南极利文斯顿岛上三叠统Miers Bluff组及其与相当地层对比

南极南设得兰群岛利文斯顿岛 Miers Bluff组 (MBF)是一套岩层倒转、强烈变形、浅变质的浊流沉积地层 ,主要由砂岩、泥岩、粉砂岩及含砾砂岩组成 ,具有很好的韵律层 ,形成鲍玛序列 ,通常被认为属于近海底扇浊流沉积 ,并当作中新生代火山岩的基底。最近发现的孢粉化石指明其时代属晚三叠世 ,从而解决了久来时代的疑问(石炭—三叠纪 ,二叠—三叠纪 ,或前侏罗纪 )。分布在南极半岛格雷厄姆地的特里尼蒂半岛群、南奥克尼群岛的杂砂岩—页岩组、智利南部乔诺斯群岛乔诺斯变质杂岩的 Potranca组以及新西兰惠灵顿的 Torlesse杂岩应是时代相当、岩性及沉积环境相似的岩层。三叠纪末受太平洋板块俯冲影响 ,这一浊流地层褶皱、变形、隆升 ,具有相同的构造风格 ,是冈瓦纳古陆在侏罗纪早期开始裂解前夕一次构造事件的重要佐证     

Isotopic studies of leaf water. Part 1: A physically based two-dimensional model for pine needles

Understanding of isotopic variations in leaf water is important for reconstruction of paleoclimate and assessment of global biochemical processes. We report here a study of isotopic distributions within a single needle of two pine species, Pinus resinosa Ait and Pinus strobes L., with the objective of understanding how isotopic compositions of leaf water are controlled by environmental and physiological variables. A 2D model was developed to simulate along-leaf isotopic variations and bulk leaf water isotopic compositions. In addition to variables common to all leaf water isotopic models, this 2D model also takes into account the specific geometry and dimensions of pine needles and the isotopic transport in xylem and mesophyll. The model can successfully simulate oxygen isotopic variations along a single needle and averaged over a leaf (bulk leaf water). The simulations suggest that isotopic composition of the bulk leaf water does not always depend only upon the average transpiration rate, which in turn raises questions about using leaf water isotopic values to estimate transpiration rates. An unsuccessful attempt to simulate along-needle hydrogen isotopic variations suggests that certain unknown biological process(es) may not have been incorporated into our 2D model, and if so, it calls for a reevaluation of all other models for hydrogen isotopic simulations of leaf water since they too lack these processes.Existing leaf water isotopic models are reviewed in this work. In particular, we evaluate the most frequently used model, the stomatal boundary layer model (also referred to as the Craig-Gordon model). We point out that discrepancy between the boundary layer model and the measured bulk leaf water seems to depend upon relative humidity. Using our 2D model, we show that this humidity dependency is a result of an interplay between environmental and physiological conditions: if the transpiration rate of plant leaves decreases with increasing relative humidity, our 2D model can reproduce the pattern of isotopic discrepancy between boundary layer model predictions and observations, enabling us to understand better the reason behind this discrepancy.     

Study of portable infrastructure-free cell phone detector for disaster relief

Natural Hazards - In this paper, we investigate the spatial and temporal distributions of rainfall in Qatar, which falls in the arid region of the middle-east. We use rainfall data from 29 rain...     

云南墨江金厂矿床金镍赋存状态及成因关系探讨

墨江金厂金镍矿床位于哀牢山造山带中段,九甲—安定大断裂上盘,是西南三江成矿带内一个独特的金镍矿床。本文在详细野外地质调查基础上,通过显微镜下观察、扫描电镜和能谱分析,结合矿石微量元素分析,对矿石中金、镍赋存状态及成因关系进行了研究。结果显示,金赋存形式主要有可见金和不可见金。可见金又可分为粒间金和包体金;不可见金是以Au~+赋存于硫锑铜银矿、黄铁矿中。镍赋存状态有两种:一是以独立矿物,如辉砷镍矿、锑硫镍矿等存在;二是以离子态赋存于黄铁矿、硫锑铜银矿中。矿石结构构造、矿物共生组合及微量元素含量等显示,金和镍为同期热液成矿,金来自岩浆热液系统远端的低温热液,镍是含金低温热液流经超基性岩体时萃取而来。成矿过程可分为早期富硅质热液和晚期富钙质热液两个阶段,成矿是在幕式构造活动下多期流体运移和沉淀的结果。     

An approach for estimating sustainable yield of karst water in data sparse regions

This study presents an approach for transferring the qualitative analysis of groundwater sustainability for development to quantitative evaluation by an analogy of two similar regions. A concept of groundwater exploitation sustainability (GES), which is an evaluation index based on water supply capability, eco-geo-environment maintaining capability and the harmony between water and society, is put forward. The fuzzy analytic hierarchy process method is applied to calculate the GES for the Xiangshan and Dianchang karst groundwater sources in the Huaibei city, Anhui Province, China. The GES of the Xiangshan karst system was calculated to be 0.53 and represents medium exploitation sustainability, while that for the Dianchang is relatively high with a value of 0.70. These two karst systems are separate units but have similar hydrogeological conditions. The Dianchang area had limited groundwater observation data, while the Xiangshan area had long series of observation data, which enabled the computation of the sustainable yield. The sustainable yield of the Xiangshan karst area was used to calibrate the GES, and develop a linear equation between the GES and sustainable yield, which was used to calculate the sustainable yield of the Diangchang karst area as 40.4 million m³.     

三峡工程库区巴东县赵树岭滑坡稳定性与防治对策研究

赵树岭滑坡是三峡工程库区的重要滑坡，其稳定性直接关系到巴东新县城沿江大道的安全，并对新县城土地利用意义重大。在阐述赵树岭滑坡基本特征的基础上，运用水岩耦合三维有限元数值方法模拟了滑坡稳定性，预测了三峡水库蓄水后滑坡稳定性发展趋势和渗流特征。研究表明，水库蓄水及水位波动是影响滑坡稳定性的主要因素，三峡水库蓄水后，滑坡将发生局部失稳，必须加以治理，提出了滑坡防治的原则与对策。     

Mechanical characteristics of dip basement effects on dump stability in the Shengli open pit mine in Inner Mongolia,China

For waste dump slopes that form basements, landslides can be prevented by determining a stability evolving law of dynamic development. Keeping this issue in mind, the relationship between the mechanical structure and stability of waste dumps with basements is studied. Three key factors that influence waste dump stability are presented, and judgment criteria for self-locking and unlocking states of dump basements are provided. From the friction coefficient of waste dump basement stability analyses of the Shengli open pit mine, the results indicate that waste dump basements on the right side of fault F8 and on the left side of fault F61 are subjected to self-locking. However, between faults F61 and F8, the basement is subjected to unlocking. Regarding the residual thrusting of unlocking areas, structure and stability optimization schemes for waste dumps in the Shengli open pit mine are provided through a mechanics analysis. Reducing the slopes and basement angles of waste dumps can enhance their stability by increasing basement roughness levels.     

拉萨地块林芝杂岩体石榴角闪岩的地球化学特征和年代学研究

本文对位于青藏高原拉萨地体东南缘林芝杂岩中的两类石榴角闪岩进行了详细的地球化学和锆石U-Pb年代学研究。这两类石榴角闪岩分别为硅不饱和的含十字石石榴角闪岩和硅饱和的含石英石榴角闪岩。含十字石石榴角闪岩矿物组合为十字石、石榴子石、角闪石、钠云母、绿泥石、斜长石。石英石榴角闪岩矿物组合为石榴子石、角闪石、石英、斜长石、黑云母。岩石学及变质相平衡研究表明两类石榴角闪岩均经历了高压角闪岩相变质作用。含十字石石榴角闪岩和石英石榴角闪岩具有MORB的地球化学特征,锆石U-Pb年代学分析获得了800~200 Ma的206Pb/238U年龄范围,出现了~430 Ma、~268 Ma和~216 Ma年龄峰值。~430 Ma年龄可能和拉萨地体岩浆活动有关,~268 Ma变质年龄和~216 Ma变质年龄和拉萨地块经历的高压变质作用有关。其中~268 Ma年龄和拉萨地块内部松多高压带榴辉岩的峰期变质年龄一致,而~216 Ma年龄和榴辉岩的围岩含石榴子石片岩年龄一致。对比该区域的年代学研究成果,这表明林芝杂岩体不仅经历了中新生代的变质和岩浆再造活动,还经历了古特提斯洋闭合,南北拉萨地块发生碰撞的晚二叠世的高压变质作用和三叠纪的中压变质作用。     

Laboratory Estimation of Rock Joint Stiffness and Frictional Parameters

Numerical modeling of complex rock engineering problems involves the use of various input parameters which control usefulness of the output results. Hence, it is of utmost importance to select the right range of input physical and mechanical parameters based on laboratory or field estimation, and engineering judgment. Joint normal and shear stiffnesses are two popular input parameters to describe discontinuities in rock, which do not have specific guidelines for their estimation in literature. This study attempts to provide simple methods to estimate joint normal and shear stiffnesses in the laboratory using the uniaxial compression and small-scale direct shear tests. Samples have been prepared using rocks procured from different depths, geographical locations and formations. The study uses a mixture of relatively smooth natural joints and saw-cut joints in the various rock samples tested. The results indicate acceptable levels of uncertainty in the calculation of the stiffness parameters and provide a database of good first estimates and empirical relations which can be used for calculating values for joint stiffnesses when laboratory estimation is not possible. Joint basic friction angles have also been estimated as by-products in the small scale direct shear tests.