人造冰和冰芯冰蠕变和方位组构发展对比

本描述了单轴压缩蠕变实验结果。试样包括ｃ轴取向为随机分布和非随机分布的冰、人造冰和取自南极洛多姆冰帽的冰芯冰，各向同性冰芯冰和人造的最小应变率存在差别，未获得合理的解释。方位组构与应力状态相容时，各赂异性冰的最小应变率高于各向同性冰的最小应变率，随着第三应谱阶段的发展，冰芯冰和人造冰的第三应变率趋近相同的恒定值，实验后冰芯冰和人造冰ｃ轴方位组构类型相同，晶粒尺寸也接近。     

乌鲁木齐河源1号冰川含岩屑冰川冰的恒应力蠕变试验

在天山乌鲁木齐河源１号冰川度部取冰样１２个，加工成直径１１３ｍｍ，长２００ｍｍ的试样，在－１±０．３℃和０．４２ＭＰａ（其中一试样为０．８４ＭＰａ）的条件下，作恒应力单轴压缩蠕变试验，试样岩屑含量为０．０１－２．５０％的体积比。试验得出最小应变率出现在变为１％左右，流动参数Ａ与纯冰实验结果相近，未发现岩屑含量对冰的蠕变有明显影响。     

乌鲁木齐河源1号冰川积累区透底冰芯地层及冰结构分析

对乌鲁木齐河源１号冰川积累区一支深达９１．６４ｍ的透底冰芯进行了详细的层位及冰结构分析，结果表明，在２０ｍ深度以内，很好地保存了原始沉积的特征，但在７０￣８０ｍ深处还发现小密度的乳白色冰占优势的冰层，可能形成于小冰期，中层具有动力变质及再结晶作用共存及反复消长的结构特征（冰晶尺寸、气泡），未见单极大型组构，但出现弱竖环形组构，底层出现弱宝石状的多极大组构。     

初始组构各向异性对砂土力学特性及临界状态的影响

采用离散元方法,利用半径扩展法和重力沉积法分别生成具有初始各向同性和各向异性内结构的试样,并开展三轴不排水压缩和拉伸试验,研究不同制样方法产生的初始各向异性对砂土宏微观力学特性及其临界状态的影响。运用组构张量对砂土的各向异性进行量化,分析不同初始组构各向异性对组构张量演化的影响并确定了组构张量的临界值。试验结果表明：初始组构各向异性对试样的剪胀性有重要影响,由于受重力影响形成初始各向异性,其各向异性程度越大、组构方向与加载方向越一致,剪胀性越显著;初始组构各向异性对试样的临界状态没有影响,砂土的组构张量具有唯一的临界状态值。     

人造多晶冰三轴压缩强度特性试验研究

为研究冰的三轴强度特性,对人造宏观各向同性冰进行了不同温度和不同围压下的恒定加载速率三轴压缩试验,得到多晶冰三轴压缩的应力-应变曲线、抗压强度与温度之间的关系,利用莫尔-库仑强度准则分析了温度和围压对强度参数的影响.结果表明：轴向应变加载速率为1.67×10-4 s-1时,不同温度、不同围压下冰的应力-应变曲线均为应变...     

孔隙填充型能源土的宏微观力学特性真三轴试验离散元分析

天然气水合物沉积物因其作为绿色新型能源且具有广阔的开发前景而备受全球瞩目。水合物在水合物沉积物（俗称能源土试样）中有不同的赋存型式,如孔隙填充型和胶结型等。针对孔隙填充型水合物的赋存形态,生成特定饱和度的能源土试样。开展了同一 平面上不同中主应力系数（b = 0、0.25、0.50、0.75、1.00）的真三轴排水试验的三维离散元模拟,将微观参数接触组构及剪切滑移率的演化规律与材料的宏观力学响应相结合,分析了中主应力对孔隙填充型能源土的宏微观力学响应的影响。结果表明：强接触处组构张量的大、中、小主值随b的变化规律与大、中、小主应力及大、中、小主应变随b的变化规律表现出良好的相关性。三向应力状态下的破坏强度接近Lade-Duncan破坏准则。能源土试样剪切滑移率随着中主应力系数的增大而增大;当处于三轴拉伸状态时,试样的剪切滑移率最大。     

初始含冰量对冻结粉质砂土变形与强度的影响

基于一系列同一温度、不同初始含冰量和应变率条件下的高含冰冻结粉质砂土的单轴压缩试验,开展了高含冰量对冻结粉质砂土变形行为和强度特性的初步研究。结果表明：随着试样中初始含冰量的增加,冻结粉质砂土的塑性增强,当初始含冰量超过210.1%后,应力-应变曲线趋近于冰的特性,可用修正的Duncan-Chang双曲线模型较好地描述其单轴压缩应力-应变关系;当应变率为0.083×10-3 s-1和0.467×10-3 s-1时,其初始切线模量呈非线性增大,但当应变率为0.667×10-3 s-1时,初始切线模量增大到一最大值之后转而减小,并且影响程度与应变率大小有关;当初始含冰量从32.9%增加到304.0%,冻结粉质砂土强度也是先非线性增大,然后逐渐趋于稳定,两者可用对数函数关系很好地描述。其研究结果可为开展高含冰冻土区路基的稳定性评价提供基础。     

东天山庙儿沟平顶冰川冰组构和微构造的特征分析

在德国Alfred-Wegener极地与海洋研究所用自动组构分析仪G50测试了东天山庙儿沟冰芯(43°03'19″N,94°19'21″E,4 512 m a.s.l.;2005年钻取,长58.7 m)冰微构造和组构,分析其特征并解释其所蕴含的意义。冰微构造和组构随深度的演变总体相似于其他中国山地冰川冰的观测结果,同时展示了其季节性特征。部分样品的测试结果有所波动,可能是样品在运输和存储过程中的热力学性质发生改变所致。组构型反应的力场较为简单,主要为中下部的单轴压应力作用。正常晶粒生长、多边形化作用和应变导致的边界迁移再结晶不能解释其在某一深段占据主导,而可能是三者共同作用于所有冰芯深部。     

北极生长的多年海冰晶体结构分析

对中国首次北极科学考察钻取的一根从表面到底面长2.2m的海冰冰芯样，依据冰芯样采取时造成的长度，不等间距地自上而下垂直切片，剖析了冰芯样的晶体结构，获得以纯热力学生长为主的多年海冰正交偏光镜下晶体结构剖面，由晶体结构剖面确定出该海冰为三年冰，此外，还发现北极海冰越夏过程中生成一种动力碎屑凝聚冰，除给出偏光镜下晶体结构和冰芯层理分析外，还描述了动力碎屑凝聚冰的结构特点。     

－1℃下多晶冰在振动荷载下的蠕变

应用人造多晶冰开展了正弦振动荷载和恒荷载压缩蠕变实验。振动应力的最大值为０．５０ＭＰａ，最小值为０．３４ＭＰａ，对时间的平均值为０．４２ＭＰａ，实验频率在１０￣（－２）—５Ｈｚ范围内变动。恒荷载实验的初始应力为０．４２ＭＰａ，实验温度一律为－１℃。当应变很小时（低于～０．１４％）样品在一个振动周期内发生的可恢复应变随应变的增加而增加。一个振动周期内可恢复应变的量级为１０￣（－４）。振动荷载下样品最小平均应变率为恒荷载实验结果的１．４倍。为获得最小平均应变率所需的应变与恒荷载实验所得结果相同。     

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