韧性剪切变形对岩石地球化学行为的制约——以北阿尔金巴什考供韧性剪切带为例   总被引：6，自引：0，他引：6  

戚学祥李海兵  吴才来陈松永 《地质通报》2005,24(3):252-257

韧性剪切变形对岩石地球化学行为的制约一直是地质学家们探讨的课题。本文以构成北阿尔金红柳沟——拉配泉俯冲碰撞杂岩带与北阿尔金地块边界的巴什考供斜向逆冲型韧性剪切带为例，通过对韧性剪切带内花岗岩变形前后不同变形强度构造岩的地球化学组成进行对比，确定等比线斜率，探讨韧性变形对岩石体积和成分变异的影响。计算结果表明，在糜棱岩化过程中，糜棱岩化花岗岩体积亏损21％，花岗质糜棱岩体积亏损31％。质量平衡计算结果和等比线图表明，韧；陛剪切作用导致SiO2，流失量最大，A12O3、K2O及Ba、Rb、Sr等都有不同程度的丢失，显示出较强的活动性，MnO、P2O5、Sc位于等比线上或附近，表现出相对的稳定性。岩石中活动组分的变异是流体渗滤作用引起的，不活动组分的变异是体．积亏损造成的。  相似文献   

The fall and rise of metropolitan government in Copenhagen     

Hans Thor Andersen  Frank Hansen  John Jørgensen 《GeoJournal》2002,58(1):43-52

In this paper it is argued that the re-establishment of a metropolitan government in the Greater Copenhagen Area in 2000 (Greater Copenhagen Authority) is not to be seen as a return to the kind of regional, coordinative authority (Greater Copenhagen Council) that was abolished in the Thatcherite climate of the 1980s. Throughout the 1980s and 1990s new forms of urban governance, entrepreneurialism and a higher national priority to the capital region were introduced, which changed the conditions under which the new metropolitan government is operating. This `contextualization' of the analysis of the two generations of metropolitan government points to the fact that typologies of metropolitan government, such as the one put forward by Sharpe (1995), often lacks analytical cogency. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

Elemental and isotopic fractionation of Type B calcium-, aluminum-rich inclusions: experiments, theoretical considerations, and constraints on their thermal evolution     

Frank M. Richter  Andrew M. Davis  Denton S. EbelAkihiko Hashimoto 《Geochimica et cosmochimica acta》2002,66(3):521-540

Experiments exposing Type B calcium-, aluminum-rich inclusion (CAI)-like melts at high temperatures to high vacuum or reducing hydrogen-rich gas mixtures were used to determine the rates and consequences of elemental and isotopic fractionation by evaporation. Silicon and magnesium were found to evaporate much faster than calcium and aluminum, and the resulting residual liquid trajectories in composition space are reproduced via a thermodynamic model for the saturation vapor pressure of the evaporating species. Isotopic fractionations associated with evaporation were measured for magnesium. The resulting relationship between fraction of magnesium lost and enrichment of the residue in the heavy isotopes of magnesium follows a Rayleigh fractionation curve with a fractionation factor that is close to, but not exactly, the theoretically expected value. The rate of evaporation is found to be a strong function of temperature, oxygen fugacity, and melt composition, which can be understood and modeled in terms of the dependence of the saturation vapor pressures on these variables. The relationship between evaporation rate, which we measure, and calculated saturation vapor involves empirical evaporation coefficients that we find to be significantly less than one (∼0.1). Analytical and numerical models are used to characterize how diffusion in both the melt and in the surrounding gas affects evaporation rates and the degree of chemical and isotopic fractionation. The experimental data and theoretical considerations are combined to give a parameterization of the rates and consequences of evaporation of Type B CAI-like liquids, which is then used to translate the measured isotopic fractionation of Type B CAIs into constraints on their thermal history. Cooling rates of the order of 10°C per hour are indicated.  相似文献   

A new technique for precise uranium-series dating of travertine micro-samples   总被引：2，自引：0，他引：2  

Ronzon Mallick  Norbert Frank 《Geochimica et cosmochimica acta》2002,66(24):4261-4272

Secondary carbonate formations, such as travertine and calcareous tufa deposits, are important archives for quaternary continental climate studies and archaeology. The extremely complex growth mechanisms result in some serious problems for precise mass spectrometric uranium-series dating. Often, detrital and organic particles contaminate the carbonate and large pore volumes yield a great potential for open system behavior. We utilized microscopic, mineralogical and geochemical methods prior to sample selection to determine the abundance of primary calcite, i.e. micrite and spar. Furthermore, the state of alteration was characterized by cathodoluminescence and trace-element analysis. We conclude that travertine and calcareous tufa are appropriate for precise U-series age determination if a) micrite and/or spar are the dominant phases; b) cathodoluminescence of both phases is weak or absent; c) Fe and Al levels are low; and d) Sr concentrations are close to the average of the studied site. We mapped and sampled solely areas of major micrite/spar abundance having minor alteration for accurate U-series dating. When this new method was applied, travertines located in eastern Germany (sites Bad Langensalza, Burgtonna and Weimar-Ehringsdorf) gave single ²³⁰Th/²³⁸U-ages consistent with the lithological growth sequence and greatly improved compared to previously published chronologies. In addition, we determined ²³⁰Th/U isochron ages on bulk samples that confirm our single ages. In contrast to primary calcite, pore cements are homogeneously distributed throughout the travertine fabric and reflect early diagenetic processes and/or weathering.  相似文献   

新时期我国区域经济地理学发展问题初探   总被引：4，自引：0，他引：4  

刘曙光 《地域研究与开发》2002,21(2):1-4

我国新时期的区域经济地理学在取得全面发展的同时，在理论体系，研究方法和实践领域等方面还需要进一步的发展，文章根据学习和实践区域经济地理学的体会，初步提出基础理论和应用理论，思维方法和技术方法等方面发展见解，并指出区域创新系统和国际经济技术合作等学科应注意拓展的重要实践领域，最后提出我国区域经济地理学科发展的建议。  相似文献   

华南地区凉果加工业与凉果资源的匹配关系分析——以广东省新兴县为例     

刘一明  胡新艳  牛宝俊 《地域研究与开发》2002,21(2):60-63

文章以广东省新兴县为例，从凉果资源分布与加工能力的匹配关系角度对华南地区凉果资源的分布，凉果加工业的分布与布局，凉果市场分布与竞争力，凉果加工业与资源的匹配关系等进行了分析，并针对华南地区凉果加工业面临的主要问题提供了一些建议。  相似文献   

成都市民消费结构与休闲活动关系研究   总被引：6，自引：0，他引：6  

杨国良 《地域研究与开发》2002,21(2):77-80

城市居民消费水平，消费结构会影响其休闲消费能力，消费意愿，消费方式，消费态度和休闲时空结构，文章以成都市7个城区歌舞，茶棋牌，电影及城市公园休闲活动调查为基础，探讨了城市居民消费结构及其变化与休闲活动特征的关系。研究结果表明，城市居民消费结构的改变对歌舞，茶棋牌娱乐活动影响最大。  相似文献   

南水北调中线工程建设与河南水资源可持续利用   总被引：2，自引：0，他引：2  

赵永江  刘荷芬  贾虎 《地域研究与开发》2002,21(2):85-88

文章通过对河南省水资源开发利用现状，存在的主要问题，水资源供需平衡以及南水北调工程对河南省水资源利用的影响论述，提出了在拟定南水北调工程供水方案中，应通过强化节水，加强水资源保护，严格控制地下水开采，将水资源作为商品等措施，促进河南省水资源的可持续开发利用。  相似文献   

区域视觉形象识别系统设计的理论与实践   总被引：6，自引：0，他引：6  

禹贡 《地域研究与开发》2002,21(4):7-9

目前，全国各地正在兴起区域形象设计与建设的浪潮，但如何把区域形象信息系统地传递出去，这方面的理论研究大大落后于实践。文章就区域形象信息传递的有效工具－区域视觉识别系统设计的主要内容，设计的原则，设计的基本流程等在理论与实践上作了较为详细的探讨，并就区域视觉识别系统设计方案的经济学论证作了一些有益探讨。  相似文献   

河南经济技术开发区发展前景与对策     

杨延哲  张教平  刘燕茹  杨文新 《地域研究与开发》2002,21(4):24-27

文章阐述了经济技术开发区在区域经济发展过程中的作用。根据河南省经济技术开发区的发展现状和存在的问题，分析了加入WTO后开发区所面临的机遇和挑战，并在此基础上从开发区环境营造，运行机制，筹资方式，产业发展，城市建设等方面提出了加快河南省经济技术开发区发展的对策。  相似文献