Subglacially precipitated carbonates record geochemical interactions and pollen preservation at the base of the Laurentide Ice Sheet on central Baffin Island,eastern Canadian Arctic

The mineralogy and isotopic compositions of subglacially precipitated carbonate crusts (SPCCs) provide information on conditions and processes beneath former glaciers and ice sheets. Here we describe SPCCs formed on gneissic bedrock at the bed of the Laurentide Ice Sheet (LIS) during the last glacial maximum on central Baffin Island. Geochemical data indicate that the Ca in the crusts was likely derived from the subglacial chemical weathering Ca-bearing minerals in the local bedrock. C and Sr isotopic analyses reveal that the C in the calcite was derived predominantly from older plant debris. The δ¹⁸O values of the SPCCs suggest that these crusts formed in isotopic equilibrium with basal ice LIS preserved in the Barnes Ice Cap (BIC). Columnar crystal fabric and the predominance of sparite over micrite in the SPCCs are indicative of carbonate precipitation under open-system conditions. However, the mean δ¹⁸O value of the calcite crusts is ~ 10‰ higher than those of primary LIS ice preserved in the BIC, demonstrating that SPCCs record the isotopic composition of only basal ice. Palynomorph assemblages preserved within the calcite and basal BIC ice include species last endemic to the Arctic in the early Tertiary. The source of these palynomorphs remains enigmatic.     

西藏自治区谢通门县斯弄多铅锌矿区地球物理特征及找矿方向

浅成低温热液型矿床是一类主要产于陆相火山岩或与陆相火山岩有关的低温热液矿床,矿床埋藏深度浅是其最大的特点,这也使地球物理勘探方法在这类矿床的勘查中具有先天优势。本文通过对西藏斯弄多Pb-Zn-Ag多金属浅成低温热液型矿床的地球物理参数特征研究,采用激发极化法等综合物探技术在矿体外围探获具有巨大前景的Pb-Zn-Au-Ag浅成低温热液型矿体。目前单工程控制有3段矿体:顶部Au-Ag矿体,中部Au矿体,底部Pb-Zn-Ag矿体。矿体最高Au品位可达5.3g/t,Ag最高品位410g/t,Pb+Zn综合平均品位5.9%。研究结果表明,斯弄多地区林子宗群火山岩物性参数稳定,对矿体异常干扰较小,产于该套火山岩中极强硅化体中的浅成低温热液型Au矿多具有中高极化率和中低阻特征。     

阿拉善沙漠植物钙质根管:形态特征、分类及其环境指示意义

在系统总结前人对植物钙质根管定义及形成机制的基础上,采用形态学方法对阿拉善沙漠26组不同形态的植物钙质根管进行了分类,初步统一了我国植物钙质根管的定义及其分类;通过统计阿拉善沙漠不同类型植物钙质根管在全新世的数量分布,探讨了其分布特征可能蕴含的古环境意义。结果表明,植物钙质根管是陆生植物形成的次生碳酸盐结壳,包括钙质根套、绕根结核、根模具、根导管和根状结核五种类型。其中钙质根套和绕根结核的形成受到植物生长及其根围微生物活动的影响,而根模具、根导管和根状结核的形成则不受上述作用的影响。据此将阿拉善沙漠植物钙质根管分为钙质根套和绕根结核两种类型。这两类植物钙质根管在不同时期的相对数量百分比能够指示植物钙质根管形成时期有效湿度的高低,绕根结核数量百分比较高能够指示较高的有效湿度,而钙质根套数量百分比较高则指示了较低的有效湿度。因此,从植物钙质根管中能够提取丰富的古环境信号,并将其运用于沙漠地区的古环境研究中。     

水封式巷道瓦斯抽放技术探讨

为降低矿井瓦斯含量,依据瓦斯难溶于水的性质,提出水封式巷道抽放瓦斯技术。某矿井瓦斯抽放实例显示,水封式抽放密闭性好,瓦斯抽放浓度高(达95%),且抽放量大(该矿累计抽采瓦斯2.8×109m3)。预抽后,矿井的绝对瓦斯涌出量由40 m3/min降为24.27 m3/min,相对瓦斯涌出量由12 m3/t降为6.9 m3/t,使高瓦斯矿井变为低瓦斯矿井。该技术真正实现了煤与瓦斯共采,有效解决了瓦斯治理难题,其安全效益、经济效益和社会效益显著。     

甘肃省文县阳山特大型金矿床地质特征及控矿因素分析

阳山金矿位于川陕甘交界地带，为近年发现的一特大微细浸染型金矿床，该矿目前已发现4个矿段，均赋存于泥盆系中，矿体在平面上呈舒缓波状，在剖面上为脉冲，似层状，矿石中金属矿物主要为黄铁矿和毒砂，金主要以微细粒金（2～3μm）包裹于毒砂，黄铁矿等矿物之中，矿石中As、Sb及有机碳含量较高，矿带受安昌河一观音坝断裂带控制，矿体产于断裂带内的次级断裂中，泥盆系三河口群粉砂质千枚岩渗透性较好，且碳质含量，金丰度值较高，是矿区最有利的赋矿层位；矿体在时间、时间上与侏罗纪早期岩浆活动密切相关，稳定同位素分析了表明成矿作用与岩浆活动有关，所以，该矿为受构造直接控制的，与沉积作用和岩浆活动有成因联系的金矿床。     

改造现有LIS支持时空数据管理和土地变更的实现

尝试为现有的GIS和LIS的数据管理系统增加时空数据管理功能，并扩展现有的数据管理功能，以便最大可能地应用数据库中的数据，最后以一个具体的LIS为例，描述如何对其改造以实现对时空数据的管理并完成土地变更的过程。     

万山、梵净山在铜仁夏季的比较优势

以《贵州省气候避暑地评价标准》为主要评价标准,应用铜仁10个国家气象观测站和梵净山无人值守7要素站观测的逐日气温观测资料和整编资料为基础,对梵净山、万山的度夏气候进行评价得出,梵净山、万山具有凉爽、湿润、清新、太阳辐射低的特点,是度夏的理想去处。与此同时,结合本地气候特点,初步设想了铜仁市的评价标准:在辅助指标中引入暑热日数作为评价指标之一。     

The impact of microphysical schemes on hurricane intensity and track

During the past decade, both research and operational numerical weather prediction models [e.g. the Weather Research and Forecasting Model (WRF)] have started using more complex microphysical schemes originally developed for high-resolution cloud resolving models (CRMs) with 1–2 km or less horizontal resolutions. WRF is a next-generation meso-scale forecast model and assimilation system. It incorporates a modern software framework, advanced dynamics, numerics and data assimilation techniques, a multiple moveable nesting capability, and improved physical packages. WRF can be used for a wide range of applications, from idealized research to operational forecasting, with an emphasis on horizontal grid sizes in the range of 1–10 km. The current WRF includes several different microphysics options. At NASA Goddard, four different cloud microphysics options have been implemented into WRF. The performance of these schemes is compared to those of the other microphysics schemes available in WRF for an Atlantic hurricane case (Katrina). In addition, a brief review of previous modeling studies on the impact of microphysics schemes and processes on the intensity and track of hurricanes is presented and compared against the current Katrina study. In general, all of the studies show that microphysics schemes do not have a major impact on track forecasts but do have more of an effect on the simulated intensity. Also, nearly all of the previous studies found that simulated hurricanes had the strongest deepening or intensification when using only warm rain physics. This is because all of the simulated precipitating hydrometeors are large raindrops that quickly fall out near the eye-wall region, which would hydrostatically produce the lowest pressure. In addition, these studies suggested that intensities become unrealistically strong when evaporative cooling from cloud droplets and melting from ice particles are removed as this results in much weaker downdrafts in the simulated storms. However, there are many differences between the different modeling studies, which are identified and discussed.     

柴达木盆地三湖地区生物气横向运聚成藏研究

本文系统研究了地层水盐度对微生物菌生长发育的制约，矿化度对生物气在地层水中溶解度的影响，泥岩盖层中高矿化度地层水对封盖性能的控制作用。柴达木盆地三湖（台吉乃尔湖，涩聂湖，达布逊湖）地区主要受南缘昆仑山冰雪溶水的补给，地层水从南向北运移，北斜坡第四系地层水的矿化度最高，北斜坡泻水-汇水区高盐度条件下生物菌的活跃程度受到抑制，影响生物气大量生成并从水中游离出来，中央凹陷及其南部低矿化度条件下更适宜生物气的生成，生物气在地层水中的溶解度随矿化度的增高明显降低，南缘低矿化度水中饱含的生物气经地层水从南向北携带，在北斜坡高矿化度条件上大量游离出来，实验测试证明泥岩饱和高矿化度地层水时，其突破压力增加约100倍，封盖性能大大提高，有效地保存了北斜坡游离相生物气，研究显示生物气总体上具有向北斜坡以水溶气方式进行横向运聚的特征，展示了北斜坡气源补给充足，具有满坡含气的巨大勘探潜力。结合生物气本身的发育特征和三湖地区的水文地质条件，提出了生物所首先以水溶气方式发生远距离的横向运移以后再以游离相进行垂向运聚成藏，这一结论对下一步三湖地区生物气勘探具有直接的指导意义。