The Western Pearl River Delta: Growth and Opportunities for Cooperative Development with Hong Kong by Y. M. Yeung,Shen Jianfa,and Zhang Li     

Mike Rudibaugh 《The Professional geographer》2007,59(3):397-398

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桂西岩溶堆积型铝土矿地质异常分析及基于GIS的找矿有利地段圈定     

何海洲  张起钻 《矿产与地质》2007,21(4):436-439

桂西岩溶堆积型铝土矿床受地层岩性、构造、岩溶地貌、气候与水文等因素控制。通过对岩溶堆积型铝土矿床地质异常的分析和识别,利用G IS技术圈定铝土矿找矿的有利地段,并预测其资源潜力。  相似文献   

印尼苏门答腊MW9.0级地震对全球及中国大陆地震趋势影响研究的反思     

韩渭宾  蒋国芳 《四川地震》2007,(4):1-4

本文对2004年12月26日印尼苏门答腊以西发生MW9.0级地震后所做的地震趋势预测做了反思,指出:关于全球特大地震近年可能连发,特大地震对几年内世界7级以上地震年频度没有明显影响,但未来几年内7级以上强震可能集中在这次特大地震附近或相关构造上的预测意见是正确的;而有关近年中国大陆及川滇地区可能发生7级强震的预测是错误的;并认为,2001年昆仑山口西8.1级地震释放了已积累的应变可能是这次特大地震不能触发中国大陆及川滇地区发生强震的重要原因。  相似文献   

Pb and Th in settling particles in the western Northwest Pacific Ocean: Particle flux and scavenging     

Masatoshi Yamada  Jian Zheng 《Continental Shelf Research》2007

A mooring of three conical time-series sediment traps was deployed at two sites in the western Northwest Pacific Ocean for 9 months. Total mass fluxes and activities of ²¹⁰Pb and ²³⁰Th were determined for the settling particles to elucidate their scavenging and transport processes. Sediment samples also were analyzed for ²¹⁰Pb activities. Total mass fluxes, ²¹⁰Pb fluxes and ²³⁰Th fluxes showed large seasonal variations and their weighted mean fluxes tended to increase with depth, with an especially large increase near-bottom. The ratios of the observed ²¹⁰Pb fluxes to the ²¹⁰Pb deficiency fluxes in the upper traps at the two sites were only 0.02 and 0.12, and were attributable to advective export of ²¹⁰Pb from the surface waters. Those ratios in the near-bottom traps ranged between 1.22 and 2.63. This suggests that these high ratios are due to effective particle scavenging, large lateral ²¹⁰Pb import and input of resuspended particles that have not become incorporated into the sediments. The mean total ²³⁰Th fluxes at the near-bottom traps were 4.2–6.7 times higher than that expected from production in the overlying water column. The ²¹⁰Pb activities in the surficial sediments were much lower than those in the near-bottom traps. The ²¹⁰Pb accumulation rates estimated from the excess ²¹⁰Pb inventory in the sediment column were 40–70% higher than the mean ²¹⁰Pb fluxes at the near-bottom traps. The ratios of the ²¹⁰Pb accumulation rates to the ²¹⁰Pb deficiency fluxes at the near-bottom traps ranged between 2.0 and 3.7. The high fluxes of particulate ²¹⁰Pb and ²³⁰Th at the near-bottom traps reflected a combination of enhanced scavenging of dissolved nuclides and the lateral redistribution of particulate matter by downslope and alongshore transports. However, it was not possible to discriminate among the various processes contributing to high nuclide fluxes.  相似文献   

塔里木盆地西部碳酸盐岩成岩演化与储层形成关系   总被引：4，自引：0，他引：4  

王琪  陈国俊 《新疆地质》2002,20(1):23-28

塔里木盆地西部碳酸盐岩的地质演化，主要经历了大气淡水成岩环境，海水成岩环境和埋藏成岩环境的改造，形成丰富的储人间类型和4种典型的孔隙结构特征，即溶孔－晶间孔复合型，粒间孔－粒间溶孔型，缝合线－微裂缝型和致密微孔型，大气淡水淋滤溶解作用和各种类型白云岩化作用有利于优质储层的形成，而胶结作用及压实，压溶作用则阻碍了储集空间的形成，奥陶系微晶灰岩和生屑灰岩由于主要经历了海水成岩－埋藏成岩环境的改造，胶结和压实作用特征明显，未能形成有效储集空间，整体属Ⅳ类差储集层，石炭系碳酸盐岩储层特征具有分区性，麦盖提斜坡区的储层物性明显优于巴楚隆起区，这与斜坡区碳酸盐岩遭后期大气淡水淋溶改造有关，古近系卡拉尔组碳酸盐岩经去膏化作用和大气淡水淋溶作用的复合改造，储层整体面貌呈Ⅲ-Ⅰ类的优良储层。  相似文献   

布尔津盆地西部凹陷铀成矿水文地球化学条件初探   总被引：1，自引：0，他引：1  

陈贤春  成海 《铀矿地质》2002,18(3):168-173

根据水成铀矿床理论，本在论述布尔津盆地水动力及水化学特征的基础上，通过资料综合整理，着重分析西部凹陷第三系层间水的铀水迁移分带规律，对层间氧化带砂岩型铀矿成矿水地球化学条件进行初步探讨。  相似文献   

中国西北大陆碰撞带的深部特征及其动力学意义   总被引：21，自引：7，他引：21       下载免费PDF全文

胥颐  刘福田  刘建华  陈辉  孙若昧 《地球物理学报》2001,44(1):40-47

以中国大陆西北地区地震层析成像的结果为基础，通过分析大陆块体内部岩石层和软流层的深部形态，提出西部造山带与相邻块体之间几种可能的碰撞类型：天山与塔里木之间存在地块的嵌入拼合、俯冲、岩石层拆离下沉以及层间插入等多种构造样式；青藏高原与北部地质单元之间存在十分清晰的深部边界，反映出上地幔物质向北扩展的痕迹；推测青藏高原的岩石层在向北运动的过程中由于受到塔里木刚性块体的阻滞发生弯曲甚至折断，但是祁连山以北较浅的软流层相当于一个开放边界，使高原的上地幔物质得以进一步向北迁移.大陆碰撞不仅造成中国西部造山带岩石层结构的变动，而且导致软流层中一部分熔融的岩浆体沿着碰撞边界上涌到岩石层底部，它们对青藏高原以及西部造山带的形成演化起到重要的作用.  相似文献   

对国家战略西移与西部经济发展的思考          下载免费PDF全文

石生仁  安成谋 《盐湖研究》2001,9(1):13-18

世纪之交 ,我国经济面临着增长困境 ,其深层原因是地区发展不平衡所致。为解决这一问题必须加速推动西部地区经济发展 ,西部大开发的过程也就是缩小西部与东部差距的过程。为此 ,应遵循市场机制的原则 ,更新观念 ,采取一系列有效措施 ;调整产业结构 ,选择重点产业 ;加强基础设施建设 ;治理生态环境 ;实施分类扶持政策等 ,是西部社会、经济走上可持续发展道路的唯一选择  相似文献   

Metastability of granulites and processes of eclogitisation in the UHP region of western Norway   总被引：1，自引：1，他引：1  

A. L. Wain †  D. J. Waters  H. Austrheim 《Journal of Metamorphic Geology》2001,19(5):609-625

The Flatraket Complex, a granulite facies low strain enclave within the Western Gneiss Region, provides an excellent example of metastability of plagioclase‐bearing assemblages under eclogite facies conditions. Coesite eclogites are found <200 m structurally above and <1 km below the Flatraket Complex, and are separated from it by amphibolite facies gneisses related to pervasive late‐orogenic deformation and overprinting. Granulites within the Flatraket Complex equilibrated at 9–11 kbar, 700–800°C. These predate eclogite facies metamorphism and were preserved metastably in dry undeformed zones under eclogite facies conditions. Approximately 5% of the complex was transformed to eclogite in zones of fluid infiltration and deformation, which were focused along lithological contacts in the margin of the complex. Eclogitisation proceeded by domainal re‐equilibration and disequilibrium breakdown of plagioclase by predominantly hydration reactions. Both hydration and anhydrous plagioclase breakdown reactions were kinetically linked to input of fluid. More pervasive hydration of the complex occurred during exhumation, with fluid infiltration linked to dehydration of external gneisses. Eclogite facies shear zones within the complex equilibrated at 20–23 kbar, 650–800°C, consistent with the lack of coesite and with the equilibration conditions of external HP eclogites. If the complex experienced pressures equivalent to those of nearby coesite eclogites (> 28 kbar), unprecedented metastability of plagioclase and quartz is implied. Alternatively, a tectonic break exists between the Flatraket Complex and UHP eclogites, supporting the concept of a tectonic boundary to the UHP zone of the Western Gneiss Region. The distribution of eclogite and amphibolite facies metamorphic overprints demonstrates that the reactivity of the crust during deep burial and exhumation is strongly controlled by fluid availability, and is a function of the protolith.  相似文献   

Emplacement at granulite facies conditions of the Sesia–Lanzo metagabbros: an early record of Permian rifting?     

Gisella Rebay  Maria Iole Spalla 《Lithos》2001,58(3-4):85-104

The evolution of the pre-Alpine Corio and Monastero metagabbros points to strong chemical and mineralogical similarities with that of other Permian gabbro bodies of the Alps, which are concentrated in the Southalpine and Austroalpine domains. The structural and metamorphic pre-Alpine evolution of these gabbros records a re-equilibration following the emplacement in the deep crust (P=0.6–0.9 GPa and T=850±70 °C), exhumation through amphibolite facies conditions (P=0.5–0.35 GPa and T=570–670 °C), followed by a greenschist facies imprint (0.25≤P≤0.35 GPa and T<550 °C). This retrograde P–T evolution suggests that the exhumation occurred in a high thermal gradient regime, such as that induced by upwelling of an asthenospheric plume during continental rifting. This would be consistent with the crustal thinning known to have occurred in both the Southalpine and Austroalpine domains during Permian times. The gabbros and their country acid granulites are spatially associated with the serpentinised subcontinental mantle of the Lanzo Massif. This lithologic association and the metamorphic evolution is similar to that of the Fedoz gabbro (Austroalpine Domain of the Central Alps) and completely different from that observed in passive margins, where no remnants of the lower crust occur and the upper granitic crust directly overlies the serpentinized lherzolites. The location of Permian gabbro bodies in the Austroalpine and Southalpine domains and their absence in the Helvetic domain is evidence for asymmetric rifting.  相似文献