Three sessions of the International Geological Congress held in Russia and the USSR （1897,1937, 1984）

Editorial note--The International Commission on the History of Geological Sciences has undertaken to organize a series of short articles for Episodes on the history of the different Sessions of the International Geological Congress. These were held as follows:France (1878), Italy (1881), Germany (1885), UK (1888), USA(1891), Switzerland (1894), Russia (1897), France (1900), Austria(1903), Mexico (1906), Sweden (1910), Canada (1913), Belgium(1922), Spain (1926), South Africa (1929), USA (1933), USSR(1937), UK (1948), Algeria (1952), Mexico (1956), Denmark/Finland/Norway/Sweden/Iceland (1960), India (1964), Czechoslovakia(1968), Canada (1972), Australia (1976), France (1980), USSR(1984), USA (1989), Japan (1992), China (1996), Brazil (2000). Any authors wishing to offer contributions on the meetings in Mexico(1906), Canada (1913), Belgium, Denmark, India, Canada (1972),and Brazil are invited to contact the INHIGEO Secretary-General at: doldroyd@optushome.com.au. The papers will not appear inchronological order.     

扬子地台西南缘传统型铂族矿产地质特征

传统型铂族矿产，系指与镁铁质岩浆成矿作用有关的铂族矿产资源。华力西运动时期，扬子地台西南缘沿超壳深断裂带发生的大陆裂谷作用，为来自上地幔的镁铁质(拉斑玄武岩质)岩浆的上涌和侵位提供了极为有利的前提条件。含铂基性超基性岩的时空分布，受到大陆裂谷作用的主要发生发展时期和裂谷活动带的控制。通过对典型矿床特征及其成矿作用的探讨，论述了扬子地台西南缘主要的铂族矿床类型；并从四维成矿的角度，阐述了对区域成矿规律的一些基本认识。     

Pre-Tertiary Orogenies in the Himalaya: A review of various evidences

Various sedimentary sequences of the Himalaya reflecting different tectonic cycles when compared with the ages of (i) unconformity, (ii) pre-Tertiary metamorphism, (iii) granites and (iv) pre-Tertiary deformations point to following pre-Tertiary Orogenies: (i) Sundernagar (Middle Precambrian), (ii) Shali (Vendian), (iii) Jasim-Kurgiakh (Ordovician), (iv) Blaini-Thidsi (Upper Paleozoic) and (v) Tal-Chikkim (Middle-Upper Cretaceous). Besides these, minor impulses identifiable are: (i) Bandel-2 (Middle Riphean), (ii) Tangze (Devonian), (iii) Infra Krol (Upper Permian), (iv) Tandi (? Callovian) and (v) Krol (Upper Jurassic - Lower Cretaceous). Due to paucity of deformation structures related to these earth movements, it is suggested that these were either (i) mainly epeirogenic, (ii) feebly orogenic or (iii) they produced folds which were coaxial with subsequent Himalayan folds hence indistinguishable from the latter.     

秦巴北部商县—卢氏地区变质方解石—白云石地质压力计的研究

秦巴北部的商县-卢氏县地区广泛分布有区域变质的方解石-白云石共生矿物对,它们对于估计变质作用和断裂构造作用的温压条件,有着重要的意义。本文着重就该地区Fe~(2+)在方解石-白云石中的X_(Fe)~(Co)>X_(Fe)~(Dol)分配情况,提出新的计压方法。     

对于氟碳钡铈矿（Cordylite—Ce）成分与结构的质疑

本文讨论了氟碳钡铈矿的成分和结构问题。发现氟碳钡铈矿的成分、密度、折射率三者间的一致性参数很差,晶体结构与光性和空间群相矛盾,单个大阳离子的平均占有体积远大于同类矿物的平均占有体积,它的晶体结构与同类矿物不可类比。由于受当时条件的限制,在以往有关氟碳钡铈矿的成分和结构的资料中存在着一些明显的错误,有必要对其进行重新定义。其结构化学式应改为:(Na_(1-x),Ca_(0·5x))BaCe_2(CO_3)_4F。     

未定名矿物(Bi38CrO60)的矿物学研究

人工合成立方晶体Bi38CrO60在自然界首次发现于中国陕西省洛南县驾鹿金矿床中,暂称之为未定名矿物.其共生和伴生矿物有黄铁矿、自然金、碲金矿、含氧金矿物等.常呈不规则粒状集合体,偶见立方体微晶(粒径小于0.05 mm),棕黑色,金属光泽;HV=232.78 kg/mm2 ,HM=4.15;D=14.10(3)g/cm3,Dx=14.08(2)g/cm3,n=3.14(3).EPM8100探针分析Bi2O3为98.854%、CrO3为1.111%,合计99.965%,化学式为Bi38.009Cr0.995O60;CAMEBAX-SX51探针分析Bi2O3为98.862%,CrO3为1.112%,合计99.974%,化学式为Bi38.008Cr0.996O60.均可写为Bi38CrO60.X射线粉晶分析主要强度线d(I)(hkl)分别为0.321 5(100),(310);0.272 11(72),(321);0.171 45(40),(530);0.169 6(30),(600);0.165 1(30),(611);0.160 8(30),(620);0.294 11(25),(222);0.359 6(22),(220);0.217 1(20),(332);0.150 3(20),(631),等轴晶系,可能的空间群为Im3m;a=1.018 1(1)nm,c/a=1,晶胞体积v=1.055 29(1)nm3,z=1.1-Kp/Kc=0.019.Cr6 ,Bi3 ,O2-.未定名矿物和人工晶体的化学成分与X射线粉晶数据基本一致.     

岩溶水锶元素水文地球化学特征

通过对桂林地区地下河系统不同类型岩溶水水样Sr2+ 含量和87 Sr /86 Sr 值分析,得到如下结论: ( 1)桂林地区岩溶水中Sr2+ 含量普遍较低,流经不同岩层的地下水Sr2+ 含量不同,岩溶水中Sr2+ 含量随着Ca2+ 含量的增大而增大,随着Mg2+含量的增大而减小;地下河水中的Sr2+ 含量始终介于表层岩溶带水、饱水带裂隙水、地表坡面流和外源水(如果存在外源水补给)的最大、最小值之间。( 2)流经不同岩层地下水的87 Sr /86 Sr值不同,流经砂岩层地下水87 Sr /86 Sr 值较高,其次为流经白云岩层和灰岩层的地下水;地下河水87 Sr /86 Sr 值也是介于表层岩溶带水、饱水带裂隙水、地表坡面流和外源水(如果有外源水补给)的最大、最小值之间。因此Sr2+和87 Sr /86 Sr能反映岩溶水形成的信息,是较理想的天然示踪剂,在岩溶水研究中具有很广阔的应用前景。      

北苏鲁仰口地区变辉长岩中锆石U-Pb定年、微量元素和Hf同位素特征及其地质意义

北苏鲁仰口地区出露超高压的变辉长岩.锆石阴极发光图像和其内部矿物包体激光拉曼测试的联合研究结果表明,变辉长岩锆石具有弱发光效应的岩浆韵律环带的核和被改造的强发光效应的边.岩浆韵律环带的核部保存大量而复杂的矿物包体,包括普通辉石(Cpx)+斜方辉石(Opx)+斜长石(P1)+石英(Qtz)+黑云母(Bt)+钛铁矿(Ilm)+磷灰石(Ap);边部保存的矿物包体则相对较少,包括普通辉石(Cpx)+斜方辉石(Opx)+斜长石(Pl)+磷灰石(Ap).尽管岩浆韵律环带核部的稀土元素总合量比被改造的锆石边部明显偏高,但二者稀土元素配分模式具有明显的相似性,主要表现为轻稀土相对亏损,而重稀土明显富集,相应的(La/Yb)N=0.00015～0.00039,并具有明显的负Eu异常(Eu/Eu*=0.20～0.26)、相对明显的正Ce异常(Ce/Ce*=71.5～147.4)和较高的Th/U比值(1.97～2.69).上述特征表明,仰口地区变辉长岩中的锆石均为继承性的岩浆锆石,而没有新生的变质锆石.LA-(MC)-ICP-MS锆石原位U-Pb定年和Lu-Hf同位素分析结果表明,两件锆石样品Y1和Y2的年龄数据所构成的不一致线显示了十分接近的上交点和下交点年龄.其上交点年龄分别为785±15Ma(2σ)和784±12Ma(2σ),应代表原岩的形成时代,表明变辉长岩的原岩与Rodinia超大陆裂解的岩浆事件存在密切的成因关系;而下交点年龄分别为226±24Ma(2σ)和228±26Ma(2σ),与苏鲁其它类型超高压岩石中含柯石英锆石微区记录的变质年龄十分吻合,应代表变辉长岩的超高压变质时代.岩浆结晶锆石的核部具有明显偏高的176Lu/177Hf(0.00044～0.00291)和176Yh/177Hf(0.0165～0.1168)比值,而176Hf/177Hf比值变化于0.281956～0.282048之间,相应的εHf(t)=-8.5～-14.0,tDM2=2.03～2.32Ga,表明仰口地区变辉长岩的原岩起源于古元古代时期的富集地幔或发生部分熔融的下地壳残留体.被改造的岩浆结晶锆石的边部则具有明显偏低的176Lu/177Hf(0.00029～0.00060)和176Yh/177Hf(0.0112～0.0200)比值,而176Hf/177Hf(t)比值变化于0.281953～0.282002之间,相应的εHf(t)=-10.2～-11.9,tDM2=2.12～2.21Ga.与岩浆结晶锆石核部相比,被改造的岩浆锆石边部的176Lu/177Hf、176Yb/177Hf、176Hf/177Hf(t)比值和εHf(t)和tDM2值的变化范围更小,表明中-新三叠纪的超高压变质作用使岩浆结晶锆石边部的Lu-Hf同位素体系发生调整,更趋向于均一化.     

缅甸大地构造单元的划分与特征

为合作开发周边国家矿产资源,在实地调研的基础上,结合前人资料的收集与整理,将缅甸的大地构造单元自西向东划分为5个Ⅰ级构造单元、10个Ⅱ级构造单元.具体是：①西克钦邦-若开邦结合带（E-N₁）（Ⅰ）,进一步划分为钦邦-若开邦结合带（E-N₁）（Ⅰ₁）、西克钦邦结合带（E-N₁）（Ⅰ₂）;②西缅甸-苏门答腊弧盆系（E-N₁）（Ⅱ）,进一步划分为蒙育瓦-勃生岛弧带（E-N₁）（Ⅱ₁）、瑞保-仰光弧后盆地（E-N₁）（Ⅱ₂）、密支那岛弧带（E-N₁）（Ⅱ₃）;③腾冲-马来半岛造山带（T₃-K）（Ⅲ）,进一步划分为八莫陆缘弧（T₃-K）（Ⅲ1）、毛淡棉陆缘弧（T₃-K）（Ⅲ₂）、德林依达地块（P_z2）（Ⅲ₃）;④保山-掸邦陆块（€-T₂）（Ⅳ）;⑤昌宁-孟连-清莱结合带（C-T₂）（Ⅴ）.这10个构造单元以9条断裂为边界.自西向东为：那加山-若开山逆冲断裂（F₁）、平梨铺-卑谬伸展断裂（F₂）、实皆-勃固右行平移断裂（F₃）、葡萄-格杜逆冲断裂（F₄）、英昆-八莫伸展断裂（F₅）、南坎-抹谷右行平移断裂（F₆）、曼德勒-垒固左行平移断裂（F₇）、锡当-三塔左行平移断裂（F₈）、孟宾-清迈逆冲断裂（F₉）.     

海拉尔盆地海参1井伊敏组孢粉组合的地层意义

海参1井伊敏组孢粉化石异常丰富,自下而上可以划分出3个孢粉组合:Impardecispora-Cyathidites-Clavatipollenites组合,Stereisporites-Deltoidospora-Asteropollis组合,Appendicisporites-Asteropollis-Tricolpites组合,分别分布于伊敏组一段、二段和三段,组合特征明显,是海拉尔盆地乌尔逊凹陷划分伊敏组与大磨拐河组的重要生物依据之一,更是伊敏组内三段划分和井间对比的生物依据之一。3个孢粉组合中见有属种繁多的海金沙科孢子及其他繁盛于早白垩世中晚期的孢子花粉,结合在绝大多数样品中发现的早期被子植物花粉的情况分析,推测含这3个孢粉组合的伊敏组地质时代为早白垩世巴列姆期—早阿尔必期(Barremian—Early Albian)。     

我国首次发现的锌—砷黝铜矿

锌-砷黝铜矿产于内蒙的某一铅锌矽卡岩矿床中,呈它形粒状集合体,粒径0.2-0.5mm,铅灰色,硬度HvHN=339-388kg/mm2。反射色呈灰蓝色微带绿色。均质性。其成分经电子探针分析(平均值)为:S 25.94,As 10.70,Cu 39.67,Zn 7.36,Sb 9.81,Bi 5.81,Ag 0.18,Fe 0.37(%),化学式为:(Cu10.02Age03)10.05(Zn1.81Fe0.11)1.82(As2.29Sb1.29Bi0.45)4.03S18。X射线分析:晶胞参数a=10.322,粉末衍射强线是2.98,1.82,1.56。     

Molecular-level modes of As binding to Fe(III) (oxyhydr)oxides precipitated by the anaerobic nitrate-reducing Fe(II)-oxidizing Acidovorax sp. strain BoFeN1

Sorption of contaminants such as arsenic (As) to natural Fe(III) (oxyhydr)oxides is very common and has been demonstrated to occur during abiotic and biotic Fe(II) oxidation. The molecular mechanism of adsorption- and co-precipitation of As has been studied extensively for synthetic Fe(III) (oxyhydr)oxide minerals but is less documented for biogenic ones. In the present study, we used Fe and As K-edge X-ray Absorption Near Edge Structure (XANES), extended X-ray Absorption Fine Structure (EXAFS) spectroscopy, Mössbauer spectroscopy, XRD, and TEM in order to investigate the interactions of As(V) and As(III) with biogenic Fe(III) (oxyhydr)oxide minerals formed by the nitrate-reducing Fe(II)-oxidizing bacterium Acidovorax sp. strain BoFeN1. The present results show the As immobilization potential of strain BoFeN1 as well as the influence of As(III) and As(V) on biogenic Fe(III) (oxyhydr)oxide formation. In the absence of As, and at low As loading (As:Fe ≤ 0.008 mol/mol), goethite (Gt) formed exclusively. In contrast, at higher As/Fe ratios (As:Fe = 0.020-0.067), a ferrihydrite (Fh) phase also formed, and its relative amount systematically increased with increasing As:Fe ratio, this effect being stronger for As(V) than for As(III). Therefore, we conclude that the presence of As influences the type of biogenic Fe(III) (oxyhydr)oxide minerals formed during microbial Fe(II) oxidation. Arsenic-K-edge EXAFS analysis of biogenic As-Fe-mineral co-precipitates indicates that both As(V) and As(III) form inner-sphere surface complexes at the surface of the biogenic Fe(III) (oxyhydr)oxides. Differences observed between As-surface complexes in BoFeN1-produced Fe(III) (oxyhydr)oxide samples and in abiotic model compounds suggest that associated organic exopolymers in our biogenic samples may compete with As oxoanions for sorption on Fe(III) (oxyhydr)oxides surfaces. In addition HRTEM-EDXS analysis suggests that As(V) preferentially binds to poorly crystalline phases, such as ferrihydrite, while As(III) did not show any preferential association regarding Fh or Gt.     

The effect of maturation on the configuration of pristane in sediments and petroleum

The absolute stereochemistry of pristane in a sample of contemporary marine Zooplankton, Messel shale (Germany) and Djatibarang (Java) crude has been determined by gas Chromatographic methods. The relative stereochemistry in Irati shale (Brazil), Green River (U.S.) crude, Halibut (Australia) crude has also been determined, and confirmed for a sample of the Green River shale. The stereoisomer distributions indicate a loss of stereospecificity of the phytol-derived 6(R),10(S) pristane with increasing geological maturation. For example, the least mature geological sample, the Eocene Messel shale, contains solely the 6(R),10(S) isomer, whereas a mature sample, Djatibarang crude, contains 50% of the 6(R),10(S) isomer and 25% of each of the 6(R),10(R) and 6(S),10(S) isomers.     

Identification of Archaean plate tectonic processes from multidimensional discrimination diagrams and probability calculations

We applied our group's previously published multidimensional diagrams in 2006–2012 and corresponding probability estimates in 2011–2012 to geochemical data for Archaean rocks compiled from cratons in Australia, South Africa, Brazil, Canada, and India. Tectonic processes similar to present-day plate tectonics evidently were active at least since the Palaeoarchaean (?3570 Ma). This seems to be true in spite of a presumably hotter Earth at that time. For the eastern part of the Pilbara craton (Australia), a Palaeoarchaean (3570–3450 Ma) and Mesoarchaean (2900 Ma) continental arc setting apparently evolved to a collision (Col) setting during the Neoarchaean (2600 Ma). We infer an island arc (IA) environment for Kambalda (Australia) during the Neoarchaean (2700 Ma). For the Barberton belt (South Africa), a transition from a mid-ocean ridge regime during the older part of the Palaeoarchaean (3470 Ma) to an IA setting during the younger part (3300–3260 Ma) is likely. We inferred an arc environment for the São Francisco craton (Brazil) and the Rio Maria terrane (Brazil) during the Mesoarchaean (3085–2983 Ma and 2870 Ma, respectively), whereas a within-plate setting is clearly indicated for the Carajás metallogenic province (Brazil) during the Neoarchaean (2740–2700 Ma). We also recognize an IA regime for the Mesoarchaean (3000 Ma) North Caribou and Neoarchaean (2700 Ma) Abitibi greenstone belts (Canada), and for the Gadwal greenstone belt (India) during the Neoarchaean (2700–2500 Ma). A Col setting was inferred for the Archaean sanukitoid suite (Canada) and the Kolar suture zone (India) during the Neoarchaean (2700–2660 Ma and 2630–2520 Ma, respectively).     

显生宙全球气候变化与生物绝灭事件的联系

根据显生宙各地质时期全球气候敏感沉积物和生物地理单元数据库，显生宙（寒武纪至中新世）可识别出２４次全球范围内不同级别的气候变化事件。有些事件与全球生物事件有着密切的联系，而不少则并无重要联系，即使这两种事件发生的时间和规模上存在着明显的一致性，也并不一定就存在着因果关系。这２４次事件根据二者的一致性和不一致性，可归纳为两类：（１）早寒武世末（一致）；（２）晚寒武世末（不一致）；（３）早奥陶世末（Ｉｂｅｘｉａｎ末，不一致）；（４）奥陶纪末（一致）；（５）志留纪兰多维列世（不一致）；（６）志留纪文洛克世早期（不一致）；（７）志留纪文洛克世末（不一致）；（８）志留纪罗德洛世末（不一致）；（９）志留纪普利道里世末（不一致）；（１０）早泥盆世埃姆斯期初（不一致）；（１１）中泥盆世艾菲尔期末（一致）；（１２）中泥盆世吉维特期末（一致）；（１３）晚泥盆世弗拉斯期末（一致）；（１４）泥盆纪末（不一致）；（１５）早石炭世末（一致）；（１６）晚石炭世维斯发期末（一致）；（１７）早二叠世萨克马尔晚期（一致）；（１８）二叠纪末（一致）；（１９）早三叠世（一致）；（２０）中—晚三叠世（不一致）；（２１）早侏罗世赫塘期（不一致）；（２?     

Abiotic reduction of uranium by Fe(II) in soil

Structural Fe(II) has been shown to reduce several oxidized environmental contaminants, including NO₃, chlorinated solvents, Cr(VI), and U(VI). Studies investigating reduction of U(VI) by soils and sediments, however, suggest that abiotic reduction of U(VI) by Fe(II) is not significant, and that direct enzymatic reduction of U(VI) by metal-reducing bacteria is required for U(VI) immobilization as U(IV). Here evidence is presented for abiotic reduction and immobilization of U(VI) by structural Fe(II) in a redoximorphic soil collected from a hillside spring in Iowa. Oxidation of Fe(II) in the soil after reaction with U(VI) was demonstrated by Mössbauer spectroscopy and reduction of U(VI) by the pasteurized soil using U L_III-edge X-ray absorption spectroscopy (XAS). XAS indicates that both reduced U(IV) and oxidized U(VI) or U(V) are present after U(VI) interaction with the Fe(II) containing soil. The EXAFS data show the presence of a non-uraninite U(IV) phase and evidence of the oxidized U(V) or U(VI) fraction being present as a non-uranyl species. Little U(VI) reduction is observed by soil that has been exposed to air and oxidation of Fe(II) to goethite has occurred. Soil characterization based on chemical extractions, Mössbauer spectroscopy, and Fe K-edge XAS indicate that the majority of Fe(II) in the soil is structural in nature, existing in clay minerals and possibly a green rust-like phase. These data provide compelling evidence for abiotic reduction of U(VI) by structural Fe(II) from soil near Fe-rich oxic–anoxic boundaries in natural environments. The work highlights the potential for abiotic reduction of U(VI) by Fe(II) in reduced, Fe-rich environments.     

Raman Micro-Spectroscopic Study of Sulfate Ion in the System Na2SO4 – H2O

This work aims to quantify sulfate ion concentrations in the system Na₂SO₄-H₂O using Raman micro-spectroscopy.Raman spectra of sodium sulfate solutions with known concentrations were collected at ambient temperature（293 K） and in the 500 cm^₁-4000 cm^-1 spectral region.The results indicate that the intensity of the SO₄^2- band increases with increasing concentrations of sulfate ion.A linear correlation was found between the concentration of SO₄^2-（c） and parameter I₁,which represents the ratio of the area of the SO₄^2- band to that of the O-H stretching band of water（A_s/A_w）:I₁=-0.00102+0.01538 c.Furthermore,we deconvoluted the O-H stretching band of water(2800 cm^-1-3800 cm^-1) at 3232 and 3430 cm^-1 into two sub-Gaussian bands,and then defined Raman intensity of the two sub-bands as A_Bi(3232 cm^-1) and A_B2(3430 cm^-1),defined the full width of half maximum（FWHM） of the two sub-bands as W_B1(3232 cm^-1) and W_B2(3430 cm^-1).A linear correlation between the concentration of SO₄^2-（c） and parameter I₂,which represents the ratio of Raman intensity of SO₄^2-（A_s）(in 981 cm^-1) to(A_B1+A_B2),was also established:I₂=-0.0111+0.3653 c.However,no correlations were found between concentration of SO₄^2-（c） and FWHM ratios,which includes the ratio of FWHM of SO₄^2-（W_s） to W_B1 W_B2 and W_B1+B2(the sum of W_B1 and W_B2),suggesting that FWHM is not suitable for quantitative studies of sulfate solutions with Raman spectroscopy.A comparison of Raman spectroscopic studies of mixed Na₂SO₄ and NaCI solutions with a constant SO₄^2- concentration and variable CI^- concentrations suggest that the I\ parameter is affected by CI^-,whereas the I₂ parameter was not.Therefore,even if the solution is not purely Na₂SO₄-H₂O,SO₄^2- concentrations can still be calculated from the Raman spectra if the H₂O band is deconvoluted into two sub-bands,making this method potentially applicable to analysis of natural fluid inclusions.     

塔里木盆地巴楚隆起寒武系及奥陶系白云岩类型及形成机理

采用染色薄片鉴定、阴极发光显微镜观察、微量元素分析、碳氧稳定同位素测定及包体侧温等手段，对塔里木盆地巴楚断隆区寒武系和奥陶系白云岩的特征及成因进行了研究，共划分出四种类型的白云岩：①泥粉晶白云岩，其m(Ca)/m(Mg)平均为3-10，Sr含量高（>300×10-6 ），m(Sr)/m(Ba)>>1，?13C值较高（-1‰-+1‰），₁₈O值较低（-5‰--8‰），沉积环境为潮上带云坪，为准同生作用阶段潮上萨布哈白云化作用形成。②含雾心亮边白云石的细晶白云岩，其m(Ca)/m(Mg)较低（1-2），Sr含量中等（100×10-6-200×10-6），m(Sr)/m(Ba) >1，?13C值在-2‰左右，₁₈O值低，在-7‰左右，沉积环境为开阔台地浅滩，为准同生或早期成岩作用阶段回流渗透白云化作用形成。③含明亮白云石晶体及钙质残余的钙质白云岩，其m(Ca)/m(Mg)较低（1左右），Sr含量最低（100×10-6左右），m(Sr)/m(Ba) < 1，?13C值最低（-1‰--3‰），?18O值较低（-6‰左右），沉积环境为灰坪、云坪及开阔台地，为准同生或早期成岩作用阶段混合水白云化作用形成。④砂糖状白云岩，其m(Ca)/m(Mg)较低（1-2），Sr含量低（<100×10-6），m(Sr)/m(Ba)<1，?13C值较高（-1‰-+3‰），₁₈O值较低（-5‰--8‰），沉积环境多为浅滩，为晚期成岩作用阶段埋藏白云化作用形成。     

An iron isotope signature related to electron transfer between aqueous ferrous iron and goethite

We measured the Fe isotope fractionation during the reactions of Fe(II) with goethite in the presence and absence of a strong Fe(III) chelator (desferrioxamine mesylate, DFAM). All experiments were completed in an O₂-free glove box. The concentrations of aqueous Fe(II) ([Fe(II)_aq]) decreased below the initial total dissolved Fe concentrations ([Fe(II)_total], 2.15 mM) due to fast adsorption within 0.2 day. The concentration of adsorbed Fe(II) ([Fe(II)_ads]) was determined as the difference between [Fe(II)_aq] and the concentration of extracted Fe(II) in 0.5 M HCl ([Fe(II)_extr]) (i.e., [Fe(II)_ads] = [Fe(II)_extr] − [Fe(II)_aq]). [Fe(II)_ads] also decreased with time in experiments with and without DFAM, documenting that fast adsorption was accompanied by a second, slower reaction. Interestingly, [Fe(II)_extr] was always smaller than [Fe(II)_total], indicating that some Fe(II) was sequestered into a pool that is not HCl-extractable. The difference was attributed to Fe(II) incorporated into goethite structure (i.e., [Fe(II)_inc] = [Fe(II)_total] −[Fe(II)_extr]). More Fe(II) was incorporated in the presence of DFAM than in its absence at all time steps. Regardless of the presence of DFAM, both aqueous and extracted Fe(II) (δ^56/54Fe(II)_aq and δ^56/54Fe(II)_extr) became isotopically lighter than or similar to goethite (− 0.27‰) at day 7, implying that the isotope exchange occurred between bulk goethite and aqueous Fe. Consistently, the mass balance indicated that the incorporated Fe is isotopically heavier than extracted Fe. These observations suggested that (i) co-adsorption of Fe(II) with DFAM resulted in more pervasive electron transfer, (ii) the electron transfer from heavy Fe(II) in the adsorbed Fe(II) to light Fe(III) in goethite results in the fixation of heavy adsorbed Fe(III) on the surface and accumulation of Fe(II) within the goethite, and (iii) desorption of the reduced, light Fe from goethite does not necessarily occur at the same surface sites where adsorption occurred.     

中国金矿床工业类型

作为勘查和开发直接对象的含金地质体是金矿床工业价值的决定性要素,是金矿床地质特征的本质规定,也是人们最易识别和掌握的直观标志,以此作为金矿床工业类型的分类基础,划分出10类金矿床:（1）石英脉型;（2）糜棱岩型;（3）蚀变碎裂岩型;（4）冰长石-绢云母石英脉型;（5）角砾岩型;（6）矽卡岩型;（7）微细浸染型;（8）红土型;（9）铁帽型;（10）砂砾层型