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1.
对Ag_2S-Bi_2S_3体系相图重新测定发现,硫铋银矿温度稳定范围是从室温直到其熔点773±5℃。在二元体系Ag_2S-Bi_2S_3内,硫铋银矿有一狭窄的固溶体区,在600℃时其组分变化范围是50.0+—54mol%Bi_2S_3,500℃时是50.0+—53.5mol%Bi_2S_3,400℃时是50.0+—52.5mol%Bi_2S_3。与此同时,α-AgBiS_2是在高于195±5℃富Ag_2S条件下稳定,低于此温度,转变为硫铋银矿。α-AgBiS_2在600℃时,其组分变化范围为46.5—50.0mol%Bi_2S_3,500℃时为47.0—50.0mol%Bi_2S_3,400℃时为48.0—50.0mol%Bi_2S_3。铜银铅铋矿纯银端元Ag_2Bi_4S_7最高稳定温度是697±5℃。高于此温度,转变为硫铋银矿和液相。块硫铋银矿(AgBi_3S_5)为同成分熔化,其熔点为745±5℃。  相似文献   

2.
在温度为200—420℃,盐度为0—10wt%,填充度为50%的条件下,完成了由NaWO_4·2H_2O+FeCl_2·4H_2O或/和MnCl_2·4H_2O组成的水溶液在带黄金衬套的不锈钢高压釜中合成黑钨矿(钨锰矿或钨铁矿)的氧同位素分馏作用实验研究。我们获得的结果表明,在310℃条件下,黑钨矿和钨锰矿或钨铁矿与水之间氧同位素分馏作用几乎没有什么差别。在高温条件下(>370℃),黑钨矿与水之间氧同位素分馏值趋于相同,而在低温条件下(<870℃),随温度降低分馏值趋于增大。所获黑钨矿-水分馏方程式为: 1000 Inα_(黑钨矿-水)=0.21×10~6T~(-2)-2.91(370±—420℃) 1000 Inα_(黑钨矿-水)=1.03×10~6T~(-2)-4.91(200—370℃±)  相似文献   

3.
新的锂矿物——扎布耶石   总被引:4,自引:0,他引:4  
在西藏扎布耶盐湖首次发现的天然碳酸锂呈细小棱柱状,单斜晶系,D=2.09±0.01(实测)。无色透明。解理沿 {100}完全,{011}中等,(011)与(011)的解理交角等于45°,具淡黄至浅棕色多色性。正交偏光下具高级干涉色。β平行b轴。光轴面垂直(010),Ng∧c=10°,沿(100)具双晶。Ng=1.5743±0.001,Nm=1.5672±0.001,Np=1.4285±0.001,2V(-)≈25°。化学式为Li_2CO_3。X射线特征线条:4.16(8),2.92(8),2.81(10)。α=0.835±0.0003nm,b=0.4964±0.001nm,c=0.6185±0.0009nm,β=114°36′±7′,V=0.233±0.1nm~3,Z=4。红外光谱特征峰有1473(s,sh),1430(v,s),1088(w),862(m),739(v,w),713(v,w),488(s),414(s),259(m)。  相似文献   

4.
用合成和天然样品对硫尖晶石序列硫镍矿(Ni_3S_4)—紫硫镍矿(FeNi_2S_4)—胶黄铁矿(Fe_3S_4),特别是其中间组分〔“紫硫镍矿”(Fe,Ni)_3S_4〕的晶体化学和矿物性质进行了研究。在Ni_3S_4—FeNi_2S_4序列中,随着Fe含量增加,其热稳定性增大,晶胞参数a近似呈线性减小,反射率增大(波长为859nm时,反射谱线则表现出更复杂的变化。当成分在Fe_0.25Ni_2.75S_4—FeNi_2S_4之间时,其穆斯堡尔谱基本由双峰组成,同质异能位移和四极分裂值皆很小,并且前者还随Fe的增加而减小(0.23~0.35mm/sec)。我们认为,这是由于八面体位中Fe~(2+)处于低自旋状态所致。对谱线的进一步考察表明,在四面体中可能有铁存在(~18%)。这些数据与以前提出的硫尖晶石成键模型相吻合。虽然对天然样品的电子探针分析表明,从Ni_3S_4到Fe_3S_4,存在有完全固溶体,但成键模型表明,如果Fe含量超过FeNi_2S_4组分,则会变为亚稳相。这种可能的亚稳组分的形成和对成分相应于Fe_3S_4、贫硫达1—2%的紫硫镍矿的观察,以及与紫硫镍矿有关的低温相的不确定性,都可解释为是由于紫硫镍矿为原生矿物(镍黄铁矿)的变生矿物所致。因此,这种矿物在自然界中的形成,反应机制和动力学因素起着决定作用。  相似文献   

5.
郑绵平  刘文高 《地质论评》1987,33(4):365-368
在西藏扎布耶盐湖中首次发现天然碳酸锂,呈细小棱柱状,单斜晶系,D=2.09±0.01(实测)。无色透明,β平行b轴,光轴面垂直(010),γ∧C=10°,沿(100)具双晶。γ=1.5743±0.001,β=1.5672±0.001,α=1.4285±0.001,2V(-)?25°。经化学全分析配算其化学式为Li_2CO_3。X射线特征线条:4.16(8)、2.92(8)、2.81(10)。α_0=0.835±0.0003nm,b_0=0.4964±0.001nm,c_0=0.6185±0.0009nm,  相似文献   

6.
龚国洪  张宝贵 《矿物学报》1993,13(1):87-91,T001
Ag_2S有低温单斜变体a-Ag_2S和高温等轴变体β-Ag_2S,前者称螺状硫银矿(Acanthite),后者称辉银矿(Argentite)。在前人工作的基础上对20多个样品包括人工合成Ag_2S和国内不同产状Ag_2S详细观察、分析测试和反复实验后,认为:①至今可能还未发现天然等轴变体的辉银矿Ag_2S,亦无X射线粉晶数据报道。②Ag_2S从低温单斜到高温等轴变体的相变温度不可能是173,179或180℃,而是在550~680℃之间。  相似文献   

7.
金川铜镍矿床年龄和源区同位素地球化学特征   总被引:19,自引:4,他引:19       下载免费PDF全文
本文报道了金川铜镍硫化物矿床 Sm- Nd、Rb- Sr、Re- Os同位素年龄测定结果 ,讨论了矿床物质源区。金川铜镍矿床 Re- Os年龄为 10 4 3± 2 8(2 σ) Ma,IOs=0 .15 0 3± 5 0 (2 σ) ;Sm- Nd等时年龄约 0 .97± 0 .31(2 σ)Ga,INd=0 .5 110 6± 2 8(2 σ) ;Rb- Sr等时年龄约 819Ma,ISr=0 .7118。矿床物质来自富集地幔源区。矿床形成可能与Rodinia超大陆的形成和裂解过程有关  相似文献   

8.
本工作首次在实验室条件下对浅生区紫硫镍矿(Ni,Fe)3S4交代镍黄铁矿(Ni,Fe)9S8水热反应的机理及动力学进行了研究。起始反应矿物采用高纯自然镍黄铁矿,合成纯镍黄铁矿或合成镍黄铁矿-磁黄铁矿集合体。反应pH值采用0.2M醋酸-醋酸纳缓冲溶液控制在3~5的范围内。反应进程由X-射线衍射物相定量分析及扫描电镜观察进行跟踪。结果表明,当反应温度恒定在80℃时,交代20(4)%的镍黄铁矿需792h。相同条件下加入少量H2S可将反应速率提高一倍。当反应在125℃饱和蒸汽压水热环境下进行时,完全交代纯镍黄铁矿需约168h。此过程由于磁黄铁矿的存在而被催化,交代集合体中的镍黄铁矿仅需68h,进一步反应磁黄铁矿被交代成白铁矿。磁黄铁矿的催化作用可能源于溶解产生的微裂纹加速了流体的传质过程。当反应温度升高至145℃时,速率反而下降,不遵循Arrhenius经验规律。动力学分析得80℃速率常数介于5.8×10-8~3.0×10-7/s之间,125℃及145℃速率常数分别介于2.8×10-6~2.08×10-5/s及1×10-6~5.1×10-6/s之间,远高于同温度下固相扩散反应的速率常数,表明该反应在地质时标上为一快速反应。此外,用背散射电子显微技术对矿物表面形貌进行了分析,发现交代产物紫硫镍矿具有颗粒细小及存在微裂纹等特征,与自然界浅生矿床中的紫硫镍矿非常相似;电镜实验还表明该交代作用是一个典型的耦合溶解-再沉淀反应。其耦合机制的驱动力可能与反应界面处微空隙对流体饱和度的控制有关。  相似文献   

9.
1982年笔者在河北符山矿镁矽卡岩的裂隙中发现了碳硅钙石,具完好的板状晶体,发育有{100},{101},{120},{201}等单形。Ng=1.628,Nm=1.615,Np=1.609,(+)2V=67°;比重为2.76;空间群I2/m;a_o=10.1206,b_o=15.2058,c_o=6.6345;β=100°37′;Z=2.结构式为(Ca_(7.03)Fe_(0.01)Mn_(0.01)K_(0.002))〔Si_6O_(18)〕_(0.98)(CO_3)_1.06·2.1 H_2O,主要X—射线衍射线为3.02(100),2.99(80),2.78(35),2.49(40),1.896(40)。红外光谱有21个吸收带,CO_3群的伸缩振动谱带有明显分裂。DTA曲线表现有240℃及757℃两个吸热谷及895℃的放热峰。该地产出的碳硅钙石是矽卡岩晚期的低温热液矿物,与方解石,钙沸石,雪硅钙石,吉水硅钙石和硅灰石产膏等共生。  相似文献   

10.
西藏蛇绿岩中二种合金矿物新变种   总被引:5,自引:0,他引:5  
在西藏雅鲁藏布江蛇绿岩带的东部,距拉萨200km的泽当罗莎蛇绿岩的铬铁矿中,发现有种类繁多的合金矿物,铬铁镍矿和依铁镍矿就是其中二种。铬铁镍矿分子式:Ni0.41Fe0.35Cr0.24,为等轴晶系,空间群为Fm3m,晶胞参数a=0.35622(2)nm。铱铁镍矿分子式:Ni0.66Fe0.18Ir0.16,属等轴晶系,空间群Oh^5-Fm3m,晶胞参数a=0.46486(4)mm。  相似文献   

11.
Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.  相似文献   

12.
Robert L. Linnen   《Lithos》2005,80(1-4):267-280
The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H2O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H2O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species.  相似文献   

13.
Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414.  相似文献   

14.
Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ1 roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003).  相似文献   

15.
《地学前缘(英文版)》2014,(3):I0001-I0003
正1 AIM AND SCOPE GEOSCIENCE FRONTIERS(GSF) is a bi-monthly international journal that publishes in English high quality original research articles and timely reviews in interdisciplinary fields of Earth and Planetary Sciences.GSF aims to bridge innovative,provocative and challenging concepts and models related to various fields of research including petrology and geochemistry in understanding lithospheric architecture  相似文献   

16.
正1 Introduction In the present paper,MgCl2·6H2O,FeCl3·6H2O,and CeCl3·6H2O were used as raw materials in the precipitationhydrothermal method to synthesize MgF eC e hydrotalcite.The effects of the Fe:Ce molar ratio on the composition,crystal structure,and thermal stability of hydrotalcite are examined.Energy-dispersive X-ray spectroscopy(EDS),X-  相似文献   

17.
正20141430 Chen Ji(Key Laboratory of Petroleum Resources,Chinese Academy of Sciences,Lanzhou 730000,China);Shi Ji’an Sedimentary Facies and Models for the Palaeogene-Neogene Deposits on the Northern Margin of the Qaidam Basin,Qinghai Province(Sedimentary Geology and Tethyan Geology,ISSN1009-3850,CN51-1593/P,33(3),2013,p.16-26,14 illus.,16 refs.)  相似文献   

18.
SEISMIC GEOLOGY     
正20141967An Zhanghui(Lanzhou Base of Institute of Earthquake Prediction,CEA,Lanzhou 730000,China);Du Xuebin Study onthe Geo-Electric Field Variation of Sichuan Lushan MS7.0and Wenchuan MS8.0Earthquake(Chinese Journal of Geophysics,ISSN0001-5733,CN11-2074/P,56(11),  相似文献   

19.
GEOCHEMISTRY     
正20141357 Guo Tao(School of Mathematics and Science,Shijiazhuang University of Economics,Shijiazhuang 050031,China);Hu Jiawen Assessment on the New Pressure-Volume-Temperature(PVT) Data of Supercritical Water(Geological Journal of China Universities,ISSN1006-7493,CN32-1440/P,19(3),2013,p.447-455,9 illus.,3 tables,32 refs.)Key words:supercritical fluids  相似文献   

20.
正20141074Bao Xijie(Research Institute of Exploration and Development,Daqing Oilfield Company,PetroChina,Daqing 163712,China)Gather Optimal Processing and Application Effect of Prestack AVA Instantaneous Inversion  相似文献   

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