluid–mineral interactions. We propose a synthetic model of fluid circulation in the folded series that involves the mixing of mainly-horizontal fluid circulation (potentially meteoric) with an upward flow of high-salinity fluid throughout the deepest formations (potentially related to underlying evaporite-rich layers). The northward deformational gradient, as exposed along the French Basque coast, is likely to be responsible for such a vertical circulation, by increasing the volume of fracture (particularly cross-cutting fractures) in the deeply buried formations.

Genesis and evolution of the Leimengou porphyry Mo deposit in West Henan Province, East Qinling–Dabie belt, China: Constraints from hydrothermal alteration, fluid inclusions and stable isotope data

The Leimengou Mo deposit is located in the East Qinling–Dabie metallogenic Mo belt, located at the southern margin of the North China Craton. The deposit is hosted within the Mesozoic Leimengou granite porphyry pluton and at the contact between the granite and Late Archean gneisses. In light of mineral assemblage and crosscutting relationships among veinlets, the mineralization and alteration can be classified in four distinct stages: (1) a Mo–barren pre-mineralization stage of alteration characterized by massive K-feldspar alteration of the granite porphyry; (2) a K-feldspar–quartz vein stage that formed veinlets with minor molybdenite; (3) a quartz–sulfide veinlet stage, which is the main stage of mineralization; and (4) post-mineralization quartz–calcite vein stage.Stage 1 alteration is associated with fluid inclusions of low–medium salinity (2.4–13.1wt.% NaClequiv) that homogenized at medium to high temperatures (238–476°C). Stage 2 mineralization is associated with fluid inclusions that homogenized at 201–389°C and that have salinities of 2.0–13.6wt.% NaClequiv. Fluid inclusions that formed during stage 3 have homogenization temperatures of 205–370°C and corresponding salinities of 1.0–17.6wt.% NaClequiv to 31.4–40.6wt.% NaClequiv, indicative of fluid immiscibility and mixing of hydrothermal fluids with meteoric water. Stage 4 H2O–NaCl fluids were trapped at lower temperatures (148–246°C) and have salinities of 1.7–7.9wt.% NaClequiv.Stages 1 to 4 have calculated δ18Ofluid values of 3.6–4.3‰, 2.7–2.8‰, 0.6–2.3‰, and −3.2‰ to −3.8‰, respectively, with δDfluid values of –72‰ to −80‰, −83‰ to −90‰, −68‰ to −82‰, and −81‰ to −90‰, respectively. These results are consistent with the fluid inclusion data outlined above and suggest that early fluids were exsolved from the granitic magma and underwent progressive mixing with meteoric water. Molybdenum was initially transported from the crystallizing magma in a hot, alkaline, and oxidized fluid, while decreasing temperatures and pH, water–rock interaction, and fluid immiscibility during fluid ascent resulted in its precipitation and deposition.

Hydrothermal Fluid Processes and Evolution of the Giant Serra Norte Jaspilite-Hosted Iron Ore Deposits, Carajas Mineral Province, Brazil

Hydrothermal Fluid Processes and Evolution of the Giant Serra Norte Jaspilite-Hosted Iron Ore Deposits, Carajas Mineral Province, Brazil

An improved model for calculating CO2 solubility in aqueous NaCl solutions and the application to CO2–H2O–NaCl fluid inclusions

To determine compositions, homogenization pressures and isopleths of CO2–H2O–NaCl fluid inclusions, an improved activity–fugacity model is developed to calculate CO2 solubility in aqueous NaCl solutions. The model can predict the CO2 solubility in aqueous NaCl solutions from 273.15K to 723.15K, from 1bar to 1500bar and from 0 to 4.5molkg−1 of NaCl, within or close to experimental uncertainties. Compared to a large number of reliable experimental solubility data available, the average absolute deviation is 4.62% for the CO2 solubility in aqueous NaCl solutions. In the near-critical region, the calculated CO2 solubility deviations increase to over 10%. The CO2 solubility model, together with the updated volumetric model of CO2–H2O–NaCl fluid mixtures, is applied to calculate the CO2 contents, homogenization pressures, molar volumes and volume fractions of the CO2–H2O–NaCl fluid inclusions by an iterative method based on the assumption that the volume of an inclusion keeps constant during heating and cooling. Calculation program code of the CO2 solubility in aqueous NaCl solutions can be obtained from Chemical Geology or the correspondence author (maoshide@163.com).

Is 6% tetrastarch 130 kDa (hydroxyethyl starch 130/0.4 or 130/0.42) suitable for severe sepsis?

British Journal of Hospital MedicineVol. 74, No. 3 Anaesthetic and Critical Care DilemmaIs 6% tetrastarch 130 kDa (hydroxyethyl starch 130/0.4 or 130/0.42) suitable for severe sepsis?Amit Patel, Stephen J BrettAmit PatelSearch for more papers by this author, Stephen J BrettSearch for more papers by this authorAmit Patel; Stephen J BrettPublished Online:16 Aug 2013https://doi.org/10.12968/hmed.2013.74.3.178AboutSectionsView articleView Full TextPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareShare onFacebookTwitterLinked InEmail View article References Dolecek M, Svoboda P, Kantorova I et al. (2009) Therapeutic influence of 20% albumin versus 6% hydroxyethylstarch on extravascular lung water in septic patients: a randomized controlled trial. Hepato-gastroenterology 56: 1622–8 Medline, Google ScholarDubin A, Pozo MO, Casabella CA et al. (2010) Comparison of 6% hydroxyethyl starch 130/0.4 and saline solution for resuscitation of the microcirculation during the early goal-directed therapy of septic patients. J Crit Care 25: 659 e1–8 Medline, Google ScholarGuidet B, Martinet O, Boulain T et al. (2012) Assessment of hemodynamic efficacy and safety of 6% hydroxyethylstarch 130/0.4 vs. 0.9% NaCl fluid replacement in patients with severe sepsis: The CRYSTMAS study. Crit Care 16: R94 Crossref, Medline, Google ScholarMyburgh JA, Finfer S, Bellomo R et al. (2012) Hydroxyethyl starch or saline for fluid resuscitation in intensive care. N Engl J Med 367: 1901–11 Crossref, Medline, Google ScholarPalumbo D, Servillo G, D'Amato L et al. (2006) The effects of hydroxyethyl starch solution in critically ill patients. Minerva Anestesiol 72: 655–64 Medline, Google ScholarPatel A, Waheed U, Brett SJ (2013) Randomised trials of 6 % tetrastarch (hydroxyethyl starch 130/0.4 or 0.42) for severe sepsis reporting mortality: systematic review and meta-analysis. Intensive Care Med Feb 22 (Epub ahead of print) Google ScholarPerner A, Haase N, Guttormsen AB et al. (2012) Hydroxyethyl starch 130/0.42 versus Ringer's acetate in severe sepsis. N Engl J Med 367: 124–34 Crossref, Medline, Google Scholar FiguresReferencesRelatedDetails 1 March 2013Volume 74Issue 3ISSN (print): 1750-8460ISSN (online): 1759-7390 Metrics History Published online 16 August 2013 Published in print 1 March 2013 Information© MA Healthcare LimitedPDF download

대화 Mo-W 열수 맥상 광상의 유체 진화 특성

대화광상은 경기육괴의 편마암류와 화강암류에 발달한 열극을 충진 발달한 함 Mo-W 열수 맥상 광상이다. 대화광상의 몰리브덴-텅스텐 광화작용과 관련된 주요 수반광물인 석영에서 관찰되는 유체포유물은 상온 (<TEX>$20^{\circ}C$</TEX>) 에서의 상(phase) 관계와 냉각 및 가열 실험을 통해 측정된 균일화 온도와 상변화를 기초로 하여 3가지 주요 유형 (Type I, 액상이 우세한 <TEX>$H_2O$</TEX>-NaCl 유형; Type II, 기상이 우세한 <TEX>$H_2O$</TEX>-NaCl 유형; Type III; <TEX>$CO_2-H_2O$</TEX>-NaCl 유형) 으로 분류된다. 또한, 함 <TEX>$CO_2$</TEX> Type III 유체포유물은 <TEX>$CO_2$</TEX> 균일화 및 최종 균일화 특성을 바탕으로 4가지 유형 (IIIa, IIIb, IIIc, IIId)으로 세분된다. 대화광상 Type I 유체포유물의 균일화 온도는 약 <TEX>$374^{\circ}C{\sim}161^{\circ}C$</TEX>로 넓은 범위를 보여주며, 염농도 역시 약 13.6~0.5 equiv. wt. % NaCl의 넓은 조성 범위를 보인다. Type III 유체포유물 냉각 실험 시 측정된 <TEX>$CO_2$</TEX> 상의 용융 온도는 <TEX>$-57.4{\sim}-56.6^{\circ}C$</TEX>이며, <TEX>$CO_2$</TEX> 균일화 온도는 <TEX>$29.0{\sim}30.8^{\circ}C$</TEX>이다. 또한 <TEX>$CO_2$</TEX> clathrate 용융 온도는 <TEX>$7.3{\sim}9.5^{\circ}C$</TEX>로 염농도는 5.2~1.0 equiv. wt. % NaCl이고, 최종 균일화 온도는 <TEX>$303^{\circ}C{\sim}251^{\circ}C$</TEX>로 비교적 좁은 범위로 확인되었다. <TEX>$CO_2-H_2O$</TEX>-NaCl계 (Type III) 유체포유물의 경우 온도가 감소함에 따라 염농도 역시 감소하는데, 이는 높은 염농도를 가진 <TEX>$H_2O$</TEX>-NaCl계 유체와 낮은 염농도를 가진 <TEX>$CO_2-H_2O$</TEX>-NaCl계 유체의 불혼화에 의해 열수의 진화가 이루어졌음을 의미한다. Type I 유체포유물은 온도 감소와 염농도 사이의 뚜렷한 변화가 인지되지 않았다. 따라서, 대화 열수계의 함 몰리브덴-중석 광화작용은 <TEX>$400^{\circ}C$</TEX>, 5.2 equiv. wt.% NaCl의 염농도를 가진 광화유체로부터 시작되어, 약 <TEX>$350^{\circ}C$</TEX> 부근에서 유체의 불혼화 용융에 의해 진행되었다. 이후 대화 열수계에 유입된 상대적으로 낮은 온도와 염농도를 갖는 유체 (천수 또는 상대적으로 높은 물/암석 비를 갖는 열수유체) 의 혼입 작용에 의해 후기 천금속 광화작용이 야기되었다. The Daehwa Mo-W deposit is located within the Gyeonggi massif. Quartz and calcite vein mineralization occurred in the Precambrian gneiss and Jurassic granites. Three main types (Type I: liquid-rich <TEX>$H_2O$</TEX> type, Type II: vapor-rich <TEX>$H_2O$</TEX> type, Type III: <TEX>$CO_2-H_2O$</TEX> type) of fluid inclusions were observed and are classified herein based on their phase relations at room temperature. Within ore shoots, type III fluid inclusions have been classified into four subtypes (type IIIa, IIIb, IIIc and IIId) based on their volume percent of aqueous and carbonaceous (<TEX>$CO_2$</TEX>) phase at room temperatures combined with their total homogenization behavior and homogenization behavior of <TEX>$CO_2$</TEX> phase. Homogenization temperatures of primary type I fluid inclusions in the quartz range from <TEX>$374^{\circ}C$</TEX> to <TEX>$161^{\circ}C$</TEX> with salinities between 13.6 and 0.5 equiv. wt.% NaCl. Homogenization temperatures of primary type III fluid inclusions in quartz of main generation, are in the range of <TEX>$303^{\circ}C$</TEX> to <TEX>$251^{\circ}C$</TEX>. Clathrate melting temperatures of the type III fluid inclusions were 7.3 to <TEX>$9.5^{\circ}C$</TEX>, corresponding to salinities of 5.2 to 1.0 equiv. wt. % NaCl. Melting and homogenization temperatures of <TEX>$CO_2$</TEX> phase of type III fluid inclusions were -57.4 to <TEX>$-56.6^{\circ}C$</TEX> and 29.0 to <TEX>$30.8^{\circ}C$</TEX>, respectively. Fluid inclusion data indicate a complex geochemical evolution of hydrothermal fluids. The Daehwa early hydrothermal system is characterized by <TEX>$H_2O-CO_2$</TEX>-NaCl fluid at about <TEX>$400^{\circ}C$</TEX>. The main mineralization occurred by <TEX>$CO_2$</TEX> immiscibility at temperatures of about 300 to <TEX>$250^{\circ}C$</TEX>. At the late base-metal mineralization aqueous fluid formed by mixing with cooler and less saline meteoric groundwater.

The Jiguanshan porphyry Mo deposit in the Xilamulun metallogenic belt, northern margin of the North China Craton, U–Pb geochronology, isotope systematics, geochemistry and fluid inclusion studies: Implications for a genetic model

The Jiguanshan porphyry Mo deposit is located in the southern part of Xilamulun metallogenic belt at the northern margin of the North China Craton (NCC). In the Jiguanshan mining district, two stages of granitoids intrusions have been recognized: a pre-ore granite porphyry with stockworks and veins of Mo mineralization, and a granite porphyry with disseminated Mo mineralization. Zircon U–Pb data and Hf isotope analyses show that the dissemination-mineralized granite porphyry yielded a weighted mean 206Pb/238U age of 156.0±1.3Ma, with a crustal εHf(t) values from −5.6 to +0.2, and that the main group of magmatic zircons from the pre-ore granite porphyry have a weighted mean 206Pb/238U age of 167.7±1.7Ma with εHf(t) values from −3.2 to +1.0. Combined with groundmass Ar–Ar age data of the granite porphyry and molybdenite Re–Os age, it is suggested that the Mo mineralization of Jiguanshan deposit was formed in the late Jurassic (153~155Ma) during tectonic and magmatic events that affected northeast China. The Mo mineralization was a little bit later than the host granite porphyry. Besides disseminated in the host granite porphyry, Mo mineralization also presents in middle Jurassic pre-ore granite porphyry, Jurassic fine-grained diabase, Triassic quartz porphyry, and in rhyolitic volcanic rocks as well as syenite of Devonian age.The Jiguanshan mining district was affected by the tectonic events associated with the Paleo-Asian Ocean closure, and later by far-field tectonism, related to subduction of the Paleo-Pacific plate (Izanagi) in the Jurassic-Cretaceous. The tectonic and thermal events linked with the latter are commonly referred to as Yanshanian tectono-thermal event, and consists of a series of geodynamic, magmatic and ore-forming processes, which in the mining district area included the intrusion of the pre-ore granite porphyry, the host granite porphyry, Mo mineralization, and fine-grained diabase. Major and trace element analyses show that the host granite porphyry is characterized by high silica abundances (SiO2=77.16 to 77.51%), high Rb/Sr ratios (13.57 to 14.83), high oxidation (Fe2O3/FeO=34.25 to 62.00) and high alkalies (Na2O+K2O=8.21 to 8.38%). Petrographic and microthermometry studies of the fluid inclusions from Mo mineralized veins, characterized by plenty of daughter mineral-bearing inclusions, showed that the predominant homogenization temperatures range from 250 to 440°C. Combined with Laser Raman analysis of the fluid inclusions, it is indicated that Mo mineralization is related to a high-temperature, hypersaline and high-oxygen fugacity H2O–NaCl fluid system, with high F contents.Based on geology, geochronology, isotope systematics, geochemistry and fluid inclusion studies as well as regional geology, we propose, for the first time, a genetic model for the Jiguanshan porphyry Mo deposit. During the Jurassic geodynamic evolution of northeast China, high silicic, high oxidized and alkaline-rich granitic magma probably derived from partial melting of the lower crust, episodically intruded along faults into the country rocks. This fluid system, fractionating from the highly differentiated granitic magma and bearing Mo with minor Cu metals, migrated upwards and interacted with the older wall rocks and associated fractures, in which the ore minerals precipitated, resulting in the development of what we refer to as the “Jiguanshan-type” porphyry Mo deposit.

Mineralogy, fluid inclusion and stable isotope constraints on the genesis of the Namseong Au-Ag deposit, Republic of Korea

The Namseong gold and silver deposit is located in the Seolcheon metallogenic province, one of the most important gold production areas in the Republic of Korea. It consists of three gold and silver-bearing quartz veins that fill fractures oriented NW along fault zones in Triassic porphyritic granite. The gold and silver-bearing quartz veins are simple and consist of only one mineralization stage on basis of vein mineralogy and paragenesis. Coarse-grained quartz is found in mainly comb, and partially cockade and cavity-filling textures throughout most of the veins. Wall-rock alteration minerals include sericite, minor pyrite and chlorite. Ore minerals deposited along with electrum include pyrite, sphalerite, chalcopyrite, galena, pyrargyrite, argentite and native silver. Its mineralization age (78.2 ± 1.7 Ma) determined on sericite from wall-rock alteration indicates that the gold and silver mineralization was synchronous with Cretaceous igneous activity. Petrographic examination of textural relationships among sulfides, fluid inclusions, and quartz from one stage shows the genetic relationships between Au–Ag deposition and fluid entrapment. Early wall-rock alteration in one stage was produced and sulfides were deposited from H 2 O–NaCl–CO2 fluids (260–1,700 bar, average 1,000 bar) with Th total values of 250°C to 380°C and salinities less than about 4 wt.% NaCl. The late sulfides and electrum in one stage were deposited from H 2 O–NaCl fluids (100 bar) with Th total values of 195°C to 331°C and salinities less than about 7 wt.% NaCl. The H 2 O–NaCl fluids either evolved through unmixing of H 2 O–NaCl–CO 2 fluids or through mixing with circulating meteoric waters as a result of uplift or unloading during mineralization, or both. The deposition of electrum and silver minerals was caused by a decrease in sulfur fugacity/aH 2 S/aCl, oxygen fugacity and temperature during wallrock alteration, cooling and dilution produced by mixing of the saline aqueous fluids with meteoric water. The calculated sulfur isotope compositions of hydrothermal fluids from the Namseong deposit (δ 34 S H2S = 3.7‰ to 7.2‰) indicate that ore sulfur was derived mainly from a magmatic source but also in part from sulfur contained in the host rocks. The calculated and measured oxygen and hydrogen isotope compositions of the ore-forming fluids (δ 18 O H2O = –2.2‰ to 1.6‰, δD = –83‰ to –64‰) indicate that the fluids were derived from meteoric water and evolved by mixing with local meteoric water and by limited water-rock exchange during mineralization in uplift zones.

Assessment of hemodynamic efficacy and safety of 6% hydroxyethyl starch 130/0.4 vs. 0.9% NaCl fluid replacement in patients with severe sepsis: how to guide fluid therapy?

We argue that assessing the hemodynamic effi cacy of hydroxyethyl starch (HES) versus NaCl in patients with severe sepsis requires an algorithm to direct the timing and amount of fl uid resuscitation. Such an algorithm may include hemodynamic fl ow parameters. In a recent issue of Critical Care, Guidet and colleagues [1] reported that a smaller amount of 6% HES 130/0.4 versus 0.9% NaCl was required to achieve hemodynamic stability (HDS) during the initial phase of fl uid resuscitation in patients with severe sepsis. Th e target parameters indicating HDS included central venous pressure (CVP) (8 to 12 mm Hg), a poor indicator of fl uid responsiveness [2], and a large urine output (>2 mL/kg per hour), and therefore pose a risk of over-infusion. Other authors have reported that over-infusion, elevated CVP, and excessive fl uid resuscitation with HES are associated with increased mortality in patients with sepsis [3,4]. In contrast, after initial HDS was achieved, no such target parameters were defi ned, and so the cumulative volumes of study drug infused over the course of four consecutive days in the intensive care unit (ICU) were similar for the HES (2,615 mL) and NaCl (2,788 mL) groups. No diff erences in mortality, hospital length of stay, or kidney function were found. Th is study may be showing only that, in the absence of an algorithm to guide fl uid resuscitation, intensivists use an unvarying amount of fl uids, but it is impossible to know whether these fl uids were, in fact, indicated. In patients undergoing major abdominal surgery, hemodynamic algorithms that guide the timing and amount of fl uid administration have helped determine the clinical effi cacy of fl uid therapy [5]. Th e negative results reported by Guidet and colleagues suggest that hemodynamic algorithms for patients with sepsis are urgently required to accurately compare the hemodynamic effi cacy, safety, and outcome of HES versus NaCl fl uid replacement.

Experimental and petrological constraints on local-scale interaction of biotite-amphibole gneiss with H2O-CO2-(K, Na)Cl fluids at middle-crustal conditions: Example from the Limpopo Complex, South Africa

Reaction textures and fluid inclusions in the ∼2.0 Ga pyroxene-bearing dehydration zones within the Sand River biotite-hornblende orthogneisses (Central Zone of the Limpopo Complex) suggest that the formation of these zones is a result of close interplay between dehydration process along ductile shear zones triggered by H2O-CO2-salt fluids at 750–800 °C and 5.5–6.2 kbar, partial melting, and later exsolution of residual brine and H2O-CO2 fluids during melt crystallization at 650–700 °C. These processes caused local variations of water and alkali activity in the fluids, resulting in various mineral assemblages within the dehydration zone. The petrological observations are substantiated by experiments on the interaction of the Sand River gneiss with the H2O-CO2-(K, Na)Cl fluids at 750 and 800 °C and 5.5 kbar. It follows that the interaction of biotite-amphibole gneiss with H2O-CO2-(K, Na)Cl fluids is accompanied by partial melting at 750–800 °C. Orthopyroxene-bearing assemblages are characteristic for temperature 800 °C and are stable in equilibrium with fluids with low salt concentrations, while salt-rich fluids produce clinopyroxene-bearing assemblages. These observations are in good agreement with the petrological data on the dehydration zones within the Sand River orthogneisses.

Assessment of hemodynamic efficacy and safety of 6% hydroxyethylstarch 130/0.4 vs. 0.9% NaCl fluid replacement in patients with severe sepsis: The CRYSTMAS study

Abstract Introduction Inadequate initial treatment and delayed hemodynamic stabilization (HDS) may be associated with increased risk of death in severe sepsis patients. Methods In order to compare the hemodynamic efficacy and safety of 6% HES 130/0.4 and NaCl 0.9% for HDS in patients with severe sepsis, we designed a prospective, multicenter, active-controlled, double-blind, randomized study in intensive care units. Results 174 out of 196 patients reached HDS (88 and 86 patients for HES and NaCl, respectively). Significantly less HES was used to reach HDS vs. NaCl (1,379 ±886 ml in the HES group and 1,709 ±1,164 ml in the NaCl group (mean difference = -331± 1,033, 95% CI -640 to -21, P = 0.0185). Time to reach HDS was 11.8 10.1 hours vs. 14.3 ±11.1 hours for HES and NaCl, respectively. Total quantity of study drug infused over four consecutive days, ICU and hospital LOS, and area under the curve of SOFA score were comparable. Acute renal failure occurred in 24 (24.5%) and 19 (20%) patients for HES and NaCl, respectively (P = 0.454). There was no difference between AKIN and RIFLE criteria among groups and no difference in mortality, coagulation, or pruritus up to 90 days after treatment initiation. Conclusion Significantly less volume was required to achieve HDS for HES vs. NaCl in the initial phase of fluid resuscitation in severe sepsis patients without any difference for adverse events in both groups. ClinicalTrials.gov NCT00464204

The CO 2 -rich magmatic-hydrothermal fluid of the Qiyugou breccia pipe, Henan Province, China: implication for breccia genesis and gold mineralization

The Qiyugou deposit, in the Xiong’er terrane, Qinling Orogen, is an auriferous breccia pipe developed in continental collision setting. The breccia pipe exhibits variable-sized clasts and clast mixing, which are typical of fluidized breccias. Brecciation, alteration, and gold mineralization are related to granite porphyry emplaced at c . 134 Ma. However, the relationships of the CO 2 -rich ore-forming fluids with the tectonic setting, structural control, granite magma evolution, and hydrothermal brecciation have not been clearly discussed. New fluid inclusion data presented in this paper indicate that the formation of the Qiyugou deposit includes: (1) an early stage defined by K-feldspar-epidote-quartz-pyrite assemblage; (2) a middle stage of quartz-polymetallic sulphides; and (3) a late stage typified by quartz-carbonate±adularia. Alteration and mineralization resulted from escape of hot (&gt;320 °C), high-salinity (&gt;40 wt% NaCl eq.) magmatic fluid exsolved during the final stage of crystallization of the granite porphyry. Significant pressure drop from 85–90 to 20–38 MPa resulted in breccia formation and precipitation of quartz, sulphides, and gold. A vapour phase was produced at 355–403 °C due to fluid boiling, and then was cooled and condensed under near-critical conditions to a moderately saline, warm liquid. Aqueous-carbonic inclusions were formed by trapping of heterogeneous fluids unmixed from the original H 2 O-CO 2 -NaCl fluid. Late magmatic-hydrothermal fluid mixed with meteoric fluid, and was cooled and diluted to produce lukewarm, low-salinity fluid that precipitated clear quartz and calcite with little or no mineralization. Our review of the literature suggests that the brecciation and mineralization likely coincided with sinistral transtensive faulting during 140–120 Ma. Therefore, synthesis of the foregoing geochemical information with pertinent geological information from the literature lead us to propose that fluidization and seismic pumping were important in the breccia formation and associated gold mineralization at Qiyugou.

Controlled release of prednisolone acetate from molecularly imprinted hydrogel contact lenses

AbstractThe aim of this work was to study the influence of methacrylic acid (MAA) as a comonomer and the application of a molecular imprinting technique on the loading and release properties of weakly crosslinked 2‐hydroxyethyl methacrylate (HEMA) hydrogels, with a view toward their use as reloadable soft contact lenses for the administration of prednisolone acetate (PA). The hydrogels were prepared with HEMA (95.90–98.30 mol %) as a backbone monomer, ethylene glycol dimethacrylate (140 mM) as a crosslinker, and MAA (0, 50, 100, or 200 mM) as a functional monomer. Different PA/MAA molar ratios (0, 1 : 8, 1 : 6, and 1 : 4) in the feed composition of the hydrogels were also applied to study the influence of the molecular imprinting technique on their binding properties. The hydrogels (0.4 mm thick) were synthesized by thermal polymerization at 60°C for 24 h in a polypropylene mold. The hydrogels were then characterized by the determination of their swelling and binding properties in water. Their loading and release properties were also studied in 0.9% NaCl and artificial lachrymal fluid. Increasing the MAA content of the hydrogel and applying the molecular imprinting technique led to an increase in the loading capacity of the hydrogel. The optimized imprinted hydrogel showed the highest affinity for PA and the greatest ability to control the release process, sustaining it for 48 h. The results obtained clearly indicate that the incorporation of MAA as a comonomer increased the PA loading capacity of hydrogel. Our data showed that the molecular imprinting technique also had a significant effect on the loading and release properties of the hydrogels. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Arsenic in volcanic geothermal fluids of Latin America

Numerous volcanoes, hot springs, fumaroles, and geothermal wells occur in the Pacific region of Latin America. These systems are characterized by high As concentrations and other typical geothermal elements such as Li and B. This paper presents a review of the available data on As concentrations in geothermal systems and their surficial discharges and As data on volcanic gases of Latin America. Data for geothermal systems in Mexico, Guatemala, Honduras, El Salvador, Nicaragua, Costa Rica, Ecuador, Bolivia, and Chile are presented. Two sources of As can be recognized in the investigated sites: Arsenic partitioned into volcanic gases and emitted in plumes and fumaroles, and arsenic in rocks of volcanic edifices that are leached by groundwaters enriched in volcanic gases. Water containing the most elevated concentrations of As are mature Na–Cl fluids with relatively low sulfate content and As concentrations reaching up to 73.6mgL−1 (Los Humeros geothermal field in Mexico), but more commonly ranging from a few mgL−1 to tens of mgL−1. Fluids derived from Na–Cl enriched waters formed through evaporation and condensation at shallower depths have As levels of only a few μgL−1. Mixing of Na–Cl waters with shallower meteoric waters results in low to intermediate As concentrations (up to a few mgL−1). After the waters are discharged at the ground surface, As(III) oxidizes to As(V) and attenuation of As concentration can occur due to sorption and co-precipitation processes with iron minerals and organic matter present in sediments. Understanding the mechanisms of As enrichment in geothermal waters and their fate upon mixing with shallower groundwater and surface waters is important for the protection of water resources in Latin America.