大学专业英语课件

nullMineralogy and geochemistry of trace elements in bauxites: the Devonian Schugorsk deposit, RussiaMineralogy and geochemistry of trace elements in bauxites: the Devonian Schugorsk deposit, RussiaL. E. MORDBERG1,2,3, C. J. STANLEY2 , AND K. GERMANN3 1. Russian Research Geological Institute (VSEGEI), Sredny pr 74, St. Petersburg, Russia 2. The NaturalHistory Museum, Cromwell Road, London SW7 5BD, UK 3. Technische Universita¨t Berlin, Lagersta¨ttenforschung, Sekr. BH4, Ernst-Reuter-Platz 1, 10587 Berlin, GermanynullAbstract: Processes of mineral alteration involving the mobilization and deposition of more than 30 chemical elements during bauxite formation and epigenesis have been studied on specimens from the Devonian Schugorsk bauxite deposit, Timan, Russia. Chemical analyses of the minerals were obtained by electron microprobe and element distribution in the minerals was studied by element mapping. Interpretation of these data also utilized high-resolution BSE and SE images.Specialized Vocabulary: Mobilization [məubilai'zei-ʃən] n. 动员; 调动 Formation [fɔ:'meiʃən] n. 构造, 编队, 形成 Epigenesis [epi'dʒenisis] n. 渐成说; [地]外力变质;后成 specimen ['spesimən] n. 样本, 标本 electron microprobe 电子微探针; 电子显微探针; 电子探针null The main rock-forming minerals of the Vendian parent rock are calcite, dolomite, feldspar, aegirine, riebeckite, mica, chlorite and quartz; accessory minerals are pyrite, galena, apatite, ilmenite, monazite, xenotime, zircon, columbite, pyrochlore, chromite, bastnaesite and some others. Typically, the grainsize of the accessory minerals in both parent rock and bauxite is from 1 to 40 mm. However, even within these rather small grains, the processes of crystal growth and alteration during weathering can be determined from the zonal distribution of the elements. The most widespread processes observed are:Specialized Vocabulary: parent rock 母岩 Calcite ['kælsait] n. [矿]方解石 Dolomite ['dɔləmait] n. 白云石 Feldspar [‘feldspɑ:] n. 长石 Aegirine ['eiɡə,ri:n] n. [矿]霓石 riebeckite['ri:bekait] n. 钠闪石 mica ['maikə] n. 云母 chlorite [‘klɔ:rait] n. 绿泥石 quartz [kwɔ:ts] n. 石英 accessory minerals 副矿物 pyrite ['pairait] n. [矿]黄铁矿 galena [ɡə‘li:nə] n. [矿]方铅矿 apatite ['æpətait] n. 磷灰石 ilmenite [‘ilmənait]n.[矿]钛铁矿 Please follow the next page for the other Specialized Vocabulary of this page null (1) Decomposition of Ti-bearing minerals such as ilmenite, aegirine and riebeckite with the formation of ‘leucoxene’, which is the main concentrator of Nb, Cr, V and W. Crystal growth can be traced from the zonal distribution of Nb (up to 16 wt.%). Vein-like ‘leucoxene’ is also observed in association with organics. (2) Weathering of columbite and pyrochlore: the source of Nb in ‘leucoxene’ is now strongly weathered columbite, while the alteration of pyrochlore is expressed in the growth of plumbopyrochlore rims around Ca-rich cores. Specialized Vocabulary: Monazite ['mɔnəzait] n. 独居石 xenotime ['zenətaim] n. 磷钇矿 zircon ['zə:kɔn] n. 锆石 columbite [kə'lʌmbait] n. 钶铁矿；铌铁矿 pyrochlore [‘pairəklɔ:]n. [矿]烧绿石 chromite [‘krəumait] n. 亚铬酸盐；铬铁矿 bastnaesite n. 氟碳铈矿 grainsize n. 粒度；粒径 decomposition [,di:kɔmpə'ziʃən] n. 分解,腐败,变质 Ti-bearing mineral; leucoxene [lju:'kɔksi:n] n. 白钛石；金红石；白榍石 plumbopyrochlore.. 烧绿石 rim [rim] n. 边,轮缘,框 Please follow the next page for the other Specialized Vocabulary of this pagenull(3) Dissolution of sulphide minerals and apatite and the formation of crandallite group minerals: ‘crandallite’ crystals of up to 40 mm size show a very clear zonation. From the core to the rim of a crystal, the following sequence of elements is observed: Ca ? Ba ? Ce ? Pb ? Sr ? Nd. Sulphur also shows a zoned but more complicated distribution, while the distribution of Fe is rather variable. A possible source of REE is bastnaesite from the parent rock. More than twelve crandallite type cells can be identified in a single ‘crandallite’ grain. Specialized Vocabulary: sulphide ['sʌlfaid] n. 硫化物 apatite [‘æpətait] n. 磷灰石 crandallite [‘krændəlait] n. 纤磷钙铝石 zonation [zəu'neiʃən] n. 成带；动植物的生物地理学的地带分布；带状配列 Nb：Niobium [nai‘əubiəm] n. [化] 铌（41号元素，汉语发言[ní] ） Cr：chromium [‘krəumjəm] n. [化] 铬（24号元素，汉语发音[gè] ) V：vanadium [və'neidiəm] n. [化] 钒（23号元素，汉语发音[fán] ) W：tungsten [‘tʌŋstən] n. [化] 钨 （ 74号元素，汉语发音[wū]） Ca：calcium [‘kælsiəm] n. [化] 钙（20号元素，汉语发音[gài] ) Ba：barium ['bεəriəm] n. [化] 钡（56号元素，汉语发音[bèi]） Ce：cerium ['siəriəm] n. [化] 铈（58号元素，汉语发音[shì]）null(4) Alteration of stoichiometric zircon and xenotime with the formation of metamict solid solution of zircon and xenotime: altered zircon rims also bear large amounts of Sc (up to 3.5 wt.%), Fe, Ca and Al in the form of as yet unidentified inclusions of 12 mm. Monazite seems to be the least altered mineral of the profile. In the parent rock, an unknown mineral of the composition (wt.%): ThO2 54.8; FeO 14.6; Y2O5 2.3; CaO 2.0; REE 1.8; SiO2 12.2; P2O5 2.8; total 94.2 (average from ten analyses) was determined. In bauxite, another mineral was found, which has the composition (wt.%): Specialized Vocabulary: stoichiometric [,stɔikiə'metrik] adj. 化学计算的；化学计量的 metamict [‘metəmikt] n. 蜕晶质 Pb：lead [li:d] n. [化] 铅（82号元素，汉语发音[qiān]） Sr：strontium ['strɔnʃiəm] n. [化] 锶（38号元素，汉语发音[sī]） Sc：scandium ['skændiəm] n. [化] 钪（21号元素，汉语发音[kàng]） Fe：iron ['aiən] n. [化] 铁（26号元素，汉语发音[tiě] ） Ca：calcium [‘kælsiəm] n. [化] 钙（20号元素，汉语发音[gài] ) 铝（13号元素，汉语发音[lǚ]） Th：thorium ['θɔ:riəm,] n. [化] 钍（90号元素，汉语发音[tǔ]） Cu：copper ['kɔpə] n. [化] 铜（29号元素，汉语发音[tóng]） Cd：cadmium ['kædmiəm] n. [化] 镉（48号元素，汉语发音[gé]） Bi：bismuth ['bizməθ] n. [化] 铋（83号元素，汉语发音[bì]） nullThO2 24.9; FeO 20.5; Y2O5 6.7; CaO 2.0; ZrO 17.6; SiO2 8.8; P2O5 5.4; total 89.3 (F was not analysed; average from nine analyses). Presumably, the second mineral is the result of weathering of the first one. Although the Th content is very high, the mineral is almost free of Pb. However,intergrowths of galena and pyrite are observed around the partially decomposed crystals of the mineral. Another generation of galena is enriched in chalcophile elements such as Cu, Cd, Bi etc., and is related to epigenetic alteration of the profile, as are secondary apatite and muscovite. Specialized Vocabulary: weathering [‘weðəriŋ] n. 风化 intergrowth ['intəɡrəuθ] n. 共生，交互生长 pyrite ['pairait] n. [矿]黄铁矿 galena [ɡə‘li:nə] n. [矿]方铅矿 Decomposed a. 已分解的, 已腐烂的 chalcophile [‘kælkə,fail] adj. 【地球化学】亲铜的，亲硫的 epigenetic [,epidʒi'netik] adj. [生]外成的；后生的 Muscovite [,mʌskə‘vait] 白云母 Al：aluminum [,ælju'miniəm,] n. [化] 铝（13号元素，汉语发音[lǚ]） Y：yttrium ['itriəm] n. [化] 钇（39号元素，汉语发音[yǐ]） Si：silicon ['silikən] n. [化] 硅（14号元素，汉语发音[guī]） P：phosphorus ['fɔsfərəs] n. [化] 磷（15号元素，汉语发音[lín]） Zr：zirconium [zə:'kəuniəm] n. [化] 锆（40号元素，汉语发音[gào]） null KEYWORDS: bauxite, laterite, weathering, geochemistry, mineralogy, trace elements, leucoxene, crandallite, zircon, xenotime, pyrochlore, galena.Specialized Vocabulary: leucoxene [lju:'kɔksi:n] n. 白钛石；金红石；白榍石Introduction The problem of trace elements in bauxite profiles is important for a number of reasons. Firstly, deep chemical weathering is a geochemical process which is as important as magmatism, metamorphism or sedimentation. In addition, principles of concentration and/or differentiation of chemical elements during bauxite formation differ from those typical for magmatic, metamorphic and sedimentary processes.Introduction The problem of trace elements in bauxite profiles is important for a number of reasons. Firstly, deep chemical weathering is a geochemical process which is as important as magmatism, metamorphism or sedimentation. In addition, principles of concentration and/or differentiation of chemical elements during bauxite formation differ from those typical for magmatic, metamorphic and sedimentary processes.Specialized Vocabulary: Bauxite [‘bɔ:ksait] n. 矾土, 铁铝氧石, [化]铝土矿 Magmatism：岩浆作用 Metamorphism [metəmɔ:fi zəm] n. 变质作用 Chemical weathering 化学 风化,化学风化作用,化学气候 sedimentation [sedimen'teiʃən] n. 沉淀,沉降 Geochemical [,dʒi:ə'kemikəl] adj. 地球化学的 Sedimentary [sedi'mentəri] a. 沉淀性的 nullSecondly, only a few elements such as Ga and V are successfully extracted as by-products of Al production, although some other elements may show high concentrations within bauxite profiles. Thus, the nature of the minerals containing trace elements is an important key for the understanding of their behaviour during bauxite formation. The problem of mobility of chemical elements during deep weathering has been discussed for many years. However, the very small grain-size of bauxite (a few microns or even smaller) has hindered detailed investigations. Specialized Vocabulary: extracted [iks'træktid] 萃取的 by-product ['bai,prɔdʌkt] n. 副产品；附带产生的结果；意外收获 mobility [məu'biliti] n. 可动性,变动性,情感不定 Ga：gallium ['ɡæliəm] n. [化]镓 镓（23号元素，汉语发音[jiā]） V：vanadium [və'neidiəm] n. [化] 钒（23号元素，汉语发音[fán] ) Al：aluminum [,ælju'miniəm,] n. [化] 铝（13号元素，汉语发音[lǚ]）nullThe most widespread method used to determine element mobility was a comparison of its bulk content in the parent rock and in the weathering profile, frequently using isovolumetric calculations. Bardossy and Aleva (1990) compared data on six bauxite districts and concluded that ‘‘there exist a number of elements for which their chemical properties unequivocally determine enrichment or depletion in all lateritic-bauxite districts’’ (p. 145). This conclusion needs explanation.Specialized Vocabulary: isovolumetric adj. 等容的，定容的 depletion [di'pli:ʃən] n. 消耗,罄尽,放血 lateritic [,lætə'ritik] adj. 含有红土的；红壤的 lateritic-bauxite：红土型铝土矿null This study on the mineralogy and geochemistry of trace elements in bauxite was carried out on samples from the Schugorsk bauxite deposit from the Middle Timan, Russia. Material from this deposit contains higher levels of certain elements than normal(Mordberg, 1996, 1997) and is hence suitable for a detailed mineralogical investigation.Specialized Vocabulary: mineralogy [,minə'rælədʒi] 矿物学nullGeology Bauxite deposits of the Middle Timan are located in the North of European Russia, between the NE edge of the Russian Plate and the Pechorsk Depression (Fig. 1). Specialized Vocabulary: Plate [pleit] n. 板块nullThe geology of the bauxite region has been given in detail by Likhachev (1993) and Mordberg (1996, 1997). Devonian bauxite deposits located within the Chetlass orogenic structure occur on folded, mostly carbonate strata of the Riphean. Deposits of both lateritic and karstic origin are found. The overlying rocks are Upper Devonian volcanogenic and sedimentary sequences; in some instances the bauxite profile is covered directly by Late Devonian trap basalt. The Schugorsk bauxite deposit, the largest in the region, was formed over a Precambrian carbonate sequence which had been altered by alkali metasomatic processes. Specialized Vocabulary: Orogenic: adj. 造山的；造山运动的 carbonate ['kɑ:bəneit] n. 碳酸盐 strata ['streitə]: n. 层(地层,岩歧,阶层,薄片) lateritic [,lætə'ritik] adj. 含有红土的；红壤的 karstic.. adj.喀斯特的 Upper Devonian:(地质学)晚泥盆世 volcanogenic [,vɔlkənə'dʒenik] adj. 源于火山的；火山生成的 sedimentary sequence:沉积层序 Precambrian ['pri:'kæmbriən] n. 前寒武纪,前塞武层 carbonate ['kɑ:bəneit] n. 碳酸盐 Alkali n. 碱 Metasomatic [,metəsəu'mætik] adj. [地]交代的null Rock-forming minerals of the metasomatite are dolomite, calcite and K-feldspars. Plagioclase, aegerine, riebeckite, biotite and ‘sericite’ are also present in various amounts. The weathered profile attains a total depth here of 100-120 m, and the main ore-forming minerals are boehmite, kaolinite and hematite with nearly monomineralic white boehmitic bauxites being widespread within the deposit. The ratio of carbonate and silicate minerals in the parent rock varies broadly with an average of ~1:1. Due to this heterogeneity, the deposit cannot be treated as either the lateritic or the karstic type.Specialized Vocabulary: Metasomatite: n. 交代岩，换质岩 dolomite [‘dɔləmait] n. 白云石 K-feldspars 钾长石 plagioclase ['pleidʒiəkleis, -kleiz] n. [矿]斜长石 riebeckite [‘ri:bekait] n. [矿]钠闪石 biotite [‘baiətait] n. [矿]黑云母 sericite [‘serisait] n. [矿]丝（绢）云母 boehmite ['bə:mait] n. [矿]勃姆石（一种水软铝石） hematite ['hemətait,] n. [矿]赤铁矿 monomineralic ['mɔnəu,mainə'rælik] adj. 单矿物的 silicate [‘silikit] n. 硅酸盐 heterogeneity [,hetərəudʒi'ni:iti] n. 多相性,异质性 lateritic [,lætə'ritik] adj. 含有红土的；红壤的nullMaterial and methods Samples for the investigation were taken from drill cores. A part of each sample was powdered, and the levels present of 60 elements (including the major ones) were determined by XRF following standard methods at the Technical University of Berlin. A full description of the methods is given by Krumb (1998). The contents of elements in minerals were determined in polished sections using a wavlength-dispersive (WD) electron probe microanalyser (Cameca SX50) at the Natural History Museum, London. Specialized Vocabulary: drill cores：岩心 polished ['pɔliʃt] 擦亮的,精练的,优美的 Microanalyser[maikrəu'ænəlaizə] n. 微量 分析 定性数据统计分析pdf销售业绩分析模板建筑结构震害分析销售进度分析表京东商城竞争战略分析 仪null International standards were used for calibration of each element. The analytical conditions used were 15 kV and 20 nA with counting times of 20 s for Zr, Ca, Ti, Nb, P, Sc, Pb, Mn, Fe, Hf, Na, Mg, Al and Si; of 30 s for La, Ce, Th, U, Pb and W; and of 50 s for Y, Pr, Nd, Sm and Dy. Elemental X-ray maps were obtained using the following conditions: 15 kV, 100 nA and 200 mS per point.Specialized Vocabulary: calibration [,kæli'breiʃən] n. 刻度,校准， Zr：zirconium [zə:'kəuniəm] n. [化] 锆（40号元素，汉语发音[gào]） Ca：calcium [‘kælsiəm] n. [化] 钙（20号元素，汉语发音[gài] ) Ti：titanium [tai'teinjəm] n. [化] 钛（22号元素，汉语发音[tài]） Nb ：Niobium [nai‘əubiəm] n. [化] 铌（41号元素，汉语发言[ní] ） P：phosphorus ['fɔsfərəs] n. [化] 磷（15号元素，汉语发音[lín]） Sc：scandium ['skændiəm] n. [化] 钪（21号元素，汉语发音[kàng]） Pb：lead [li:d] n. [化] 铅（82号元素，汉语发音[qiān]） Mn：manganese [,mæŋgə'ni:z] n. [化] 锰（25号元素，汉语发音[měng] Fe：iron ['aiən] n. [化] 铁（26号元素，汉语发音[tiě] ） Hf：hafnium ['hæfniəm] n. [化] 铪（72号元素，汉语发音[hā]）nullResults Rock geochemistry The distribution parameters of Ti, P, S and trace elements within the Schugorsk weathering profile are given in Table 1. Specialized Vocabulary: parameter [pə'ræmitə] n. 参数,参量 weathering profile (岩层) 风化剖面，风化壳 Na：sodium ['səudjəm, -diəm] n. [化] 钠（11号元素，汉语发音[nà]） Mg：magnesium [mæg'ni:zjəm] n. [化] 镁（12号元素，汉语发音[měi]） Al：aluminum [,ælju'miniəm,] n. [化] 铝（13号元素，汉语发音[lǚ]） Si：silicon ['silikən] n. [化] 硅（14号元素，汉语发音[guī]） La：lanthanum ['lænθənəm] n. [化] 镧（57号元素，汉语发音[lán]） Ce：cerium ['siəriəm] n. [化] 铈（ 58号元素，汉语发音[shì] ） Th：thorium ['θɔ:riəm,] n. [化] 钍（90号元素，汉语发音[tǔ]） U：uranium [juə'reiniəm] n. [化] 铀（92号元素，汉语发音[yóu]） W：tungsten [‘tʌŋstən] n. [化] 钨 （ 74号元素，汉语发[wū]）nullFor comparison, data for the average composition of bauxite deposits of the world (Bronevoy et al., 1985) are also supplied. It can be seen that the studied profile is strongly enriched in lithophile elements such as Nb, Th, REE and Zr which are typical of alkali rocks. Chalcophile elements such as Pb, Sb, Bi and presumably Cd are also prominent, and the enrichment in W and Tl is of great interest also. The other elements which are found in amounts greater than average for bauxite are Ti, P, Ga, Ni, Sc, Sn, Sr and Zn. Some elements such as Ag, Co, U and V show concentrations close to average, while S, As, Cr, Cu and Hf occur in relatively small amounts. Specialized Vocabulary: lithophile element 亲石元素Chalcophile element亲铜元素 prominent ['prɔminənt] adj. 突出的，显著的；杰出的 Tl：thallium ['θæliəm] n. [化] 铊（22号元素，汉语发音[tā]） Y：yttrium ['itriəm] n. [化] 钇（39号元素，汉语发音[yǐ]） Pr：praseodymium [,preiziəu'dimiəm] 镨（59号元素，汉语发音[pǔ]） Nd：neodymium [ni:əu'dimiəm]n. [化] 钕（60号元素，汉语发音[nǚ]） Sm：samarium [sə'mɛəriəm] n. [化] 钐（62号元素，汉语发音[shān] Dy：dysprosium [dis'prəusiəm] n. [化] 镝（66号元素，汉语发音[dí]） Sb：stibium ['stibiəm] n. [化] 锑（66号元素，汉语发音[tī]） Cd：cadmium ['kædmiəm] n. [化] 镉（48号元素，汉语发音[gé]）nullBoth Zr/Hf (47.2) and Th/U (17.5) are much higher than their average values for bauxite. Correlation analysis of element contents (Table 2) allows at least three groups of elements to be distinguished with high positive links among elements within each group. Specialized Vocabulary: Zn：zink [ziŋk] n. [化] 锌（30号元素，汉语发音[xīn]） Ag：silver ['silvə] n. [化] 银（47号元素，汉语发音[yín]） Co：cobalt [kəu'bɔ:lt] n. [化] 钴（27号元素，汉语发音[gǔ]） As：arsenic ['ɑ:sənik] n. [化] 砷（33号元素，汉语发音[shēn]） nullOne group unites P, Ba, Sr, Bi and V; the other elements having a positive correlation with some of these are Ni and Pb. This group represents ‘crandallite’ mineralization within the profile. The second group consists of REE (La, Sm, Nd, Pr and Ce) with adjusted Y and, to a lesser extent, U. It reflects the presence of P-minerals such as monazite and xenotime.From these two groups, only Pb and Ce correlate positively with each other, both correlating with Cr and Sc as well. Specialized Vocabulary: positive correlation (化)正相关 crandallite ['krændəlait] n. 纤磷钙铝石 to a lesser extent 在较小程度上 monazite ['mɔnəzait] n. 独居石 xenotime ['zenətaim, 'zi:-] n. [矿]磷钇矿 Ni：nickel ['nikəl] n. [化] 镍（28号元素，汉语发言[niè]） La：lanthanum ['lænθənəm] n. [化] 镧（57号元素，汉语发音[lán]） Ce：cerium ['siəriəm] n. [化] 铈（58号元素，汉语发音[shì]） Nd：neodymium [ni:əu'dimiəm]n. [化] 钕（60号元素，汉语发音[nǚ]） Sm：samarium [sə'mɛəriəm] n. [化] 钐（62号元素，汉语发音[shān] Y：yttrium ['itriəm] n. [化] 钇（39号元素，汉语发音[yǐ]） U：uranium [juə'reiniəm] n. [化] 铀（92号元素，汉语发音[yóu]） Pb：lead [li:d] n. [化] 铅（82号元素，汉语发音[qiān]）nullThe third group represents Ti, Zr, Hf and Nb and reflects the presence of minerals such as ‘leucoxene’, zircon, columbite and pyrochlore. Elements without any high positive correlation are Th (due to its own mineral for m), Ga (presumably dispersed in boehmite) and Zn (host minerals are unidentified). Elements determined in selected samples or with concentrations below the detection limit were excluded from the correlation analysis.Specialized Vocabulary: leucoxene [lju:'kɔksi:n] n. 白钛石；金红石；白榍石 zircon ['zə:kɔn] n. 锆石 columbite [kə'lʌmbait] n. 钶铁矿；铌铁矿 pyrochlore ['pairəklɔ:] n. [矿]烧绿石 boehmite ['bə:mait] n. [矿]勃姆石(一种水软铝石) Sc：scandium ['skændiəm] n. [化] 钪（21号元素，汉语发音[kàng]） Cr：chromium [‘krəumjəm] n. [化] 铬（24号元素，汉语发音[gè] ) Ti：titanium [tai'teinjəm] n. [化] 钛（22号元素，汉语发音[tài]） Zr：zirconium [zə:'kəuniəm] n. [化] 锆（40号元素，汉语发音[gào]） Hf：hafnium ['hæfniəm] n. [化] 铪（72号元素，汉语发音[hā]） Nb ：Niobium [nai‘əubiəm] n. [化] 铌（41号元素，汉语发言[ní] ） Ga：gallium ['ɡæliəm] n. [化]镓 镓（23号元素，汉语发音[jiā]）nullMineralogy The parent rock is composed of calcite and dolomite (sedimentary and diagenetic minerals), K-feldspars, aegirine and riebeckite (metasomatic minerals) and some micas, chlorite and quartz (terrigenous admixture). Ilmenite, monazite, xenotime, zircon, apatite, columbite, pyrochlore, pyrite, galena, sphalerite and some minerals such as bastnaesite and thorianite represent accessory minerals. The rock-forming minerals all completely disappeared during bauxite formation. but they may occur near the bottom of the weathering profile. The main minerals of bauxite are boehmite, hematite and kaolinite. Illite occurs in the less altered zones of the profile. Hydrothermal muscovite veins cross the profile. Accessory minerals of the profile are described below.Specialized Vocabulary: diagenetic [,daiədʒə'netik] adj. 成岩作用的 aegirine ['eiɡə,ri:n] n. [矿]霓石 riebeckite ['ri:bekait] n. [矿]钠闪石 metasomatic [,metəsəu'mætik] adj. [地]交代的 mica [‘maikə] n. 云母 chlorite ['klɔ:rait] n. 绿泥石；亚氯酸盐 terrigenous [te'ridʒinəs] adj. 陆生的 galena [ɡə'li:nə] n. [矿]方铅矿；硫化铅 sphalerite ['sfælərait] n. 闪锌矿 bastnaesite n. 氟碳铈矿 thorianite ['θɔ:riənait, 'θəu-] n. 方钍石 hematite ['hemətait, 'hi:m-] n. [矿]赤铁矿 hydrothermal [,haidrəu'θə:məl] adj. 热水的；热液的 null ‘Leucoxene’ Titanium oxide minerals are quite common in bauxite profiles of different origin. Anatase is the most widespread and it has been identified in many karst and laterite deposits (Bardossy, 1982; Bardossy and Aleva,