铬铁矿中的次近邻效应

本文使用穆斯堡尔效应对三个铬铁矿进行了研究,测量了铬铁矿L-1在150K和298K温度下的穆斯堡尔谱和铬铁矿L-2和L-3在298K温度下的谱。使用次近邻效应解释了铬铁矿中的多重Fe~(2+)双峰,并使用二项式分布计算了Cr~(3+)、Fe~(3+)和Al占据次近邻位置的几率。在穆斯堡尔面积和二项式分布计算的基础上做出了Fe~(2+)双峰的指派。铬铁矿L-1谱在150K下进一步分裂,表明用来解释铬铁矿谱的模型是正确的。     

莱河矿的超结构和低温穆斯堡尔谱的对比研究

本文进行了莱河矿3C超结构和4.2K穆斯堡尔谱的对比研究。研究表明。莱河矿的非等效位置M2A+M2C,M2B,M1B,M1A和VB能够分别与Kan等(1985)测定的莱河矿穆斯堡尔谱的吸收双峰A,B,C,D和E对应,不仅解决了超结构位置和吸收双峰之间的对应,而且圆满解释了吸收双峰A:B和C:D的强度比为2:1的关系。另外,还利用莱河矿超结构的资料讨论了莱河矿的反铁磁性内部作用。     

岫岩玉的穆斯堡尔谱学研究

岫岩玉是我国的主要玉种之一,属于蛇纹石玉。在X射线衍射、红外光谱、可见光吸收谱,及电子显微镜等项研究确切查明主体矿物为叶蛇纹石的基础上,选两个优质玉样进行~(57)Fe穆斯堡尔谱学研究。岫岩玉的穆斯堡尔谱由两组四级双峰构成,第一组双峰(δ=1.12,△=2.73与2.72mm/s)系由镁氧八面体中的Fe~(2+)形成,另组双峰(δ=0.35与0.36,△=0.63与0.55mm/s)反映的是镁氧八面体中的Fe~(3+),Fe~(3+)/Fe~(2+)分别为0.90与0.78。铁是参与叶蛇纹石晶格的组分;Fe~(3+)与Fe~(2+)均处镁氧八面体中;Fe~(3+)/Fe~(2+)近于与小于1是制约它呈绿色的主要因素。     

福建马坑铁矿中角闪石的谱学特征及成因意义

文章研究了马坑铁矿中角闪石的红外光谱、穆斯堡尔谱及热谱特征,特别是阐述了角闪石的(OH)伸缩振动红外光谱的A、B、C、D振动带随Fe~(2+)和Mg含量变化而产生的规律性变化。探索了谱学参数与Fe_2O_3、Al_2O_3、FeO、MgO、MnO的关系。应用(OH)红外光谱的四个振动带的相对强度和穆斯堡尔谱参数计算了Fe~(2+)和Mg在M_1、M_2、M_3晶位中的分配及占位顺序,进而讨论了角闪石的成因。     

黑云母的穆斯堡尔谱学及其在两类不同成因花岗岩体研究中的应用

在等加速穆斯堡尔谱仪上,用25毫居里Pd衬底的~(57)Co放射源测试了25个岩体中54个黑云母的穆斯堡尔谱。Fe~(2 )为四极分裂(Q.S.)值较大的一组不对称强双峰,而Fe~(3 )则为Q.S.值小的一组不对称弱双峰。用最小二乘法计算拟合成劳伦兹线型谱表明,Fe~(2 )和Fe~(3 )在晶格中分别有两个八面体M_1和M_2晶位,但部分样品中Fe~(3 )则占据了M_1和四面体T晶位。它们均属三八面体型为主的黑云母类型。由于黑云母样品分别产出于不同成因类型(同熔型、改造型,同熔型 改造型)的花岗岩体中,反映在穆斯堡尔参数值上存在着规律性的变化。从同熔型到改造型的黑云母中,Fe~(2 )M_1和M_2位的Q.S.值逐渐减少,但I.S.值在M_1位中略有增加;Fe~(3 )M_1位的Q.S.值和I.S.值则逐渐地减少。在改造型岩体的黑云母中Fe~(3 )仅见于M_2位,而在同熔型岩体的黑云母中Fe~(3 )则占据T晶位。     

天然钛榴石的穆斯堡尔谱及晶体化学分析

本文收集了一组钛榴石样品,作了穆斯堡尔谱和化学分析。采用各对应双峰等值限制拟合。拟合结果,统计误差X~2均较小。文中还分析了钛榴石结构的阳离子占位情况,并对其五对双峰谱指派如下:Fe~(3+)在[Y]位和(Z)位,Fe~(2+)在{X}和[Y]位,而另一对双峰指派为Fe~(2+){X}→Fe~(3+)(Z)的电荷离域。从化学分析和穆斯堡尔谱数据求出二种方法Fe~(2+)/∑Fe的差值,说明钛榴石中有Ti~(3+)的存在,用此简便方法估算了Ti~(3+)的含量,得出了四面体中阳离子的占位择优为Fe~(3+)>(Al~(3+),Ti~(4+))的结论。     

钛钡铬石,钛钾铬石的穆斯堡尔谱研究及晶体化学

本文在结构测定的基础上。应用穆斯堡尔谱技术。确定了钛钡铬石和钛钾铬石中铁离子的价态及结晶学位置。测试结果表明钛钾铬石中Fe的相对含量Fe~(2+)>Fe~(3+),而钛钡铬石中Fe~(2+)相似文献   

钛榴石的晶体化学和穆斯堡尔谱研究

本文测定了六个钛榴石样品(TiO_2含量9.70—15.34％)的穆斯堡尔谱。所测样品的穆谱均星复杂谱形。对拟谱方法作了改进。观察到一组新的组分谱。确定钛榴石穆谱由六套四极双峰组成。它们被分别指派给Fe~(2+)(X)、Fe~(2+)(Y)、Fe~(3+)(Y)、Fe~(3+)(Z)和两种电子离域。根据本样品的单晶结构数据对谱线指派和有关穆斯堡尔参数作了阐述。求出了各样品中阳离子的位置分布。阳离子在四面体(Z)位上的绝对量为Fe~(3+)>Al~(3+)、Ti~(4+)。Fe~(3+)比Ti~(4+)优先占据Z位。本样品中普遍存在三价钛。Ti~(3+)/∑Ti范围为3.83％至9.26％。Fe~(2+)/ΣFe比值范围为7 32％至10.01％。给出钛进入石榴石结构的五种替代方式。并对从这些实验结果可能获取的地质信息作了探讨。     

舒兰粘土矿中铁的赋存形式

舒兰粘土矿系高岭石型粘土矿,其中Fe_2O_3的含量达1.5～2.7％。经穆斯堡尔谱研究,有二对四极双峰,IS分别为0.450～0.462、0.425～0.439mm/s,QS分别为0.938～0.958、0.397～0.476mm/s。表明其中的铁基本都是高自旋的Fe~(3+),主要赋存于蒙脱石—囊脱石晶格的配位八面体中,M_1与M_2中均分布有铁,其原子比约为1:3。     

单斜辉石巨晶氧化实验及其异常穆斯堡尔谱的解释

在1000℃和FMQ缓冲氧逸度条件下,将天然单斜辉石巨晶粉末分别加热1,2,3,5天。实验样品作X-射线粉末衍射和穆斯堡尔谱测量,结果表明发生了亚固相的氧化反应,其中M1晶格位上的Fe~(2+)氧化为Fe~(3+),而M2位上Fe~(2+)保持不变。氧化反应在2天已达到平衡。对比氧化程度不同的样品的穆谱的变化,为正确指派穆谱提供了制约。天然单斜辉石巨晶通常可以拟合4套四极分裂对称双峰,按前     

The terrestrial fauna of the Late Triassic Pant-y-ffynnon Quarry fissures,South Wales,UK and a new species of Clevosaurus (Lepidosauria: Rhynchocephalia)

Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.     

The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts

The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H₂O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H₂O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species.     

Quaternary stresses revealed by calcite twinning inversion: insights from observations in the Savonnières underground quarry (eastern France)

Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ₁ roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003).     

HYDROGEOLOGY

正20141756 Chen Ruige(Mathematical College,China University of Geosciences,Beijing100083,China);Zhou Xun Numerical Simulation of Groundwater Level Fluctuation in a Coastal Confined Aquifer with Sloping Initial Groundwater Level Induced by the Tide(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(7),2013,p.1099-1104,6 illus.,16 refs.) Key words:confined water,groundwater level     

METAMORPHIC PETROLOGY

正20141408 Cai Jia(Institute of Geology,Chinese Academy of Geological Sciences,Beijing100037,China);Liu Fulai Petrogenesis and Metamorphic P-T Conditions of Garnet-Spinel-Biotitebearing Paragneiss in Danangou Area,Daqingshan-Wulashan Metamorphic Complex Belt(Acta Petrologica Sinica,ISSN1000-0569,CN11-1922/P,29(7),     

SERIALS

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GEOPHYSICAL EXPLORATION

正20142386An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China)Application of Satellite Remote Sensing in Regional Hydrogeological Investigation:Taking Cenozoic Strata in Wenquan Sheet(1∶250 000)of Karakoram Range as an Example(Geosci-     

QUATERNARY GEOLOGY & GEOMORPHOLOGY

正20141016An Chengbang(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,Lanzhou University,Lanzhou 730000,China);Zhao Yongtao Lake Records during the Last Glacial Maximum from Xinjiang,NW China and Their Climatic Impli-     

PETROLEUM GEOLOGY

正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.)     

GEOCHEMISTRY

正20142002 Wei Hualing(Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang065000,China);Zhou Guohua Element Content and Mineral Compositions in Different Sizes of Soil in Tongling Area,Anhui Province(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(11),2013,p.1861