贵州开阳双山坪陡山沱组磷块岩地球化学特征及成因意义

本文对贵州双山坪磷块岩的常量、微量和稀土元素地球化学特征进行分析研究,并探讨区内陡山沱组磷块岩的成磷环境和成磷物质来源。研究表明,磷块岩由内碎屑、陆源碎屑和填隙物等组成,以富含Ca O、P2O5和Si O2为特点。磷块岩中Ba含量高达4290×10-6,Sr含量高达984×10-6,表明磷块岩的形成与生物作用密切相关。磷块岩Sr/Ba=0.21~3.12,反映出沉积和热液混合成因的复杂成矿作用,U/Th=1.76~16.62,均大于1,反映出热水沉积物的特征。δU=1.68~1.96,均大于1,表明磷块岩形成于缺氧沉积环境。磷块岩稀土总量较高,经北美页岩标准化的稀土配分模式曲线接近水平,具有显著的轻稀土富集、重稀土亏损特征,LREE/HREE=3.21~6.55,显示轻重稀土分异程度较高。δEu=1.01~1.40,均大于1,呈明显的正异常。Ce anom=-0.097~0.045,均大于-0.1,进一步表明磷块岩形成于缺氧环境。La/Ce=0.44~0.53,均小于1,反映磷块岩形成过程中受到热水沉积作用的影响。综合分析认为,磷块岩形成过程中有生物作用的参与,磷块岩形成于潮坪-泻湖相的缺氧沉积环境,成磷物质主要来源于富磷海水的上升洋流以及海底喷发热水中的大量含磷物质。     

黔中地区震旦系洋水组地球化学特征及其对古海洋环境的指示

为重建黔中地区震旦纪陡山沱期古海洋环境,选取小河磷矿(XH)、息烽磷矿(XF)含磷岩系剖面,通过系统采样及岩矿鉴定、扫描电镜、微量元素和稀土元素分析,揭示古海洋环境对磷块岩沉积的影响作用。结果表明,磷矿成矿受黔中古陆长期剥蚀夷平形成的无障壁海岸海滩环境控制。陡山沱期洋水组磷块岩Sr/Ba值一般大于1,均值分别为1.90 (XH)和0.95 (XF),而澄江组沉积物Sr/Ba值均小于1,均值分别为0.11 (XH)和0.18 (XF),说明沉积环境由澄江期的湖泊相转变为陡山沱期的海相。小河剖面V/Cr和Ni/Co均值分别为1.77和2.17,息烽剖面V/Cr和Ni/Co均值分别为1.26和2.83,均位于弱氧化—氧化区间。息烽磷矿磷块岩δCe为0.75～0.95,均值0.85,小河磷矿磷块岩δCe为0.74～1.09,均值0.88,Ce负异常由底部至顶部逐渐增大,显示沉积环境由次氧化—氧化的转变。这种氧化转变不仅造成了浅水富磷海岸大洋生产力的提升,进一步促使与生物作用相关的磷块岩沉积,同时造成的生命演化也改变了大洋含氧结构,因此成磷环境的氧化转变是对新元古代氧化事件与生命演化的响应。     

云南沾益小米戛磷矿渔户村组磷块岩地球化学特征及成因分析

小米戛磷矿是云南曲靖沾益地区新发现的矿床。本文对该矿床渔户村组磷块岩的主量、微量和稀土元素地球化学特征进行研究,探讨沾益渔户村组磷块岩的成磷环境和成磷物质来源。研究表明小米戛磷矿磷块岩富SiO_2(28.50%～51.47%)、CaO(20.21%～34.31%)、P_2O_5(15.48%～25.42%)。磷块岩中Ba、Sr、Cu、Pb、Zn、V、Mo等元素富集,显示生物聚磷作用。磷块岩的Sr/Ba=0.10～1.40,U/Th比值大于1(1.35～4.15),表明磷块岩的形成可能有热液活动的参与。磷块岩稀土元素总量较高(148.84×10~(-6)～232.16×10~(-6)),经北美页岩标准化的稀土配分模式曲线近水平,但LREE/HREE=2.96～5.37,显示一定程度的轻稀土元素富集,进一步暗示磷矿的形成受热水沉积成矿作用与生物成矿作用共同控制。磷块岩中U元素高度富集(富集系数平均值8.84),V/Cr=1.08～3.01(平均值为2.12),Ce_(anom)=-0.50～-0.35,介于-0.5与-0.1之间,表明磷块岩形成于次氧化环境。综上所述,在早寒武世渔户村期的潮坪-泻湖环境,磷质沉积物发生胶结作用形成初始磷矿层;后期生物繁盛,生物遗体中所含的磷被大量地分解,不同深度的大量含磷物质伴随上升洋流进一步改造初始磷矿层,最终成矿。     

黔中地区震旦系洋水组地球化学特征及其对古海洋环境的指示*

为重建黔中地区震旦纪陡山沱期古海洋环境,选取小河磷矿(XH)、息烽磷矿(XF)含磷岩系剖面,通过系统采样及岩矿鉴定、扫描电镜、微量元素和稀土元素分析,揭示古海洋环境对磷块岩沉积的影响作用。结果表明,磷矿成矿受黔中古陆长期剥蚀夷平形成的无障壁海岸海滩环境控制。陡山沱期洋水组磷块岩Sr/Ba值一般大于1,均值分别为1.90(XH)和0.95(XF),而澄江组沉积物Sr/Ba值均小于1,均值分别为0.11(XH)和0.18(XF),说明沉积环境由澄江期的湖泊相转变为陡山沱期的海相。小河剖面V/Cr和Ni/Co均值分别为1.77和2.17,息烽剖面V/Cr和Ni/Co均值分别为1.26和2.83,均位于弱氧化—氧化区间。息烽磷矿磷块岩δCe为0.75~0.95,均值0.85,小河磷矿磷块岩δCe为0.74~1.09,均值0.88,Ce负异常由底部至顶部逐渐增大,显示沉积环境由次氧化—氧化的转变。这种氧化转变不仅造成了浅水富磷海岸大洋生产力的提升,进一步促使与生物作用相关的磷块岩沉积,同时造成的生命演化也改变了大洋含氧结构,因此成磷环境的氧化转变是对新元古代氧化事件与生命演化的响应。     

贵州织金磷块岩型稀土矿含矿岩系REE地球化学特征与稀土富集

贵州织金下寒武统戈仲武组(?1gz)磷矿富集大量稀土,但是磷块岩中REE富集机制问题尚不清楚。本文对贵州织金不同稀土含量区间(262×10~(-6)、262×10~(-6)～527×10~(-6)、527×10~(-6)～761×10~(-6)、761×10~(-6))的磷块岩的研究表明,磷块岩的稀土配分均显示出Ce负异常、Eu无明显异常、MREE富集以及富集重稀土元素Y的特征。(La/Sm)N-δCe及δPr-δCe图解显示织金磷块岩Ce异常为真实的Ce异常,代表磷块岩形成在氧化环境。但当时海水的氧化环境并不是控制MREE富集的决定因素。(La/Sm)N-SmN、(Gd/Yb)N-YbN散点图显示MREE富集是稀土在富集过程中稀土发生分异的结果。(Dy/Sm)N-δEu散点图以及Eu无明显异常说明织金磷块岩形成过程中可能无热水作用的参与。地史时期"老磷块岩"普遍存在重稀土亏损的特征。     

贵州省织金县新华含稀土磷矿矿床地质特征及成因探讨

贵州织金新华含稀土磷矿床产于早寒武世梅树村阶底部含磷岩系中(上磷矿层),磷矿伴生的稀土REO含量达333.45×10-6～974.15×10-6,平均640×10-6,为含稀土磷块岩沉积矿床。通过对新华含稀土磷矿矿床的成矿地质背景、地质特征的研究,从岩相古地理、生物成矿基本特征、稀土元素物质来源、成矿作用、成矿模式等矿床成因进行的探讨,初步认为织金新华含稀土磷矿床严格受地层、岩相古地理的控制。     

陕西宁强宽川铺磷矿地质特征

宽川铺磷矿赋矿层位为寒武系牛蹄塘组,岩性为含炭页岩、含硅质炭质页岩、含炭泥质粉砂岩、含炭泥质硅质岩。该磷矿为低品位磷矿,伴生丰富的稀土元素。矿体有两种:一种为以泥质磷块岩为主,伴生稀土(∑REE)平均品位为953.68×10~(-6),另一种为灰质磷块岩偶夹硅泥质磷块岩,伴生稀土(∑REE)平均品位为869.32×10~(-6)。伴生稀土重稀土大于轻稀土,重稀土占稀土总量50%以上。沉积环境为台地边缘潮坪相。     

滇中盆地南缘富锂黏土岩地球化学特征及沉积环境初探

沉积岩中的微量元素对沉积环境变化有较高的敏感度,是研究古沉积环境的有效手段。滇中盆地倒石头组是一套富锂的黏土岩地层,其古环境的研究对恢复该时期盆地沉积格局和锂元素富集具有重要意义。基于滇中盆地倒石头组两个典型钻孔样品详细的地球化学研究,探讨了倒石头组富锂黏土岩形成时的沉积环境及其对锂元素富集的影响。研究结果表明:所有样品Sr、Ga元素含量及Sr/Ba值指示研究区古水体介质为淡水陆相沉积环境;其δU值介于0.51～1.63,U/Th值介于0.11～1.49,V/(V+Ni)值介于0.48～0.86,V/Cr值介于0.45～1.24,同时在U₍(EF))-Mo₍(EF))协变模式图中,样品数据均未落在缺氧和硫化区域,表明研究区富锂黏土岩的沉积环境为氧化—弱还原环境;且样品Sr/Cu比值介于0.69～4.87,CIA值介于86.3～99.66,XRD全岩黏土矿物分析显示高岭石为主要的黏土矿物,表明富锂黏土岩在形成过程中处于温暖潮湿的沉积环境并伴随较为强烈的化学风化作用。     

滇中昆阳磷矿成矿时代及沉积环境Re-Os同位素示踪研究

川滇黔地区下寒武地层中广泛分布一系列磷矿床,其中滇中昆阳磷矿是我国下寒武统梅树村期黑色页岩中规模最大的海相沉积型磷矿床,其成矿时代以及沉积环境对于矿床成因研究以及区域找矿具有重要意义。Re-Os同位素不仅能够对富有机质沉积岩地层进行直接定年,而且还能为物质来源及沉积环境示踪提供一种有效的技术手段。本文对昆阳磷矿中谊村段磷块岩和石岩头段黑色页岩开展热表面电离质谱法Re-Os同位素示踪及定年探索性研究,获得了石岩头段黑色页岩Re-Os等时线年龄为521.9±5.4Ma,直接限定了昆阳磷矿黑色页岩沉积时代。磷块岩187Os/188Os初始比值为0.6576~0.7671,黑色页岩187Os/188Os初始比值为0.887,另外磷块岩187Re/188Os值为2.582~240.5,而上覆黑色页岩187Re/188Os值为96.24~341.8,而且磷块岩、黑色页岩微量元素δEu和δCe值在垂向剖面上显示由低变高的变化特征,这些证据表明昆阳磷矿形成正处于大陆快速剥蚀时期,指示大量陆源碎屑汇入海洋参与成岩-成矿过程。综合前人研究,本文认为,在寒武纪,大气氧含量快速升高,加剧陆壳风化,大量高放射性陆源Os的输入造成该时期内187Os/188Os初始比值逐渐升高。另外由于全球海平面上升,导致滇中早寒武世梅树村组沉积期古海洋环境由浅水氧化向深水还原逐渐过渡,而昆阳磷矿形成于该阶段海进旋回沉积早期。     

陕西省宁强县宽川铺磷块岩稀土矿特征初探

宽川铺磷矿为一低品位磷矿床,赋矿层位为寒武系牛蹄塘组第二岩性段第二岩性层。磷矿体主要分布在选将坪一带,选将坪以西为泥质及硅质鳞块岩,矿体平均厚1.77m,P_2O_5品位11.03%～21.03%;选将坪东段为灰质磷块岩,矿层平均1.23m,P_2O_5品位9.23%～15.5%。该磷矿富含稀土,选将坪以西泥质及硅质磷块岩伴生稀土(∑REE)平均品位为953.68×10~(﹣6);选将坪以东灰质磷块岩偶夹硅泥质磷块岩,伴生稀土(∑REE)平均品位为869.32×10~(﹣6)。伴生稀土重稀土大于轻稀土,重稀土占稀土总量50%以上;以重稀土的钇(Y)为主,钇(Y)含量占稀土总量最高达48%。稀土与P_2O_5呈正相关关系;该矿磷块岩类型为泥质磷块岩、硅质磷块岩、灰质磷块岩,其中泥质磷块岩中稀土含量较高;对硅质磷块岩进行X衍射,发现其主要为石英和少量氟磷灰石。     

Flotation of calcareous Mussorie phosphate ore

Separation of Mussorie rock phosphate (P₂O₅ = 20%) from Uttar Pradesh, India, containing pyrite, calcite and other carbonaceous impurities by flotation has been successfully attempted to upgrade the phosphate values. Based on Hallimond cell flotation results of single and synthetic mineral mixtures of calcite and apatite using oleic acid and potassium phosphate, conditions were obtained for the separation of calcite from apatite which is considered to be the most difficult step in the beneficiation of calcareous phosphates. Further studies using 250 g of the mineral (?60 +150 and ?150 mesh fractions, deslimed) in laboratory size Fagergren subaeration machine employed a stagewise flotation viz. carbonaceous materials using terpineol, pyrite using potassium-ethyl xanthate and calcite using oleic acid respectively. Separation was, however, found to be unsatisfactory in the absence of a depressant.Among starch, hydrofluosilicic acid and dipotassium hydrogen phosphate, which were tried as depressants for apatite in the final flotation stage, dipotassium hydrogen phosphate proved to be superior to others. However, the tests with the above fractions did not yield the required grade. This was possibly due to insufficient liberation of the phosphate mineral from the ore body and different experimental conditions due to scale up operations. Experiments conducted using ?200 mesh deslimed fractions has yielded an acceptable grade of 27.6% P₂O₅ with a recovery of about 60%. The results have been explained in terms of the specific adsorption characteristics of phosphate ions on apatite and the liberation size of the mineral.     

The oxygen isotopic composition of phosphate as an effective tracer for phosphate sources in Hongfeng Lake

In order to characterize the oxygen isotopic composition of internal phosphate and explore the possibility of using these data to identify phosphate sources, we measured oxygen isotopic compositions of phosphate (δ¹⁸O_p) in sediment pore water in Hongfeng Lake, a typical deep-water lake in a mountainous area. These data, in combination with δ¹⁸O_p in surface water samples and water column samples, were successfully used to identify phosphate sources. The δ¹⁸O_p value of sediment pore water ranged from 15.2‰ to 15.8‰, with an average value of 15.5‰—the δ¹⁸O_p value of internal phosphate. The δ¹⁸O_p values decreased gradually through the water column from 19.4‰ in surface water to 16.4‰ in deeper water, implying that internal phosphate had more negative δ¹⁸O_p values than external phosphate. This finding was substantiated by horizontal variations in δ¹⁸O_P values, which decreased with increasing distance from inflowing rivers. All collected evidence suggests that external and internal phosphate have distinctly different isotopic signatures and that these signatures have not been considerably altered by biological mediation in Hongfeng Lake. Therefore, δ¹⁸O_P can be used to distinguish phosphate sources. A two-endmember mixing model showed that internal phosphate had an average contribution of 40%, highlighting the influence of internal phosphorus loading on aqueous phosphate and eutrophication. This study illustrates the need to reduce the internal phosphorus load from sediment and provides guidance for nutrient management and in-lake restoration treatment in Hongfeng Lake. The data presented here are limited, but serve to highlight the great potential of δ¹⁸O_p as an effective tracer for identifying phosphate sources. Systematic investigations of the oxygen isotopic compositions of external phosphate, internal phosphate, and phosphate through the water column, in combination with in-lake P biogeochemical cycle study, would be desirable in further research.     

在我国首次发现的三种磷酸锌矿物

在广东某锰矿区的南部,笔者发现三种罕见的磷酸锌矿物——副磷锌矿、磷钙锌矿、三斜磷锌矿。这三种矿物在我国均属首次发现。笔者对这三种矿物作了物理性质、化学性质、晶体光学性质、晶体结构、红外吸收光谱、差热分析等方面的测试,所得数据与国外资料对比基本相同。但经多次测定,该副磷锌矿为二轴晶负光性而与丹纳氏矿物学描述不同。本文较详细地描述了这些矿物的光性特征。     

Bacterially-mediated authigenesis of clays in phosphate stromatolites

Authigenic clays in close textural relation to carbonate fluorapatite within finely laminated phosphate stromatolites of Upper Jurassic age have been studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and analytical electron microscopy (AEM). Stromatolite laminae consist of hexagonal prisms of francolite (sizes ranging between 0·1 and 1 μm) that are surrounded by poorly crystalline smectite and amorphous Fe–Si–Al oxyhydroxides. Microanalyses show that smectite is Fe rich, with highly variable composition, particularly regarding Fe and Si contents. Smectite has significant beidellitic, montmorillonitic and non-tronitic substitutions. Although the lack of fringe contrast in some areas adjacent to the smectite packets with 1·0–1·3 nm spacing is due to differences in orientation of layers, textural and analytical data clearly indicate the presence of Fe–Si–Al amorphous phases intimately intergrown with smectite. The occurrence of poorly crystalline smectite and associated amorphous phases within microbially precipitated stromatolite laminae, both as envelopes around, and as pore-fillings between extremely small calcium phosphate crystals, demonstrates authigenic smectite growth from a precursor Fe–Si–Al amorphous material. This material is formed in close association with a phosphate-rich precursor. The textural and structural relations, the preservation of chemical precursors of glauconite such as nontronitic montmorillonite, and the presence of Fe–Si–Al amorphous mineral phases, imply crystallization of the observed crystalline phases from synsedimentary (bacterially precipitated) amorphous precursors during early diagenesis in postoxic environments. Carbonate fluorapatite was the first phase to crystallize from the primary gel; smectite and associated amorphous Fe–Si–Al oxyhydroxides were the residual material of the crystallization process. The slow rate of transformation (at low temperatures) from Fe–Si–Al-rich gels to smectite, explains the textural relations between the poorly crystalline phases and the phosphate crystals, as well as the preservation of amorphous substances in relation to clays. Authigenic smectite represents the first step in glauconitization.     

Coral skeleton P/Ca proxy for seawater phosphate: Multi-colony calibration with a contemporaneous seawater phosphate record

A geochemical proxy for surface ocean nutrient concentrations recorded in coral skeleton could provide new insight into the connections between sub-seasonal to centennial scale nutrient dynamics, ocean physics, and primary production in the past. Previous work showed that coralline P/Ca, a novel seawater phosphate proxy, varies synchronously with annual upwelling-driven cycles in surface water phosphate concentration. However, paired contemporaneous seawater phosphate time-series data, needed for rigorous calibration of the new proxy, were lacking. Here we present further development of the P/Ca proxy in Porites lutea and Montastrea sp. corals, showing that skeletal P/Ca in colonies from geographically distinct oceanic nutrient regimes is a linear function of seawater phosphate (PO_4 SW) concentration. Further, high-resolution P/Ca records in multiple colonies of Pavona gigantea and Porites lobata corals grown at the same upwelling location in the Gulf of Panamá were strongly correlated to a contemporaneous time-series record of surface water PO_4 SW at this site (r² = 0.7-0.9). This study supports application of the following multi-colony calibration equations to down-core records from comparable upwelling sites, resulting in ±0.2 and ±0.1 μmol/kg uncertainties in PO_4 SW reconstructions from P. lobata and P. gigantea, respectively.

     

贵州瓮福磷矿含磷岩系层序特征及黔中古陆控矿意义

新元古代末期震旦系陡山沱阶和早古生代早期寒武系梅树村阶是全球两大成磷时期。贵州瓮福磷矿含磷岩系—早震旦世陡山沱组磷矿a矿层与b矿层,是震旦系陡山沱阶成磷事件的典型代表。瓮福磷矿含磷岩系为在浅水陆棚地区沉积的一套与磷矿有成因联系的岩石组合,属于浅海台地相型;含磷岩系具备早期准备阶段、磷质富集阶段及晚期磷质贫化消失阶段的沉积特征,在纵向上呈三段式递变;以陡山沱组内三段(Z_1d~3)与四段(Z_1d~4)侵蚀间断面分隔,两次海侵旋回造成两次磷质的富集,经生物化学、机械破碎簸选及后期改造形成a、b两层工业磷矿体。瓮福磷矿陡山沱期构造位置位于上扬子陆块东南部,雪峰运动结束冒地槽沉积造就了黔中古陆以及东部半封闭的海湾浅滩。瓮福磷矿陡山沱期处于黔中古陆东缘,东临大海,整体地势西高东低;以黔中古陆为中心,从西到东、由陆向海形成古陆—滨岸—浅海—深海的古地理格局。黔中古陆在陡山沱期两次海侵旋回中,一方面其边缘海湾浅滩为磷质富集提供有利的沉积环境,另一方面其遭受剥蚀和夷平作用后为磷块岩矿床的形成提供含石英、长石、白云石、黏土等矿物的陆源碎屑。通过典型岩相剖面分析,黔中古陆边缘海湾浅滩的沉积环境及岩相直接控制了瓮福磷矿床的形成和分布,其具有重要的控矿意义。     

宜昌磷矿北部某矿区磷矿选矿试验研究与评价

针对宜昌磷矿北部某矿区磷矿矿石性质及可选特性,进行了单一反浮选试验、重液浮沉试验和重介质-反浮选联合工艺扩大试验,并对试验结果进行了综合评价。结果表明,采用重介质-反浮选联合工艺,比较适合该矿开发利用,在分选介质密度2.415g/cm3,磨矿细度-200目(-0.076mm)含量63.70%,原矿P2O5品位20.81%、Mg O含量6.08%时,获得了精矿产率54.69%、P2O5品位30.58%、Mg O含量0.87%,磷回收率80.36%的选矿指标。试验研究结果为该类矿石的合理开发利用提供了参考。     

Evaluation of coal as adsorbent for phosphate removal

This paper reports the adsorption of phosphate ions on coal, charcoal, and coal ash. The influences of factors such as contact time, and initial adsorbate concentration have been studied. Adsorption of phosphate ions on virgin coal was significant compared to charcoal, coal and coal ash evacuated at 200°C. The significant adsorption capability of coal is due to the porosity as well as due to organic carbon and inorganic elements present in coal. The evacuation of coal proved to be ineffective in enhancing its capability for phosphate ions retention. The adsorption behaviors of all the three adsorbent used was conformed using Freundlich’s adsorption model. The results suggest that coal could be used as an efficient adsorbent for removing phosphate ions from wastewater.     

涂氏磷钙石:一种磷酸盐高压相新矿物

在随州陨石冲击熔脉中发现了一种磷酸盐新矿物，它是白磷钙石的高压多形，经国际矿物协会新矿物和矿物命名委员会批准，定名为涂氏磷钙石(Tuitel)。该矿物属三方晶系，空间群为R-3m，a=5．258(1)A，c=18．727(3)A。一轴晶，正光性，ε=1．706(3)，ω=1．701(4)。化学式为(Ca2.31Mg0.29)2.80Na0.28(P1.01O4)2，简化式为Ca3(PO4)2。X射线粉晶衍射的强谱线有：2．628(100)、2．89l(80)、1．945(47)、1．730(25)和1．567(22)。根据与其共生的其他高压相矿物形成的温压条件和人工合成实验的结果，推定涂氏磷钙石形成的压力为12～23GPa，温度为l400到2000℃。该新矿物以中国矿物岩石地球化学学会的创建人和首任会长涂光炽的姓氏命名。     

The phosphate supply system in the Pacific region

Phosphate trade in the Pacific Basin is dominated by imports from outside the region. The principal suppliers within the area have been Nauru and Christmas Islands and the now depleted supplies of Makatea and Ocean Islands. Rapidly dwindling reserves on these islands coupled with expectations of a four to five fold increase in demand of phosphate fertilizer by the end of this century place considerable stress on the phosphate supply system in the Pacific. Anticipated developments in production from inactive deposits in Australia, Peru, and possibly Baja California, Mexico may eventually hold a major share in the Pacific markets. Other possibilities in the region include contributions from new discoveries and utilization of submarine deposits, especially those of the Chatham Rise and Baja California areas. Increased interest in small-scale mining for use in local agricultural operations may result in increased utilization of smaller deposits found throughout the Pacific.