Geochronology of metarhyolites from the Kangbutiebao Formation in the Kelang basin, Altay Mountains, Xinjiang: Implications for the tectonic evolution and metallogeny

The Altay orogenic belt (AOB), situated in the middle part of the Central Asian Orogenic Belt (CAOB), is one of the most important metallogenic belts in China. The Kangbutiebao Formation is a Late Paleozoic stratigraphic unit that hosts many important iron and Pb–Zn deposits. The Kangbutiebao Formation consists of intercalated volcanic and sedimentary rocks that have undergone regional greenschist to lower amphibolite facies metamorphism, and mainly outcrops in three NW-trending fault-bounded volcano–sedimentary basins, including the Maizi, Kelang, and Chonghuer basins. SHRIMP analyses of zircons from three metarhyolites of the Kangbutiebao Fm. in the Kelang Basin yield weighted mean ²⁰⁶Pb/²³⁸U ages of 412.6 ± 3.5 Ma, 408.7 ± 5.3 Ma and 406.7 ± 4.3 Ma, respectively, which can be interpreted as the eruption age of the Kangbutiebao silicic volcanic rocks in the Kelang Basin. These ages indicate that the Kangbutiebao Formation was formed during the Late Silurian to Early Devonian. They also demonstrate that the deposits hosted in the Kangbutiebao Formation were formed after 412–407 Ma. They play a key role in understanding the Paleozoic tectonic evolution and metallogenesis of the southern margin of the Chinese AOB.     

应用多普勒雷达作暴雨的观测分析及临近预警

本文运用多普勒雷达产品和石家庄加密自动站雨量资料对 2004 年、2005 年汛期发生在河北省境内的三场暴雨天气进行了分析,结果发现利用多普勒雷达产品时空分辨率高、产品丰富和速度场变化较降水变化超前的优点,配合加密自动站雨量的实时降水资料,努力做好暴雨的短时临近预警,及时修正和弥补前期预报的失误或不足是完全可行的.同时,探讨了几条多普勒雷达产品在暴雨临近预警应用中可参考的方法.     

基于扩展有限元法的碳酸盐岩地热储层岩体裂缝扩展行为

水力压裂作为一种主要的地热能开采手段,其压裂效果除与岩体基本物理力学性质有关外,还与裂隙分布、地应力状态、压裂工程参数等密切相关.为了探究以上因素对水力压裂过程中裂缝扩展行为的影响,以冀中坳陷碳酸盐岩储层岩体为研究对象,基于扩展有限元法,建立裂缝扩展流固耦合模型,分析了水平应力差、射孔方位角、注入液排量和压裂液黏度等参数对裂缝扩展行为的影响.结果表明:单裂缝扩展时,射孔方位角越小、注入量越大、越有利于裂缝扩展;双裂缝扩展时,水平应力差增大,裂缝偏转程度变小;水力裂缝与天然裂缝相交时,较小水平应力差有利于天然裂缝开启.     

华北三站地基GPS反演的大气可降水量及其特征

利用2005年4月-2006年10月石家庄、秦皇岛和张家口三个地基GPS站的观测资料和地面气象资料,根据GPS反演可降水量的原理以及可降水量与地面水汽压的线性对应关系,对不同站点、不同时次的大气可降水量进行了解算和补算,并对河北省GPS可降水量的时空分布特征进行了分析.结果表明:可降水量在时间上先升后降,7、8月达到最大值;在空间上由北向南递增;可降水量的日变化特征不十分显著,仅表现为小幅度波动.     

The socio-spatial dimension of behavior analysis: Frontiers and progress in Chinese behavioral geography

The interaction between urban space and individual behavior has led to essential social, economic and environmental consequences. Behavioral geography provides a new effective theoretical and methodological framework to investigate behavior patterns in cities. In recent years, behavior approach has become an influential analytical paradigm in Chinese urban geography. This paper provides an overview of behavioral geography research in China, by introducing the theoretical and empirical progress in behavior analysis. It is argued that behavioral approach offers a new perspective to understanding China’s urban sociospatial reconstruction and addressing social and environmental issues at micro scale. Although theoretical development still lags behind developed countries, Chinese scholars have made much progress in empirical investigations of classical socio-spatial behavior theories. This paper also provides an overview of new trends in Chinese behavioral geography that has started to apply the behavioral approach to urban social, economic and environmental issues. This paper suggests that social dimensions of behavior should be addressed more comprehensively and rigorously by using interdisciplinary theoretical and methodological frameworks, to better understand the complexity of Chinese cities and research the critical social and environmental issues in cities.     

南天山库勒湖蛇绿混杂岩岩石地球化学特征及其构造背景

通过对南天山独－库公路剖面，黑英山剖面出露的肢解蛇绿岩套各成员的岩石化学、微量元素、稀土元素地球化学等多方面研究，结合区域构造分析，表明该蛇绿混杂岩的构造背景为古生代弧后盆地。     

Excess pore pressure observation in marine sediment based on Fiber Bragg Grating pressure sensor

Abstract

Fiber Bragg Grating (FBG) technology has emerged as a relatively new sensing technology for engineering applications because of lots of advantages. In this study, a large diameter probe instrumented with FBG pressure sensors to monitor excess pore pressure in marine sediment is proposed. The principle of FBG differential pressure sensor was introduced. Laboratory tests were carried out to check the workability and stability of the FBG pressure sensor. Offshore field test was also conducted in a wharf in Qingdao of China to evaluate the feasibility of the proposed probe. The installation procedure of the probe was introduced in detail. The excess pore pressure in dissipation test, after installation and pulling process were reported. The permeability coefficient of marine sediment was calculated based on the measured data. The field data show that the proposed probe based on FBG pressure sensor has good feasibility and accuracy in monitoring the excess pore pressure of marine sediment. The generation and dissipation of excess pore pressure is closely related to the degree of soil disturbance. The variation of excess pore pressure after installation can reflect the tide well in the site.     

基于迁居的郊区大型居住区社会空间形成——以北京回龙观居住区为例

郊区大型居住区是我国郊区化过程中产生的一种新型居住形态,为缓解城市内部人口和功能压力起到了重要作用,但其由于过快开发、缺乏规划等原因出现的问题众多。以北京典型郊区居住区回龙观为例,从迁居行为角度探讨大型居住区的社会空间形成,以折射我国郊区化过程中存在的问题。郊区大型居住区的形成是政府、单位、开发商三者共同作用的结果,社会转型期影响居民迁居的主要推力和限制因素是家庭纽带、政府政策与经济能力;快速郊区化过程中建立的这类社区内部居民成分复杂、流动性强、社区意识较为薄弱,居民生活与城市中心及近郊内沿的联系紧密,地区吸引力有待增强。