湖南桑植-石门复向斜走廊剖面构造特征分析

为了查明桑植—石门复向斜的地表、地下构造特征及其相互间的关系,采取了详细的地表走廊剖面的测量,以及结合地震勘探资料和大地电磁测深(MT)资料的综合解释。桑植—石门复向斜可进一步划分为四个次一级的构造带,从北向南依此是:堰塘湾构造带、四望山构造带、江垭构造带及教子垭构造带。江垭构造带和教子垭构造带的地面构造特征与地下构造特征具有一致性,基本上为构造简单的北倾斜坡;而四望山构造带的地面构造特征与地下构造特征存在着明显的不协调性。这种变形特征可解释为沿盖层间滑脱面的逆冲,以及断弯背斜的形成,上覆构造层中的褶皱向下消失在滑脱面上,形成所谓的“无根褶皱”。     

苏锡常地区地面沉降及其若干问题探讨

地面沉降是苏锡常地区当前面临的最大地质灾害问题。本区的地面沉降具有两个特点:一是在时空上与 地下水开采密切相关;二是其形成主要为含水砂层的压密和顶、底板粘性土层的固结。针对地面沉降的研究多从 其宏观力学特性、水土耦合和建模等方面着手,而对土体在沉降变形过程中的结构变化研究不多,因而对土体在沉 降变形过程中的可逆和不可逆、非线性变形、弱透水层变形等的机理,还存在许多模糊认识。对此文章提出了相关 建议,主要包括:1)应系统地研究苏锡常地区第四纪土体各土层的细观和微观结构,弄清地面沉降区土体结构的演 化规律及其与抽、灌地下水、土体物性指标等之间的关系,建立土体沉降类型与土体结构演化之间的关系;2)应对 第四纪土体中的弱透水层开展系统研究;3)应从土体结构的角度,深入研究土体在排水和回灌过程中的可逆和不 可逆变形。     

单层工业厂房-TMD减震控制系统研究

提出了采用质量调谐减震控制技术对厂房结构进行减震控制的方法。利用屋盖系统作为附加质量,屋盖支座采用夹层橡胶隔震垫,建立了厂房-TMD系统模型,并用非线性时程分析法对其进行了多种地震动激励下的计算分析,探讨了厂房-TMD减震体系减震效果的参数影响及减震机理。结果表明,采用质量调谐减震技术对单层工业厂房进行减震是一种有效的方法。     

冀豫浙中小企业集群中的创业机制实证研究

理论和实证研究表明,企业集群中存在比较完善的创业机制;另一方面,正是由于创业机制的存在,企业集群才能够得以发育成长。文章通过对冀豫浙3个中小企业集群实地调研分析,证实了企业集群发育过程中创业机制的存在以及创业机制对企业集群发育成长的重要作用。认为建立健全创业机制是促进企业集群发育、成长和升级的有效方法。     

An evaluation of the genesis and suitability of groundwater for irrigation in the Volta Region,Ghana

Stable isotope data and concentrations of the major cations and anions of groundwater from the northern part of the Volta Region, Ghana, were used to determine the source of recharge and the suitability of groundwater in the area for irrigation. This study finds that the delta deuterium (δD) and delta Oxygen-18 (δ¹⁸O) data from the area fall along the global meteoric water line (GMWL). An equation of regression derived for the relationship between δD and δ¹⁸O bears very close semblance to the equation which describes the GMWL. On the basis of this, groundwater in the study area is probably meteoric and fresh. The apparently low salinities and sodicities of the groundwater seem to support this interpretation. The suitability of groundwater for domestic and irrigation purposes is related to its source, which determines its constitution. A plot of the sodium adsorption ratio (SAR) and electrical conductivity (EC) data on a semilog axis, suggests that groundwater serves good irrigation quality in the area. Sixty percent (60%), 20% and 20% of the 67 data points used in this study fall within the medium salinity–low sodicity (C2–S1), low salinity–low sodicity (C1–S1) and high salinity–low sodicity (C3–S1) fields, which ascribe good irrigation quality to groundwater from this area. Salinities range from 28.1 to 1,956 μS/cm, whilst SAR values fall within the range 0–3. Extremely low sodicity waters of this kind, with salinities lower than 600 μS/cm, have the tendency to affect the dispersive properties of irrigation soils when used for irrigation. About 50% of the groundwater in the study area fall within this category and need prior treatment before usage.     

Diagenesis and Restructuring Mechanism of Oil and Gas Reservoir in the Marine Carbonate Formation,Northeastern Sichuan:A Case Study of the Puguang Gas Reservoir

Abstract: Based on the technology of balanced cross-section and physical simulation experiments associated with natural gas geochemical characteristic analyses, core and thin section observations, it has been proven that the Puguang gas reservoir has experienced two periods of diagenesis and restructuring since the Late Indo-Chinese epoch. One is the fluid transfer controlled by the tectonic movement and the other is geochemical reconstruction controlled by thermochemical sulfate reduction (TSR). The middle Yanshan epoch was the main period that the Puguang gas reservoir experienced the geochemical reaction of TSR. TSR can recreate the fluid in the gas reservoir, which makes the gas drying index higher and carbon isotope heavier because C2+ (ethane and heavy hydrocarbon) and 12C (carbon 12 isotope) is first consumed relative to CH4 and 13C? (carbon 13 isotope). However, the reciprocity between fluid regarding TSR (hydrocarbon, sulfureted hydrogen (H2S)?, and water) and reservoir rock results in reservoir rock erosion and anhydrite alteration, which increases porosity in reservoir, thereby improving the petrophysical properties. Superimposed by later tectonic movement, the fluid in Puguang reservoir has twice experienced adjustment, one in the late Yanshan epoch to the early Himalayan epoch and the other time in late Himalayan epoch, after which Puguang gas reservoir is finally developed.     

“崆峒山组砾岩”形成演化的动力学机制分析

查明"崆峒山组砾岩"形成的动力学环境是认识鄂尔多斯盆地西南缘的盆地原型、构造属性、华北克拉通西部破坏的关键。采用野外调查、取样与室内测样分析相结合的方法,系统研究了"崆峒山组砾岩"的沉积特征、裂变径迹热史,在此基础上以盆山耦合思想为指导,结合区域及深部背景资料,认为崆峒山组砾岩形成于秦祁海槽剪刀式闭合导致的右旋走滑区域背景下,走滑使位于砾岩西侧的青铜峡-固原古断裂复活,控制了崆峒山组砾岩形成。砾岩形成的动力学过程,可分为早期(231～218Ma)走滑拉张断陷沉积阶段,晚期(231～205Ma)走滑挤压坳陷沉积阶段和末期(205～195Ma)隆升剥蚀改造阶段,其分别与裂变径迹热史重建的砾岩快速增温、缓慢降温、快速冷却三个阶段相对应。崆峒山组砾岩埋藏增温的时刻及其形成演化的动力学过程表明,崆峒山组砾岩应为晚三叠世沉积。     

区域尺度农田氮磷非点源污染与模型应用分析

分析了农田非点源污染对生态环境的危害性,并阐述农田氮、磷非点源污染的机理及其在不同自然条件下的影响因素和监测方法。同时,对农田非点源污染的定量化、应用效应等进行了对比分析。此外,结合农田非点源污染与相关模型作了应用实例分析。     

水蚀风蚀过程中土壤可蚀性研究述评

1 IntroductionSoil erosion is the process of detachm ent and transport of soil particles caused by w ater andw ind (M organ,1995).Soilerosion by w ater and w ind leads to decline in soilfertility,brings ona series of negative im pacts of land degradation …     

乌兰布和沙漠晚第四纪以来环境演化研究进展

乌兰布和沙漠晚第四纪以来环境演化呈现湖泊与沙漠多次反复的更替模式,湖相层与松散风成砂层迭覆出现.湖泊发育时间段为120-90 ka、60-50 ka、40-20 ka和8-5.5 ka;沙漠扩展时间段为150-130 ka、90-60 ka、50-40 ka、20-10 ka和5.5 ka--近现代时期.由于时空尺度差...