南极MIL 090070月球陨石的岩石矿物学特征

MIL 090070陨石是2009年美国南极陨石搜寻项目(ANSMET)在南极横断山脉米勒山区(Miller Range)发现的一块月球陨石,属于斜长岩质月表角砾岩。它具有典型的碎屑结构,主要由岩屑、晶屑、玻屑和细粒基质组成。岩屑以复合斜长岩质岩屑和斜长岩岩屑为主,其次为辉长岩质斜长岩岩屑、辉长岩岩屑、辉长苏长岩岩屑、辉长岩质橄长岩岩屑和橄榄辉长岩岩屑等。晶屑有普通辉石、易变辉石、斜长石、尖晶石、石英和钛铁矿等矿物。玻屑主要为斜长石质的玻屑,呈细长或弯曲条状,多具裂纹。MIL 090070陨石的矿物组成主要为斜长石（86 vol%,An92—99）、橄榄石（6 vol%,Fo53—89）、辉石（7 vol%,En25—83Fs7—43Wo2—45）,以及少量的尖晶石、钛铁矿和石英等;其中,辉石有单斜辉石和斜方辉石二种。MIL 090070陨石中橄榄石和辉石的Fe-Mn值分布明显不同于地球、火星、金星和小行星的样品,基本落在月球岩石范围。MIL 090070陨石在多期次冲击和胶结作用下,岩屑的矿物成分和粒度不断变化,岩屑类型更多样,更复杂。基于MIL 090070陨石的岩石矿物学特征、碎屑类型及结构的特征等研究,可以进一步丰富我们对月球物质的形成及月岩—月壤演化过程的认识。     

山东沂沭河流域2000BC前后古文化兴衰的环境考古

Neolithic culture series in the Yishu River Basin developed in the order of Beixin culture-Dawenkou culture-Longshan culture-Yueshi culture. During the early and middle stage of Longshan culture （4600-4300 cal. yr BP）, the climate in the Yishu River Basin was warm and wet. Paddy-oriented agriculture planted paddy was very developed. The society was flourishing with great amount of archaeological sites. The cooling starting in 4200 cal. yr BP made the paddies shortfall in output or even no seeds were gathered. This situation intensified the discrepancy between population and resource. The scarcity in natural resource led to substantial decrease in population and subsequent drop in archaeological sites. About 4000 cal. yr BP Longshan culture was displaced by Yueshi culture which was relatively un- derdeveloped, simple and unsophisticated.     

Automated mapping of rock slope geometry,kinematics and stability with RSS-GIS

A GIS-implemented, deterministic approach for the automated spatial evaluation of geometrical and kinematical properties of rock slope terrains is presented. Based on spatially distributed directional information on planar geological fabrics and DEM-derived topographic attribute data, the internal geometry of rock slopes can be characterized on a grid cell basis. For such computations, different approaches for the analysis and regionalization of available structural directional information applicable in specific tectonic settings are demonstrated and implemented in a GIS environment. Simple kinematical testing procedures based on feasibility criteria can be conducted on a pixel basis to determine which failure mechanisms are likely to occur at particular terrain locations. In combination with hydraulic and strength data on geological discontinuities, scenario-based rock slope stability evaluations can be performed. For conceptual investigations on rock slope failure processes, a GIS-based specification tool for a 2-D distinct element code (UDEC) was designed to operate with the GIS-encoded spatially distributed rock slope data. The concepts of the proposed methodology for rock slope hazard assessments are demonstrated at three different test sites in Germany.     

Observations of estuarine circulation and solitary internal waves in a highly energetic tidal channel

Despite vigorous tidal and wind mixing, observations in an estuarine tidal inlet in the Wadden Sea show that during part of the tidal cycle, vertical stratification and internal waves may still develop. Acoustic Doppler current profiler (ADCP) and conductivity, temperature, depth observations, collected over the past 6 years at 13 h anchor stations (ASs), reveal that these occur especially during slack tide, when there is little wind and large freshwater discharge from nearby Lake IJssel. Measurements with a moored ADCP show that in the same tidal phase, strong cross-channel circulation develops, which may suddenly reverse circulation sense due to passing density fronts. In the vertically stratified phase that follows after the front passage, propagating mode-one solitary internal waves are observed. These are resonantly generated during decelerating tidal ebb currents when the (shear) flow passes a transcritical regime (Froude number equal to 1). A combination of photographs (including one from the International Space Station), bathymetric data, and ASs data leads to the discovery of yet another source of internal waves in this area, produced during slackening tide by propagating lee waves that develop over a deep trench. We suggest that both the cross-channel circulation as well as the (solitary) internal waves may locally be of importance for the (re)distribution and transport of sediments and nutrients and may influence tidally averaged transports.     

Impact of Cloud Microphysical Processes on the Simulation of Typhoon Rananim near Shore. Part II: Typhoon Intensity and Track

The impact of cloud microphysical processes on the simulated intensity and track of Typhoon Rananim is discussed and analyzed in the second part of this study. The results indicate that when the cooling effect due to evaporation of rain water is excluded, the simulated 36-h maximum surface wind speed of Typhoon Rananim is about 7 m s⁻¹ greater than that from all other experiments; however, the typhoon landfall location has the biggest bias of about 150 km against the control experiment. The simulated strong outer rainbands and the vertical shear of the environmental flow are unfavorable for the deepening and maintenance of the typhoon and result in its intensity loss near the landfall. It is the cloud microphysical processes that strengthen and create the outer spiral rainbands, which then increase the local convergence away from the typhoon center and prevent more moisture and energy transport to the inner core of the typhoon. The developed outer rainbands are supposed to bring dry and cold air mass from the middle troposphere to the planetary boundary layer (PBL). The other branch of the cold airflow comes from the evaporation of rain water itself in the PBL while the droplets are falling. Thus, the cut-off of the warm and moist air to the inner core and the invasion of cold and dry air to the eyewall region are expected to bring about the intensity reduction of the modeled typhoon. Therefore, the deepening and maintenance of Typhoon Rananim during its landing are better simulated through the reduction of these two kinds of model errors.     

Geochemical baseline of trace elements in the sediment in Dexing area,South China

A baseline might be used as a point of reference to monitor change from some specific data without concern for whether the baseline determination is natural or has been changed by human activity. We selected 326 sediment samples from Dexing area, South China, and analyzed for 17 chemical elements. The geochemical baseline was predicted with the method of the normalization procedure combined with the relative cumulative frequency curve. The results indicate Al was the best reference element for the normalization procedure among four potential reference elements (Al, Fe, Ti, and Mn). The baseline value range obtained from the normalization procedure method included both the regional geochemical background of the sediment and the median value of the measured contents. The median value of baselines obtained from relative cumulative frequency method was lower than that obtained from normalization procedure method. In contrast to the geochemical patterns of heavy metals in 1987, the spatial distribution of anomalies sprawled in 2004 in study area, especially for Cu, Pb, Zn, Cd, As, Fe, and Cr.     

湘中锑(金)矿床成矿物质来源——Ⅰ.微量元素及其实验地球化学证据

为了查明湘中盆地中-低温梯（金）矿床的成矿物质来源，文章应用高分辨率ICP-MS、ICP-AES等方法对岩石与矿石进行了系统测定，并结合作者以往分析数据和实验地球化学结果，对该区盆地及周边基底地层与矿床中的微量元素分布特征及其水/岩反应效应进行了综合分析和系统研究。结果表明：Sb、Au等成矿元素在元古界基底碎屑岩中具有高的背景含量，在近似成矿条件下的水/岩反应实验中，成矿元素的淋出率达20%～90%，元古界基底碎屑岩中的金（锑、钨）矿床的周围蚀变围岩中出现明显的金负异常区。而盆地内泥盆系统地层中的高锑含量仅局限于锑矿床（化）及其蚀变围岩中；湘中锑（金）矿床中的矿石与基底碎屑岩具有相似的稀土元素球粒陨石标准化配分曲线特征，以上微量元素地球化学特征充分证明该区锑（金）矿床锑、金等成矿物质主要来源于元古界底碎屑岩。     

Comparative assessment of the relationship of satellite data with the above ground biomass of Sal trees (<Emphasis Type="Italic">Shorea robusta</Emphasis>) determined from phenologically different time periods

The Above Ground Biomass(AGB) estimates of vegetation comprise both the bole biomass determined through a volumetric equation and litter biomass collected from the ground.For mature trees,the AGB estimated in phenologically different time periods is directly affected by the litter biomass since the Diameter at Breast Height(DBH) and height(H) of such trees that are used in the estimation of bole biomass would remain unchanged over a reasonable time period.In the present study,we have determined the AGB of Sal trees(Shorea robusta) in two contrasting seasons:the peak green period in October being devoid of lit-ter on the ground and the leaf shedding period in February with abundant amount of litter present on the ground.Estimation of AGB for the month of February included the litter biomass.In contrast,the AGB for October represented only the bole biomass.AGB was estimated for ten different plots selected in the study area.The AGB estimated from ten sampling plots for each time period was re-gressed with the individual tree parameters such as the average DBH and height of trees measured from the corresponding plots.The regression analysis exhibited a significantly stronger relationship between the AGB and DBH for the month of October as compared to February.Furthermore,the correlation between the remotely sensed derived data and AGB was also found to be significantly higher for the month of October than February.This observation indicates that inclusion of the litter biomass in AGB will tend to decrease the re-gression relationship between AGB and DBH and also between the remotely sensed data and AGB.Therefore,these conclusions invite careful consideration while estimating AGB from satellite data in phenologically different time periods.     

Tailings composition effects on shear strength behavior of co-mixed mine waste rock and tailings

The objective of this study was to evaluate the effect of mine tailings composition on shear behavior and shear strength of co-mixed mine waste rock and tailings (WR&T). Crushed gravel was used as a synthetic waste rock and mixed with four types of tailings: (1) fine-grained garnet, (2) coarse-grained garnet, (3) copper, and (4) soda ash. Co-mixed WR&T specimens were prepared to target mixture ratios of mass of waste rock to mass of tailings (R) such that tailings “just filled” interparticle void space of the waste rock (i.e., optimum mixture ratio, R _opt). Triaxial compression tests were conducted on waste rock, tailings, and mixed waste at effective confining stresses (\(\sigma_{\text{c}}^{{\prime }}\)) ranging from 5 to 40 kPa to represent stresses anticipated in final earthen covers for waste containment facilities. Waste rock and co-mixed WR&T specimens were 150 mm in diameter by 300 mm tall, whereas tailings specimens were 38 mm in diameter by 76 mm tall. Shear strength was quantified using effective stress friction angles (?′) from undrained tests: ?′ for waste rock was 37°, ?′ for tailings ranged from 34° to 41°, and ?′ for WR&T mixtures ranged from 38° to 40°. Thus, shear strength of co-mixed WR&T was comparable to waste rock regardless of tailings composition. Shear behavior of WR&T mixtures was a function of R and tailings composition. Tailings influenced shear behavior for R < R _opt and when tailings predominantly were silt. Shear behavior was influenced by waste rock for R ≥ R _opt and when tailings predominantly were sand or included clay particles.     

A rapid seismic safety assessment method for mid-rise reinforced concrete buildings

The majority of existing buildings are not safe against earthquakes in most of the developing countries. Existing building stocks should be assessed with a seismic safety assessment method before a devastating earthquake. Cheaper and quicker rapid seismic safety assessment methods can be used instead of code-based assessment methods to determine the seismic performance of existing buildings. In this study, an approach was introduced to determine the seismic performance of existing mid-rise reinforced concrete buildings with fewer parameters and process steps than code-based detailed assessment procedures. Calibration and regulation of the introduced method were conducted on the 39 collapsed buildings’ projects in 1999 Kocaeli, Turkey, earthquake. Finally, 55 existing buildings located in Eskisehir, Turkey, assessed with this calibrated method and the results were compared with the results of a code-based detailed assessment method; the results showed a very good agreement of about 83%. This study shows that the proposed method can be applied for the determination of the seismic performance of existing mid-rise reinforced concrete buildings quickly and without compromising reliability.