地震作用下边坡稳定性分析

考虑了边坡岩土体材料的动力特性以及地震特性,利用动力有限元时程分析方法对边坡在地震荷载作用下的动力特性进行了分析,采用最小平均安全系数对边坡稳定性进行了评价,并与拟静力法的结果进行了对比分析,对某具体工程实例计算结果表明该分析方法的可行性,可为地震作用下边坡工程设计工作提供一些有益的参考。     

河南省桐柏县银洞坡金矿床深部及外围找矿前景分析

河南省桐柏县银洞坡金矿床位于桐柏山北麓的围山城金银多金属成矿带中部,矿体的空间分布严格受含矿岩系及赋矿构造双重控制,深部矿体赋存层位和上部明显不同,直接受高角度的挤压破碎带控制,说明银洞坡金矿床不仅仅受背斜轴部构造(层间破碎带)和地层的双重控制,局部矿体直接受层间破碎带控制。因此,在深部和外围进一步寻找不完全受层位控制的盲矿体,将有可能大幅度地扩大矿山的地质储量,延长矿山的服务年限。     

临沂市开发区土地集约利用评价工作分析

土地集约利用评价成果对增强政府调控土地利用的能力,构建资源节约型社会,促进经济社会可持续发展都具有重要的意义。该文在分析及评价临沂市开发区土地利用现状、结构的基础上,提出了合理化建议,对促进临沂市土地可持续利用具有重要意义。     

Assessment of the risk of rockfalls in Wu Gorge, Three Gorges, China

In 2007 and 2008, six big damaging rockfalls occurred at four sites in Wu Gorge, the second gorge of the Three Gorges, China. Detailed surveys and aerial-photographic interpretation identified 104 potentially dangerous rock masses. This paper reviews previous rock-mass risk ratings, examines dangerous rock-mass structure and presents a new assessment system for rockfall risk (ASRFR) in the Wu Gorge area. The ASRFR considers 15 factors: seven factors for hazard and eight factors for consequence. Relative importance weights for these factors are ascertained using an analytic hierarchy process. Using an equation to calculate the risk, the 104 dangerous rock masses were divided into three risk groups: high risk (33 sites), medium risk (33 sites) and low risk (38 sites). The ASRFR analysis can be used to divide the shipping route through the Wu Gorge into seven courses each of one of three classes: safe-route regions, yellow-alarm regions and red-alarm regions. The system provides geological information and a rockfall-risk management tool for local government and the shipment-route department.     

东昆仑阿牙克库木湖北巴什尔希花岗岩锆石LA-ICP-MS U-Pb定年及其地质意义

巴什尔希岩体分布在东昆仑西段白干湖断裂和阿尔金断裂之间,岩性主要为二长花岗岩和钾长花岗岩,其中二长花岗岩与白干湖钨、锡多金属矿床关系密切。对锆石内部结构、阴极发光图像特征和Th/U比值的研究表明,二长花岗岩中的锆石为岩浆锆石。锆石LA-ICP-MSU-Pb同位素分析结果显示,二长花岗岩形成年龄为(458.0±9.0)Ma。结合前人对巴什尔希钾长花岗岩的锆石U-Pb定年(432.3±0.8)Ma,初步认为该岩体为晚奥陶世—早志留世侵入体。元素地球化学特征显示,巴什尔希花岗岩为弱准铝质或弱过铝质A型花岗岩,是东昆仑地区加里东期局部弧后盆地拉张过程中,地幔底侵导致地壳物质熔融的产物。     

测井-地震多属性密度曲线重构反演技术及应用

为了提高波阻抗反演的分辨率,在密度资料对反演结果产生重要影响的基础上,利用岩心、测井及地震资料,从岩石物理性质-测井响应-地震响应角度分析,提出应用测井-地震多属性密度曲线重构技术合成拟密度曲线,其结果用全井连续取心样品测试分析数据验证的平均误差为0.05 g/cm3.应用反演效果分析表明,反演结果吻合率从重构前的78%提高到重构后的86%,密度曲线重构反演技术提高了反演精度和分辨率.     

汝阳竹园沟钼矿床地质特征及找矿方向

汝阳竹园沟钼矿床位于河南省汝阳县南部的太山庙复式花岗岩体北东侧第二次侵入的细粒花岗岩(γ53-2)岩体内接触带。在讨论成矿地质背景基础上,对矿区构造、岩体、围岩蚀变及地球化学特征进行了研究。矿体呈似层状分布,其形态、产状受第二次侵入的细粒花岗岩(γ53-2)岩体形态、产状影响较大,说明竹园沟钼矿床无论在空间上、时间上、成因上均与深部同熔型花岗岩浆有关,矿床成因为斑岩型钼矿。找矿标志和找矿方向的提出,对以后区域上花岗岩基分布区的找钼工作有一定的指导意义。     

Implication of coupled natural and human systems in sustainable rangeland ecosystem management in HKH region

The sustainable development of rangeland ecosystems, the vital ecosystems providing many important ecosystem services for millions of people in the Hindu Kush-Himalaya region is presently confronted with a number of challenges. A coupled natural and human systems approach is needed to facilitate effective collaboration among social scientists, bio/physical scientists, and management practitioners to better understand how people interact with the environment in which they live. In pursuing this argument, three existing case studies, i.e. Indigenous rangeland management in Himalayan Nepal, Cultivated Grassland Systems in Eastern Qinghai-Tibetan Plateau, and Grassland Restoration in Central Qinghai-Tibetan Plateau were synthesized in this paper to address the importance of coupled natural and human systems in promoting sustainable rangeland ecosystem management in the Hindu Kush-Himalaya (HKH) region. It was concluded although the research sites and objectives were very different, that these three case studies had many commonalities that addressed the complex interactions and feedbacks between natural and human systems, and highlighted the integration of various tools and techniques from the ecological and social sciences, as well as other disciplines, in sustainable rangeland management. These case studies have offered unique interdisciplinary insights into complexities that cannot be gained from ecological or social research alone. The results from these case studies can be applied to many other coupled systems at local, national, and global levels.     

Estimation of the methane flux from mud volcanoes along Chishan Fault,southwestern Taiwan

Because of the increasing public awareness of the greenhouse effect, geological emissions of methane (GEM) have gained more attention. The Intergovernmental Panel on Climate Change included GEM in the natural sources of methane category in the Fourth Assessment Report in 2007. The methane flux from mud volcanoes (MVs) is the second leading source within GEM. However, given that gas flux from MVs has been measured directly only in Sicily and Azerbaijan, the global methane estimation is still a conservative assumption based on limited data. The behavior of MV activities is seldom reported. This study attempts to estimate annual methane emissions through MVs by using a video recorder to record MV activities along the Chishan Fault and determining the bubble size and flux rate of each MV. Observation results, after a 1 year observation period, indicate that the annual emissions of the 19 MVs along the Chishan Fault are 0.1–0.2% of the global methane flux from MVs, highlighting that the methane emission from these MVs should not be neglected. In addition, the continuous monitoring of a particular MV disclosed periodic characteristics of MV activities. These results manifest the spatial and temporal variations of MV activities along the Chishan Fault. The spatial variations are related to the extensional kinematics of the Chishan fault, while the temporal variation relates to the earth-tide-related MV activities. The estimated annual methane emissions from the study are far more than those of previous studies and are still considered conservative. Results of this study may provide valuable information for researchers attempting to estimate the quantity of GEM.     

Characteristics and influencing factors of frontal upwelling in the Yellow Sea in summer

Frontal upwelling is an important phenomenon in summer in the Yellow Sea (YS) and plays an essential role in the distribution of nutrients and biological species. In this paper, a three-dimensional hydrodynamic model is applied to investigate the characteristics and influencing factors of frontal upwelling in the YS. The results show that the strength and distribution of frontal upwelling are largely dependent on the topography and bottom temperature fronts. The frontal upwelling in the YS is stronger and narrower near the eastern coast than near the western coast due to the steeper shelf slope. Moreover, external forcings, such as the meridional wind speed and air temperature in summer and the air temperature in the preceding winter and spring, have certain influences on the strength of frontal upwelling. An increase in air temperature in the previous winter and spring weakens the frontal upwelling in summer; in contrast, an increase in air temperature in summer strengthens the frontal upwelling. When the southerly wind in summer increases, the upwelling intensifies in the western YS and weakens in the eastern YS. The air temperature influences the strength of upwelling by changing the baroclinicity in the frontal region. Furthermore, the meridional wind speed in summer affects frontal upwelling via Ekman pumping.