Ancient Microorganisms and Carotenoids Preserved in Fluid Inclusions in Halite from Chaka Salt Lake,Western China: Evidence from Micro-observation and in situ Raman Spectroscopy

Trapped ancient microorganisms in halite fluid inclusions are of special interest to the understanding of biology and ecology in salt lake systems.With the integration of petrologic,microthermometric,and Raman spectroscopic analyses,this study utilizes fluid inclusions from Chaka Salt Lake,eastern Qaidam Basin,NW China,to assess the possibility of microorganism-trapping by fluid inclusions.Here,we report that the solid phase of some primary fluid inclusions contains carotenoids,which is interpreted as evidence of Dunaliella algae,and that the coexisting liquid phase comprises SO_4~(2-).The homogenization temperatures of single-phase primary fluid inclusions indicate that the precipitation temperature of the Holocene halite in Chaka Salt Lake ranges from 13.5°C to 36.4°C.This suggests that fluid inclusions in halite are a good medium for trapping and preserving ancient microorganisms and organic matter in salt lakes,and that Raman spectroscopy has good potential to identify halophilic archaea.     

大浪滩盐湖蒸发盐嗜盐菌培养鉴定及其天体生物学意义

通过火星遥感及火星登陆测量都发现了火星上存在大量的含水硫酸盐,这些盐类的状态和演化也见证了近代火星表面环境条件的变化。大浪滩盐湖是柴达木盆地第二大盐湖,也是中国最为干旱的地区之一,而且大浪滩盐湖分布有与火星类似的硫酸盐盐类沉积。我们采集了蒸发盐表层盐壳,盐湖结晶盐以及剖面沉积盐类等样品,进行室内分离、培养及鉴定嗜盐菌研究。结果表明,大浪滩盐结晶及盐类沉积中分布有不同类型的嗜盐菌,主要类型为Virgibacillus,Oceanobacillus,Halobacillus,和Terribacillus等。大浪滩盐湖蒸发盐中内生嗜盐菌的分离鉴定,为探索火星高盐环境中生命存在的形式和机制提供一种类比模式。     

Evaporation Stage of Paleo-saline Lake in the Sichuan Basin, China: Insight from Fluid inclusions in Halite

Sichuan Basin is one of the most important marine–salt forming basins in China. The Simian and Triassic have a large number of evaporites. The Triassic strata have found a large amount of polyhalite and potassium-rich brine. However, no soluble potassium salt deposit were found. In this study, the halite in well Changping 3 which is located at the eastern part of the Sichuan basin was studied using the characteristics, hydrogen and oxygen isotopes of the fluid inclusion in halite to reconstruct the paleoenvironment. The salt rocks in well Changping 3 can be divided into two types: grey salt rock and orange salt rock. The result shows that the isotopic composition of the halite fluid inclusion is distinct from the global precipitation line reflecting that the salt formation process is under strong evaporation conditions and the climate is extremely dry. At the same time, compared with the hydrogen and oxygen isotopes of brine in the Sichuan Basin and the hydrous isotope composition of the inclusions in the salt inclusions of other areas in China, it is shown that the evaporation depth of the ancient seawater in the Sichuan Basin was high and reached the precipitation of potassium and magnesium stage.     

Continental evaporites and the search for evidence of life on Mars

Continental evaporites are deposits that originate from the evaporation of saline waters in the low areas of saline lakes from all continents, except Europe, and mainly consist of chloride, sulphate and potash minerals. In recent years, the discovery on the Martian surface of hydrated salt minerals, including sulphates and chlorides, interpreted as deriving from the desiccation of preexisting large bodies of water, such as lakes, has provided further convincing evidence of liquid water activity on the surface of Mars and, consequently, it has reinforced the plausibility of finding life. Because evaporites require short‐term aqueous processes for their formation, they can trap and preserve over geologic times a biological record made up of halophilic extremophiles—such as microalgae, bacteria, and their remains—that recent research on Earth has shown to be characterized by unexpectedly high biodiversity. This record may consist of varying types of fossils, including morphological fossils, chemofossils and biominerals. As a consequence, continental evaporite environments and their saline deposits are now a primary target for the near future astrobiology missions devoted to the search for fossil Martian life. Lacustrine evaporite deposits and minerals have, therefore, been identified as primary targets for the NASA–ESA joint programme of the Mars sample return, planned for the end of the current decade. Copyright © 2011 John Wiley & Sons, Ltd.     

液态不混溶作用:成矿机制之一 ——以太行山地区的金矿为例

太行山地区的许多金矿产在花岗质岩体内部及其附近的围岩中,产出形式以金属硫化物石英脉为主（如蔡术庵金矿、土石金矿、九集庄金矿等）,部分金矿以爆破角砾岩体的形式出现（如窑沟金矿）,另一部分则以含矿金属硫化物浸染在花岗岩破碎带中的形式产出（如上明峪金矿）...     

流体包裹体研究:进展、地质应用及展望

在多数地质作用过程中,流体都担任着元素迁移的载体、化学反应的活化荆的角色.大量研究表明,岩石、矿物以及元素在有无流体的情况下会表现出迥异的物理和化学性质,所以对于认识某一地质过程而言,流体方面的研究往往能够提供极其重要的信息.流体包裹体则以其直接反映古流体的成分,在各种矿物中的普遍存在性,以及对各种后期改造有一定的抵抗力等特点而成为研究古地质流体的最佳样本,并已经被成功地应用到各种地质过程的研究中.从基本概念出发,讨论了流体包裹体的种类和原生、次生流体包裹体的区分,对流体包裹体的岩相学观察要点以及流体包裹体研究的最新进展做了简要的综述,着重介绍了研究中常用的分析方法及变质岩中流体包裹体的研究,并举例说明了流体包裹体在矿床学、石油地质学中的应用,以及近期的一些关于流体包裹体中保存生物标志和生物遗迹化石的研究,最后对未来流体包裹体研究的发展方向作了简单的展望.     

激光拉曼光谱法在单个流体包裹体研究中的应用进展

激光拉曼光谱法以其非破坏性、高灵敏度和高分辨率等特性,一直以来都是研究流体包裹体的重要方法之一。近年来,围绕激光拉曼光谱在流体包裹体中的应用而展开的研究主要集中在半定量-定量测试方面,即在准确定性的基础上,采用高斯-洛仑兹去卷积分峰、低温原位等定量方法获取流体包裹体的成分和含量,从而克服了激光拉曼光谱法应用于溶液中阳离子的定量分析的灵敏度、准确度较低的问题,不仅能获得流体包裹体中一些常温下不具拉曼活性的盐类物质拉曼特征峰信息,还能根据特征峰与浓度、内压之间的线性关系,进一步对盐度和压力等性质进行测定,从而拓展了激光拉曼光谱法在流体包裹体中的应用范围。本文对激光拉曼光谱法应用于分析流体包裹体成分、盐度、同位素和压力所取得的最新进展进行了评述,并认为随着分析测试技术的不断进步,激光拉曼光谱法未来的分析方向也将继续围绕多元复杂体系及其定量方面的研究展开。     

Geochemistry of the Ore-Forming Fluids in Gold Deposits from the Taihang Mountains,Northern China

Gold deposits in the Taihang Mountains, northern China, mainly consist of quartz sulfide veins in granitoid plutons. This paper describes the geological setting of the gold deposits, and presents the results of microthermometric, Fourier transform infrared spectra, and stable isotope analyses of ore—forming fluids for the purpose of examining the characteristics of these fluids. The ore—forming fluid was of high temperature (up to 380°C) and high salinity (33–41 wt% NaCl equiv.), represented by type I inclusions (with daughter minerals). This fluid evolved to low salinity at low temperatures recorded in type II (liquid-rich) and III inclusions (vapor—rich). Primary type II inclusions coexist with type III inclusions in quartz. Type III inclusions have almost the same homogenization temperatures as type II inclusions. This probably reflects boiling. The secondary fluid inclusions homogenized at lower temperatures, and have lower salinities than primary inclusions. Based on microthermometric data, we propose that the high—temperature fluid that separated from residual magma corresponded to the ore—forming fluid represented by type I inclusions. This fluid mixed with meteoric water in the upper part of the granitic pluton and was diluted. The diluted fluid boiled, probably due to abrupt pressure decrease, and formed liquid—rich type II inclusions and vapor—rich type III inclusions. The deposition of sulfide minerals and gold probably occurred during boiling.     

流体包裹体研究进展及其在矿床学中的应用

流体包裹体是近年来研究地质流体,尤其是成矿流体的关键途径,各种与之相关的测试技术与方法及理论成果日新月异。流体包裹体研究不仅可以获得成矿流体的物理化学条件,还可以示踪成矿物质来源与组成,为识别矿床类型、构建成矿模式提供直接证据。笔者等从流体包裹体岩相学、均一温度与盐度、成分分析、pH测试与计算、P—V—T—x状态方程、热液金刚石压腔及其在矿床学上的应用7个方面对流体包裹体的研究与发展进行全面的梳理。首先,系统总结了近年来流体包裹体各方面的最新研究进展和发展趋势,分析了流体包裹体成分测试中存在的主要问题,为其发展提供了一定的方向性;其次对各类矿床的成矿流体和流体包裹体特征进行了归纳整理,对分析矿床的成因类型具有重要意义;最后,提出了流体包裹体在矿床学研究中的发展方向。     

流体包裹体研究进展及其在矿床学中的应用

流体包裹体是近年来研究地质流体,尤其是成矿流体的关键途径,各种与之相关的测试技术与方法及理论成果日新月异。流体包裹体研究不仅可以获得成矿流体的物理化学条件,还可以示踪成矿物质来源与组成,为识别矿床类型、构建成矿模式提供直接证据。本文从流体包裹体岩相学、均一温度与盐度、成分分析、pH测试与计算、P—V—T—x状态方程、热液金刚石压腔及其在矿床学上的应用等7个方面对流体包裹体的研究与发展进行全面的梳理。首先,系统总结了近年来流体包裹体各方面的最新研究进展和发展趋势,分析了流体包裹体成分测试中存在的主要问题,为其发展提供了一定的方向性;其次对各类矿床的成矿流体和流体包裹体特征进行了归纳整理,对分析矿床的成因类型具有重要意义;最后,提出了流体包裹体在矿床学研究中的发展方向。     

临界包裹体及其在金矿地质研究中的应用

临界包裹体具有在热动力过程中气液相比不变直至均一成一个流体相的特征.它在超临界流体中,当临界体积为一定值时才能形成.它可以在各类岩浆岩、火山岩、深变质岩以及铁、铜、金等多金属矿床中出现.利用临界包裹体的临界均一温度结合该流体体系的相图,可以获得如成矿流体体系的热力学状态、流体基本组分特征、临界压力、盐度、密度等成矿物理化学信息.通过多年研究发现,临界包裹体在中国北方深变质岩区的很多金矿床都有出现,它的临界均一温度都小于纯水的临界温度(374.2℃),表明成矿早期的超临界流体是由一种低盐度CO₂-H₂O体系组成,它可能来自古老的深变质岩.另一种较高盐度的成矿热液来自与矿床毗邻的中生代中酸性小岩体.它们通过超临界流体成矿地质作用,形成了具有中国特色的多源多期多成因金矿床.这在包裹体冷冻法及其成分分析和包裹体水的氢氧同位素分析的结果中也得到证实.     

粤东莲花山断裂带高山寨钨多金属矿床流体包裹体研究

高山寨钨多金属矿床处于粤东梅州地区,位于莲花山断裂带的北西侧,属新华夏系第二个隆起褶皱带南段与南岭东西复杂构造带南缘交接复合部位。研究基于详细的岩相学观察,对该矿床含矿石英脉中的10个石英包裹体片中流体包裹体进行显微测温和激光拉曼光谱分析,从而为探讨其流体性质及成矿机制提供依据。通过研究分析,该矿床主要有五种类型流体包裹体,分别为:富液相、富气相、纯液相、纯气相以及含CO_2三相流体包裹体。选取富液相流体包裹体和少量的含CO_2三相流体包裹体进行测温。据温度测试结果推测,石英中的流体包裹体经历至少两次流体活动。富液相流体包裹体均一温度分布较广(156℃～380℃),可分为低温区间(181℃～240℃)、高温区间(261℃～338℃);含CO_2三相流体包裹体的均一温度(290℃～347℃)与富液相的流体包裹体均一温度高温区间的较为一致,但三相流体包裹体盐度(0.4%～4.9%)低于富液相包裹体(1.2%～12.5%)。从本次实验结果推测高山寨钨矿床成矿机制为:在成矿流体演化过程中,高温阶段发生流体沸腾作用,导致部分金属矿物发生沉淀;低温阶段成矿流体经历了自然冷却作用及与低温低盐度的流体混合作用,导致金属矿物沉淀富集成矿。     

单个流体包裹体LA-ICP-MS分析及应用进展

独立封存的单个流体包裹体,能够准确地反演被捕获时期的流体信息.激光剥蚀电感耦合等离子体质谱仪（LA-ICP-MS）是单个流体包裹体微区分析的重要手段,展现了原位、实时、高空间分辨率、高灵敏度、高精密度、低检出限、多元素同时检测的优点.单个流体包裹体组成信息的LA-ICP-MS测定技术,在单个流体包裹体选取、激光剥蚀采样方式、气溶胶传输与电离、质谱瞬时信号采集效率、定量校准与内标元素准确测定等方面逐步突破,且该技术应用于成矿元素来源及分配、成矿流体来源及特征、建立成矿模式等方面的研究广泛.因此提高单个流体包裹体分析成功率、降低小体积流体包裹体元素检出限、测定矿石矿物流体包裹体成分等成为该分析技术亟待解决的问题.      

察尔汗盐湖石盐的流质包裹体氢氧稳定同位素分析及其地球化学意义

本文是在建立了盐酸胍法制备样品用于氧同位素分析方法研究的基础上,测定了察尔汗湖区各类天然水及ZK88-01占孔岩心的原生石盐流质包裹体氢氧稳定同位素组成。该方法适用于高盐度卤水微量δ18O分析,具有成本低、操作简便和定量转化的优点,值得在国内推广。 根据原生石盐包体水δD、δ18O的分布特征,论述了察尔汗盐湖距今5万年来湖水的演化历程。划分出三种不同成盐环境下的演化期,各期中古湖水体具有波动的继承性,各期间可能存在成盐环境的突变.根据天然水δD、δ18O关系初步获得该区蒸发线为:δD=2.5δ18O-45.3;证实了剖面上部淤泥水与达布逊湖水下渗有关;下部明显地有侧向水补给.     

Characterization of fluid inclusions encaged in quartz veins of Parsoi Formation,central India

The study focuses on analysis of primary and secondary fluid inclusions present in quartz veins hosted in the phyllites to explore the stress and temperature conditions at the time of formation of metasediment sequences of the of Parsoi Formation, central India. The results reveal the two-phase liquid-rich fluid inclusions that indicate that the intrusions of quartz veins in phyllite may have taken place between the temperature from 168.8°C to 256.3°C with an average of 205.55°C from a magmatic moderately saline fluid (3.7 to 18.29 wt. % NaCl equiv.). The final ice-melting temperatures ranges from -14.6°C to -2.2°C which indicate that the aqueous fluids are mainly H₂O-NaCl. The density distribution of fluid inclusions rich in liquid H₂O only are unimodel and low in natures and appears to be entrapped between pressure 1.666 to 2.125 kbar at depth of 200m. The study supports epithermal nature of fluid inclusions. The characteristic of fluid inclusions along with lithological and structural peculiarities, nature of structural features may be helpful in exploring the future potential zone of gold mineralization in similar types of area.     

小秦岭-熊耳山地区金矿成矿的临界-超临界流体

临界-超临界流体对金属矿床，特别是对金矿成矿具有重要作用，对流体包裹体的特征研究表明，小秦岭-熊耳山地区石英脉型，构造蚀变岩型及爆破角砾岩型3种主要类型金矿床的成矿流体属临界-超临界流体，随着成矿作用由深到浅，由高温，高压到低温，低压的演化，临界-超临界流体也逐步演化成中低温非超临界流体，从而使现有的测试结果表明，目前只有少部分为超临界包裹体，大部分为非超临界包裹体。     

The genesis of sandstone‐type uranium deposits in the Ordos Basin,NW China: constraints provided by fluid inclusions and stable isotopes

Quartz from sandstone‐type uranium deposits in the east part of the Ordos Basin contains abundant secondary fluid inclusions hosted along sealed fractures or in overgrowths. These inclusions consist mainly of water with NaCl, KCl, CO₂ (135–913 ppm) and trace amounts of CO (0.22–16.8 ppm), CH₄ (0.10–1.38 ppm) and [SO₄]^2? (0.35–111 ppm). Homogenization temperatures of the studied fluid inclusions range from 90 to 210°C, with salinities varying from 0.35 to 12.6 wt‐% (converted to NaCl wt%), implying multiple stages of thermal alteration. Although high U is associated with a high homogenization temperature in one case, overall U mineralization is not correlated with homogenization temperature nor with salinity. The H and O isotopic compositions of fluid inclusions show typical characteristics of formation water, with δ¹⁸O ranging from 9.8 to 12.3‰ and δD from 26.9 to ?48.6‰, indicating that these fluid inclusions are mixtures of magmatic and meteoric waters. The oxygen isotope ratios of carbonates in cement are systematically higher than those of the fluid inclusions. Limited fluid inclusion‐cement pairs show that the oxygen closely approaches equilibrium between water and aragonite at 150°C. Highly varied and overall negative δ¹³C in calcite from cement implies different degrees of biogenetic carbon involvement. Correlations between U in bulk rocks and trace components in fluid inclusions are lacking; however, high U contents are typically coupled with high [SO₄]^2?, implying pre‐enrichment of oxidized materials in the U mineralization layer. All these relationships can be plausibly interpreted to indicate that U (IV), [SO₄]^2? as well as Na, K were washed out from the overlying thick sandstone by oxidizing meteoric water, and then were reduced by reducing agents, such as CH₄ and petroleum, likely from underlying coal and petroleum deposits, and possibly also in situ microbes at low temperatures.     

Geochemistry and genesis of brine emanations from Cretaceous strata of the Mamfe Basin, Cameroon

The geochemistry of 5 salt springs in the southwestern Mamfe Basin was investigated in order to infer the mineral content of their source and to relate the genesis of the springs to the local geology. Field observations revealed that, they are cold springs (23–28 °C), and are composed of secondary brines that are neutral to alkaline with pH values ranging from 7 to 8.7. Results of chemical analysis show that the springs contain major ions that form evaporite minerals, as well as chalcophile elements. The dominant cation is Na⁺ (>96%), and the dominant anion is Cl⁻ (>99%). Based on correlation coefficients between ions that form evaporites and field occurrence of efflorescences of halite, it is suggested that the ancient evaporites in the Mamfe Basin are composed entirely of carbonate and chloride salts. Meteoric and convective fluid flow processes are responsible for the dissolution of ancient evaporites and subsequent migration of brines to the surface from underground. The brines migrate through permeable strata with migration pathways resulting from a combination of fracture porosity created by post––Cretaceous tectonism and intergranular porosity enhanced by the chemically aggressive migrating brines.     

山东大张矽卡岩型铁矿床中铁的富集机制 ——来自流体包裹体和氢、氧同位素的证据

大张铁矿是鲁西地区近年来新发现的一个重要的矽卡岩型矿床.矿体主要赋存于石英二长闪长岩与奥陶系马家沟组灰岩接触带及其附近.根据脉体穿插关系和交代蚀变特征,将大张矽卡岩型铁矿床成矿过程划分为矽卡岩阶段、氧化物阶段、硫化物阶段和碳酸盐阶段.通过对透辉石、绿帘石、石英和方解石等透明矿物显微观察发现,大张铁矿中流体包裹体类型主要...     

延边浅成高硫化热液金矿床的成矿流体起源与演化:以杜荒岭和九三沟矿床为例

杜荒岭和九三沟矿床是延边地区两个典型的浅成热液高硫化型金矿床,两者距离不足10km。本文运用显微测温、激光拉曼成分测试和稀有气体同位素对这两个矿床的蚀变岩和矿石中的石英内流体包裹体进行研究,以便揭示成矿流体的起源和演化过程。测温及拉曼测试结果表明:蚀变早期矿化阶段主要气体成分为CO_2、N_2的两相流体包裹体,发育少量高盐度(33.4%~48.1%)高温(410~470℃)的流体包裹体,其为深部斑岩成矿系统与后期浅成矿化流体叠加的产物;主成矿阶段均一温度为90~330℃,盐度为0.4%~44.9%,成分以H2O为主,含少量的CO_2;富气相、富液相及含石盐子晶多相的流体包裹体共存,表明流体发生了沸腾作用,这些流体包裹体被捕获的深度为100~500 m,代表浅成矿化的主要流体。稀有气体同位素结果表明:3 He/4 He值为0.009 6~0.020 6Ra,20 Ne/22 Ne、21 Ne/22 Ne值分别为9.734~9.987和0.030 9~0.040 6,40 Ar/36 Ar为1 302.4~4 433.6。上述研究结果表明,延边地区杜荒岭和九三沟金矿早期成矿流体为携带Au、Ag、Cu等成矿元素的高温、高氧化的岩浆气,主成矿阶段地壳流体的混入导致沸腾作用,晚期转以低温低盐度的大气水为主。