昆仑山北坡岛状冻土区西大滩大型饮用矿泉群成因分析

在对昆仑山北坡岛状冻土区西大滩大型饮用矿泉群水文地质、导水与控水断裂、水化学等方面实地调查和EH-4高频、电测深勘探的基础上,认为矿泉群的补给源为昆仑山玉珠峰一带的现代冰川底部冰雪覆盖融区水、冰雪消融水、大气降水和地表水.补给源水通过具多期活动性的F3和F4正断层组破碎带补给深层地下水.深层地下水在西倾近南北向正断层组F2及F2-1,2的导水断层破碎带富集并继续向北径流,径流至F1南倾活动性逆断层上盘时,形成富水"三角区",并沿F1断层破碎带排泄出地表,是西大滩大型饮用矿泉群形成的主因.     

阿尔泰南缘麦兹泥盆纪火山-沉积盆地成矿特点及其铅锌、铁、金找矿潜力分析

麦兹盆地位于西伯利亚板块南缘阿尔泰陆缘活动带中,是一个重要的铅、锌、铁矿化集中区,其中著名的有蒙库大型铁矿床、可可塔勒大型铅锌矿床,是阿尔泰南缘多金属成矿带中最重要的成矿盆地之一。盆地内矿床、矿点多为火山喷流热水沉积成因,层控特征明显,具有规模大、形态规则、厚度及有用组分稳定等特点。铁矿成矿与早泥盆世早期细碧角斑质火山作用相伴,而铅锌成矿则与早泥盆世晚期长英质火山喷流沉积作用相伴。通过对麦兹盆地成矿地质特征和典型矿床中矿体分布变化规律的研究,认为北西向同生断裂、火山沉积洼地、火山喷发中心(火山机构)共同控制铅锌矿的产出,矿体还受到后期褶皱、变质作用的改造。根据有利层位、火山岩相、喷流沉积岩、热液蚀变、矿化组合、铁帽、控矿构造和地球化学异常等综合找矿评价标志,分析了可可塔勒矿区深部、什根特、铁热克萨依、H-48号异常的铅锌找矿潜力,并探讨了盆地内铁、金的找矿潜力,指出了进一步找矿的方向与有利地段。     

柴达木盆地英雄岭地区新生代构造演化动力学特征

通过分析柴达木盆地英雄岭 (YL)地区地质、2D/ 3D地震、遥感、重磁电和钻探等资料 ,提出了喜马拉雅运动几个阶段在该区的构造动力学响应特征。研究认为喜马拉雅运动晚期 ,英雄岭地区西南侧的阿卡腾能山因近SN向的区域挤压作用 ,产生了顺时针方向的旋转及隆升作用 ,从而在干柴沟一带形成了强烈的SE向局部挤压应力场 ,基底大幅隆升 ,而在英雄岭隆起的南侧则产生了局部的拉张构造环境。喜马拉雅山中期运动在该区的主要表现形式就是使古近纪的张扭构造环境转变为新近纪的坳陷构造环境 ,英雄岭西南的阿尔金地区发生隆升作用 ,沉积中心发生向东和向北的迁移。通过分析主干断裂、构造块体和沉积凹陷的分布特征等 ,得出喜马拉雅早期英雄岭及邻区发育局部拉张环境 ,为较为稳定的断陷湖盆发育期 ,沉积了一套优质烃源岩。英雄岭地区潜在勘探领域主要有构造裂缝型圈闭、地层岩性圈闭及渐新世断凸构造圈闭等。     

A Comparison of Nd Isotopes of Granitoids from the Central Asian Orogenic Belt and Qinling-Dabie Orogen,and Implications for Understanding of Crustal Growth from Accretion to Collision

正Orogens can generally be divided into two types:accretionary and collisional.The fundamental differences in deep-crustal compositions and architecture from accretion to collision and how to identify them is not well understood.This is one of the major aims of the IGCP 662 project (www.igcp662.org.cn).The Central Asian Orogenic Belt (CAOB) is a typical and the world's largest Phanerozoic accretionary orogenic belt and the     

Large tufa mounds,Searles Lake,California

Mounds that have formed around spring vents occur in a variety of environmental settings, many at sites generally difficult or inaccessible for sampling. In contrast, over 500 tufa mounds occur in the dry bed of Searles Lake, California. The mounds range from minor features to 45 m in height; most are 5 to 12 m high. These mounds, composed of calcite and aragonite, formed associated with spring vents in the Pleistocene lake bottom. Thus, analyses of these mounds in Searles Lake provide a model with regard to the origin and architecture of tufa mounds. The mounds consist of four distinctive tufa facies. The initial deposits consist of porous tufa, including the innermost (porous 1) and the outermost (porous 2) deposits, followed by nodular tufa, then columnar tufa, and laminated crusts. There are two simple sequences of tufa deposition. The first sequence is from porous 1 to nodular to laminated crusts and, finally, to porous 2. A second sequence consists of: porous 1 to columnar to laminated crusts and, lastly, to porous 2. Facies changes are a response to changes in environmental conditions from deep water (porous 1 facies) to an essentially dry lake phase (during and after the formation of laminated crusts facies), to deep water (porous 2 facies) and, at the present time, totally dry. The primary constituents that comprise the tufa deposits include thin laminae, pisoids, spherulites, peloids and stromatolite‐like crusts. On the microscopic scale, these constituents dominantly make up nano‐spheres, micro‐rods and rod‐like crystals, as well as other calcified bodies. These constituents are interpreted to be the calcified remains of bacterial bodies. These findings suggest that microbial participation in the construct of other mounds should be a major concern of investigation, both for terrestrial and extraterrestrial spring‐fed mounds.     

TRMM-retrieved Cloud Structure and Evolution of MCSs over the Northern South China Sea and Impacts of CAPE and Vertical Wind Shear

Cloud structure and evolution of Mesoscale Convective Systems(MCSs) retrieved from the Tropical Rainfall Measuring Mission Microwave Imager(TRMM TMI) and Precipitation Radar(PR) were investigated and compared with some pioneer studies based on soundings and models over the northern South China Sea(SCS).The impacts of Convective Available Potential Energy(CAPE) and environmental vertical wind shear on MCSs were also explored.The main features of MCSs over the SCS were captured well by both TRMM PR and TMI.However,the PR-retrieved surface rainfall in May was less than that in June,and the reverse for TMI.TRMM-retrieved rainfall amounts were generally consistent with those estimated from sounding and models.However,rainfall amounts from sounding-based and PR-based estimates were relatively higher than those retrieved from TRMM-TMI data.The Weather Research and Forecasting(WRF) modeling simulation underestimated the maximum rain rate by 22% compared to that derived from TRMM-PR,and underestimated mean rainfall by 10.4% compared to the TRMM-TMI estimate,and by 12.5% compared to the sounding-based estimate.The warm microphysical processes modeled from both the WRF and the Goddard Cumulus Ensemble(GCE) models were quite close to those based on TMI,but the ice water contents in the models were relatively less compared to that derived from TMI.The CAPE and wind shear induced by the monsoon circulation were found to play critical roles in maintaining and developing the intense convective clouds over SCS.The latent heating rate increased more than twofold during the monsoon period and provided favorable conditions for the upward transportation of energy from the ocean,giving rise to the possibility of inducing large-scale interactions.     

西太平洋副热带高压对华北地区降水蒸发差的影响

采用小波相关和交叉小波变换等方法, 分析了西太平洋副热带高压脊线和北界位置变化对华北地区降水蒸发差的影响。结果表明, 2000年以来华北区南部的水资源短缺问题有所缓解, 但以北京为中心的华北区东北部仍处于持续缺水期; 华北地区降水蒸发差与副热带高压脊线及北界位置变化相关密切, 存在年际和年代际尺度的显著相关振荡, 与副热带高压脊线的年代际尺度相关凝聚性最强; 时域中年际尺度相关存在局部化特征, 年代际尺度相关具有阶段性。分析认为, 2000年以来副热带高压脊线和北界位置偏北并维持反气旋型环流, 有利于水汽向华北输送, 使得华北降水增多, 是近年来华北中南部降水蒸发差增大的主要原因; 而东亚季风减弱不利于西南气流的水汽输送, 以及蒙古高原显著增暖导致蒸发增大等因素, 使得华北东北部仍处于持续缺水期。     

黄土高原半干旱区非均一下垫面粗糙度分析

利用2007年4月17日-2008年4月16日兰州大学半干旱气候与环境观测站边界层气象塔的风速、 风向、 温度、 气压、 湿度等观测资料, 采用经典的廓线法和风速、 风向标准差法, 分别计算了中性大气层结下观测站下垫面粗糙度长度, 并得到了具有黄土高原地理特征的地表粗糙度及其时空变化特征。计算结果表明, 季节变化对粗糙度的影响幅度可达0.159 m, 空间非均一性对粗糙度的影响幅度可达0.155 m。测站附近粗糙度春季为0.017 m, 夏季为0.062 m, 秋季为0.065 m, 冬季为0.018 m。测站西北方向上游粗糙度春季为0.17 m, 夏季为0.22 m, 秋季为0.34 m, 冬季为0.05 m。测站东南方向上游粗糙度春季为0.11 m, 夏季为0.17 m, 秋季为0.19 m, 冬季为0.05 m。该站下垫面粗糙度计算宜选用风速为6±1.5 m·s-1, 风向变化30°范围内的数据。     

中国地区闪电和对流层上部NOx的时空分布特征及其相关性分析

为了解闪电对对流层上部NO_x的贡献,本文利用美国全球水资源和气候中心（GHRC）提供的1995年4月~2005年12月的闪电卫星格点资料及高层大气研究卫星 (UARS) 上的卤素掩星试验装置 (HALOE) 1991年10 月~2005 年11月的观测资料,分析了中国地区闪电与对流层上部NO_x体积混合比的时空分布特征及两者的相关性.结果表明:中国地区闪电和对流层上部的NO_x在季节分布、年际分布和空间分布上保持很好的一致性,闪电是对流层上部NO_x的重要来源;NO极值高度在350 hPa左右,云闪直接产生的NO是极值产生的主要原因,NO₂的极值高度在250 hPa左右,因为闪电产生的NO在传输过程中会被氧化成NO₂并通过雷暴的垂直输送作用抬升到更高高度;强对流活动有利于NO_x的传输,而人类活动产生的NO_x一般较难输送到对流层上部,因此闪电多发区的NO_x极值较大,所在的高度也较高.     

我国东部4-9月大尺度南北旱涝的特征及变化

研究了我国东部4—9月逐月、逐季降水的跷跷板结构和气候特征,结果表明:不同时段跷跷板结构的位置和强度不同。当时间尺度加大时,南北旱涝特征更明显。定义并计算了1951—2003年我国的南北旱涝指数。对夏季和8月典型南北旱涝年进行差异的显著性t检验,表明南北旱涝年的划分是合理的。研究了1951—2003年我国南北旱涝特征的长期趋势和年代际变化;研究了南北旱涝指数与冷暖事件年的关系。结果表明,冷暖事件年对6月、6—7月以及夏季大尺度南北旱涝有影响,暖事件年有利于发生北旱南涝;而冷事件年则相反。结果还表明,冷暖事件仅是我国南北旱涝分布的一个影响因素。