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1.
冀西北水泉沟杂岩体及与其有关金矿床的~(40)Ar-~(39)Ar同位素年代学研究 总被引：8，自引：2，他引：6
冀西北金矿集中区是我国华北地台北缘金矿成矿带的重要组成部分,区内金矿主要产于水泉沟碱性杂岩体及邻近的太古宙变质岩内。Ar-Ar同位素年龄测定结果显示,金矿床成矿年龄(172～188 Ma)与水泉沟碱性杂岩体的形成年龄(304～306 Ma)相差达120 Ma。综合研究推断金矿床不是碱性岩浆直接演化产物,而是在燕山期构造—岩浆活动影响下,地下循环热流体对矿源岩——碱性杂岩体淋滤、萃取,形成富含金的成矿热液,最终在有利的成矿构造部位沉淀富集的结果。因此本区的金矿床均属于与碱性杂岩体有关的改造型热液金矿。 相似文献
2.
冀西北金矿集中区是我国华北地台北缘金矿成矿带的重要组成部分,区内金矿主要产于水泉沟碱性杂岩体及邻近的太古宙变质岩内。Ａｒ－Ａｒ同位素年龄测定结果显示,金矿床成矿年龄（１７２～１８８Ｍａ）与水泉沟碱性杂岩体的形成年龄（３０４～３０６Ｍａ）相差达１２０Ｍａ。综合研究推断金矿床不是碱性岩浆直接演化产物,而是在燕山期构造－－岩浆活动影响下,地下循环热流体对矿源岩－－碱性杂岩体淋滤、萃取,形成富含金的成矿热 相似文献
3.
华北北缘张宣地区东坪金矿中的两期锆石：对成矿年龄的约束 总被引：8，自引：1，他引：7
东坪金矿床位于华北克拉通北部边缘的张宣地区,产于水泉沟碱性杂岩体南部的中细粒正长岩中,属于低硫化物钾长石石英脉型碲金矿床。金矿石包括低硫化物碲金石英脉型和钾质蚀变岩型两种类型。文章对产于东坪金矿1号脉的钾长石石英脉中的锆石进行了成因矿物学和LA-ICP-MSU-Pb年代学的系统研究,结果表明,矿脉中的锆石可以分成岩浆锆石和热液锆石两种成因类型。岩浆锆石具有自形到半自形结构、柱状晶型,在电子探针背散射电子图像(BSE)上呈暗灰色;在阴极发光图像(CL)上具有明显的岩浆振荡环带。热液锆石多呈不规则状充填在岩浆锆石中,也有呈他形晶独立存在的;在BSE图像上呈亮灰白色,而在CL图像上为深黑色(无阴极发光)。岩浆锆石的Th、U含量和Th/U比值相对较低,其U-Pb加权平均年龄为(380.5±2.6)Ma,说明水泉沟碱性杂岩体形成于晚泥盆世。热液锆石的Th、U含量和Th/U比值较岩浆锆石明显增高,U-Pb加权平均年龄为(140.2±1.3)Ma,说明东坪金矿床形成于早白垩世。因此,成岩与成矿年龄相差近240Ma,表明东坪金矿床的形成与水泉沟碱性杂岩体的岩浆侵位事件无直接关系。通过对区域地质背景的综合分析,作者认为成矿流体... 相似文献
4.
华北克拉通北缘富碱侵入岩带是我国重要的金矿成矿带,金矿成矿与克拉通边缘深大断裂的活动、富碱侵入岩岩浆活动关系密切。河北张-宣地区与正长岩有关的金矿床产于水泉沟正长岩杂岩体的内外接触带,与水泉沟碱性杂岩体有成因联系。近年来对其及与之有关的金(碲)矿化进行了深入研究,现就岩体成因、岩体形成年龄及金矿化年龄代等问题作一简要探讨。 相似文献
5.
6.
东坪碲金矿床是与碱性侵入岩有关的国内规模最大的碲金矿床。虽然前人已对该矿床做过大量研究,但其成矿年龄仍存在较大争议。文章通过对矿床中辉钼矿Re-Os和锆石U-Pb年龄进行研究,对成矿年龄和矿床成因进行限定。矿床中的辉钼矿存在浸染状和细脉状两种产状。浸染状辉钼矿通常产于正长岩,与硫化物共生,Re-Os模式年龄为(401.1±2.1)和(402.8±2.1) Ma。细脉状辉钼矿主要产在石英-硫化物脉中,其内部及裂隙中产出大量自然金,Re-Os模式年龄为(380.3±2.0)和(376.9±2.9) Ma。含金石英脉中的岩浆锆石U-Pb年龄为(394±1.7) Ma,热液锆石U-Pb年龄为(382±4.7) Ma。辉钼矿与锆石年龄一致,且与水泉沟碱性杂岩体侵位年龄相吻合,因此认为东坪碲金矿床存在泥盆纪成矿,可能与水泉沟岩体岩浆活动有关。矿床经历了晚侏罗世—早白垩世岩浆流体的交代、活化、富集过程,最终形成大型碲金矿床。矿床中的碲主要来自上地幔或洋壳物质的部分熔融,水泉沟碱性岩浆出溶的高氧逸度、中偏碱性的流体和脱气作用为碲的迁移和富集提供了重要条件。 相似文献
7.
冀西北水泉沟杂岩体成因的Nd同位素证据 总被引：8，自引：0，他引：8
水泉沟碱性杂岩体是冀西北金矿集中区最重要的赋矿岩体。长期以来，关于水泉沟杂岩体的成因一直争议很大，严重制约了本区金矿床理论研究水平的提高。本文对水泉沟杂岩体及其围岩太古宙变质岩进行了系统的Nd同位素研究。研究结果表明，水泉沟杂岩体不可能是太古宙变质岩混合岩化或重熔的产物，而是由来自地幔的岩浆与下地壳局部熔融的物质不均匀混合形成的。 相似文献
8.
东坪式金矿床产于华北地台北缘金矿成矿带的冀西北金矿集中区,构造上位于华北克拉通北缘深大断裂-尚义-赤城断裂的南侧。金矿床产于泥盆纪早期(386～410Ma)水泉沟正长岩杂岩体内及接触带附近,矿体分布受脆-韧性剪切断裂构造的制约。金矿成矿作用具有多期次的特点,成矿时代为燕山期(156～203Ma)。矿石类型主要为石英脉型、石英网脉 脉旁钾硅化蚀变岩型和钾硅化蚀变岩型,具有典型的碱性岩金矿的金-碲组合,(含)金矿物主要为自然金、碲金矿和碲金银矿。流体包裹体的 H、O 及 He 同位素研究表明,成矿流体为以大气降水主的混合热液流体并可能存在深源流体的参与。矿床的 S、Pb、Sr 和 Si 同位素组成表明,金矿成矿物质主要来源于正长岩杂岩体,部分源于太古宙桑干群变质岩和燕山期花岗岩。因此,东坪式金矿是由燕山期伸展构造环境下热液流体在上涌地幔及岩浆活动的热驱动下对泥盆纪早期形成的正长岩交代改造的产物。 相似文献
9.
冀西北后沟金矿田脆韧性剪切带年代学新证据:来自LA-ICP-MS锆石U-Pb年龄的发现 总被引：2，自引：0，他引：2
通过系统的地质学研究,作者在后沟金矿田发现了近NE向的脆韧性剪切带,并对采自石垛口村北糜棱岩化石英正长岩样品中的锆石进行了成因矿物学研究,结果发现了两组锆石。一组为具有振荡环带的岩浆锆石,其LA-ICP-MS锆石U-Pb加权平均年龄为(383.4±2.8)Ma;另一组为在CL图像上无阴极发光充填在岩浆锆石边缘和粒间的不规则状的热液锆石,其LA-ICP-MS锆石U-Pb加权平均年龄为(154.4±1.3)Ma。通过对研究区具体情况的综合分析,作者认为前者代表水泉沟岩体东段的侵位年龄,后者代表区内脆韧性剪切带的形成年龄。考虑到东坪金矿田140Ma的成矿年龄与后沟金矿田154Ma的脆韧性剪切带的形成年龄相近,作者认为东坪和后沟金矿田可能存在多阶段构造-岩浆活动和热液流体成矿事件,但主要的成矿作用发生在燕山期,并且大多数金矿与燕山期的中酸性小岩体有关。 相似文献
10.
河北张家口水泉沟岩体SHRIMP年代学研究及其意义 总被引：26，自引：4，他引：26
采用先进的 SHRIMP测年技术对河北水泉沟碱性杂岩体进行了年龄测定，获得东坪金矿区水泉沟岩体二长岩锆石 U- Pb年龄为 (390± 6)Ma，后沟金矿区水泉沟岩体正长岩年龄 (386± 6)Ma，比较可信地确定了水泉沟岩体的成岩时代为晚加里东期—早海西期。这表明北部温都尔庙-西拉木伦河加里东俯冲造山运动强烈地影响本区，水泉沟岩体是这次运动的产物。根据前人测得的东坪和后沟金矿床蚀变围岩钾长石的 Ar- Ar和 K- Ar年龄，金矿化的时代是中生代燕山期，与岩体的成岩年龄有 200 Ma的时差，成因上可能与碱性杂岩体关系不大，因此，东坪和后沟等金矿床可能不属于碱性岩型金矿床。 相似文献
11.
The effect of the group IA and VIIA ions, as well as Mg2+, and the molecules H2O, CO2, H3O+ and OH? on the energy of the Si-O bond in a H6Si2O7 cluster has been calculated using semiempirical molecular orbital calculations (CNDO/2). Three types of elementary processes, i.e. substitution, addition, and polymerization reactions have been used to interpret data on the dynamic viscosity, surface tension and surface charge, hydrolytic weakening, diffusivity, conductivity, freezing point depression, and degree of polymerization of silicates in melts, glasses, and aqueous solutions. As a test of our calculational procedure, observed X-ray emission spectra of binary alkali silicate glasses were compared with calculated electronic spectra. The well known bondlength variations between the bridging bond [Si-O(br)] and the non-bridging bond [Si-O(nbr)] in alkali silicates are shown to be due to the propagation of oscillating bond-energy patterns through the silica framework. A kinetic interpretation of some results of our calculations is given in terms of the Bell-Evans-Polanyi reaction principle. 相似文献
12.
Charles A. Geiger Edgar Dachs Gilberto Artioli 《Geochimica et cosmochimica acta》2010,74(18):5202-5215
Armenite, ideal formula BaCa2Al6Si9O30·2H2O, and its dehydrated analog BaCa2Al6Si9O30 and epididymite, ideal formula Na2Be2Si6O15·H2O, and its dehydrated analog Na2Be2Si6O15 were studied by low-temperature relaxation calorimetry between 5 and 300 K to determine the heat capacity, Cp, behavior of their confined H2O. Differential thermal analysis and thermogravimetry measurements, FTIR spectroscopy, electron microprobe analysis and powder Rietveld refinements were undertaken to characterize the phases and the local environment around the H2O molecule.The determined structural formula for armenite is Ba0.88(0.01)Ca1.99(0.02)Na0.04(0.01)Al5.89(0.03)Si9.12(0.02)O30·2H2O and for epididymite Na1.88(0.03)K0.05(0.004)Na0.01(0.004)Be2.02(0.008)Si6.00(0.01)O15·H2O. The infrared (IR) spectra give information on the nature of the H2O molecules in the natural phases via their H2O stretching and bending vibrations, which in the case of epididymite only could be assigned. The powder X-ray diffraction data show that armenite and its dehydrated analog have similar structures, whereas in the case of epididymite there are structural differences between the natural and dehydrated phases. This is also reflected in the lattice IR mode behavior, as observed for the natural phases and the H2O-free phases. The standard entropy at 298 K for armenite is S° = 795.7 ± 6.2 J/mol K and its dehydrated analog is S° = 737.0 ± 6.2 J/mol K. For epididymite S° = 425.7 ± 4.1 J/mol K was obtained and its dehydrated analog has S° = 372.5 ± 5.0 J/mol K. The heat capacity and entropy of dehydration at 298 K are Δ = 3.4 J/mol K and ΔSrxn = 319.1 J/mol K and Δ = −14.3 J/mol K and ΔSrxn = 135.7 J/mol K for armenite and epididymite, respectively. The H2O molecules in both phases appear to be ordered. They are held in place via an ion-dipole interaction between the H2O molecule and a Ca cation in the case of armenite and a Na cation in epididymite and through hydrogen-bonding between the H2O molecule and oxygen atoms of the respective silicate frameworks. Of the three different H2O phases ice, liquid water and steam, the Cp behavior of confined H2O in both armenite and epididymite is most similar to that of ice, but there are differences between the two silicates and from the Cp behavior of ice. Hydrogen-bonding behavior and its relation to the entropy of confined H2O at 298 K is analyzed for various microporous silicates.The entropy of confined H2O at 298 K in various silicates increases approximately linearly with increasing average wavenumber of the OH-stretching vibrations. The interpretation is that decreased hydrogen-bonding strength between a H2O molecule and the silicate framework, as well as weak ion-dipole interactions, results in increased entropy of H2O. This results in increased amplitudes of external H2O vibrations, especially translations of the molecule, and they contribute strongly to the entropy of confined H2O at T < 298 K. 相似文献
13.
I. V. Pekov N. V. Chukanov I. M. Kulikova D. I. Belakovsky 《Geology of Ore Deposits》2007,49(7):530-536
Phosphoinnelite, an analogue of innelite with P > S, has been found in a peralkaline pegmatite vein crosscutting calcite carbonatite
at the phlogopite deposit, Kovdor pluton, Kola Peninsula. Cancrinite (partly replaced with thomsonite-Ca), orthoclase, aegirine-augite,
pectolite, magnesioarfvedsonite, golyshevite, and fluorapatite are associated minerals. Phosphoinnelite occurs as lath-shaped
crystals up to 0.2 × 1 × 6 mm in size, which are combined typically in bunch-, sheaf-, and rosettelike segregations. The color
is yellow-brown, with vitreous luster on crystal faces and greasy luster on broken surfaces. The mineral is transparent. The
streak is pale yellowish. Phosphoinnelite is brittle, with perfect cleavage parallel to the {010} and good cleavage parallel
to the {100}; the fracture is stepped. The Mohs hardness is 4.5 to 5. Density is 3.82 g/cm3 (meas.) and 3.92 g/cm3 (calc.). Phosphoinnelite is biaxial (+), α = 1.730, β = 1.745, and γ = 1.764, 2V (meas.) is close to 90°. Optical orientation
is Z^c ∼ 5°. Chemical composition determined by electron microprobe is as follows (wt %): 6.06 Na2O, 0.04 K2O, 0.15 CaO, 0.99 SrO, 41.60 BaO, 0.64 MgO, 1.07 MnO, 1.55 Fe2O3, 0.27 Al2O3, 17.83 SiO2, 16.88 TiO2, 0.74 Nb2O5, 5.93 P2O5, 5.29 SO3, 0.14 F, −O=F2 = −0.06, total is 99.12. The empirical formula calculated on the basis of (Si,Al)4O14 is (Ba3.59Sr0.13K0.01)Σ3.73(Na2.59Mg0.21Ca0.04)Σ3.04(Ti2.80Fe
0.26
3+
Nb0.07)Σ3.13[(Si3.93Al0.07)Σ4O14(P1.11S0.87)Σ1.98O7.96](O2.975F0.10)Σ3.075. The simplified formula is Ba4Na3Ti3Si4O14(PO4,SO4)2(O,F)3. The mineral is triclinic, space group P
or P1. The unit cell dimensions are a = 5.38, b = 7.10, c = 14.76 ?; α = 99.00°, β = 94.94°, γ = 90.14°; and V = 555 ?3, Z = 1. The strongest lines of the X-ray powder pattern [d, ? in (I)(hkl)] are: 14.5(100)(001), 3.455(40)(103), 3.382(35)(0
2), 2.921(35)(005), 2.810(40)(1
4), 2.683(90)(200,
01), 2.133(80)(
2), 2.059(40)(204, 1
3, 221), 1.772(30)(0
1, 1
7, 2
2, 2
3). The infrared spectrum is demonstrated. An admixture of P substituting S has been detected in the innelite samples from
the Inagli pluton (South Yakutia, Russia). An innelite-phosphoinnelite series with a variable S/P ratio has been discovered.
The type material of phosphoinnelite has been deposited at the Fersman Mineralogical Museum, Russian Academy of Sciences,
Moscow.
Original Russian Text ? I.V. Pekov, N.V. Chukanov, I.M. Kulikova, D.I. Belakovsky, 2006, published in Zapiski Rossiiskogo
Mineralogicheskogo Obshchestva, 2006, No. 3, pp. 52–60.
Considered and recommended by the Commission on New Minerals and Mineral Names, Russian Mineralogical Society, May 9, 2005.
Approved by the Commission on New Minerals and Mineral Names, International Mineralogical Association, July 4, 2005 (proposal
2005-022). 相似文献
14.
The short range distribution of interatomic distances in three feldspar glasses has been determined by X-ray radial distribution analysis. The resulting radial distribution functions (RDF's) are interpreted by comparison with RDF's calculated for various quasi-crystalline models of the glass structure.The experimental RDF's of the alkali feldspar glasses were found to be inconsistent with the four-membered rings of tetrahedra associated with crystalline feldspars; the structures of these glasses are probably based on interconnected six-membered rings of the type found in tridymite, nepheline, or kalsilite. In contrast, the RDF of calcic feldspar glass is consistent with a four-membered ring structure of the type found in crystalline anorthite. T-O bond lengths (T = Si,Al) increase from 1.60 Å in SiO2 glass [J. H. Konnert and J. Karle (1973) Acta Cryst.A29, 702–710] to 1.63 Å in the alkali feldspar glasses to 1.66 Å in the calcic feldspar glass due to the substitution of Al for Si in the tetrahedra] sites. The T-O-T bond angles inferred from the RDF peak positions are 151° in SiO2 glass (see reference above), 146° in the alkali feldspar glasses, and 143° in the calcic feldspar glass. Detail in the RDF at distances greater than 5 Å suggests that the alkali feldspar glasses have a higher degree of long range order than the calcic feldspar glasses.Assuming that the structural details of our feldspar glasses are similar to those of the melts, the observed structural differences between the alkali feldspar and calcic feldspar glasses helps explain the differences in crystallization kinetics of anhydrous feldspar composition melts. Structural interpretations of some thermodynamic and rheologic phenomena associated with feldspar melts are also presented based on these results. 相似文献
15.
As part of a study of the effect of geologically common network modifiers on polymerization in silicate melts, glasses, and silica-rich aqueous solutions, we have studied the energies, electronic structures, and inferred chemical properties of IVT-O-IVT linkages in the tetrahedral dimers H6,Si2O7, H6AlSiO71?, and H6Al2O72? using semi-empirical molecular orbital theory (CNDO/2). Our results indicate that the electron donating character of the bridging oxygen, O(br), linking two tetrahedra increases with increasing T-O(br) bond length but decreases with decreasing T-O(br)-T angles and increasing O-T-O(br) angles. This increase or decrease of the donor character of O(br) coincides with an increase or decrease of the affinity of O(br) for hard acceptors. The calculated electronic structure for the H6Si2O7 molecule is compared with the observed X-ray emission, absorption, and photoelectron spectra of quartz and vitreous silica; the reasonable match between calculated and observed oxygen Kα emission spectra of vitreous silica supports our assertion that non-bonded O(br) electron density energetically at the top of the valence band controls the chemical reactivity of IVT-O-IVT linkages in polymerized tetrahedral environments. 相似文献
16.
Enthalpies of solution in 2PbO· B2O3 at 712°C have been measured for glasses in the systems albite anorthite diopside, NaAlO2-SiO2, Ca0.5AlO2-SiO2 and albite-anorthite-quartz. The systems albite-anorthite and diopside-anorthite show substantial negative enthalpies of mixing, albite-diopside shows significant positive heats of mixing. For compositions up to NaAlO2 = 0.42 (which includes the subsystem albite-silica) the system NaAlO2-SiO2 shows essentially zero heats of mixing. A negative ternary excess heat of mixing is found in the plagioclase-rich portion of the albite-anorthite-diopside system. The join Si4O8-CaAl2Si2O8 shows small but significant heats of mixing. In albite-anorthite-quartz. ternary glasses, the ternary excess enthalpy of mixing is positive.Based on available heat capacity data and appropriate consideration of the glass transition, the enthalpy of the crystal-glass transition (vitrification) is a serious underestimate of the enthalpy of the crystal-liquid transition (fusion) especially when the melting point, Tf, is many hundreds of degrees higher than the glass transition temperature, Tg. On the other hand, the same heat capacity data suggest that the enthalpies of mixing in albite-anorthite-diopside liquids are calculated to be quite similar to those in the glasses. The enthalpies of mixing observed in general support the structural models proposed by Taylor and Brown (1979a, b) and others for the structure of aluminosilicate glasses. 相似文献
17.
Dualite has been found at Mount Alluaiv, the Lovozero Pluton, the Kola Peninsula in peralkaline pegmatoid as sporadic, irregularly
shaped grains up to 0.3–0.5 mm across. K-Na feldspar, nepheline, sodalite, cancrinite, aegirine, alkaline amphibole, eudialyte,
lovozerite, lomonosovite, vuonnemite, lamprophyllite, sphalerite, and villiaumite are associated minerals. Dualite is yellow,
transparent or translucent, with conchoidal fracture. The new mineral is brittle, with vitreous luster and white streaks.
The Mohs hardness is 5. The measured density is 2.84(3) g/cm3 (volumetric method); the calculated density is 2.814 g/cm3. Dualite dissolves and gelates in acid at room temperature. It is nonfluorescent. The new mineral is optically uniaxial and
positive; ω = 1.610(1), ɛ = 1.613(1). Dualite is trigonal, space group R3m. The unit cell dimensions are a = 14.153(9), c = 60.72(5) ?, V = 10533(22) ?, Z = 3. The strongest reflections in the X-ray powder pattern [d, ? (I,%)(hkl)] are as follows: 7.11(40)(110), 4.31(50)(0.2.10), 2.964(100)(1.3.10), 2.839(90)(048), 2.159(60)(2.4.10, 0.4.20), 1.770(60)(2.4.22,
4.0.28, 440), 1362(50)(5.5.12, 3.0.42). The chemical composition (electron microprobe, H2O calculated from X-ray diffraction data) is as follows, wt %: 17.74 Na2O, 0.08 K2O, 8.03 CaO, 1.37 SrO, 0.29 BaO, 2.58 MnO, 1.04 FeO, 0.79 La2O3, 1.84 C2O3, 0.88 Nd2O3, 0.20 Al2O3, 51.26 SiO2, 4.40 TiO2, 5.39 ZrO2, 1.94 Nb2O5, 0.58 Cl, 1.39 H2O,-O = 0.13 Cl2; they total is 99.67. The empirical formula calculated on the basis of 106 cations as determined by crystal structure is
(Na29.79Ba0.1K0.10)Σ30(Ca8.55Na1.39REE1.27Sr0.79)Σ12 · (Na3.01Mn1.35Fe0.872+Ti0.77)Σ6(Zr2.61Nb0.39)Σ3 (Ti2.52Nb0.48)Σ3(Mn0.82Si0.18)Σ1(Si50.77Al0.23)Σ51 O144[(OH)6.54(H2O)1.34·Cl0.98]Σ8.86). The simplified formula is Na30(Ca,Na,Ce,Sr)12(Na,Mn,Fe,Ti)6Zr3Ti3 MnSi51O144 (OH,H2O,Cl)9). The name dualite is derived from Latin dualis (dual) alluding to the dual taxonomic membership of this mineral, which is at the same time zirconosilicate and titanosilicate.
The crystal structure is characterized by two module types (alluivite-like and eudialyte-like) alternating along a threefold
axis with a doubled c period relative to eudialyte and close chemical affinity to rastsvetaevite (Khomyakov et al., 2006a) and labyrynthite (Khomyakov
et al., 2006b). According to the authors’ crystal chemical taxonomy of the eudialyte group, the new mineral belongs to one
of three subgroups characterized by a 24-layered structural framework. Dualite is a mineral formed during the final stages
of peralkaline pegmatite formation. The type material of dualite is deposited at the Fersman Mineralogical Museum, Russian
Academy of Sciences, Moscow.
Original Russian Text ? A.P. Khomyakov, G.N. Nechelyustov, R.K. Rastsvetaeva, 2007, published in Zapiski Rossiiskogo Mineralogicheskogo
Obshchestva, 2007, Pt CXXXVI, No. 4, pp. 68–73.
Approved by the Commission on New Minerals and Mineral Names, International Mineralogical Association, July 8, 2005. 相似文献
18.
高锰酸盐指数(CODMn)、硝酸根(NO-3)、铵根(NH+4)是判断水体是否受到三氮污染的重要指标。对于测定这三个指标的水样保存方式和时间,地质行业标准和国内外主要国家标准间存在明显差异。地质行业标准规定地下水样品原水室温保存,CODMn和NH+4在3天内测定;NO-3在20天内测定;国家标准和美国标准推荐样品硫酸酸化,避光或冷藏保存,在2~7天内完成CODMn和NO-3和1~7天内完成NH+4测试。为了分析各类标准在样品保存要求上的差异对检测结果的影响,确保检测数据能真实地反映水体污染状况,找寻简便的保存方式,本文在广州地区采集地下水,按照地质行业标准与国家标准进行处理和保存,并在不同时间段对三个指标进行测试。分析验证结果表明:地质行业标准与国家和美国标准关于水样的保存方法均非常可靠。地质行业标准主要针对静态地下水,保存方法相对宽松;国家标准和美国标准适用范围除了地下水,还包括动态的地表水和废水,采样对象成分更为复杂,更不稳定,更容易受外界影响发生变化,故保存条件高于地质标准。在广州地区,采用原水室温避光保存水样,CODMn、NH+4保存时间可为5天,NO-3保存时间可为30天;采用酸化水室温保存水样,CODMn、NO-3和NH+4保存时间可长达30天。这两种方式均比地质行业标准和国家标准推荐的有效时间长,且原水和酸化水室温保存方式相对于冷藏保存方式更为方便。本文提出,如果采集的水样能方便、快速送达实验室,可采用原水保存;如果不能在短时间内送达实验室检测,可采用硫酸酸化保存。 相似文献
19.
Anders Lindh 《Lithos》1972,5(4):325-343
Phase relations in the system FeO---Fe2O3---TiO2, at temperatures ranging between 300°C and 700°C, have been investigated experimentally with special refference to the reaction Fe3O4 + TiO2 = Fe2O3 + FeTiO3. Pressure was varied between 500 and 2000 bars but its effect was negligible. Magnetite and rutile are the stable assemblage at temperatures above 550 dgC, and hematite and ilmenite are stable for lower temperatures. The equilibrium oxygen fugacity is estimated to be 10−17.5 bars at equilibrium temperature. It is suggested that intermediate hematite-ilmenite solid solutions are inhomogeneous, consisting of ‘domains’ of hematite and ilmenite. The ‘domains’ are too small to be resolved by X-ray diffraction techniques. The top of the solvus curve in the hematite-ilmenite solution corresponds to a temperature of 660°C. Regular solution theory is not applicable to the solid solution. 相似文献
20.
Six natural chloritoid crystals with Fe2+ and Fe3+ contents ranging from 4.15 to 12.81 and from 0.411 to 0.849g-atoms/l, respectively, as determined by means of microprobe and Mössbauer techniques, served as reference material to develop non-destructive microscope-spectrophotometric methods for quantitative Fe2+ – Fe3+ determinations in chloritoids from unpolarized spectra of (001) platelets. Fe2+ concentrations in g-atom/l can be obtained from [ [Fe3+]=C1xD1/t where D1 = log10(I0/I at 28,000 cm-1 and t=crystal thickness in cm; C1 is a conttant that may be influenced somewhat by experimental conditions and is found to be 0.002289 with the experimental set-up used in this study. Fe2+ concentrations in g-atom/l can be obtained from [Fe2+]=C1xD1/D1-C3 with D2=log10(I0/I) at 16,300 cm?1 and constants C4 = 45.36 and C5 = 3.540. Due to the uncertainties in absorbance measurements, D1 and D2 and the thickness measurements, the accuracies are ±0.05 and ±0.15 g-atom/l for [Fe3+] and [Fe2+], respectively. The determinations may be carried out on chloritoid grains in normal thin sections with an areal resolution of ～10 μm. 相似文献