青藏高原新生代岩浆活动与地热关系探讨

青藏高原地热资源丰富,具有分布广、温度高、潜力大等特点。为了更好地评价该区地热资源潜力,探索符合青藏高原地热资源特点的勘查、开发方案,需要对地热资源分布规律及成因进行研究。在总结前人对青藏高原新生代岩浆活动和地热资源特征的基础上,从青藏高原地质演化的角度分析地热资源分布的控制因素,探讨新生代岩浆活动与地热资源的空间展布关系,重点讨论藏南地区地热区划和雅鲁藏布缝合带岩浆活动之间的关系。结果表明: 青藏高原地热活动受控于地质构造演化,具有南强北弱的分布特点; EW向区域性构造缝合带和SN向深大断裂的交汇部位是地热的主要活跃区域,不同的岩浆活动为地热提供热源。     

小波分析在重力界面反演中的应用

基于Parker-Oldenburg反演方法,分析了低通滤波器B(K)的不同阈值对位场分离的影响。分别采用小波变换和低通滤波对青藏高原地区布格重力异常进行了位场分解和莫霍面反演,并将反演结果与地震资料作比较。结果表明,在重力位场分解中小波多尺度分解可以代替低通滤波器B(K),避免了阈值的选取。     

Effect of ENSO events on sediment production in a large coastal basin in northern Peru

Although the importance of ENSO on hydrological anomalies has been recognized, variations in sediment fluxes caused by these extreme events are poorly documented. The effect of ENSO is not limited to changes in sediment mobilization. Since ENSO events can affect terrestrial ecosystems, they may have important effects on sediment production and transport in river basins over time spans that are longer than the duration of the event itself. The Catamayo‐Chira basin is an interesting casestudy for investigating these geomorphic implications. The objectives were: (i) to study the effect of ENSO on stream flow and sediment yields in the basin, (ii) to investigate if ENSO events affect sediment yields in the post‐ENSO period and (iii) to understand which factors control the ENSO and post‐ENSO basin response. During strong negative ENSO periods, mean annual stream flow discharge at the inlet of the Poechos reservoir in the lower basin was 5.4 times higher than normal annual discharges, while average sediment fluxes exceeded those of normal years by a factor of about 11. In two heavily affected periods, 45.9% of the total sediment yield in the 29 years observation period was generated. Sediment fluxes in the post‐ENSO period are lower than expected, which proves post‐ENSO event dynamics are significantly different from pre‐event dynamics. Our analysis indicates the increase of vegetation growth in the lower basin is not the main reason explaining considerable sediment flux decrease in post‐ENSO periods. During strong ENSO events, sediment in alluvial stores in the lower part of the basin is removed due to enlarging and deepening of channels. In post‐ENSO periods, normal discharges and persisting sediment supplies from the middle/upper basin lead to river aggradation and storage of large amounts of sediment in alluvial plains. The decrease in sediment export will last for several years until the equilibrium is re‐established. Copyright © 2011 John Wiley & Sons, Ltd.     

积雪升华过程对高寒湿地陆气相互作用的影响

利用青海玉树隆宝地区2014年12月积雪升华过程的观测资料,分析了积雪升华过程中高寒湿地陆气相互作用特征及积雪深度对陆气相互作用的影响。结果表明：在降雪和积雪升华过程中,高寒湿地浅层土壤温度在短时期内有所升高,而深层土壤温度和土壤体积含水量对降雪过程的响应不敏感。积雪升华过程中净辐射、感热通量和潜热通量的日平均值增加,向上短波辐射的日平均值减少。积雪逐渐升华导致地表吸收的能量增加,同时地表向大气传递的能量也随之增加。随着积雪的逐步升华,感热占比和潜热占比逐渐升高,而土壤热通量占比和热储存占比逐渐降低。积雪深度增加会导致地表反照率和地表比辐射率增大,感热输送系数减小。     

河北洞子沟银铜多金属矿床地质特征及成因分析

洞子沟银铜多金属矿床产于华北克拉通北缘长城系常州沟组地层中,受地层控制明显。通过对该矿床地质特征及矿石的稀土元素地球化学特征、矿物流体包裹体特征、硫氢氧同位素组成及U-Pb同位素年代研究表明:成矿物质来源于幔源;矿床形成于古元古代晚期华北克拉通吕梁运动后的伸展裂解过程中,在断陷盆地接受沉积的同时,有沿同生断裂上升的幔源热液、银铜金铅锌等成矿物质组分与常州沟组陆源碎屑一同沉积,形成洞子沟银铜多金属沉积层控型矿床。     

祁连山构造地貌特征:青藏高原东北缘晚新生代构造变形和地貌演化过程的启示

祁连山地区作为青藏高原向北东方向扩展生长的前缘地区之一,对构造地貌发育特征及其控制因素研究是理解青藏高原东北缘晚新生代构造变形过程的重要内容之一。通过地形坡度、起伏度以及河流纵剖面分析,研究揭示出祁连山高坡度、高陡度的造山带边缘山系及高海拔、低起伏山间盆地发育地貌特征。结合区域隆升、侵蚀速率研究表明,祁连山山脉边缘部分山系发育接近平衡状态,而河流裂点的广泛发育进一步表明整个祁连山山脉地区的地貌特征,特别是河流地貌发育仍然处于瞬时(transient)状态。通过对比祁连山山脉10个不同背景下的流域盆地,发现无论是内流水系,还是外流水系,流域上游地区均发育有低起伏、低坡度的山间盆地,这一特征表明控制祁连山内部发育平坦地形的因素并非取决于是内流还是外流水系,而可能主要受控于河流水系搬运能力的强弱。除此之外,通过对比祁连山地区盆地形态研究表明,西北侧的狭长、平行盆地主要受控于阿尔金断裂走滑应变在祁连山地区的缩短吸收,而东南侧的菱形盆地则受控于海原、东昆仑左旋走滑断裂带及其次级鄂拉山、日月山右旋走滑断裂所夹持的块体。以现有流域盆地宽度与面积之间的关系为基础,我们初步推测了祁连山造山带西北侧的构造缩短量大致为61km,对应整个祁连山的缩短率大致为17%,与祁连山南侧区域结果相当。当然,考虑到祁连山东南侧大通河流域区的缩短量与周边研究的差异,我们不能排除祁连山造山带早期的构造缝合线或先存断裂对部分流域的线性排列也起到了一定的控制作用。     

GIS技术在房地产市场信息系统中的应用研究

简要介绍了当前国内房地产现状、存在的问题,以及房地产市场信息系统（Real Estate Market Information System,以下简称REMIS）当前所处的发展背景,指出房产GIS在标准和应用上存在的一些问题。对房地产管理和REMIS对GIS的需求情况进行了分析。根据需求分析作者提出了GIS技术在REMIS中的几种应用模式,并指出基于楼盘表为核心的GIS应用模式将是未来房产GIS发展的方向。针对房产GIS应用的不同模式采用的几种关键技术也做了相应描述。     

Mesoscale surface circulation and variability of Southern Indian Ocean derived by combining satellite altimetry and drifter observations

High resoultion Eulerian mean velocity field has been derived by combining the satellite tracked surface drifter data with satellite altimetry and ocean surface winds. The drifter data used in this study includes Argos and surface drifter data from Global Drifter Program. Maps of Sea Level Anomaly(MSLA) weekly files with a resolution of(1/3)° in both Latitude and Longitude for the period 1993–2012 have been used. The Ekman current is computed using ocean surface mean wind fields from scatterometers onboard ERS 1/2,Quikscat and ASCAT. The derived mean velocity field exhibits the broad flow of Antarctic Circumpolar Current with speeds up to 0.6 m/s.Anomalous field is quite significant in the western part between 20° and 40°E and in the eastern part between 80°E and 100°E with velocity anomaly up to 0.3 m/s. The estimated mean flow pattern well agrees with the dynamic topography derived from in-situ observations. Also,the derived velocity field is consistent with the in-situ ADCP current measurements. Eddy kinetic energy illustrates an increasing trend during 1993–2008 and is in phase coherence with the Southern Annular Mode by three month lag. Periodic modulations are found in the eddy kinetic energy due the low frequency Antarctic Circumpolar Wave propagation.     

Geochemistry,detrital zircon geochronology and Hf isotope of the clastic rocks in southern Tibet: Implications for the Jurassic-Cretaceous tectonic evolution of the Lhasa terrane

In order to reconstruct tectonic evolution history of the southern margin of Asia (i.e., Lhasa terrane) before the India-Asia collision, here we present a comprehensive study on the clastic rocks in the southern Lhasa terrane with new perspectives from sedimentary geochemistry, detrital zircon geochronology and Hf isotope. Clasts from the Jurassic-Early Cretaceous sedimentary sequences (i.e., Yeba and Chumulong Formations) display high compositional maturity and experienced moderate to high degree of chemical weathering, whereas those from the late Early-Late Cretaceous sequences (Ngamring and Shexing Formations) are characterized by low compositional maturity with insignificant chemical weathering. Our results lead to a coherent scenario for the evolution history of the Lhasa terrane. During the Early-Middle Jurassic (∼192-168Ma), the Lhasa terrane was speculated to be an isolated geological block. The Yeba Formation is best understood as being deposited in a back-arc basin induced by northward subduction of the Neo-Tethys ocean with sediments coming from the interiors of the Lhasa terrane. The Middle Jurassic-Early Cretaceous Lhasa-Qiangtang collision resulted in the formation of a composite foreland basin with southward-flowing rivers carrying clastic materials from the uplifted northern Lhasa and/or Qiangtang terranes. During the late Early-Late Cretaceous (∼104-72Ma), the Gangdese magmatic arc was uplifted rapidly above the sea level, forming turbidites (Ngamring Formation) in the Xigaze forearc basin and fluvial red beds (Shexing Formation) on the retro-arc side. At the end of Late Cretaceous, the Lhasa terrane was likely to have been uplifted to high elevation forming an Andean-type margin resembling the modern South America before the India-Asia collision.     

西藏松西地区辉绿玢岩岩石化学、地球化学特征及构造环境

青藏高原南羌塘石炭纪-二叠世地层中侵入大量的辉绿玢岩岩墙群，其侵位时代为晚古生代。区域资料显示，这一时期该地区处于冈瓦纳大陆北部边缘。岩石化学、地球化学特征表明，辉绿玢岩与洋脊型、洋岛型及典型的大陆裂谷玄武岩都有明显区别，显示出大陆拉张带（或初始裂谷）的拉斑玄武岩特征。辉绿玢岩是冈瓦纳被动陆缘在晚古生代裂解的产物。