德国蔡希斯坦蒸发岩中流体包裹体的成分和来源

蒸发岩中所见的盐溶液不仅赋存于石盐、钾石盐和光卤石的流体包裹体（直径从１～１００μｍ不等）之中，而且也蕴藏于它们的裂隙与洞穴中。这些溶液的成分最好用四元和五元体系图来表示。从个别流体包裹体中提取的溶液，Ｎａ，Ｋ，Ｍｇ，Ｃｌ和ＳＯ４为主要成分，Ｂｒ和Ｌｉ为常见的微量元素。用离子色谱法对这些成分可以进行定量测定。对Ｇｏｒｌｅｂｅｎ盐丘（德国下萨克森州）莱伊（Ｌｅｉｎｅ）组岩盐的６个流体包裹体进行了分析，其中溶液的化学特点是，ＭｇＣｌ２含量高甚至饱和。这些溶液是蔡希斯坦盆地中正常海水氯化物矿物再溶解后的产物。     

对青藏大冰盖目前存在的一些“凝问”,“质凝”及“误解”的答复

西伯利亚含盐地位于西伯利亚地台。含钾盐系属下寒武统安加拉组，岩盐层总厚６００余米，钾盐层厚７０－１５０ｍ，共有钾石盐岩和钾石盐－光卤石岩６层。钾石盐层中ＫＣｌ含量达３５％－４５％，ＭｇＣｌ２和水下溶物含量均小于１％，含盐盆地四周以堡礁带和陆岛与广海相隔，含钾坳陷处于地台上坳陷最深部位。     

河北沧州和山东烟台地区某些天然水的稳定氯同位素组成

氯元素有两个稳定同位素：＾３５Ｃｌ（７５．７７％）和＾３７Ｃｌ（２４．２３％）。过去一直认为稳定氯同位素的比值（＾３７Ｃｌ／＾３５Ｃｌ）几乎不变。８０年代以来利用高精度质谱法成功地发现了自然界氯同位素分馏作用。各地不同深度海水的氯同位素组成极为一致，故以标准平均海水氯（ＳＭＯＣ）作为对比标准。河北沧州和山东烟台地区地下淡水和热水的δ＾３７Ｃｌ为－１．５０￣＋０．８０‰，深层油田卤水的δ＾３７Ｃｌ为     

新发现的沂蒙矿类质同象系列矿物：K（Ti5Fe3Cr2Mg2）12O19及Ba（…

在山东蒙阴金伯利岩中，首次发现了沂蒙矿类质同象系列新的富Ｔｉ矿物（变）种。理想的晶体化学式可表达为：Ｋ（Ｔｉ５Ｆｅ３Ｃｒ２Ｍｇ２）１２Ｏ１９（简称Ｋ－Ｔｉ沂蒙矿）（Ｂａ，Ｋ）（Ｔｉ５Ｆｅ４Ｍｇ２Ｃｒ）１２Ｏ１９（简称Ｂａ－Ｔｉ沂蒙矿）从而与原来确定的沂蒙矿Ｋ（Ｃｒ５Ｔｉ３Ｆｅ２Ｍｇ２）１２Ｏ１９和钡钛铁铬矿（Ｂａ，Ｋ）（Ｃｒ４Ｆｅ４Ｔｉ３Ｍｇ）１２Ｏ１９ｇ一起构成了金伯利岩中ＡＭ１２Ｏ１９磁铁铅矿     

四川盆地三叠系蒸发岩的变质作用与富钾卤水的成因

在四川盆地三叠系蒸发岩建造中已发现钾盐镁矾、无水钾镁矾、软钾镁矾、杂卤石、钾石膏、多钙钾石膏、钙芒硝等矿物,并在多处发现富钾卤水。已有的资料表明,这些矿物组合是已沉积的固体钾盐层在成岩期水溶变质作用过程中形成的变质矿物组合。在此过程中大量的钾质转入水溶液,形成了富钾卤水。这种富钾卤水是可综合利用的ＫＣｌ、ＮａＣｌ和Ｌｉ、Ｓｒ、Ｃｓ、Ｒｂ、Ｂ、Ｂｒ、Ｉ的优质盐化工业原料卤水。     

西伯利亚涅帕钾盐矿床地质,发展经过及其对我国找钾工作的启示

西伯利亚含盐盆地位于西伯利亚地台。含钾盐系属下寒武统安加拉组，岩盐层总厚６００余米，钾盐层厚７０－１５０ｍ，共有钾石盐岩和钾石盐－光卤石岩６层。钾石盐层中ＫＣｌ含量达３５％－４５％，Ｍｇｃｌ＿２和水不溶物含量均小于１％，含盐盆地四周以堡礁带和陆岛与广海相隔，含钾坳陷处于地台上坳陷最深部位。作者介绍了涅帕钾盐矿床的地质特征和形成条件，从钾盐预测－钾盐普查－发现钾盐矿床历经４０余年，在找钾工作中总结了大量的成功经验，对我国地质工作者如何寻找钾盐矿床是一种很好的启示。     

海水蒸发轨迹线及其应用

利用海水蒸发实验资料，在双对数图上，可以建立Ｃｌ＾－、Ｎ＾＋、Ｍｇ＾２＋、ＳＯ４＾２＋、Ｋ＾＋、Ｃａ＾２＋、ＨＣＯ３＾－、ｓＲ＾２＋、Ｂ＾３＋、Ｌｉ＾＋、Ｒｂ＾＋、Ｃｓ＾＋、Ｉ＾＋含量及矿化度与Ｂｒ＾－含量的关系曲线，称为海水蒸发轨迹线。它们可以和来帮助判断沉积盆地地下卤水的起源。分析沉积盆地蒸发岩卤水在后来的成岩环境中是否发生过成岩反应。     

柴达木盆地氯同位素组成特征

采用正热电离高精度测定Ｃｌ同位素的方法对我国柴达木盆地水体及盐类沉积的Ｃｌ同位素组成进行了精确测定，结果表明，柴达木盆地Ｃｌ同位素组成存在着明显的变化。各种水体的平均δ＾３７Ｃｌ值顺序为：河水（０．９４‰）〉咸水湖水（－０．２‰）〉油田水（－０．６２‰）〉盐湖卤水（－０．９７‰）。卤水具有低的δ＾３７Ｃｌ值，这是盐湖卤水蒸发析盐的结果。盐湖卤水与共存盐类矿物间的分馏系数为１．０００１－１．００２１     

稳定氯同位素地球化学方法的研究进展

稳定氯同位素地球化学方法的研究进展自然界的氯具有两个天然稳定同位素（３５Ｃｌ、３７Ｃｌ），其丰度３５Ｃｌ为２４．４７％，３７Ｃｌ为７５．５３％。氯的天然同位素比值可能存在的差别在原子量测定中极为重要。由于氯是自然界各种水体及卤水沉积物大含量组分，又是...     

中国三叠纪钾盐沉积——以四川为例

中国三叠系蒸发岩分布于华南,面积超过１００×１０４ｋｍ２,发现硫酸钾盐及富钾卤水,钾盐矿物有杂卤石、无水钾镁矾、硫锶钾石及多钙钾石膏等,富钾卤水矿化度２５５～３８２ｇ／ｌ,含钾量４～４９ｇ／ｌ。蒸发盆地的发展受控于古构造及古地理,经历了开放台地—局限台地—堰塞湖—盐湖的发展阶段。钾盐沉积后,经历多阶段的复杂演变。富钾卤水中的钾主要来自硫酸钾盐的深滤,其次来自蒸发浓缩卤水及火山灰吸附钾的释放。杂卤石与富钾卤水的钾同位素测年值分别为２１０～１５０Ｍａ及２６４～１５０Ｍａ,说明固液相钾盐同源。从地质背景及成矿环境预测,三叠系的钾盐类型只能是硫酸钾盐,主要目的层为Ｔ１ｊ５～２及Ｔ２ｌ４～２,主要成矿带为构造分异及钾异常明显的四川盆地东、西部,富钾卤水的储集取决于蒸发岩地层的含钾性、碳酸盐夹层的裂隙发育程度及构造控矿条件。找矿模型应是油气钾卤兼探。     

云南勐野井钾盐矿床特征,微量元素地球化学及成因探讨

勐野井钾盐矿床位于云南兰坪、恩茅拗陷带的南部。该带地处藏滇印支地槽褶皱系中段,点苍山、哀牢山断裂带以西,澜沧江断裂带以东。区内发育有巨厚的中新生代红色碎屑岩和含盐建造,本区的主要含盐层为晚白垩世至老第三纪勐野井组。 勐野井组有上下两套含盐层,中部为棕红色钙泥质粉砂岩,下含盐层在区域上是含膏层;上含盐层为石盐岩夹钾盐透镜体。下覆地层是上白垩统扒沙河紫红色石英砂岩,上覆为老第三系等黑组棕红色粉砂岩。矿区为一向斜构造呈北西—南东向分布,盐矿体呈穹窿状,石盐层平均厚196米,钾盐厚29米,NaCl平均含量71.67％ KCl 8.70％,为混有碎屑物的氯化物型钾盐矿床。 本文研究了富钾盐层剖面结构、碎屑物沉积特征、溴、铷、锶、硼等微量元素赋存规律及其在寻找钾盐矿床工作中的标志意义,并探讨了盐矿床的成因。全文蒙袁见齐教授审阅,并提出修改意见,在此表示感谢。     

A Multi–fluid Constrain for the Forming of Potash Deposits in the Savannakhet Basin: Geochemical Evidence from Halite

The Khorat Plateau on the Indochina Terrane is known to have formed during the closure of the Tethys Ocean, although the origin of its potash mineral deposits is a topic of current debate. Data from a borehole on Savannakhet Basin is used in this study to re-define the evaporation processes of the study area. Geochemical analyses of halite from various borehole-derived evaporite strata have elucidated the fluid sources from which these ores formed. Measured δ11 B indicated that ore deposits formed primarily due to evaporation of seawater, although non-marine fluids affected the later stages of the evaporation process. Fluctuations in B and Br concentrations in carnallite-and sylvite-rich strata indicate the influence of fresh water. Boron concentration in carnallite unit indicated the influence of hydrothermal fluids. From the relative timings of these various fluid influxes, the evolution of these evaporates can be divided into four stages:(1) an initial marine evaporation at the beginning of the deposit's formation, where seawater(and minor fresh water) trapped on the uplifted Khorat Plateau produced sediments and salts with Br contents lower than those of normal marine-derived evaporites;(2) a transgression stage, where seawater recharged the basin;(3) a hydrothermal infiltration stage, which was coeval with the late Yanshan movement; and(4) a stage of fresh water supply, as recorded by fluctuations in B and Br contents, inferring intermittent fresh water influx into the basin. Thus, although evaporites on the Savannakhet Basin primarily formed via marine evaporation, they were also influenced to a significant degree by the addition of non–marine fresh water and hydrothermal fluids.     

Formation and chemical evolution of magnesium chloride brines by evaporite dissolution processes—Implications for evaporite geochemistry

The evolution of magnesium chloride brines with high bromide contents via a multistage reaction and dissolution process has been studied in brine seeps of a German potash mine. The observed chemical trends and phase equilibria can be modeled and interpreted in terms of a NaCl solution (cap rock brine) infiltrating into a potash zone characterized by the metamorphic mineral assemblage kieserite + sylvite + halite + anhydrite. Establishment of a persistent, stable equilibrium assemblage and constant fluid composition in the invariant point IP1 of the six component (Na-K-Mg-Ca-Cl-SO₄-H₂O) system of oceanic salts is prevented by the perpetually renewed input of NaCl-brine and by the intermittent exposure of incompatible kieserite. Instead, the solutions develop towards the metastable invariant point IP1(gy), with the mineral assemblage carnallite + polyhalite + sylvite + halite + gypsum, where gypsum takes the place of anhydrite (stage I). The temporary exposure of kieserite and the ensuing formation of polyhalite effectively buffer the solutions along the metastable polyhalite phase boundary during stages II and III. Eventually, in stage IV, polyhalite becomes depleted and admixture of more NaCl brine leads to low sulfate solution compositions, which are now only constrained by carnallite + sylvite + halite, and the once hexary system degenerates to a quaternary one (Na-K-Mg-Cl-H₂O) in point E. Bromide in brines shows equilibrium partitioning with respect to the wall rock minerals. The pattern of evolving brine compositions may serve as a model for similar brine occurrences, which in some cases may have been misinterpreted as remains of fossil, highly concentrated and chemically modified seawater. Similar magnesium chloride brines of salt lakes (e.g., Dead Sea, Dabusun Lake) show subtle differences and are constrained by fewer mineral equilibria (more degrees of freedom), and their low sulfate contents are due to gypsum precipitation, driven by calcium chloride input from dolomitization reactions. Finally, the observed reaction sequence is generalized, and a model for the formation of magnesium sulfate depleted, chloride-type potash salts and bischofite deposits by leaching of sulfate-type evaporites is proposed.     

Geochemistry of saline minerals separated from Lake Qarun brine

Lake Qarun is an inland saline lake of the type Na---(Mg)---Cl---(SO₄). The SO₄/Cl weight ratio exceeds 0.6. The sequence of salt deposition, upon mechanical evaporation at 70°C, starts with basanite and halite, passes with magnesium sulphate minerals and ends with sylvite and carnallite. High concentrations of Sr in the gypsiferous fraction and B in the end-residue are recorded.     

非洲下刚果盆地钾盐矿床特征、沉积旋回与沉积模式

下刚果盆地位于西非大陆边缘,形成于南美大陆与非洲大陆裂开初期,大西洋打开之时,在早白垩世形成了巨型钾盐矿床。文章在盆地内布谷马西矿区钻孔的岩芯编录的基础上,结合岩相学、地球化学和沉积韵律等研究,探究钾盐矿床沉积特征和盆地内蒸发岩沉积旋回,并总结了矿床沉积模式。下刚果盆地总体较平缓,西南低,北东高,自盆地边缘向中部,沉积厚度逐渐增大,钾盐矿床赋存于下白垩统Aptian阶蒸发岩系中。蒸发岩系主要由石盐岩与光卤石岩互层构成,局部夹(含水氯镁石)溢晶石岩、石膏岩和黑色碳质页岩夹层。矿床由多层水平_近水平层状矿体组成,单层矿体厚度几米至几十米,矿层比较稳定,延续范围广,主要矿层——光卤石层累计厚度超过100 m。主要矿石类型为光卤石型,仅局部为钾石盐型。矿石品位高,KCl平均品位为16.49%。成盐盆地在早白垩世只有一个成盐期,含盐系即为Ⅰ级韵律;根据沉积特征,又可划分为8个Ⅱ级盐韵律和若干个Ⅲ级盐韵律。整个成盐期总体沉积环境较稳定,未出现蒸发岩序列中断,但受地面的沉降变化和海水周期性灌入的影响,出现了石盐与光卤石的韵律互层沉积。下刚果盆地内蒸发岩沉积序列与正常的海相蒸发岩不同,底部缺乏碳酸盐和硫酸盐地层,指示其成钾物质来源于经过一定程度蒸发浓缩的古海水。在上述研究的基础上,结合成盐期盆地岩相古地理与构造条件,总结出下刚果盆地裂谷型钾盐矿床沉积模式。     

老挝甘蒙省钾镁盐矿床含矿段的矿物学和地球化学特征及成因

老挝甘蒙省钾镁盐矿床位于呵叻盆地的东隅,本文以该矿床ZK318钻孔的含矿段———下盐层为研究对象,对其开展了系统的矿物学和地球化学特征研究。结果表明,矿石矿物以石盐、钾石盐和光卤石为主,含少量方硼石和硬石膏。根据矿物与主量元素的分布特征,将下盐层分为5个次层,由下至上顺序为:盐岩层(石盐为主)→钾盐岩层(钾石盐为主)→光卤石岩层(光卤石为主)→薄盐岩层(石盐为主)→钾盐岩层(钾石盐为主)。微量元素Br值均大于200×10-6,表明卤水来源于海水;由盐岩层→钾盐岩层→光卤石岩层,B含量呈现出逐渐升高的趋势,表明B含量与卤水盐度呈线性关系。但顶部钾盐岩层的B含量高达890×10-6,与少量方硼石的存在相吻合,指示成矿卤水除了海水外,还有深部热液的贡献。按照卤化物卤水蒸发浓缩的顺序,光卤石是该卤水浓缩的最后阶段,但在光卤石沉积之后,又晶出一薄层石盐,表明曾经历过一次短暂的淡水补给。上、下两层钾石盐具有基本相同的Br含量,分别为1 790×10-6和1 792×10-6,且均直接沉积在石盐之上,故为原生钾石盐,而非光卤石的次生淋滤产物。认为甘蒙省钾镁盐矿床为海源陆相沉积,海水和深部热液是成钾物质的主要来源,钻孔中出露的两层钾石盐均为原生沉积。     

Stable chlorine isotopes in arid non-marine basins: Instances and possible fractionation mechanisms

Stable chlorine isotopes are useful geochemical tracers in processes involving the formation and evolution of evaporitic halite. Halite and dissolved chloride in groundwater that has interacted with halite in arid non-marine basins has a δ³⁷Cl range of 0 ± 3‰, far greater than the range for marine evaporites. Basins characterized by high positive (+1 to +3‰), near-0‰, and negative (−0.3 to −2.6‰) are documented. Halite in weathered crusts of sedimentary rocks has δ³⁷Cl values as high as +5.6‰. Salt-excluding halophyte plants excrete salt with a δ³⁷Cl range of −2.1 to −0.8‰. Differentiated rock chloride sources exist, e.g. in granitoid micas, but cannot provide sufficient chloride to account for the observed data. Single-pass application of known fractionating mechanisms, equilibrium salt-crystal interaction and disequilibrium diffusive transport, cannot account for the large ranges of δ³⁷Cl. Cumulative fractionation as a result of multiple wetting-drying cycles in vadose playas that produce halite crusts can produce observed positive δ³⁷Cl values in hundreds to thousands of cycles. Diffusive isotope fractionation as a result of multiple wetting-drying cycles operating at a spatial scale of 1–10 cm can produce high δ³⁷Cl values in residual halite. Chloride in rainwater is subject to complex fractionation, but develops negative δ³⁷Cl values in certain situations; such may explain halite deposits with bulk negative δ³⁷Cl values. Future field studies will benefit from a better understanding of hydrology and rainwater chemistry, and systematic collection of data for both Cl and Br.     

Origin of fluids in iron oxide–copper–gold deposits: constraints from δ 37Cl, 87Sr/86Sri and Cl/Br

The origin of the hypersaline fluids (magmatic or basinal brine?), associated with iron oxide (Cu–U–Au–REE) deposits, is controversial. We report the first chlorine and strontium isotope data combined with Cl/Br ratios of fluid inclusions from selected iron oxide–copper–gold (IOCG) deposits (Candelaria, Raúl–Condestable, Sossego), a deposit considered to represent a magmatic end member of the IOCG class of deposit (Gameleira), and a magnetite–apatite deposit (El Romeral) from South America. Our data indicate mixing of a high δ ³⁷Cl magmatic fluid with near 0‰ δ ³⁷Cl basinal brines in the Candelaria, Raúl–Condestable, and Sossego IOCG deposits and leaching of a few weight percent of evaporites by magmatic-hydrothermal (?) fluids at Gameleira and El Romeral. The Sr isotopic composition of the inclusion fluids of Candelaria, Raúl–Condestable, and El Romeral confirms the presence of a non-magmatic fluid component in these deposits. The heavy chlorine isotope signatures of fluids from the IOCG deposits (Candelaria, Raúl–Condestable, Sossego), reflecting the magmatic-hydrothermal component of these fluids, contrast with the near 0‰ δ ³⁷Cl values of porphyry copper fluids known from the literature. The heavy chlorine isotope compositions of fluids of the investigated IOCG deposits may indicate a prevailing mantle Cl component in contrast to porphyry copper fluids, an argument also supported by Os isotopes, or could result from differential Cl isotope fractionation processes (e.g. phase separation) in fluids of IOCG and porphyry Cu deposits.     

呵叻高原农波盆地龙湖钾盐矿床特征及其形成的古环境条件

位于藏滇印支地槽褶皱系南段印支中间地块呵叻高原北部沙空那空盆地东南缘的农波盆地在古新世发生3次沉积旋回,钾盐矿体主要产于第一沉积旋回形成的下岩段膏盐岩层上部,第二、第三沉积旋回沉积成盐时期较短、盐类矿产沉积厚度较薄,未形成工业意义的钾盐矿体,只在局部地段形成了钾盐矿化.龙湖矿区钾盐矿矿石类型主要为钾石盐矿、光卤石矿,钾...     

江陵凹陷沙钾3井古近系沙市组地球化学特征及成钾指示

在盐湖沉积演化过程中,钾镁盐在盐类矿物沉积的中晚期才开始结晶析出。因此,研究含盐系地层中盐类矿物的沉积地球化学特征,不仅可以从侧面获取岩盐的沉积物物质来源和成盐期古卤水蒸发浓缩程度等地球化学信息,而且可以直接揭示古盐湖期钾盐富集趋势及规律。目前,除在江陵凹陷的古近系沙市组等含盐系内发现了富钾卤水外,还在中-南部的钻孔盐矿盐岩中,发现了微量钾石盐和钾石膏,这些说明该凹陷古近纪具有成钾潜力。本文通过对SK3井蒸发岩特征研究及岩芯中K、Mg、Cl、Br离子含量与Br×103/Cl系数的垂向变化分析,揭示古盐湖浓缩演化与钾盐富集趋势,进一步揭示该层段沉积时期及所在凹陷古盐湖卤水钾的富集程度。