Statistical analyses of the zeolites clinoptilolite and heulandite

Cluster analysis showed that at least five compositional subgroups exist within the heulandite family of zeolites. The two extreme members of these five groups are the traditional heulandites and clinoptilolites. At a coarser level of clustering, two subgroups, clinoptilolite and heulandite, are evident. As shown by discriminant analysis, the most important compositional variable distinguishing all these groups is calcium. From principal components analysis, it was found that the c cell dimensions of the heulandite family of zeolites varies directly with aluminum and inversely with silicon. The a cell dimension and the β angle seem to vary inversely with the iron content. The b cell dimension may vary inversely with iron and aluminum and directly with silicon.     

青藏高原中部冻土环境下土壤水分监测

利用2006-2007年冬季青藏高原中部那曲布交(BJ)站测量的土壤水势、未冻水含量以及土壤温度资料, 分析了冻土环境下土壤水势、 未冻水含量和土壤温度三者的关系. 结果表明: 青藏高原中部冻土环境下, 土壤水势随着土壤温度及未冻水含量的变化而变化, 土壤质地是决定土壤水势的一个重要因素;未冻水含量与土壤温度保持着动态平衡, 随着土壤温度的降低, 未冻水含量减小, 土壤水势也随之减小;20 cm处砂质壤土的未冻水含量与土壤温度呈指数函数关系, 土壤水势与未冻水含量可用二次曲线拟合, 土壤水势与土壤温度呈指数函数关系;Clausius-Clapeyron方程对于计算青藏高原中部非饱和冻土水势存在局限性.     

珠江三角洲地区浅层地下水铍的分布及成因探讨

通过对珠江三角洲地区900余组浅层地下水样中铍及铝、pH值等元素的分析,研究了珠江三角洲浅层地下水中铍的分布特征,探讨了铍的主要影响因素及其成因。结果表明,珠江三角洲地区浅层地下水中铍的含量介于0~40.3μg.L-1,普遍低于0.5μg.L-1,平均值0.66μg.L-1。超标点仅零散分布于广州、深圳、东莞、佛山和惠州地区,超标率2.24%。地下水铍污染呈局部点状分布特征。pH值和铝是影响该区地下水中铍分布的最主要因素。偏酸及高铝含量的地下水及土壤环境为铍的迁移提供了有利条件。岩石风化及天然土壤的形成是地下水中铍的来源之一,人类活动造成的污染对地下水铍超标有重要贡献。     

Temperature effects on non-bridging oxygen and aluminum coordination number in calcium aluminosilicate glasses and melts

Configurational changes with temperature are important for the thermodynamic and transport properties of most aluminosilicate melts, but in general are not well understood. Here, we present high-resolution ²⁷Al and ¹⁷O NMR data on several calcium aluminosilicate glasses prepared with varying quench rates and thus with fictive temperatures that span ranges up to about 200 K. In all compositions the content of five-coordinated aluminum increases with fictive temperature, in agreement with recent high temperature NMR data on melts. In a glass of CaAl₂Si₂O₈ (“anorthite”) composition, the content of non-bridging oxygens also increases with temperature; however this effect was not observed in a sample with a much higher CaO/Al₂O₃ ratio. We present a consistent notation for reactions among structural species in these systems that clarify why in some cases, high-coordinated network cations may appear on the same side of the reaction, while in others they occur on the opposite sides: the key difference is in accounting for all coordination changes for oxygens. Mixing of non-bridging oxygens and of high-coordinated aluminum make significant contributions to the overall configurational entropy and heat capacity of the melts, as does the mixing of various bridging oxygens and of tetrahedral network cations. Other, less well known, types of increase in disorder with temperature may be important as well.     

滇西南大麦地锡矿区花岗闪长岩的地球化学特征

对大麦地锡矿区出露的云岭花岗闪长岩体地球化学特征进行了研究,岩石中Si02含量变化范围为60.25％～ 66.44％,平均值64.41％;K20含量为0.37％～ 4.39％,平均值3.07％;全碱(wK2o +wNa2o)为3.44％ ～ 11.47％,平均值5.92％;岩石铝指数(ACNK)平均值为2.62.大麦地锡矿区花岗闪长岩的地球化学特征表明,该岩石属于富硅、铝的高钾钙碱性系列花岗岩,全碱含量较高,Nb、Ta、Sr、P、Zr和Hf亏损,轻、重稀土元素分馏明显,显示一定程度的负铕异常,岩石处于挤压碰撞的构造环境中.从区域构造演化特征分析,这一结论与云岭岩体所处位置比较吻合.     

Horizontal frost heave thrust acting on buttress constructions

Frost heave thrust of soil varies with its water content. When the water content of the soil is less than its plastic limit, the horizontal frost heave thrust of soil does not appear. When the water content of the soil is greater than its plastic limit the frost heave thrust increases with increasing water content and when the water content is a little over its liquid limit, it reaches a maximum value.

Also, the horizontal frost heave thrust of soil varies with temperature. It increases as the negative temperature falls, until it reaches a maximum value at about −7°C.

It should be noted that the distribution of the horizontal frost heave thrust along the lateral surface of the structure is not always uniform: its value is greatest at the middle, less at the bottom, and least at the top. The maximum value generally appears at the place where the depth is about 60–80% of the depth of frost penetration.

According to laboratory data and engineering practice, the values of horizontal frost heave thrust vary greatly, but its maximum value is generally about 4.1–4.2 kg/cm².     

Reversible control of aqueous aluminum and silica during the irreversible evolution of natural waters

Primary aluminosilicates are transformed at low temperature into a sequence of metastable and thermodynamically stable secondary minerals by an irreversible process. The aqueous concentrations in the associated solution may continuously change during the process or they may be maintained constant through hydrodynamic or chemical steady-state mechanisms or through chemical equilibrium with a reversible metastable solid.Disequilibrium indices calculated for 152 natural waters and experimental solutions show that the solutions are unsaturated with amorphous aluminum hydroxide, microcrystalline gibbsite, amorphous silica and amorphous aluminosilicate, and they are supersaturated with gibbsite and kaolinite. The disequilibrium index for halloysite varies widely from unsaturation to supersaturation.Only the index for the reversible metastable cryptocrystalline aluminosilicate whose composition is pH dependent is very close to zero indicating saturation. The index varies in a narrow range. This, supported by electron micrographs and the results of X-ray fluorescence spectroscopy presented by other authors, suggests that this metastable solid, and not the secondary aluminosilicate minerals, controls the concentrations of alumina and silica in natural waters.     

The Phase Relations of Aluminous Iron Biotites in the System KAISi3O8-KAISiO4-AI2O3-Fe-O-H

The experimental work on biotites has primarily involved compositionsalong the annite-phlogopite join, but most natural biotitescontain significantly larger amounts of aluminum. At the sametime, the aluminum content of natural biotites varies considerably.The available evidence indicates that these variations in thealuminum content of biotite depend on the conditions of formationand the whole rock chemistry. Experiments on the phase relations of aluminous iron biotitesin the silica deficient system KAlSiO₄-KAlSi₃O₈-Al₂O₃-Fe-O-H(pfluid = 2 kb) indicate that compositions up to Ann₇₅ can besynthesized on the join annite [K₂Fe₆Al₂Si₆O₂₀(OH)₄]-aluminumbiotite [K₂Al₆Al₂Al₆O₂₀(OH)₄]. The aluminous biotites are stableto higher temperatures than annite. An isobaric divariant equilibrium,Bio_ss-Mt_ss-Sa-Lc-V, extends to higher oxygen fugacities fromthe Ann-Mt-Sa-Lc-V curve of Eugster & Wones (1962). Compositioncontours on this surface indicate that both the magnetite andbiotite become more aluminous with increasing temperature and/oroxygen fugacity. The Bio_ss-Mt_ss-Sa-Lc-V reaction surface isterminated by equilibria involving the additional phases muscovite,corundum, and hercynite respectively as the conditions becomemore reducing. At 2 kb fluid pressure; aluminum-rich iron biotiteis stable to 555 °C on the HM buffer, 763 °C on theMt-Hc-Cor buffer, 820 °C on NNO, and about 860 °C onQFM. The data obtained can be applied to a number of biotitesyenites and appears to explain why iron-rich aluminum biotitesoccur in these rocks.     

Rates of oxygen exchange between the Al2O8Al28(OH)56(H2O)26(aq) (Al30) molecule and aqueous solution

Rates of steady exchange of oxygens between bulk solution and the largest known aluminum polyoxocation: Al₂O₈Al₂₈(OH)₅₆(H₂O)₂₆¹⁸⁺(aq) (Al₃₀) are reported at pH≈4.7 and 32-40°C. The Al₃₀ molecule is a useful model for geochemists because it is ≈2 nm in length, comparable to the smallest colloidal solids, and it has structural complexity greater than the surfaces of most aluminum (hydr)oxide minerals. The Al₃₀ molecule has 15 distinct hydroxyl sites and eight symmetrically distinct bound waters. Among the hydroxyl bridges are two sets of μ₃-OH, which are not present in any of the other aluminum polyoxocations that have yet been studied by NMR methods. Rates of isotopic equilibration of the μ₂-OH and μ₃-OH hydroxyls and bound water molecules fall within the same range as we have determined for other aluminum solutes, although it is impossible to determine rate laws for exchange at the large number of individual oxygen sites. After injection of ¹⁷O-enriched water, growth of the ¹⁷O-NMR peak near 37 ppm, which is assigned to μ₂-OH and μ₃-OH hydroxyl bridges, indicates that these bridges equilibrate within two weeks at temperatures near 35°C. The peak at +22 ppm in the ¹⁷O-NMR spectra, assigned to bound water molecules (η-OH₂), varies in width with temperature in a similar fashion as for other aluminum solutes, suggesting that most of the η-OH₂ sites exchange with bulk solution at rates that fall within the range observed for other aluminum complexes. Signal from one anomalous group of four η-OH₂ sites is not observed, indicating that these sites exchange at least a factor of ten more rapidly than the other η-OH₂ sites on the Al₃₀.     

兰新客运专线浩门区间路基温度、水分及冻胀变形特征

粗细颗粒混合填料的微冻胀严重影响着寒冷地区高速铁路的安全运营.基于对兰新客运专线浩门区间运营期4个路基断面不同深度的温度、水分及冻胀变形现场监测,分析了冻结期该铁路路基在不同深度下的温度、水分及冻胀随季节变化特征.结果表明：越接近地表,对外界环境温度变化的敏感性越高,温度传递随时间的滞后性呈指数递减规律,深度超过3 m时全年无负温.寒季2.7 m厚的路基最大冻胀量约2.1 cm,其中,0～0.5 m处寒季最低温度介于-10.3～-15.6℃,暖季及冻结初期含水量相对较高有15%左右,其冻胀率约4.86 mm·m^-1,故级配碎石在低温含水量高情况下能有效减弱冻胀.冻胀率最大值（14.34 mm·m^-1）发生在0.5～1.5 m之间的普通AB组填料层,寒季最低温度介于-7.2～-12.4℃,暖季及冻结初期含水量介于10%～15%.1.5～2.7 m之间的填料层冻胀率约为1.94 mm·m^-1,寒季最低气温-3.2～0.4℃,暖季及冻结初期含水量介于12.5%～15%.路基填料细颗粒（粒径小于0.25 mm）含量越高,冻胀率越大,建议将细颗粒料控制在15%以内.     

岩溶山区石灰土剖面硅铁铝元素分布特征——以贵州省晴隆县为例

选取贵州省晴隆县岩溶山区石灰土剖面土壤为研究对象,采用土壤学常规测定方法对土壤硅、铁、铝全量及风化度指标进行研究,初步分析了研究区石灰土剖面硅、铁、铝元素含量和分布特征。结果表明:区内土壤质地较黏,应进行土壤改良;土壤中氮、磷流失严重,需加强秸秆还地和增施有机肥;其硅、铁、铝元素含量较高,但主要以矿物态形式存在,受成土要素与环境的制约导致土壤脱硅富铁铝化程度较低,土壤剖面缺乏过渡层,由降雨冲刷易造成水土流失和加剧石漠化,应采取工程和自然保护措施防治植被覆盖减少和生态恶化。      

Study of antigorite Crystal Cell Parameters Changing with Temperature and Pressure by TEM

To determine the P‐T conditions of serpentinite without any specific metamorphic minerals is a difficult work, because the main mineral antigorite could stable at a wide P‐T range of about 400–700°C, 10–50 kbar. Observations from natural rocks and high‐pressure experiments both suggest that the length of a‐axis of antigorite (can calculate as m value) is related to temperature and pressure, which could be used as a thermobarometer. However, some researchers disagree with this point. In this study, transmission electron microscope (TEM) technique is used to measure the crystal structure of antigorite obtained by whole‐rock system high pressure experiments, and then compare with the experimental results in the predecessors’ MgO‐SiO₂‐H₂O (MSH) system, to find out the correlation between m value of antigorite and P‐T conditions in the whole‐rock system. According to this study, several conclusions have been drawn: (1) the m value of antigorite is elevated with increasing pressure; (2) the increase content of aluminum in antigorite migrate the m values to high temperature field; (3) as the temperature rises, the m value of antigorite decreases, and the water content increases.     

丰山斑岩型铜(钼)矿床中铂、钯的富集特征研究

文章以湖北丰山斑岩型铜(钼)矿床为研究对象,利用ICP-MS分析了Pt、Pd含量,发现丰山斑岩型铜(钼)矿床矿石中Pt、Pd发生了富集现象.其中,Pt含量范围在0.037×10-9～1.765×10-9,Pd含量范围在0.165×10-9～17.979×10-9,Pd含量普遍较Pt含量高出1个数量级,表明丰山斑岩型铜(钼)矿床中Pd较Pt易富集.测试结果表明,斑岩体中Pt、Pd含量很低,说明岩体发生了分异,且Pt、Pd来源与中酸性岩体关系密切.研究发现,Au与Pt、Pd表现出明显的镜像关系,成为丰山宽岩型铜(钼)矿床Pt、Pd富集的特征表现.     

细粒土含量对粗粒硫酸盐渍土路基填料盐胀特性的影响试验及分析模型

为了明确细粒土含量对粗粒硫酸盐渍土路基填料盐胀量的影响,针对 1% 和 3%含盐量工况下的砂、砾类盐渍土,采用降温试验研究了细粒土含量递增条件下粗粒硫酸盐渍土的盐胀特点。在此基础上,利用 PFC^3D技术模拟了粗粒盐渍土的盐胀变形并分析其机制,结合微观试验分析了盐胀状态中粗粒土骨架典型状态。结果表明：随着细粒土含量的增加,粗粒硫酸盐渍土的盐（冻）胀量均先增加后减少再增大,分界细粒土含量因含盐量及土类不同而异,1%、3% 含盐量的砂、砾类土样分别在15%和10%细粒土含量时产生最大盐（冻）胀量;3%含盐量砂、砾类土的起始盐胀温度约 20 ℃,1%含盐量土样的起始盐胀温度随细粒土含量及土种类不同差异较大且存在明显的界限细粒土含量,当细粒土含量低于界限值时土体的起始盐胀温度约为0.5～2 ℃,高于界限值时土体的起始盐胀温度约为 4～12 ℃;同时提出了盐胀状态中粗粒土骨架典型状态模型及其作为路基填料的细粒土含量界限值。     

温度和含冰量对冻结土石混合体力学特性的影响

冻结土石混合体是一种力学特性极为复杂的岩土材料,其力学特性对温度和含冰量等因素非常敏感。然而到目前为止,对于其力学行为随温度、含冰量及法向压力等的变化特征仍然缺乏足够的了解。本文开展了一系列的冻结土石混合体的直剪试验,研究了温度、含冰量及法向压力对冻结土石混合体剪切特性的影响。结果显示温度、含冰量及法向压力对冻结土石混合体的剪切行为都有重要影响。在其他条件相同时,冻结土石混合体的抗剪强度随着温度的下降呈指数形式增长。当温度高于-5℃时,抗剪强度增加很快,而当温度低于-5℃时,抗剪强度仅有微小增加。在-5℃时,冻结土石混合体的抗剪强度随着含冰量的增加先增加后减少。抗剪强度最大值出现在含冰量在11%左右。冻结土石混合体的粘聚力随着含冰量的增加先迅速增加,在含冰量大于11%以后,粘聚力又有微小下降,而内摩擦角随着含冰量的增加缓慢减小。冻结土石混合体的抗剪强度随着法向应力的增加而增加,但在高法向应力下,其塑性增强。     

铬天青S光度法及非线性拟合测定高纯硅中微量铝

铬天青S光度法是硅中铝含量的测定方法之一,该方法的标准曲线大多采用不过零点的线性拟合,导致低铝含量测定误差大。为提高方法准确度并降低方法检出限,研究了铝标准曲线低浓度部分的拟合问题,探讨了不同拟合模型对检测结果准确度的影响。实验结果表明,不同浓度铝标准液的吸光度在0~0.3 μg/mL范围内并不满足一次函数线性关系,采用三次函数关系y=-17.45230x³+10.42883x²+1.04047x (y为扣空白的吸光度,x为铝的质量浓度)拟合能获得良好结果,其相关系数R²为0.99975。利用已知铝含量的硅试液检验该公式,其相对标准偏差(RSD)为2.55%。样品中铝的测定值与电感耦合等离子体发射光谱法测定值吻合。该法可以显著提高低浓度的铝测定的准确性,可用于测定高纯硅中含量在0.55 μg/g以上的铝杂质。     

Structural localization of Al<Superscript>3+</Superscript> ions in aluminosilicates: application of heteronuclear chemical shift correlation to 2:1 phyllosilicates

The main objective of this paper is to apply an NMR-based methodology to clay minerals that provides resolution enhancement in ²⁷Al NMR spectra, permitting the differentiation of aluminum ions with one same coordination number, but with different chemical environments. For this purpose, we have performed two-dimensional ¹H²⁷Al cross-polarization experiments, which facilitate the identification of the different aluminum crystallographic sites by means of the nature of the proton polarization source. For the development of this methodology, we have carried out a systematic study of a set of well-characterized 2:1 phyllosilicates with aluminum in different crystallographic sites. The structural locations of aluminum in the selected layered silicates have been established unequivocally. Once the correlation between all different aluminum and proton sites in smectite was well established, an unknown material was examined, the utility of this methodology being illustrated. This methodology can be applied to a great variety of materials, such as zeolites, ALPOs and mesoporous aluminosilicates, in which a precise determination of the aluminum location is demanded.     

深熔过程中熔体成分与锆石行为模拟计算

发生深熔作用是高级变质作用的一个重要特征。深熔过程中产生的熔体可为淡色花岗岩提供潜在的源区;深熔过程中锆石的行为直接影响对变质锆石记年地质意义的理解。在含Zr体系下的相平衡模拟显示泥质成分深熔过程中产生熔体的成分在P-T空间中规律变化。温度升高时熔体Zr/Si值、Zr、FeO、MgO以及CaO等含量明显增加,压力较高时K2O含量也随温度升高而明显增加。Na2O含量随温度升高而降低,但随压力升高而增加。压力升高时Al/Si值显著升高。温度较高时Na/(Na+K)等值线较陡,减压熔融过程不会显著改变熔体Na/(Na+K)值,而升温减压过程以及近等压升温过程都会明显降低熔体Na/(Na+K)值。中压时随温度升高熔体Fe/(Fe+Mg)值缓慢升高,而石榴石的生长发育会迅速降低熔体Fe/(Fe+Mg)值。不同温压条件下对应的固相线熔融、白云母脱水熔融以及黑云母脱水熔融形成的熔体成分具有明显差异。对比模拟熔体成分在P-T空间的演化,喜马拉雅地区电气石淡色花岗岩对应熔体的形成温压条件应低于二云母淡色花岗岩,同类型淡色花岗岩之间在形成条件上也可能存在一定差异,并经历了差异性演化过程。含Zr体系下的相平衡关系显示进变过程是消耗锆石的过程,因而在进变过程中变质锆石难以生长,发生深熔作用的岩石中的变质锆石主要在退变过程中形成并记录退变质年龄。熔体丢失相关模拟显示不同温度阶段发生熔体丢失对锆石稳定性的影响不同。温度较低时Zr含量较少的熔体丢失会扩大持续进变过程中锆石的稳定范围,而温度较高时富Zr熔体的丢失会降低持续进变过程中锆石的稳定温度。类似于分离熔融作用的过程最利于残留相中剩余锆石在持续进变过程中的保存。     

新疆喀什凹陷巴什布拉克铀矿流体包裹体及有机地球化学特征

巴什布拉克铀矿床位于新疆喀什凹陷北西部一套陆相碎屑沉积岩中。野外调查发现,伴随铀矿化发育大量地沥青、油气残留物。本文对采自巴什布拉克铀矿床的地沥青含矿砂岩矿石进行了流体包裹体测试和有机地球化学分析,以确定成矿流体的温度和盐度以及成矿物理化学背景,追索有机质的来源,进而探讨矿床成因。镜下观测发现,含矿砂岩中含有大量的油气包裹体,其中以液烃包裹体为主,含有少量气液烃包裹体和含烃盐水包裹体。流体包裹体测温结果表明,成矿流体均一温度为71~193℃,盐度为0.71~23.05(wt%NaCl),整体上属于低温低盐度的成矿流体。同时求得巴什布拉克铀矿成矿压力为77.90~211.75(105Pa),成矿深度在0.26~0.71 km。有机地球化学分析表明,矿区有机质的氯仿沥青"A"变化不大,为0.0019%~0.0026%,有机质来源以海相藻类为主。样品的OEP(奇偶优势指数)为0.72~0.84,平均为0.78,显示了有机质高成熟的特征;CPI(碳优势指数)为1.16~1.35,平均为1.25,指示热演化程度较高;Pr/Ph(姥鲛烷/植烷)为0.77~1.01,平均为0.89,说明有机质处在还原环境中。结合野外地质特征,认为巴什布拉克铀矿床为油气还原成因,沿断裂和岩石孔隙上升的油气的还原作用是铀成矿的主要因素。     

Magnetic phases in lunar fines: metallic Fe or ferric oxides?

The ferromagnetic resonance (g = 2.08 ± 0.03) observed for the Apollo 11 and 12 lunar fines is characterized by an asymmetric lineshape with a narrower appearance on the high field side. This asymmetry together with an anisotropy energy which varies from + 640 to + 500 G over the temperature range of 80 to 298 K indicates that the ferromagnetic resonance arises from metallic Pe having the body-centered cubic structure and not from hematite, magnetite or other Fe³⁺ ions in magnetite-like phases. The g-value, the lineshape asymmetry, and the temperature dependence of the linewidth for the Apollo 14 and 15 fines as reported by other workers are found to be essentially similar to those observed for the Apollo 11 and 12 fines, except a narrower linewidth is observed in the case of the Apollo 14 fines (600–650 G vs 700–800 G, at X-band and room temperature). This difference in linewidth is found to be correlated with the Ni and/or Co content in these samples. The ESR signal for the so-called ‘unknown ferric oxide’ phase of Griscom and Marquardt is also shown to have frequency and temperature dependences significantly different from those for the lunar fines.