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1.
在我国发现的钙碳锶铈矿和碳铈钠矿 总被引：1，自引：0，他引：1
1973年,我们在对山东某地稀土矿床的岩矿薄片鉴定中,发现了两个很少见的稀土矿物。钙碳锶铈矿和碳铈钠矿。钙碳锶铈矿是碳锶铈矿的一个含钙较高的亚种。碳锶铈矿族的通式为Ce(Sr,Ca)[(CO_3)·(OH)]·H_2O。按但纳的意见,碳锶铈矿(ancylite)和钙锥锶铈矿(calcio-ancylite)的区别在于其化学武中二价阳离子钙和锶的比例不同:前者Sr>Ca,后者Ca>Sr。而calcian ancylite(至今尚无汉译名)与钙锥锶铈矿的区别在于前者含钙较高但尚未超过锶,我们发现的钙碳锶铈 相似文献
2.
全球N-MORB和E-MORB分类方案对比 总被引：3，自引：2，他引：1
N-MORB与E-MORB是大洋中脊玄武岩常用的分类,二者地球动力学意义不同,备受学术界关注。对于N-MORB与E-MORB的分类识别标志,不同作者有不同的见解。MORB中可以根据Rb/Nd≤0.15、K/Ti≤0.11、(La/Sm)_N≤0.8、K_2O/TiO_20.09、ΔNb=1.74+lg(Nb/Y)-1.92lg(Zr/Y)0、(La/Sm)_N1、100K_2O/TiO_2≤13等7种指标来识别N-MORB,否则为E-MORB。究竟何种标志区分效果较好、比较适合大多数MORB的情况?学术界对此还较少有人讨论。为此,本文尝试利用大数据方法,采用全球全体扩张中心数据,对上述7种标志进行对比,发现(La/Sm)_N1的标志比较适合大多数MORB的情况。为此,我们将(La/Sm)_N1和(La/Sm)_N≥1的所有数据,选取La、Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb、Lu、Ba、Cs、Hf、K、Nb、Pb、Rb、Sc、Sr、Ta、Th、Ti、Tl、U、V、Y、Zr等31个元素,利用两两元素对数比值进行投图,并计算85%置信度的置信椭圆交叠率,共得出36856个元素对组合,根据最小交叠率的原则,得出使用稀土元素La、Ce、Pr、Sm和其他高场强元素Nb、Zr、Hf、Y之间的比值关系判别效果较好。我们又利用以上得出的8种元素进行投图判定,发现以La为分子或以La/Hf、La/Zr元素比值做为区分标志可以得出更好的结果。因此建议考虑应用以上元素之间的相关关系共同判定N-MORB与E-MORB。 相似文献
3.
《矿物学报》2016,(3)
苗龙金锑矿床位于贵州三都-丹寨金锑汞成矿带,矿体赋存于上寒武统三都组海相碳酸盐岩中。本文对该矿床的成矿期方解石微量元素含量、Sr-Nd同位素组成进行了研究。结果表明,该矿床成矿期方解石稀土元素总量变化范围大(5.98~139μg/g,平均值为43.7μg/g),在球粒陨石标准化稀土元素配分模式图中大多数方解石样品具有轻稀土富集特征((La/Yb)_N=1.84~9.18,(Gd/Yb)_N=2.55~6.14),少量样品表现为中稀土富集特征((La/Yb)_N=0.33~1.39,(Gd/Yb)_N=1.29~2.24)。该矿床成矿期方解石样品不具有Ce异常(δCe=0.97~1.19),但具有Eu异常(δEu=0.61~1.72),指示其形成于相对还原条件下。方解石样品的~(87)Sr/~(86)Sr值为0.7108~0.7144,平均值为0.7119,高于赋矿围岩的~(87)Sr/~(86)Sr值(0.7090),表明成矿流体相对富放射成因锶,其不可能主要由赋矿的三都组灰岩提供,而可能来自富放射成因锶的前寒武纪基底。Sm-Nd同位素研究表明,该矿床成矿期方解石样品可构筑两条Sm-Nd等时线,其对应的等时线年龄分别为273±14 Ma和272±43 Ma,但与地质背景不符,因此该次方解石Sm-Nd同位素定年等时线无地质意义。这种假等时线现象可能是由成矿流体初始~(143)Nd/~(144)Nd不均一造成的。方解石ε_(Nd)(0)(-14.02~-9.48)远小于0,指示成矿流体中的Sm和Nd来源于陆壳。 相似文献
4.
本文研究的羟硅铈矿是国内首次发现的该种矿物,产于河南太平镇稀土矿的破碎带蚀变岩中,与铈褐帘石、gatelite-(Ce)、富氟硅铈石、氟碳铈矿、直氟碳钙铈矿、氟铈矿、氟镧矿等稀土矿物紧密共生,多呈铈褐帘石假象细粒状集合体或与gatelite-(Ce)平行交生沿外围交代铈褐帘石产出,粒径一般小于0.1 mm,为自形-半自形,粒状-板状。该矿物呈浅绿色至橄榄绿色,透明,玻璃光泽,不规则断口,摩氏硬度约为4.5,计算密度5.08 g/cm3。光学性质:二轴晶,正光性,多色性明显,单偏光下呈绿色,正交偏光下具有鲜艳的高级干涉色。电子探针分析显示,矿物成分w(Ce_2O_3) 32.05%～34.26%,w(La_2O_3) 13.67%～17.66%,w(Pr_2O_3) 2.92%～3.68%,w(Nd_2O_3) 7.52%～10.34%,w(Al_2O_3) 8.59%～10.93%,w(SiO_2) 21.35%～24.97%,按照Si+P=2(apfu)计算单位分子式中阳离子数,OH+F=1(apfu)计算单位分子式中羟基的离子数,得出该矿物的经验化学式为(Ce1.02La0.49Nd0.27Pr0.10 Sm0.02Gd0.01Th0.01Mg0.06 Ca0.01)Σ2.00 (Al0.99Fe0.03)Σ1.02(SiO4)Σ2.00(OH0.81F0.19)Σ1.00。X射线单晶衍射分析表明,该矿物属于单斜晶系,晶胞参数:a=7.4382(3)?, b=5.6730(2)?, c=16.9819(8)?,β=118.84(0)°, Z=4, V=655.13(5)?3,空间群为P21/c。矿物的激光拉曼光谱特征峰主要为241、362,862、895、954和3722cm-1等,上述特征均与国外已发表的羟硅铈矿数据非常相似,是对羟硅铈矿分子振动光谱特征的首次探索。本文还对羟硅铈矿的矿物族归属以及矿物成因进行了初步的探讨。 相似文献
5.
四川省土壤元素含量和生态农业地质研究 总被引：7，自引：0，他引：7
论述了四川省土壤元素含量和农作物优质高产与土壤环境中化学元素N、P、K、S、Fe、Mn、Cu、Zn、B、Mo、V、Sr、Ti、Mg、La、Ce、Pr、Nd、Sm、Eu、Y、Gd、Tb、Dy、Ho、Er、Tm、Yb、Lu、Ca、Co、Ni、F、F、Tl、Si、Na、Cr、Pb、Cd、Hg、Se、Ba、Te、Ta有密切的关系。提出了生态农业地质研究的目的、内容、方法、管理及其前景。 相似文献
6.
XU Zhitao SUN Liying LI Mengmeng LI Zhongwei WU Chengzhi QI Wei LIU Hongyan 《《地质学报》英文版》2023,97(6):1671-1682
We report the oxide, element geochemistry and Nd isotopic geochemical data of apatite in the middle Pleistocene medium- and fine-grained trachyte in the Tianchi volcanic area (TVA) of Changbai Mountain, discussing the relationship between apatite and the composition of the whole rock. The purpose is to use the apatite geochemical data to constrain the evolutionary process of trachytic magma and the petrogenesis of trachyte in the cone-forming period of the Tianchi volcano. Apatite (Ca5(PO4)3(OH, F, Cl)) is a common accessory mineral that occurs widely in volcanic rocks in the TVA. The apatites in the trachyte are mainly subhedral–anhedral, having the characteristics of magmatic apatite. In terms of oxide and element geochemistry, they have homogeneous Al2O3, SiO2, MgO, P2O5, K2O, CaO and heterogeneous TiO2, with high F content. They are generally enriched in Th, U and LREEs, depleted in Nb, Ta, Zr, Hf and HFSEs, showing negative Ba, Sr and Ti anomalies, similar to those of the whole-rock host trachytes. The ratios of high (La/Yb)N, low δEu (Eu/Eu*), Sr/Y value and ΣREE content in apatite, and the F, Sr, Y, Th/U, La/Sm, and Nd/Tb with ΣREE and δEu anomalies showed a linear correlation, all of those indicating that the host magma has the characteristic of high differentiation. The apatite grains generally having 147Sm/144Nd, 143Nd/144Nd ratios and εNd(t) values of 0.1072–0.1195, 0.5123–0.5126 and ?3.49 to ?0.10, respectively, are similiar to those of the host rock. The Nd model ages TDM1 are 949–803 Ma in apatite. Combined with the εNd(t) value of the apatite core (?7.06 to ?3.49), we conclude that the initial magma of the host trachyte was derived from the partial melting of Proterozoic crustal material and there was an assimilation of wall rocks during its evolution. 相似文献
7.
论述了宁夏回族自治区土壤元素含量和农作物优质高产与土壤环境中化学元素N、P、K、S、Fe、Mn、Cu、Zn、B、Mo、V、Sr、Ti、Mg、La、Ce、Pr、Nd、Sm、Eu、Y、Gd、Tb、Dy、Ho、Er、Tm、Yb、Lu、Ca、Co、Ni、F、Tl、Si、Na、Cr、Pb、Cd、Hg、Se、Ba、Te、Ta有密切的关系.提出了生态农业地质研究的目的、内容、方法、管理及其前景。 相似文献
8.
在野外地质调查的基础上,结合室内显微镜观察及电子探针分析测试,对新疆拜城波孜果尔碱性岩中的副矿物的矿物学特征和化学成分进行了研究.发现这些副矿物常以共生组合的形式产在碱性岩中,主要分布在石英二长闪长岩和石英二长岩中.烧绿石中U、Th和REE替代Ca、Na.独居石富含LREE,Th和LREE相互替代;根据独居石中w(La+ Ce) ＞40％和La/Nd比值在1.6～4.5,推断独居石为热液成因.磷钇矿中富含REE,且以HREE为主;w(Th)＞w(U).锆石中Zr/Hf比值在60％以上,符合碱性岩特征;其Th/U比值为0.6,属于岩浆锆石.星叶石中w(Rb2O)、w(Cs2O)较高.萤石中Y、Ce替代Ca.锆石中的钍石w(U)明显高于磁铁矿中钍石w(U).在石英二长岩中,烧绿石的w(CaO)、w(TiO2)、w(ZrO2)、w(U3O8),磷钇矿的w(Y2O3),星叶石的w(TiO2),萤石的w(Ca),氟碳铈镧矿的w(CaO)较丰富;而在石英二长闪长岩中,烧绿石的w(Ce2O3),磷钇矿的REE含量,星叶石的w(Nb2O5)、w(Rb2O),萤石w(Ce)、w(Y)和氟碳铈镧矿的w(La2O3)较高. 相似文献
9.
《矿物岩石地球化学通报》2016,(5)
为研究滇西小龙河锡矿床和来利山锡矿床的成矿流体演化特征和矿床成因,采用等离子质谱法(ICP-MS)对2个矿床中的脉石矿物萤石和方解石进行了微量元素和稀土元素分析测试。结果表明,小龙河矿床萤石的稀土元素总量(ΣREE)为12.86×10-6~2275.96×10-6,具有弱的负Ce异常和强的负Eu异常,相对富集Rb、Th、U、Pr、Nd和Sm等元素。来利山矿床方解石的ΣREE值低,为3.18×10-6~29.16×10-6,具有弱的负Ce异常,相对富集Rb、Ba、Th、U、Sr和Eu等元素。2个矿床的Y/HoLa/Ho图解和Tb/Ca-Tb/La图解指示萤石和方解石均为热液成因。小龙河矿床成矿物质主要来源于岩浆热液,随着成矿流体的演化,后期明显带有沉积地层物质加入,而来利山矿床成矿物质主要来源于围岩地层。 相似文献
10.
四川昌北稀土矿床中的硅钛铈矿 总被引：4，自引：2，他引：4
1986年笔者在四川昌北稀土矿床中发现一种结晶完好的硅钛铈矿。矿物物理性质与我国白云鄂博产出者相似。矿物组分中富铌。晶体化学式为(Ce,La,Nd…Ca)_4Fe~(2+)(FeTiNb)_2Ti_2O_8[Si_2O_7]_2。经四圆单晶衍射和电子衍射测得晶胞参数相同,α=13.385(2),b=5.742(1),c=10.059(2),β=100.60(0.01)°,空间群C 2/m。对矿物晶体定向带轴进行了高分辨晶格象观测。 相似文献
11.
Popova Elena A. Lushnikov Sergey G. Yakovenchuk Victor N. Krivovichev Sergey V. 《Mineralogy and Petrology》2017,111(6):827-832
Mineralogy and Petrology - The crystal structure of a new structural variety of loparite (Na0.56Ce0.21La0.14Ca0.06Sr0.03Nd0.02Pr0.01)Σ=1.03(Ti0.83Nb0.15)Σ=0.98O3 from the Khibiny alkaline... 相似文献
12.
Based on geological mapping and grid channel geochemical sampling, a carbonatite plug hosted REE deposit has been discovered at Kamthai, Barmer district, Rajasthan. The main REE minerals hosted by carbonatite plug are bastanesite (La), basnaesite (Ce), synchysite (Ce), carbocernaite (Ce), cerianite (Ce), ancylite and parisite. The highest value of LREE is 17.31%, whereas, mean works out 3.33% and weighted average is 2.97%. The carbonatite plug covers 19475 sq. meters and the resources have been estimated upto 84 m depth under Proved, Probable and Possible categories. The total resource estimation for carbonatite plug and other carbonate sills, dykes and veins is 4.91 million tons, making this as truly world class deposit. The TMC of individual LREO (lower rare earth oxide) calculated for carbonatite plug only are La=52196 tonnes, Ce =66026 tonnes, Nd = 13663 tonnes, Pr = 5415 tonnes, Sm = 920 tonnes and Eu = 207 tonnes. Besides these REE, the Kamthai resource will produce 551 tonnes of Ga, 44 tonnes of Ge and 1,12,830 tonnes of SrO during its mining life. 相似文献
13.
木洛稀土矿床成因上与碳酸岩-碱性杂岩密切相关。碳酸岩主要由方解石组成,CaO/（CaO＋MgO＋FeO＋Fe2O3＋MnO）比值在95.7%～99.6%,为方解石碳酸岩。碳酸岩相对富集大离子亲石元素Ba、Sr、LREE,亏损高场强元素Nb、Ta、Ti、Zr、P,高Zr/Hf和La/Nb值,低Sm/Nd和Rb/Sr值,暗示岩石来自富集地幔EMI。地质、地球化学研究表明,木洛碳酸岩是在峨眉山地幔柱地幔遗存物经喜马拉雅造山运动再次活化的产物,但碳酸岩熔浆在上侵过程中受到地壳物质混染。碳酸岩-碱性岩熔浆带来大量稀土元素,并在喜马拉雅造山期造山运动派生的局部引张部位成矿。 相似文献
14.
白云鄂博碳酸岩墙的稀土和微量元素地球化学及对其成因的启示 总被引：11，自引：1，他引：11
根据矿物组成白云鄂博矿区的碳酸岩岩可墙可分为白云石型、白云石－方解石共存型和方解石型三种类型。REE和微量元素地球化学表明，这三类碳酸岩岩墙为碳酸岩浆演化不同阶段的产物，白云石型和白云石－方解石共存型对应于早期岩浆阶段，其（La/Nd)n、(La/Yb)n比值随稀土总量的增加而增大，方解石型则对应于碳酸岩浆演化的晚期热液阶段，其稀土总量明显富集，但其（La/Nd)n、(La/Y)n和（La/Yb)n比值随稀土总量的增加却有减小的趋势，热液阶段也是白云鄂博稀土矿化的主要阶段。 相似文献
15.
Based on 225 analyses of quartzites, siliceous granoblastites,calc silicate rocks, calcite and dolomite marbles, including120 analyses of pelites and semipelites, sedimentary trendsof chemical variation are identified in staurolite and sillimanitegrade rocks. The correlation of original clay mineral contentwith Ti, Fe, K, Rb, Y, Nb, Ca, Ni, Ga, Zn and probably Ba andMn is shown. A similar clay mineral (whose composition is calculated)was added to all the sediments except the quartz-rich sandstones,now quartzites. This pattern appears to be general for mostsediments, based on crustal averages. The form of the originaladdition of Sr in the sediments might be identified as eithercarbonate or feldspar by a Ca vs. Sr plot. The southern pelites in a 2–4 km peripheral zone to theConnemara orthogneisses and migmatites have been metasomatized.The crude order of elemental enrichment from the elements increasedthe most to those increased the least relative to the same stratigraphicalhorizons in the north is: Mn, Ba, Th, Cu, Ca, Sr, Y, Pb, Zn,Pr, Ge, Nd, La, Mg, S, Ce, Rb, Sm, Ti, Na, K and Ga while Si,Al, Cr, Ni, Co, Fe and P are unchanged or removed. The sourceof the material added is postulated to be the water-rich residualfraction of the migmatitic quartz diorite gneiss, the transportbeing by movement of a water-rich fluid out of the migmatites,the fixation being mainly in biotite and new, more calcic, plagioclaseporphyroblasts, there being a positive correlation between elementenrichment and ionic radius. 相似文献
16.
A detailed Sr−Nd isotopic study of primary apatite, calcite and dolomite from phoscorites and carbonatites of the Kovdor massif
(380 Ma), Kola peninsula, Russia, reveals a complicated evolutionary history. At least six types of phoscorites and five types
of carbonatite have been identified from Kovdor by previous investigators based on relative ages and their major and accessory
minerals. Isotopic data from apatite define at least two distinct groups of phoscorite and carbonatite. Apatite from the earlier
phoscorites and carbonatites (group 1) are characterized by relatively low87Sr/86Sr (0.70330–0.70349) and143Nd/144Nd initial ratios (0.51230–0.51240) with F=2.01–2.23 wt%, Sr=2185–2975 ppm, Nd=275–660 ppm and Sm=31.7–96.2 ppm. Apatite from
the second group has higher87Sr/86Sr (0.70350–0.70363) and143Nd/144Nd initial ratios (0.51240–0.51247) and higher F (2.63–3.16 wt%), Sr (4790–7500 ppm), Nd (457–1074 ppm) and Sm (68.7–147.6
ppm) contents. This group corresponds to the later phoscorites and carbonatites. One apatite sample from a carbonatite from
the earlier group fits into neither of the two groups and is characterized by the highest initial87Sr/86Sr (0.70385) and lowest143Nd/144Nd (0.51229) of any of the apatites. Within both groups initial87Sr/86Sr and143Nd/144Nd ratios show negative correlations. Strontium isotope data from coexisting calcite and dolomite support the findings from
the apatite study. The Sr and Nd isotopic similarities between carbonatites and phoscorites indicate a genetic relationship
between the two rock types. Wide variations in Sr and Nd isotopic composition within some of the earlier carbonatites indicate
several distinct intrusive phases. Oxygen isotopic data from calcite and dolomite (δ18O=+7.2 to +7.7‰ SMOW) indicate the absence of any low-temerature secondary processes in phoscorites and carbonatites, and
are consistent with a mantle origin for their parental melts. Apatite data from both groups of phoscorite plot in the depleted
quadrant of an εNd versus εSr diagram. Data for the earlier group lie along the Kola Carbonatite Line (KCL) as defined by Kramm (1993) and data from the
later group plot above the KCL. The evolution of the phoscorites and carbonatites cannot be explained by simple magmatic differentiation
assuming closed system conditions. The Sr−Nd data can best be explained by the mixing of three components. Two of these are
similar to the end-members that define the Kola Carbonatite Line and these were involved in the genesis of the early phoscorites
and carbonatites. An additional component is needed to explain the isotopic characteristics of the later group. Our study
shows that apatite from rocks of different mineralogy and age is ideal for placing constraints on mantle sources and for monitoring
the Sr−Nd evolution of carbonatites.
Editorial responsibility: W. Schreyer 相似文献
17.
The Eocene (ca. 55–38 Ma) Bear Lodge alkaline complex in the northern Black Hills region of northeastern Wyoming (USA) is host to stockwork-style carbonatite dikes and veins with high concentrations of rare earth elements (e.g., La: 4140–21000 ppm, Ce: 9220–35800 ppm, Nd: 4800–13900 ppm). The central carbonatite dike swarm is characterized by zones of variable REE content, with peripheral zones enriched in HREE including yttrium. The principle REE-bearing phases in unoxidized carbonatite are ancylite and carbocernaite, with subordinate monazite, fluorapatite, burbankite, and Ca-REE fluorocarbonates. In oxidized carbonatite, REE are hosted primarily by Ca-REE fluorocarbonates (bastnäsite, parisite, synchysite, and mixed varieties), with lesser REE phosphates (rhabdophane and monazite), fluorapatite, and cerianite. REE abundances were substantially upgraded (e.g., La: 54500–66800 ppm, Ce: 11500–92100 ppm, Nd: 4740–31200 ppm) in carbonatite that was altered by oxidizing hydrothermal and supergene processes. Vertical, near surface increases in REE concentrations correlate with replacement of REE(±Sr,Ca,Na,Ba) carbonate minerals by Ca-REE fluorocarbonate minerals, dissolution of matrix calcite, development of Fe- and Mn-rich gossan, crystallization of cerianite and accompanying negative Ce anomalies in secondary fluorocarbonates and phosphates, and increasing δ18O values. These vertical changes demonstrate the importance of oxidizing meteoric water during the most recent modifications to the carbonatite stockwork. Scanning electron microscopy, energy dispersive spectroscopy, and electron probe microanalysis were used to investigate variations in mineral chemistry controlling the lateral complex-wide geochemical heterogeneity. HREE-enrichment in some peripheral zones can be attributed to an increase in the abundance of secondary REE phosphates (rhabdophane group, monazite, and fluorapatite), while HREE-enrichment in other zones is a result of HREE substitution in the otherwise LREE-selective fluorocarbonate minerals. Microprobe analyses show that HREE substitution is most pronounced in Ca-rich fluorocarbonates (parisite, synchysite, and mixed syntaxial varieties). Peripheral, late-stage HREE-enrichment is attributed to: 1) fractionation during early crystallization of LREE selective minerals, such as ancylite, carbocernaite, and Ca-REE fluorocarbonates in the central Bull Hill dike swarm, 2) REE liberated during breakdown of primary calcite and apatite with higher HREE/LREE ratios, and 3) differential transport of REE in fluids with higher PO43−/CO32− and F−/CO32− ratios, leading to phosphate and pseudomorphic fluorocarbonate mineralization. Supergene weathering processes were important at the stratigraphically highest peripheral REE occurrence, which consists of fine, acicular monazite, jarosite, rutile/pseudorutile, barite, and plumbopyrochlore, an assemblage mineralogically similar to carbonatite laterites in tropical regions. 相似文献
18.
Summary Within the Nkombwa Hill carbonatite complex, bastnäsite-(Ce), (Ce,La)CO3F, has been identified as an abundant mineral in xenoliths hosted by late-stage ferrocarbonatite sills and dykes. Bastnäsite-(Ce) occurs as fibrous yellow crystals, about 1 µm in size, replacing monazite and in association with baryte, in a matrix of dolomite. In common with bastnäsite-(Ce) from other locations, the bastnäsite-(Ce) of Nkombwa Hill contains up to 70% RE2O3, almost entirely as light rare-earth oxides. However, Nkombwa Hill bastnäsite-(Ce) is relatively deficient in La and enriched in Pr and Nd.
Bastnäsit-(Ce) im Nkombwa Hill Karbonatit-Komplex, Isoka-Distrikt, Nordost-Sambia
Zusammenfassung Im Karbonatit-Komplex von Nkombwa Hill kommt Bastnäsit-(Ce), (Ce-La) CO3F, als eine weitverbreitete Komponente in Xenolithen in späten Ferrokarbonatit-Lagergängen und Gängen vor. Bastnäsit-(Ce) bildet faserige gelbe Kristalle in einer Matrix aus Dolomit, die ungefähr 1 µm groß sind, Monazit verdrängen und mit Baryt assoziiert sind. Ähnlich wie Bastnäsit von anderen Lokalitäten, enthält auch dieser bis zu 70% RE2O3 fast ausschließlich als Oxide der Leichten Seltenen Erden. Der Bastnäsite-(Ce) von Nkombwa Hill ist jedoch relativ verarmt an La und an Pr und Nd angereichert.相似文献