天然气输送管线中水合物形成的边界条件

运用水合物形成的热力学相平衡模拟计算方法及根据输气管线中的天然气组成，确定了青海和甘肃输气管线中水合物形成的边界条件，提出预防水合物堵塞的热力学方法。在青海和甘肃输气管线工作压力约为2．5～4．11MPa的范围内，水合物形成最低温度约为1～5℃。在-7～5℃时，在体系中加入甲醇或增加盐度可有效地控制管线中水合物的形成。在低于-7℃的条件下，盐度和甲醇的联合应用，才能有效抑制输气管线中水合物的形成。在温度低于0℃和压力为2．5～4．11MPa的水合物热力学稳定范围内，降低输气管线中的水含量可有效地控制水合物形成而产生的堵塞。     

Geochronology and Geochemical Characteristics of the Early Mesozoic Tangquan Pluton in Southwestern Fujian and Its Tectonic Implications

The Tangquan granodioritic pluton in Dalian County, southwestern Fujian, China, which extends in a NE direction with an exposed area of about 130 km2, used to be considered a product of Early Cretaceous magmatism. The present study suggests for the first time that the pluton was formed in the Early Jurassic by using multiple methods for isotopic dating, which give zircon U-Pb ages of 186.8 Ma and 179.0 Ma, Rb-Sr isochron age of 162.02±4.5 Ma, and biotite 40Ar/39Ar plateau age of 158.1±0.7 Ma. The cooling rate for the pluton was relatively low (4.76℃/Ma) during the early stage (183-162 Ma) because of the compressional environment. It was emplaced in a higher cooling rate (50℃/Ma) in an extensional environment during the later stage (162-158 Ma). The granodiorites are metaluminous-peraluminous, relatively enriched in Na2O and depleted in K2O, and characteristic of I-type granites of crust-mantle mixed sources. They are moderately enriched in Rb, Th, Hf and LREE, and depleted in Ti, Nb, Ta and Sr, and     

云南三江造山带近东西向构造特征及其研究意义

对地球物理位场进行处理分析的结果表明 ,在云南三江造山带近南—北向为主的构造框架背景中 ,存在有多处与之相互正交或斜交的近东—西向构造 ,这些近东西方向展布的构造呈现出隐伏或深部构造特点。在布格重力异常影像中表现为大波长、幅值低的深部构造带特征 ;地质上表现为一系列近东—西向出现的断裂、岩体和矿床的成带分布 ;遥感解译结果则表现出在三江造山带内有多条平行展布的浅埋深东西向隐伏构造带。本文结合地质、地球物理地震波速信息等资料 ,对该区近东西向构造特征及分布规律进行探讨后提出三江地区存在的近东西—向展布的近东西向构造可能是青藏高原主碰撞造山后 ,各块体物质向东南挤出的深部物质流变构造的反映 ,也可能是在三江造山带挤压碰撞及走滑拉张环境下的伸展构造或老构造的再活化。它的形成机制可能类似于青藏高原南部南—北向伸展构造 (裂谷 )。近东—西向构造的深入研究和成因再认识对于深入分析云南三江地区复杂的地质构造 ,区域地壳演化历史 ,特别对是重新认识区域成矿规律、指导找矿具有重要意义     

Sporopollen Assemblages from the Cretaceous Yimin Formation of the Hailar Basin, Inner Mongolia, China

Three sporopollen assemblages are recognized for the first time from the Cretaceous Yimin Formation in the Hailar Basin of eastern Inner Mongolia. They are （in ascending order）： the lmpardecispora-Aequitriradites- Clawttipollenites assemblage; the Triporoletes-Pilosisporites-Asteropollis assemblage; and the Appendicisporites- Asteropollis-Tricolpites assemblage, distributed in Members 1, 2 and 3 of the Yimin Formation respectively. Recognition of this biostratigraphic sequence is very important for the division and correlation of the Yimin Formation in the basin. Meanwhile, the age of the Yimin Formation is considered to be Barremian to Early Albian based on the palynological data.     

Elemental Geochemistry of the Interlayer Oxidation Zonein the Shihongtan Sandstone Type Uranium Deposit, Xinjiang

1 Geological Setting making the southern margin of Turpan-Hami basin one of the important uranium-productive regions of interlayer The Turpan-Hami basin is one of the three greatest basins oxidation type sandstone-hosted uranium deposits inin the Xinjiang Uygur Autonomous Region. It is located in China. Up to now, the large-scale Shihongtan uraniumthe Junggar-Turpan microplate at the southeastern end of deposit and some uranium ore occurrences have beenthe Kazakhstan-Junggar plate. The b…     

A feasible methodology for landslide susceptibility assessment in developing countries: A case-study of NW Nicaragua after Hurricane Mitch

In October 1998, Hurricane Mitch triggered a large number of landslides (mainly debris flows) in Honduras and Nicaragua, resulting in a high death toll and in considerable damage to property. In recent years, a number of risk assessment methodologies have been devised to mitigate natural disasters. However, due to scarcity of funds and lack of specialised personnel few of these methodologies are accessible to developing countries. To explore the potential application of relatively simple and affordable landslide susceptibility methodologies in such countries, we focused on a region in NW Nicaragua which was among the most severely hit during the Mitch event. Our study included (1) detailed field work to produce a high-resolution inventory landslide map at 1 : 10,000 scale, and (2) a selection of the relevant instability factors from a Terrain Units Map which had previously been generated in a project for rural development. Based on the combination of these two datasets and using GIS tools we developed a comparative analysis of failure-zones and terrain factors in an attempt to classify the land into zones according to the propensity to landslides triggered by heavy rainfalls. The resulting susceptibility map was validated by using a training and a test zone, providing results comparable to those reached in studies based in more sophisticated methodologies. Thus, we provide an example of a methodology which is simple enough to be fully comprehended by non-specialised technicians and which could be of help in landslide risk mitigation through implementation of non-structural measures, such as land planning or emergency measures.     

广东河源白石冈岩体:一个高分异的I型花岗岩

广东河源白石冈岩体位于近东西向展布的佛冈花岗岩带的东端,主体岩性为中粗粒黑云母花岗岩,主要组成矿物为石英(25%～35%)、微纹长石(45%～50%)、斜长石(An=20～30,15%～20%)和黑云母(5%～10%)。锆石U-Pb定年结果表明其形成年龄为148.5±1.6Ma,属晚侏罗世岩浆活动的产物。化学成分上,该岩体铝弱过饱和,A/NKC值主要变化于1.0～1.1之间;富硅,富钾(K2O/Na2O=1.31～1.70),全碱含量中等偏低(K2O Na2O=7.44%～8.48%),碱铝指数(AKI值)为0.75～0.88,可归为高钾钙碱性岩系。微量和稀土元素组成上,岩体富Rb、Th、U、Pb和轻稀土,贫Ba、Sr、P、Ti,Rb/Sr比值高,K/Rb比值低,铕负异常显著(δEu=0.05～0.28),Nb、Ta、Zr、Hf等高场强元素含量及104×Ga/Al比值(2.43～3.26)较之典型A型花岗岩均偏低。岩体的εNd(t)值为-5.99～-7.51,TDM值偏低(1.42～1.54Ga),综合地球化学资料指示其应属高分异的I型花岗岩。结合对区域动力地质背景的全面分析,表明白石冈岩体形成于后造山的伸展引张环境,是由底侵的幔源基性岩浆及其诱发的长英质岩浆在深部岩浆房混合,并经高程度分离结晶的产物。     

Zircon SHRIMP Dating for the Weiya Pluton, Eastern Tianshan: Its Geological Implications

1 Introduction Voluminous literature has resulted from study of the geology and tectonic evironments of post-orogenic granitoids in eastern Tianshan (He et al., 1995; Han et al., 1997; Gu et al., 1999, 2001; Li et al., 2003; Chen et al., 2004). Previous contributions (Hu et al., 1997; Li et al., 2003) indicate that major events of continental collision in northern Xinjiang occurred around 300 Ma. Then, the tectonics converted from compression to extension, resulting in the uplifting of th…     

四川三台膨润土的基本物化性能及其对铅、钴的吸附性研究

对四川三台钙基膨润土的基本物化性能和对Pb^2 ，Co^2 离子的吸附性能作了初步的研究。基本物化性能主要包括化学成分、阳离子交换容量、密度、比表面积、孔径、渗透系数及热稳定性。通过实验得出：1)经过钠化改型并酸化处理后的膨润土的阳离子交换容量(CEC)明显高于未经处理的原土；2)膨润土的最佳酸活化条件为在96℃左右以15％的硫酸活化4小时的性能最佳；3)膨润土土的密度为2．11g／cm^3，颗粒密度钠化土为1．996g／cm^3，原土为2．079g／cm^3；渗透系数为0．013cm／s(20C)；体积平均粒径为30．950μm；比表面积为329．7482m^2／g，平均孔径为33．238nm；4)膨润土对对重金属离子的吸附实验，得出膨润土对重金属离子Pb^2 的吸附性能优于Co^2 ，Pb^2 和Co^2 的吸附比(Rd)分别为167．8ml／g及53．3ml／g；Pb^2 和Co^2 去除率(r)分别为45．87%和21．20％。     

贵东岩体铀成矿交代作用特性研究

贵东岩体是一个铀成矿分区明显的岩体，东部产有花岗岩型铀矿床，西部则无铀矿化。区分铀成矿场和非成矿场的识别标志是一项既有实际价值又有理论意义的课题。本文基于大量的野外观测、室内鉴定资料和定量分析数据，研究了贵东岩体铀成矿区交代作用的种类、方式和演化，特别是其强度和能力，进而总结了该岩体铀成矿场蚀变交代作用的特性：交代作用发生的滞后性、交代方式的多样性、交代作用在空间分布上的叠置性、交代作用演化的规律性和交代作用的彻底性；指出贵东岩体交代作用与铀成矿作用有着密切的关系。交代作用特性和标志对寻找铀矿化具有重要意义。