新疆阿尔泰花岗岩源区混合-结晶分异复合过程的微量元素效应

根据微量元素e1、e2、e3总分配系数的相对大小,源区混合-结晶分异复合过程在它们的比值-比值相关图上造成三种综合效应。新疆阿尔泰花岗岩微量元素的比值-比值相关图清晰地反映了三种效应,暗示着源区混合-结晶分异复合过程。源区混合机制可能为沉积物质在沉积盆地里的掺合。混合端员可能为:1)成熟度差异悬殊的陆源碎屑物质;2)陆源碎屑与基性火山物质。     

Crystal structure refinement of hendricksite,A Zn- and Mn-rich trioctahedral potassium mica: A contribution to the crystal chemistry of zinc-bearing minerals

Summary The crystal structure of hendricksite, a trioctahedral mica of biotite type, characterized by high Zn²⁺ and Mn²⁺ contents has been refined by least square methods. The structural formula is: (K_0.89Na_0.10Ba_0.04)(Mg_1.57Zn_0.54Mn _0.40 ²⁺ Fe _0.25 ²⁺ Al_0.07Ti_0.07Cr_0.01)(Si_2.92Al_1.08)O₁₀ (OH)₂. The space group isC2/m and the cell parameters are:a=5.340(2) Å,b=9.524(2) Å,c=10.235(3) Å, =100.07(2)^o, the cell volume isV=497.98 ų. The final unweightedR=0.072. Average cation-anion distances in polyhedra are: T–O=1.659 Å, M(1)–O=2.093 Å, M(2)–O=2.088 Å, A–O_long=3.316 Å and A–O_short=3.004 Å; A is the alkaline cation. The rotation angle of tetrahedra is =6.7°. The analysis of electron densities, of the dimensions and distorsions of polyhedra shows that Zn²⁺ is exclusively in octahedral sites; there is no order between six-fold coordinated cations. A comparison between the structural features of hendricksite and those of the two main end-members of biotites, phlogopite and annite, is presented.The effect of the strong covalence of Zn–O bonds is particularly visible on the dimensions and orientations of the thermal ellipsoids of octahedral sites M(1) and M(2) which contain zinc. In all the published structures of trioctahedral micas, the ellipsoids of cationic sites are uniaxial positive, elongated parallel toc ^*. In hendricksite, this is observed only for the two zinc-free sites (T and A; in the octahedra M(1) and M(2), which contain zinc, the ellipsoids are approximately uniaxial negative, flattened parallel toa, which is a unique situation.Zinc which habitually favours the tetrahedral coordinations with oxygen, enters the octahedra only, i.e. the chemically anisotropic sites, in hendricksite. The strong polarizability of Zn²⁺ is proposed to explain this behaviour.An examination of the behaviour of Zn²⁺ in other compounds shows that this situation is general, zinc favours chemically anisotropic sites and specially those adjacent to OH or H₂O.

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Affinement de la structure cristalline de la hendricksite, mica trioctaédrique potassique riche en Zn et Mn; une contribution à la connaissance cristallochimique des minéraux zincifères

Résumé On a affiné par moindres carrés la structure de la hendricksite, mica trioctaédrique de type biotite, caractérisé par une teneur élevée en Zn²⁺ et Mn²⁺. La formule structurale de ce mica est: (K_0m89Na_0,10Ba_0,04)(Mg_1,57Zn_0,54Mn _0,40 ²⁺ Fe _0,25 ²⁺ Al_0,07Ti_0,07Cr_0,01)(Si_2,92Al_1,08)O₁₀(OH)₂. Le groupe spatial estC2/m et les paramètres de la maille:a=5,340(2) Å,b=9,254(2) Å,c=10,235(3) Å, =100,07(2)°; le volume de la maille estV=497,98 ų. Le résidu final non-pondéré estR=0,072. Les distances cation-anion moyennes dans les polyèdres sont les suivantes: T–O=1,659 Å, M(1)–O=2,093 Å, M(2)–O=2,088 Å, A–O_long=3,316 Å et A–O_court=3,004 Å où A désigne le cation alcalin. L'angle de rotation tétraédrique, =6,7°, est très semblable à celui de la phlogopite. L'analyse des densités électroniques, des dimensions et distorsions des polyèdres montre que Zn²⁺ est exclusivement en coordinance octaédrique et qu'il n'y a pas d'ordre entre les cations hexacoordonnés. On présente une comparaison des caractères structuraux de la hendricksite avec ceux des deux principaux pôles des biotites, la phlogopite et l'annite.L'effet de la forte covalence de la liaison Zn–O est particulièrement visible sur les dimensions et orientations des ellipsoides d'agitation thermique des deux sites octaédriques, sites zincifères. Dans toutes les structures de micas trioctaédriques publiées, les ellipsoides des sites cationiques sont uniaxes positifs, allongés parallèlement àc ^*, ce qui s' observe effectivement dans les deux sites non-zincifères (T et A) de la hendricksite, par contre, dans les octaèdres M(1) et M(2), qui contiennent le zinc, les ellipsoides sont approximativement uniaxes négatifs, applatis parallèlement àa, ce qui est une situation unique.Le zinc, qui se fixe généralement en sites tétraédriques dans les structures de type oxyde, occupe les sites octaédriques, c'est-à-dire les sites chimiquement anisotropes dans la hendricksite. La forte polarisabilité de Zn²⁺ est proposée pour expliquer ce comportement.Un examen du comportement de Zn²⁺ dans d'autres phases montre que cette situation est tout à fait générale, le zinc privilégiant les sites chimiquement anisotropes et en particulier ceux adjacents à OH où H₂O.

     

X-ray diffraction investigation of native Si-Fe alloy minerals from Luobusha, Tibet

The origin of native Si-Fe alloy mineral is thought to be related with mantle and aerolite. The native Si-Fe alloy minerals from podiform chromites of the Luobusha ophiolite in the Yarlong Zangbo suture zone were examined by a new method for powder-like diffractograms of small single crystals, using an SMART APEX-CCD area-detector X-ray diffractometer. The powder diffraction pattern shows that the minerals are composed of FeSi, FeSi₂, β-FeSi₂ and native silicon. The association of these minerals suggests that the crystallization order of the mineral may be from early to late FeSi→FeSi₂→native silicon, accompanied by gradually increasing deoxidization. Translated from Acta Petrologica et Mineralogica, 2005, 24(5): 453–456 [译自: 岩石矿物学杂志]     

塔里木盆地哈得4油田成藏年代学研究

哈得4油田是近年来在满加尔凹陷北部发现的第一个海相油田，一直被认为是喜山期形成的油藏。然而，根据包裹体测温、伊利石K／Ar同位素测年以及油气水界面追溯等多种方法对其成藏年代重新研究表明，该油田主力油藏石碳系CⅢ油藏主杰晚海西期形成的古油藏，C5薄砂层油藏则可能为喜山期由CⅢ油藏垂向调整形成的次生油藏。     

首都圈年累积释放地震能量的拓扑预测

拓补预测实际上是ＧＭ（１，１）模型群的预测。将首都圈年累积释放地震能量的统计结果作为建模的基本数据，建立相应的拓扑预测模型，对２０００年以前首都圈年累积释放地震能量的发展趋势作出初步预测。     

观赏石及其分类

本文首先介绍了观赏石的概念,然后提出了观赏石的命名原则,进而按矿物的化学成分和晶形、岩石的成因、化石种类、陨石的化学和矿物成分、天然造型、用途等方面对观赏石进行了分类。最后阐明了观赏石是重要的自然资源。     

Prediction of Apparent Equivalent Thickness Using the Spontaneous Potential Method and Its Application to Oilfield Development

The upper spontaneous potential produced by oil and gas accumulation is of a stable potential field, and its intensity is directly proportional to the content of the source and inversely proportional to the radius apart from the source. Theoretical research and practical results show that anomalies of spontaneous potential can indicate oil-bearing sandstone bodies and locate the areas of oil and gas accumulation. In oil areas which have fewer reservoir beds, the petroleum reservoir thickness can be predicted by determining the linear relationship between potential intensity and apparent equivalent thickness. In the Weixing （卫星） oilfield, which is devoid of sufficient reservoir beds, its apparent equivalent thickness can be predicted by the linear equation h= -0.19x＋0.74. On the basis of geological research, we use the spontaneous potential method to predict the equivalent thickness, helping in the selection of the most appropriate drill sites to enhance the probability of successful well boring so as to serve the next round development of the oilfield.     

Investigations of the effects of manganese addition to Dry Creek Saltfield brines

Trials conducted at Dry Creek, a solar saltfield north of Adelaide, Australia, indicate that manganese, as manganous sulphate, can increase both the purity and strength of salt crystals grown at an ambient or neutral-slightly acid pH range resulting in a salt suitable for high purity uses. The improved load bearing strength of the crystals indicates that manganous sulphate could also be useful in salt floor maintenance. However, the impact of an apparently slight rise in pH to 8.5 was significant. Crystals produced at the higher pH from the manganese enriched brine were opaque with many tiny, almost colloidal crystals. The salt did not drain well, had low load bearing strength and was notably impure.     

鄂西利川复向斜南部储层矿物包体与油气生盖运聚关系

应用相邻生油层生油条件的好坏和“恢复有机碳全岩热模拟法”计算生烃量与储层包体对比,发现利川复向斜南部石炭系－三叠系储层包体的有机包体富集程度可定性反映生油层的优劣,生油层好者有机包体丰富,反之则差。同样,利用相邻储层有机包体的多寡,结合生油条件的好坏,在一定程度上也可判别相应盖层条件挂否。包体均一温度经压力校正后,可明显看出各储层油气的运移都发生在印支运动后的侏罗纪;油气的初次聚集,各储层并不完全     

层序古地理背景下河南省二_1煤聚集规律研究

对河南省晚石炭世-早二叠世含煤岩系(太原组中部碎屑岩段、上部灰岩段和山西组二1煤层段、大占砂岩段)进行层序分析,共识别出以胡石砂岩底面、二1煤底面、大占砂岩底面和香炭砂岩底面为代表的4个层序界面,将该层段含煤岩系划分为3个三级层序。通过对层序S1和层序S3岩相古地理图和二1煤厚度等值线图耦合分析发现,障壁岛-潟湖沉积环境为二1煤的聚集提供一个较好的前期环境,分流间湾沉积环境为二1煤的保存提供一个较好的后期环境,而分流河道对二1煤的保存起到了破坏性的作用。