华北克拉通破坏与岩石圈减薄   总被引：20，自引：2，他引：18  

嵇少丞  王茜  许志琴 《地质学报》2008,82(2):174-193

古太古代（约4.0 Ga）时地球上可能只有一个超级大陆, 它的岩石圈厚度高达400 km。在早元古代,这个超级大陆减薄、裂解成十几块,每块中心是太古宙岩石,边缘是元古宙岩石,且各块厚度不等（150~350km）。从元古宙之后这些被称之为稳定克拉通的大陆岩石圈就一直漂游在地幔软流圈之上。中国华北地块就是这些克拉通之一,与众不同的是它在中生代时遭受了第二次破坏,岩石圈厚度从古生代时的180~200 km 减少到现今的80~100 km。本文作者从流变学的视角出发,围绕华北克拉通破坏和岩石圈减薄这一核心问题,从  相似文献   

扬子及周缘地区上奥陶统-下志留统烃源岩发育环境及其控制因素   总被引：6，自引：0，他引：6  

严德天  王清晨  陈代钊  汪建国  王卓卓 《地质学报》2008,82(3):321-327

扬子地区下古生界发育了上奥陶统五峰组和下志留统龙马溪组两套有效烃源岩,查清其发育环境及其控制因素具有重要的科学理论和油气勘探意义.晚奥陶世开始,扬子地区进入碎屑岩陆棚演化阶段;五峰期-龙马溪期,扬子地区主体为局限的深水陆棚环境,总体呈现出浅水陆棚、深水陆棚、次深海共存的古地理格局.沉积体系展布和沉积演化主要受扬子陆块与华夏陆块的汇聚作用控制.扬子地区上奥陶统-下志留统烃源岩的形成与生烃母质生物的高生产力和高埋藏率、冰期-冰后期之交的气温快速转暖、海平面快速上升以及粘土矿物在有机质富集保存过程中的赋存驻留作用等密切相关.  相似文献   

鄂尔多斯盆地东缘煤储层微孔隙结构特征及其影响因素   总被引：2，自引：0，他引：2  

张松航  汤达祯  唐书恒  许浩  林文姬  张彪 《地质学报》2008,82(10):1341-1349

在对鄂尔多斯盆地东缘58套采自不同层位不同地域煤样显微组分测试和低温液氮比表面测试的基础上,从比表面积、吸附曲线形态、阶段孔径结构分布、阶段孔径比表面积贡献、FHH分形特征几个方面刻画了煤储层微孔隙特征。同时,就“孔比表面积—孔隙结构—煤物质组成与化学结构”这一因果链,分析了鄂尔多斯盆地东缘煤微孔隙特征与煤变质程度、煤岩显微组分以及矿物组分与类型的关系。研究发现,Ro在0.60%~1.91%范围内,比表面积及FHH分形分维数先明显降低,Ro至1.3%后又略有回升,同时吸附回线“滞后环”及分形尺度对应的压力范围明显减小,孔径3~4 nm“墨水瓶”型孔明显减少乃至消失,并成为比表面积减少的主要贡献者。在相似煤级条件下,惰质组分较镜质组分有更多的比表面积贡献。粘土矿物组分含量>10%时,孔径3~4 nm“墨水瓶”型孔对比表面贡献明显,且随煤级增高影响作用相对加大。  相似文献   

Impact of land use covers upon karst processes in a typical Fengcong depression system of Nongla, Guangxi, China   总被引：2，自引：0，他引：2  

Cheng Zhang  Jianguo Pei  Yunqiu Xie  Jianhua Cao  Lanling Wang 《Environmental Geology》2008,55(8):1621-1626

The direction and intensity of karst processes can be deeply affected by soil physical and chemical variations which were resulted from land use. Taking Nongla Fengcong depression area, Mashan County, Guangxi as an example, authors discussed the impact of land use on karst processes based on the data of field limestone tablet. The results showed that the corrosional rates at varied soil depth are quite different. Corrosional rate in woodland and orchard is mostly bigger than 20 mg/a, which is much higher than that in tilled land and shrub. Generally, corrosional rate decreased from orchard, woodland, tilled land, fallow land and shrub successively, in which soil organic matter (OM) and soil pH are two major controlling factors: corrosion process is controlled remarkably by soil OM in woodland and orchard. The higher the organic matter content is and the less the pH value is, the higher the corrosional rate is. Owing to lower organic matter content, the corrosional rate is mainly affected by soil CO₂ in tilled land and shrub.  相似文献   

Development of a 3D GIS and its application to karst areas   总被引：1，自引：0，他引：1  

Qiang Wu  Hua Xu  Wanfang Zhou 《Environmental Geology》2008,54(5):1037-1045

There is a growing interest in modeling and analyzing karst phenomena in three dimensions. This paper integrates geology, groundwater hydrology, geographic information system (GIS), database management system (DBMS), visualization and data mining to study karst features in Huaibei, China. The 3D geo-objects retrieved from the karst area are analyzed and mapped into different abstract levels. The spatial relationships among the objects are constructed by a dual-linker. The shapes of the 3D objects and the topological models with attributes are stored and maintained in the DBMS. Spatial analysis was then used to integrate the data in the DBMS and the 3D model to form a virtual reality (VR) to provide analytical functions such as distribution analysis, correlation query, and probability assessment. The research successfully implements 3D modeling and analyses in the karst area, and meanwhile provides an efficient tool for government policy-makers to set out restrictions on water resource development in the area.  相似文献   

Application of MODFLOW and geographic information system to groundwater flow simulation in North China Plain, China   总被引：2，自引：0，他引：2  

Shiqin Wang  Jingli Shao  Xianfang Song  Yongbo Zhang  Zhibin Huo  Xiaoyuan Zhou 《Environmental Geology》2008,55(7):1449-1462

MODFLOW is a groundwater modeling program. It can be compiled and remedied according to the practical applications. Because of its structure and fixed data format, MODFLOW can be integrated with Geographic Information Systems (GIS) technology for water resource management. The North China Plain (NCP), which is the politic, economic and cultural center of China, is facing with water resources shortage and water pollution. Groundwater is the main water resource for industrial, agricultural and domestic usage. It is necessary to evaluate the groundwater resources of the NCP as an entire aquifer system. With the development of computer and internet information technology it is also necessary to integrate the groundwater model with the GIS technology. Because the geological and hydrogeological data in the NCP was mainly in MAPGIS format, the powerful function of GIS of disposing of and analyzing spatial data and computer languages such as Visual C and Visual Basic were used to define the relationship between the original data and model data. After analyzing the geological and hydrogeological conditions of the NCP, the groundwater flow numerical simulation modeling was constructed with MODFLOW. On the basis of GIS, a dynamic evaluation system for groundwater resources under the internet circumstance was completed. During the process of constructing the groundwater model, a water budget was analyzed, which showed a negative budget in the NCP. The simulation period was from 1 January 2002 to 31 December 2003. During this period, the total recharge of the groundwater system was 49,374 × 10⁶ m³ and the total discharge was 56,530 × 10⁶ m³ the budget deficit was −7,156 × 10⁶ m³. In this integrated system, the original data including graphs and attribution data could be stored in the database. When the process of evaluating and predicting groundwater flow was started, these data were transformed into files that the core program of MODFLOW could read. The calculated water level and drawdown could be displayed and reviewed online.  相似文献   

Wind wave-forced fine sediment erosion during the slack water periods in Hangzhou Bay,China     

John Z. Shi  Wen-Jun Gu  Dian-Zhi Wang 《Environmental Geology》2008,55(3):629-638

The shallow water wave simulation model-SWAN incorporated with a simple fine sediment erosion model is applied to Hangzhou Bay, China, to model the horizontal distribution of the maximum bottom orbital velocity and corresponding fine sediment erosion rates induced by: (1) southeasterly steady winds (5, 20 and 30 m/s), (2) southwesterly steady winds (5 and 20 m/s); (3) northwesterly steady winds (5 and 20 m/s); (4) east-southeasterly steady winds (5 and 20 m/s); (5) easterly steady winds (5 and 20 m/s) under closed and unclosed boundaries; and (6) unsteady winds during the slack water periods. Results suggest: (1) the steady wind wave-induced maximum bottom orbital velocities and corresponding fine sediment erosion rates generally increased with the increasing steady winds; (2) closed and unclosed boundary conditions had more significant influences on modeled fine sediment erosion rates under 5 m/s easterly steady winds than 20 m/s; and (3) steady and unsteady wind wave-induced maximum bottom currents could be significant in eroding fine sediment bed in Hangzhou Bay. The results show implications for geomorphology, sedimentology, coastal erosion, and environmental pollution mitigation in Hangzhou Bay.  相似文献   

Dissolved trace elements and heavy metals in the Danjiangkou Reservoir,China   总被引：9，自引：0，他引：9  

Siyue Li  Zhifang Xu  Xiaoli Cheng  Quanfa Zhang 《Environmental Geology》2008,55(5):977-983

Concentrations of trace elements and heavy metals (Al, As, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb, Se, Sr, V and Zn) in the Danjiangkou Reservoir, the water source area of the Middle Route of China’s interbasin South to North Water Transfer Project, were analyzed using an Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES) and compared with the national and international standards for drinking water. The results indicated that concentrations of As, Pb, Sb and Se in the Reservoir exceeded the standards and they would pose health risk for residents in the region and the water receiving areas of the interbasin water transfer project. Spatial and temporal variability of the trace elements and heavy metals in the Reservoir implies their mixed sources of natural processing and anthropogenic activities in the upper drainage of the Reservoir. The research results would help develop water resource management and conservation strategy for the interbasin water transfer project.  相似文献   

Experimental study on the deterioration and natural remediation of the Ariake Sea tidal mud caused by the sea laver treatment acid practice and the upward seepage of pore water liquid     

Yan-Jun Du  Song-Yu Liu  Shigenori Hayashi 《Environmental Geology》2008,55(4):889-900

This study presents a laboratory study of the following two aspects: (1) the influence of sea laver treatment acid on the geoenvironmental properties of Ariake Sea tidal mud, and (2) the natural remediation effect on the sea laver treatment acid contaminated Ariake Sea tidal mud caused by the upward seepage of pore water liquid in the mud. Firstly, the mechanisms of the transport of sea laver treatment acid in the Ariake Sea tidal mud and the generation mechanisms of the upward seepage flow in the Ariake Sea tidal mud are discussed. Secondly, a series of one-dimensional laboratory infiltration tests were carried out to investigate the deterioration of the Ariake Sea tidal mud caused by the sea laver acid treatment practice. Test results reveal that the acid treatment practice caused considerable change in the geochemical properties of the mud in terms of increase in sulfide content and decrease in pH value. After the treatment by the sea laver treatment acid, the sulfide content of the mud even exceeded the safe limit value for the benthos, which represents undesirable living condition for benthos. Thirdly, series of laboratory fresh seawater infiltration tests for the deteriorated Iida site mud were conducted to illustrate this natural remediation efficiency. It is found that with the infiltration of the fresh seawater, the sulfide content of the Iida site mud was considerably reduced and pH value increased to an acceptable range for benthos living in the tidal flat mud. With the increase in the infiltration time and the hydraulic gradient, the remediation efficiency could be increased.  相似文献   

Geotechnical properties of evaporite soils of the Dead Sea area     

Sam Frydman  Josef Charrach  Ian Goretsky 《Engineering Geology》2008,101(3-4):236-244

The Dead Sea Basin is the lowest point on earth and is tectonically subsiding. During the Holocene Period the climate became much drier with increasing evaporation whereby initially lacustrine sediments were deposited from the non-marine brines, giving a multi-layered stratigraphy of lime carbonate and halite sediments. The lime carbonate sediments are comprised of laminated, clay to silt sized, clastic sediments (calcite) and authigenic aragonite and gypsum. The halite commonly appears as rock salt. Chemical industries, based on harvesting the salts from the Dead Sea, have developed on both the Israeli and the Jordanian sides of the basin. The lime carbonate soils are used for dike construction, and these soils, together with significant salt layers, are encountered in the foundations of structures, dikes, and tailings dams, requiring definition of their geotechnical properties. Use of standard soil mechanics definitions and testing approaches for the lime carbonates have been found inapplicable, particularly in view of their exceptionally high saline content, and it has been necessary to develop new concepts. The rock salt is encountered at shallow depths, with unit weights considerably lower than those usually discussed in the literature, and with correspondingly different mechanical properties. The geotechnical properties of these soils, and approaches used to define them, are discussed in the paper.  相似文献