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1.
广东茂名地区二叠以状硅质岩成因地球化学特征及其沉积环境意义 总被引:2,自引:0,他引:2
徐跃通 《西安地质学院学报》1997,19(3):27-33
在广东茂名地区二叠系地层中存在地导整合产生的层状硅质岩。硅质岩富Fe,Mn,相对贫Al;富集As,Sb,Bi,Ga等微量元素,稀土元素总量低,Ce弱负异常,重稀土相对富集,δ^30Si值变化范围为0.0003~0.0007,。δ^18O值变化范围为0.0148~0.0223,均具热水沉积硅质岩的地球化学特征,在Al-Fe-Mn-(Ni+Co+Cu)三角图上,本区硅质岩均属于典型的热水积硅质岩,硅质 相似文献
2.
西秦岭寒武系金矿床中硅岩的地质地球化学特征及其沉积环境意义 总被引:31,自引:4,他引:27
西秦岭寒武系中的硅岩是拉尔玛-邛莫层控金矿床的主要赋矿岩石之一。含矿硅岩呈块状、条带状、层纹状、多孔状和同生角砾状等。硅岩单层厚度一般为30~200m。主要成分SiO2平均含量高达95.30%,其余为FeO、Fe2O3和有机炭等。硅岩的Al/(Al+Fe+Mn)比值低于0.3(平均0.153),投点于Fe/Ti-Al/(Al+Fe+Mn)图解和Al-Fe-Mn三角图解上,均落于热水沉积物区。硅岩中微量元素十分丰富,不仅含有具基性、超基性特征的元素群(如Cu、Cr、Pt、Pd、Os等),而且还含有具酸性特征的元素群(如W、Mo、U等)。硅岩中稀土以总量(3.29~100μg/g)低和铈亏损为特征。经北美页岩标准化后的稀土比值随原子序数的增大而增大。硅岩的δ18O值为17.60‰~23.24‰,据此得到它形成的温度为70.9℃~118.1℃。硅岩的δ30Si值主要为+0.4‰~+0.8‰。上述硅岩的特点均显示其与喷流热水沉积作用有关。硅岩中P2O5含量、Sr/Ba比值、δCe值以及δ30Si值表明,它主要是在深海—半深海环境下形成的。 相似文献
3.
江西东乡矿区沉积硅质岩的地球化学特征和成因 总被引:9,自引:2,他引:9
江西东乡矿区石炭系地层中存在三层与地层整合产出的层状硅质岩。硅质岩富Fe,As,Sb,Bi和Ga;稀土元素总量低,Ce呈弱负异常,重稀土相对富集,δ^30Si值变化范围为0.5‰-0.8‰,δ^18O变化范围为12.54‰-21.11‰。硅质岩地球化学特征表明其成因为介于热水沉积与生物沉积之间的过渡类型。 相似文献
4.
西太平洋冲绳海槽烟囱硫化物矿床矿石化学特征与分带型式 总被引:12,自引:0,他引:12
西太平洋冲绳海槽烟囱式硫化物矿床分布于琉球弧后扩张盆地、产于尹是名洼陷盆地(深1400m),其特征与日本黑矿类似。硫化物矿石及烟囱主要有3种化学类型:Pb-Zn-Ba型、Zn-Pb型和Cu-Zn型,三者分别代表温度不断升高的热液体系的早、中、晚3个成矿阶段产物,其中,Pb-Zn-Ba矿石及烟囱形成于高fo2环境和高流速、低温、富Pb、Zn、Ba热液体系,Cu-Zn矿石及烟囱形成于低流速、高温、富Cu热液体系,Zn-Pb矿石则介于其间。硫化物烟囱显示明显的矿物-化学分带。在Pb-Zn-Ba矿石(烟囱),Zn、Cd集中于烟囱中央,Ba、Fe、As、Sb、Ag、Pb集中于烟囱外带,Cu则富集于烟囱中外部。在Cu-Zn矿石,As、Sb、Fe、Ag、Au仍富集于烟囱外带,Cu、Zn、Pb则在烟囱中央富集。依此元素化学分带型式,建立了古代黑矿硫化物矿体分带与硫化物堆积模式。 相似文献
5.
蔡家营铅—锌—银矿床的稳定同位素地球化学研究 总被引:3,自引:0,他引:3
河北蔡家营矿床是大型中温热液充填-交代脉型铅-锌-银矿床。其硫化物的δ^34S值为2.2‰-7.8‰,同世代共存的10个硫化物对的Δ^34S值表明,Fe-(Zn、Pb)-S系统的硫同位素非平衡分馏占主导,硫是岩浆(为主)与老变质岩层硫的混合来源。石英及其流体包裹体的δ^18OSMOW和δDSMOW值(‰)按混合模式计算表明,成矿流体为混合的岩浆和大气降水,早期成矿流体以岩浆为主,尔后则变为以大气降 相似文献
6.
夏杖子金矿严格受构造破碎带控制,围岩蚀变主要为钾长石化、黄铁矿化、硅化和碳酸盐化。矿石中自然金有显微金和次显微金两种状态,金的成色为835~929;矿石包裹体成分主要以H2O为主,另含有CO2、K+、Na+、F-、Cl-和SO2-4等离子;矿石的稳定同位素组成:δ34S为-23.38‰~-14.47‰,δD为-91.7‰~73.1‰,δ18OH2O为5.68~6.25‰,206Pb/204Pb为16.411~16.615,207Pb/204Pb为15.228~15.256,208Pb/204Pb为36.268~36.356;矿石、脉岩和岩体具有相似的REE、K、Rb、Sr及微量元素地球化学特征。矿床中金的富集与成矿构造、围岩蚀变、矿化期次和矿石类型等多种因素有关,成矿作用发生于燕山晚期(105.4±7.2Ma),成矿热液主要为岩浆热液,成矿物质来源于硅铝壳中下部太古代结晶基底,矿床成因为中-低温热液金矿床。最后对矿床的找矿标志进行了总结,指出了找矿方向,认为夏杖子金矿具有较好的找矿远景,尤其是矿床深部 相似文献
7.
湖南大庸慈利一带下寒武统黑色页岩中海底喷流沉积硅岩的地质特征 总被引:15,自引:3,他引:12
湘西北大庸慈利一带下寒武统黑色页岩中的硅岩,分布上受深断裂控制,具多孔状构造,微量元素Se、As、Ba含量较高,Al/(Al+Fe+Mn)比值为0.15~0.32,稀土元素ΣREE含量大于围岩的数倍,Ce亏损,δ18O(对SMOW)值为17.62‰~22.91‰。这些特征表明,该硅岩是一种典型的喷流岩,并构成湘西北镍钼多金属矿床的容矿岩系 相似文献
8.
本文通过钢铁工业废水淋溶钢铁工业渗漏区土壤,不同pH值,不同含Ca^2+,F^-浓度与放心水与工业淋溶各种土壤,以及电厂冲灰水淋溶粉煤灰的三种试验,讨论废水中C6H5OH、CN^-AS、Cr,Pb,Zn,H2S,BOD,COD,F^-,Cl^-,SO^2-R,NO^-3,NH^+4,Na^+和硬度等的污染与自净规律,并提出了防治地下水污染的措施。 相似文献
9.
扬子板块东南大陆边缘上震旦统热水成因硅质岩的地球化学标志 总被引:1,自引:0,他引:1
晚震旦世时,在扬子板块东南大陆边缘地带发育一套层状硅质岩建造,岩石化学成分纯净,SiO2含量在90%以上,其它化学成分含量均很低。但Fe和Mn相对富集,而Al,Ti,Mg相对贫乏。微量元素含量变化大,大部分微量元素含量相对地壳克拉克值偏低,仅U,As,Sb,Ag,Ba等富集。岩石的δ^30Si为0.0‰~0.7‰,δ^18O为20.2‰~23.6‰,δ^30Si和δ^18O值及岩石的形成温度清楚地 相似文献
10.
吉林省金城洞地区金矿类型及成因 总被引:1,自引:1,他引:0
吉林省金城洞地区是吉林省夹皮沟-金城洞金矿成矿带的重要组成之一,该区金矿发育,按春产出的地质背景可划分为两类:一类为产于晚太古宙绿岩带变质岩系中的金矿;一类为产于花岗岩侵入体中的金矿,两类金矿容矿构造均为中生代(75Ma~145Ma)脆性断裂,矿脉均以石英脉型为主,矿床氢氧同位素组成为δD=-87‰~-92‰,δ^18OH2xo=+2‰~+5.26‰,硫同位素δ^34S为+0.6‰~+4.8‰,其 相似文献
11.
Emily Keeble David I. Whiteside Michael J. Benton 《Proceedings of the Geologists' Association. Geologists' Association》2018,129(2):99-119
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.
The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts 总被引:4,自引:0,他引:4
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.
Muriel Rocher Stéphane Baize Stéphane Jaillet Edward Marc Cushing Yannick Lozach Francis Lemeille 《Comptes Rendus Geoscience》2003,335(8):701-708
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
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正20141756 Chen Ruige(Mathematical College,China University of Geosciences,Beijing100083,China);Zhou Xun Numerical Simulation of Groundwater Level Fluctuation in a Coastal Confined Aquifer with Sloping Initial Groundwater Level Induced by the Tide(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(7),2013,p.1099-1104,6 illus.,16 refs.) Key words:confined water,groundwater level 相似文献
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正20141408 Cai Jia(Institute of Geology,Chinese Academy of Geological Sciences,Beijing100037,China);Liu Fulai Petrogenesis and Metamorphic P-T Conditions of Garnet-Spinel-Biotitebearing Paragneiss in Danangou Area,Daqingshan-Wulashan Metamorphic Complex Belt(Acta Petrologica Sinica,ISSN1000-0569,CN11-1922/P,29(7), 相似文献
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正20142386An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China)Application of Satellite Remote Sensing in Regional Hydrogeological Investigation:Taking Cenozoic Strata in Wenquan Sheet(1∶250 000)of Karakoram Range as an Example(Geosci- 相似文献
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正20141016An Chengbang(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,Lanzhou University,Lanzhou 730000,China);Zhao Yongtao Lake Records during the Last Glacial Maximum from Xinjiang,NW China and Their Climatic Impli- 相似文献
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正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.) 相似文献
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正20142002 Wei Hualing(Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang065000,China);Zhou Guohua Element Content and Mineral Compositions in Different Sizes of Soil in Tongling Area,Anhui Province(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(11),2013,p.1861 相似文献