低熟煤中的孢粉与常量元素和微量元素的相关性初探

运用电离耦合等离子体原子发射光谱(ICP-AES)和X射线荧光光谱分析(XRF),对新疆八道湾煤矿中侏罗统西山窑组煤中的孢粉角质层进行了分析,测定了煤中的常量和微量元素。并对煤中孢粉和共伴生元素进行了回归分析,探讨了微量和常量元素的煤岩学及孢粉学属性,在微量元素与孢粉的煤相学应用方面作了初步尝试。结果表明,成煤的蕨类植物孢子和裸子植物花粉与某些常量元素和微量元素有着很高的相关性;蕨类植物孢子和裸子植物花粉的相对含量在煤中具有互补性,决定了它们与微量元素的关系也具有一定的互补性。     

Minor and trace elements in some meteoritic minerals

The mineral phases including olivine, orthopyroxene, clinopyroxene, troilite, nickel-iron, plagioclase, chromite and the phosphates were separated from several meteorites. These were a hypersthene chondrite (Modoc), a bronzite chondrite (Guareña), an enstatite chondrite (Khairpur), and two eucrites (Haraiya and Moore County); diopside was separated from the Nakhla achondrite. The purified minerals were analyzed for trace and minor elements by spark source mass spectrometry and instrumental neutron activation analysis. On the meteorites examined our results show that Co, Ni, Cu, Ge, As, Ru, Rh, Pd, Sn, Sb, W, Re, Os, Ir, Pt and Au are entirely or almost entirely siderophile; Na, Rb, Sr, Y, Ba and the rare earth elements lithophile; Se chalcophile. The transition elements So, Ti, V, Cr and Mn are lithophile in most stony meteorites, but show chalcophile affinities in the enstatite chondrites (and enstatite achondrites), as do Zn, Zr and Nb. In the ordinary chondrites Ga shows both lithophile and siderophile affinities, but becomes entirely siderophile in the enstatite chondrites. Molybdenum and tellurium show strong siderophile and weaker chalcophile affinity. The lithophile elements are distributed among the minerals according to the crystallochemical factors, the most effective controlling factor being ionic size.     

Systematic use of trace elements in igneous processes

Trace element concentration data can be used in a systematic way for the study of igneous processes by means of constructing models of such processes which satisfactorily account for the observations. We propose to treat the problem as an inverse problem. The concept of trace element paths (TEP) is introduced as a representation of the solution to the direct problem. The inverse problem consists of estimating, by a resolution of the equations, the various parameters of a model so as to provide a best fit to observed TEP. A detailed account of the theory is given in the case of equilibrium fractional crystallization. The estimated parameters are then those figuring in the Rayleigh distillation law, namely, 1) the initial concentrations of trace elements in the parental magma, 2) the bulk partition coefficients of the elements, and 3) the degree of crystallization corresponding to each sample of the magmatic suite analyzed.A slightly generalized maximum likelihood method is used to solve the linearized equation by a stable, iterative algorithm. Information theory is then shown to yield an account of the distribution and flow of information during the process of solving the inverse problem. The concept of Data Importances is generalized, and its use in optimizing the study justified. The technique is successfully applied to a synthetic data set, and then illustrated on a data set from Terceira (Azores). The results are used to refine the conclusions reached in part I, and permit a more detailed discussion of the model.Now at Dept. Geological and Planetary Sciences, California Institute of Technology, Pasadena, Calif., USA     

Systematic use of trace elements in igneous processes

This paper develops an application of the inverse method proposed by Allégre et al. (1977) and Minster et al. (1977). Using a set of trace element data in a suite of primary lavas, it is possible to statistically test whether the data can be described by batch partial melting. Once this is achieved, one can inverse the problem and calculate the parameters which govern the process, that is: the degrees of melting corresponding to each lava, the initial source concentrations and partition coefficients for each element. This is a non-linear, strongly underdetermined problem, but when the set of trace elements is restricted to REE, taking advantage of the fact that their properties are smoothly related, the problem can be overconstrained by assuming a set of poorly constrained model parameters. Information contained in the data and in the external constraints can then be estimated and used to build a strategy of data acquisition. From a table of mineral-liquid partition coefficients, the mineralogies of the source and of the material entering the liquid can be calculated. The method has been tested on synthetic data sets representing natural cases, and proved to converge towards the real solution even when a very poor definition of the external constraints is introduced.The calculations have been applied to REE data on Grenada basanitoids (Shimizu and Arculus, 1976). It is confirmed that these lavas can be derived by 4 to 17% batch partial melting of a garnet lherzolite source (7% gt, 23% cpx) that is relatively enriched in light REE. This result is discussed in relation with Nd and Sr isotopic composition data.     

Relationship between monogenetic magmatism and stratovolcanoes in western Mexico: The role of low-pressure magmatic processes

A large Quaternary monogenetic volcanic field is present in the western part of the Trans-Mexican Volcanic Belt. It is composed by mafic-intermediate scoria cones and silicic domes that are arranged in two NNW–SSE alignments. These mark the north and south borders (Northern Volcanic Chain and Southern Volcanic Chain, SVC) of the San Pedro–Ceboruco graben. The products of this monogenetic volcanic field span a large range of compositions (from basalt to rhyolite) and magma affinities (from sub-alkaline to Na-alkaline), defining different magmatic groups. Mafic and silicic monogenetic centres from the north alignment also coexist with two stratovolcanoes (Ceboruco and Tepetiltic) and sometimes punctuate their flanks.Whole-rock analyses indicate the existence of 4 different types of primitive magmas (Na-alkaline, High-Ti, Low-Ti/SVC and sub-alkaline) which have evolved independently by low-P magmatic processes. Despite the relatively small size and simplicity of the monogenetic magmatism, open-system processes have modified the geochemical and isotope composition of erupted products. The negative correlation between Sr isotope ratios and MgO contents observed for Southern Volcanic Chain and High-Ti groups points to crustal interaction via AFC processes, involving upper granitic crust and mafic lower crust respectively. In contrast, the large variability in Nd-isotopic ratios, combined with low and less variable ⁸⁷Sr/⁸⁶Sr, shown by the most mafic compositions of the High-Ti group is mostly due to mantle source heterogeneities. Low-Ti and Na-alkaline compositions are only slightly modified by crustal contamination processes and their whole-rock geochemistry reflects the complex nature of the western Mexico sub-arc mantle. It is therefore apparent that a combination of mantle source processes plus crustal assimilation has generated complex geochemical and isotopic characteristics in the western part of the Trans-Mexican Volcanic belt.Despite the presence of monogenetic cones on the flanks of stratovolcanoes, limited magma interaction between monogenetic and polygenetic magmatism has been recognised only at Ceboruco, possibly producing the chemical variability of post-caldera lavas. Indeed, mafic magma feeding High-Ti monogenetic systems might represent the possible mafic end-member which triggered the Ceboruco caldera-forming event. This may have important implications for other explosive systems in which monogenetic magmatism is associated with stratovolcanoes.A geographic/tectonic control is also suggested by the geochemical data. Na-alkaline compositions are only found in the northern part of the Northern Volcanic Chain. Parental magmas of both the High-Ti and Low-Ti monogenetic series, erupted between the Ceboruco and Tepetiltic stratovolcanoes, were modified by lower crust AFC processes possibly favoured by the stress regime. Indeed, the presence of a local left-hand step over along the northern main fault systems between the two stratovolcanoes might inhibit free uprising of monogenetic mafic magmas. The preferential alignment of stratovolcanoes and monogenetic volcanic vents parallel to the northern main fault systems and the possible mixing between High-Ti mafic monogenetic magmas and more evolved Ceboruco magmas suggests that, under the predominance of regional stress, the influence of central volcanic vents on monogenetic magmatism might be more complex than simple control of vent directions and might favours magma mixing processes.     

锆石微量元素及其揭示的深部过程

近十年来对锆石研究已从早期的U-Pb放射性同位素定年和锆石同位素分析,发展到大量研究锆石的微量元素。锆石微量元素不仅可以作为锆石Ti温度计估算岩浆温度,也可以用来识别锆石及其母岩的岩石类型和成因,区分岩浆熔体或者流体控制的岩浆作用、变质作用、成矿作用等深部作用过程。文中在归纳总结岩浆锆石、变质锆石、热液锆石、碎屑锆石等不同类型锆石的微量元素成分基础上,以青藏高原碰撞后超钾质岩石中产出的锆石为例,系统介绍了超钾质岩石中各类锆石的结构、年龄和微量元素特征,并应用于解释超钾质岩石成因、岩浆源区成分、岩浆演化和上部地壳物质的混染、下地壳加厚和高原隆升之间的关系。     

Concentration and distribution of trace elements in some coals from Northern China

The concentration, distribution and modes of occurrence of trace elements in thirty coals, four floors and two roofs from Northern China were studied. The samples were collected from the major coalfields of Shanxi Province, Shaanxi Province, Inner Mongolian Autonomous Region, and Ningxia Hui Autonomous Region. The concentrations of seventeen potential hazardous trace elements, including Hg, As, Se, Pb, Cd, Br, Ni, Cr, Co, Mo, Mn, Be, Sb, Th, V, U, Zn, and five major elements P, Na, Fe, Al, and Ca in coals were determined.Compared with average concentration of trace elements in Chinese coal, the coals from Northern China contain a higher concentration of Hg, Se, Cd, Mn, and Zn. They may be harmful to the environment in the process of combustion and utilization. Vertical variations of trace elements in three coal seams indicated the distributions of most elements in coal seam are heterogeneous. Based on statistical analyses, trace elements including Mo, Cr, Se, Th, Pb, Sb, V, Be and major elements including Al, P shows an affinity to ash content. In contrast, Br is generally associated with organic matter. Elements As, Ni, Be, Mo, and Fe appear to be associated with pyrite. The concentrations of trace elements weakly correlate either to coal rank or to maceral compositions.     

高铝粉煤灰中部分主微量元素的分布规律研究

本文旨在研究部分主微量元素在高铝粉煤灰中的分布规律,从而为其资源化利用提供科学依据。首先根据高铝粉煤灰的物相组成特点采用新的分离方法将之分离为三个相(或相组合):铁质微珠、莫来石-刚玉相以及玻璃相;然后分别用化学分析和ICP-MS测试主微量元素在高铝粉煤灰、铁质微珠以及莫来石-刚玉相中的含量,并结合相关数据计算出这些元素在玻璃相中的含量。结果表明,除Al、Mn外,其他元素均在玻璃相中有不同程度的富集;除Al外,其他元素则在莫来石-刚玉相中有不同程度的贫化;除Ti以外的铁族元素以及除Ga、Pb以外的金属成矿元素均在铁质微珠中富集,其他元素则在其中贫化。     

Natural concentrations of major and trace elements in some Norwegian bedrock groundwaters

Twenty-eight groundwater samples have been collected from boreholes in bedrock aquifers in Nord Trøndelag (Central Norway), the Hvaler archipelago and other areas around Oslofjord (South-eastern Norway). A clear relationship is demonstrated between many chemical parameters and lithology or geographical location. The parameters electrical conductivity, Cl⁻, SO₄²⁻, F⁻, Na, Al, Fe, Be, Bi, Cd, Cu, La, Mo, Pb, Th, Tl, U, Y, Zn, Zr, B, Rn, and Si have generally higher values in the Iddefjord Granite of Hvaler, while pH, alkalinity, Ca, Mg, Cs, Rb, and Sr are highest in Trøndelag. Several parameters such as F⁻, Na, Fe, U, Rn and possibly Al exceed drinking water norms on Hvaler. Measured values of the analyzed parameters compare well (except F⁻) with the Dutch “A” (background) values, developed for assessment of anthropogenic contamination. The authors warn, however, against uncritical use of “norms” developed in countries with other dominant lithologies than Norway.     

梅田矿区岩浆热变煤中微量元素分布特征

梅田矿区主采煤层－龙谭组１２号煤层主要是受矿区北部骑田岭花岗岩侵入体影响的典型岩浆热液变质无烟煤,煤的变质指标如挥发分和镜质组反射率Ｒ＾０（ｍａｘ）等与岩体有密切关系。本次研究按距离岩体由近而远采集了一系列煤样,运用中子活化（ＩＮＡＡ）和微区分析等测试手段研究了样品中近４０种微量元素的分布特征,结果表明：（１）Ａｓ,ｄ,Ｈｇ,Ｐｂ,Ｓｅ等对人体有毒元素在煤中的质量分数较地壳克拉克值高数倍至数十倍,     

Determination of some trace elements in geochemical standards by X-ray fluorescence

The following trace elements Cr, Cu, Nb, Ni, Pb, Rb, Sr, Y, Zn, and Zr were determined by X-ray fluorescence in some geochemical standards from Japan and France. The internal standard method was applied using a Philips PW 1410 X-ray spectrometer. The results were compared with the published data.     

On Linear Relationships between Trace Elements in Oceanic Basalts

On the basis of the batch melting model^*,the author explains the linear relationships between the elements which are often recognized in oceanic basalts,has established mathematic models,discusses some relevant questions,and finally gives an example to show how to apply the method to research on basalts.     

A study of trace elements in lithotypes of some selected Indian coals

Ashes of the lithotypes from some Indian coals were analyzed by emission spectroscopy for some selected elements. Based on the combined concentration and differential fixation, the elements Pb and Co appear to be supplied by the woody portion of the proto-coal material whereas Ga, Nb, Ni, Cr and In can be attributed to the non-woody portions of the proto-coal. On the other hand, Cu, Mo and part of the available Cr appear to come from both organic and inorganic sources, whereas V, Mn, Sr, La and Ba have been attributed to an extraneous inorganic source. The differential fixation of the trace elements appears to be mainly dependent on the physicochemical environment of the basin.     

Chemical mass transfer in magmatic processes

Lasaga's (1982) Master Equation for crystal growth is solved for multicomponent systems in situations which allow for coupled diffusion of melt species. The structure of the solution is explored in some detail for the case of a constant diffusion coefficient matrix. Incorporating these results, the growth of plagioclase is modeled in undercooled tholeiitic melts by approximating interface growth rates with (1) a reduced growth rate function and with (2) calculated solid-liquid solution properties obtained from the silicate liquid solution model of Ghiorso et al. (1983; appendix of Ghiorso 1985). For this purpose algorithms are provided for estimating the liquidus temperature or the chemical affinity of a multicomponent solid solution precipitating from a complex melt of specified bulk composition. Compositional trends in initial solids produced by successive degrees of undercooling are opposite to those predicted in the binary system NaAlSi₃O₈-CaAl₂Si₂O₈. Calculations suggest that the solid phase and interface melt compositions rapidly approach a steady state for a given degree of undercooling. Consequently, the overall isothermal growth rate of plagioclase forming from tholeiitic melts appears to be entirely diffusion controlled. In magmatic systems the multicomponent growth equations allow for the formation of oscillatory zoned crystals as a consequence of the couplingr between interface reaction kinetics and melt diffusion. The magnitude of this effect is largely dependent upon the asymmetry of the diffusion coefficient matrix. Methods are described to facilitate the calibration of diffusion matrices from experimental data on multicomponent penetration curves.Experimental results (Lesher and Walker 1986) on steady state Soret concentration profiles resulting from thermal diffusion in MORB and andesitic liquids are analyzed using the theory of multicomponent linear irreversible thermodynamics. Under conditions where the entropy production is minimized, a linear relationship is derived between liquid chemical potentials and temperature. This relationship is utilized to evaluate the validity of the solution model of Ghiorso et al. (1983) in melts up to 300° C above their liquidus. The results indicate that configurational entropies are accurately modeled for MORB and andesite bulk compositions. The modeling fails in two four-component systems tested. Equations are derived which allow the calibration of multicomponent regular solution parameters from steady state Soret arrays. An algorithm is demonstrated which permits the calculation of steady state Soret concentration profiles, given an overall bulk melt composition and temperature gradient. This algorithm uses the liquid solution properties of Ghiorso et al. (1983) and constants obtained from the experimental measurements of Lesher and Walker (1986).     

淮北煤中几种具有环境意义的微量元素分布

通过中子活化法,对淮北煤田主采煤层中和相对应的灰中几种具有环境意义的微量元素含量进行了测试,分析了它们在煤中和灰中的含量分布,并与中国和华北煤田煤中的平均值进行了对比,以便为煤和煤灰的综合利用提供基础资料。     

Use of major and selected trace elements to describe mixing processes in a water reservoir

Data on temperature, major constituents and some trace elements, measured in the dissolved and particulate phases, were used to identify the hydrodynamics of a reservoir (the Bicaz reservoir, Romania). Results revealed that the reservoir experiences two thermal stratifications per year (summer and winter). However, the summer stratification is delayed by the high river inflow of June–July. Two layers were identified, a surface and a deep layer, whose location and impact vary with time. The surface layer originates from the river inflow (intrusion layer) and the deep current is produced by the outflow (velocity current). According to season, the river inflow either supplies the deep current or remains recordable up to the dam. Consequently, the structure of the water column, and thus the biogeochemical processes within it, are governed both by thermal stratification and by these layers.