鄂东南大冶矿区地质环境影响性评价

在我国,矿业城市的地质环境问题日趋严重,需要探索一套适合于区域矿山地质环境影响性评价的技术方法,以指导矿业城市或重点矿区的矿产资源开发和环境保护。以鄂东南大冶矿区(即大冶市)为例,以遥感调查数据为基础,建立了由地质环境背景、已有地质环境问题和矿山开采活动三方面组成的区域矿山地质环境影响性评价指标体系,采用传统的模糊综合评价方法,分别对自然状态下矿区的地质灾害易发性和采矿状态下的矿区地质环境影响性进行了定量评价。结果表明:(1)自然状态下,大冶矿区地质灾害高易发区、较高易发区、较低易发区及低易发区分别占评价总面积的3.29%、12.55%、24.53%及59.62%;(2)采矿状态下,大冶矿区地质环境影响性严重区、较严重区、一般、轻微区分别占评价总面积的13.63%、22.96%、33.95%及24.96%。评价结果可作为大冶矿区矿产开发规划和综合性地质环境治理的重要依据。     

碱泉子-洛包泉活动断裂带几何学特征及分段研究

碱泉子—洛包泉活动断裂带总体走向北东东 ,平面上由 7条呈左阶斜列状排列的活动断裂组成。断裂带自晚更新世晚期以来一直在活动 ,184 2年与 1914年发生了 2次 7.5级地震 ,并沿断裂带形成地震破裂带。对断裂带的新活动特征及断裂活动与地震活动关系的研究表明 ,碱泉子—洛包泉活动断裂带自晚更新世晚期以来约发生过 10次显著活动 ,其中大多数活动与 7级以上地震活动有关     

稳健基准应变分析法用于鲜水河断裂带活动特征研究

本文运用稳健估计法确定位移基准,以此为基础,识别影响均匀应变场的特殊位移信息,并在估计均匀应变参数的同时,也对特殊位移信息作出估计。用所提的分析方法对覆盖鲜水河断裂带的甘孜一塔公寺三角锁网三期成果进行了分析处理,研究了该断裂带的活动特征。     

吉林西部洋沙泡水库高氟水的形成

在调查、分析洋沙泡周边地质、水文地质和氟土壤特征的基础上,结合洋沙泡水库模拟实验结果对吉林西部洋沙泡水库高氟水的形成进行了深入研究。结果表明,吉林西部高氟环境的形成是地表环境长期演化的结果:大兴安岭岩浆岩和松嫩低平原松散沉积物提供了含氟丰富的物质基础,河流及地下水径流提供了氟迁移的动力条件,典型的低平原是高氟形成的地理条件,干旱半干旱的气候条件成为高氟环境的促进条件。洋沙泡的氟主要来源为二龙涛河径流携带,多年平均携带量占年内氟总来源的99%以上;周边径流占0.014%～0.28%;降水携带量占0.012%;蒸发浓缩作用对洋沙泡水库的氟质量浓度也有一定影响。此外,内源底泥的释放也是洋沙泡水库水体氟质量浓度增高的原因之一,并且在引嫩入白工程实施后,依然使洋沙泡水库水体中氟质量浓度增加。在每年引水的情况下,需要5年时间水库水体氟的质量浓度才会降至1.0mg/L以下。风动力和人为活动也对洋沙泡水库的氟质量浓度变化产生影响。     

Gnargoo: a possible 75 km-diameter post-Early Permian – pre-Cretaceous buried impact structure,Carnarvon Basin,Western Australia

The Gnargoo structure is located on the Gascoyne Platform, Southern Carnarvon Basin, Western Australia, and is buried beneath about 500 m of Cretaceous and younger strata. The structure is interpreted as being of possible impact origin from major geophysical and morphometric signatures, characteristic of impact deformation, and its remarkable similarities with the proven Woodleigh impact structure, about 275 km to the south on the Gascoyne Platform. These similarities include: a circular Bouguer anomaly (slightly less well-defined at Gnargoo than at Woodleigh); a central structurally uplifted area comprising a buried dome with a central uplifted plug; and the lack of a significant magnetic anomaly. Gnargoo shows a weakly defined inner 10 km-diameter circular Bouguer anomaly surrounded by a broadly circular zone, ～75 km in diameter. The north?–?south Bouguer anomaly lineament of the Giralia Range (a regional topographic and structural feature) terminates abruptly against the outer circular zone which is, in turn, intersected on the eastern flank by the Wandagee Fault. A <?28 km-diameter layered sedimentary dome of Ordovician to Lower Permian strata, surrounding a cone-shaped, central uplift plug of 7?–?10 km diameter, are inferred from the seismic data. Seismic-reflection data indicate a minimum central structural uplift of 1.5 km, as compared to a model uplift of 7.3 km calculated from the outer structural diameter. An interpretation of Gnargoo in terms of a plutonic or volcanic caldera/ring origin is unlikely as these features display less regular geometry, are typically smaller and no volcanic rocks are known in the onshore Gascoyne Platform. An interpretation of Gnargoo as a salt dome is likewise unlikely because salt structures tend to have irregular geometry, and no extensive evaporite units are known in the Southern Carnarvon Basin. Morphometric estimates of the rim-to-rim diameter based on seismic data for the central dome correspond to the observed diameter deduced from gravity data, and fall within the range of morphometric parameters of known impact structures. The age of Gnargoo is constrained between the deformed Lower Permian target rocks and unconformably overlying undeformed Lower Cretaceous strata. Because of its large dimensions, if Gnargoo is an impact structure, it may have influenced an environmental catastrophe during this period.     

郯庐断裂带莱州湾段的构造特征

本文利用海上浅层地震勘探剖面分析了郯庐断裂带莱州湾段的上更新统、全新统和活动构造的某些特征。晚更新世末期发生的构造运动使上更新统产生断裂与褶皱,沿郯庐断裂带东主干断裂发育了狭长的背斜构造,在西主干断裂两侧次级横向(东西向)断裂十分发育,这些横向断裂是一些高角度的张性正断层。     

Focal Fault and Stress Field of the Yao‘ an M 6.5 Earthquake on January15,2001

Using the 78 focal mechanism solutions of the fore shocks, main shock and after shocks of the earthquake sequence for the Yao'an earthquake, the characteristics of the focal faults and stress field for the earthquake sequence are analyzed. The results show that the main rupture plane of the Yao'an earthquake sequence is a tectonic fault with N50°W strike and steep dip and all the main shock, the fore shocks and the vast majority of after shocks occurred on the main rupture plane. A tectonic fracture with NNE-NE strike also participated in development process of the sequence. The focal stress field of the sequence dominated by principal compressional stress with nearly horizontal orientation SSE is consistent with the regional tectonic stress field. In the sequence development, the stress field in the focal region was complex with multi-azimuths and multi-action models and the focal rupture showed complex features with multi-directions and multi-patterns.     

岫岩陨石坑撞击角砾岩的岩相学和冲击变质特征SCIEI北大核心CSCD

撞击角砾岩是陨石撞击过程形成的特有岩石种类,是研究撞击成坑过程、陨石坑定年、矿物岩石冲击变质的理想对象。岫岩陨石坑是一个直径1800m的简单陨石坑,坑内有大量松散堆积的撞击角砾岩。本研究通过光学显微镜、费氏台、电子探针、X射线荧光光谱仪、电感耦合等离子质谱仪等分析测试手段,主要研究了岫岩陨石坑撞击角砾岩的岩相学和冲击变质特征,并在此基础上讨论了撞击角砾岩的形成过程和陨石坑的形貌特征。岫岩陨石坑内产出有三种撞击角砾岩,分别是来自上部的玄武质角砾岩和复成分岩屑角砾岩,以及底部的含熔体角砾岩。组成玄武质角砾岩和复成分岩屑角砾岩的碎屑受到的冲击程度较低,仅有少量石英发育面状变形页理,指示不超过20GPa的冲击压力。而组成含熔体角砾岩的碎屑受到了很强的冲击,发育了熔融硅酸盐玻璃、石英面状变形页理、柯石英、二氧化硅玻璃、击变长石玻璃、莱氏石等冲击变质特征,指示的峰值压力超过50GPa。本研究证实了含熔体角砾岩通常产出在简单陨石坑底部,由瞬间坑的坑缘和坑壁垮塌的岩石碎屑与坑底的冲击熔体混合形成。岫岩坑的真实深度是495m,真实深度与直径的比值为0.275,符合简单陨石坑的尺寸特征。陨石坑内的撞击角砾岩中心厚度为188m,与直径之比为0.104,略低于其它简单坑,可能是受丘陵地貌影响导致改造阶段垮塌到坑内的岩石角砾偏少。     

An efficient methodology for simulating earthquake‐induced 3D pounding of buildings

The current paper presents an efficient methodology for numerically simulating in three dimensions adjacent buildings that may experience pounding during strong earthquakes. In particular, a new approach to the numerical problem of spatial impact modeling that does not require the ‘a priori’ determination of the contact points is presented, taking also into account the geometry at the vicinity of an impact. In the current study, the buildings are simulated as linear multi‐degree‐of‐freedom‐systems, but the methodology can be easily extended to consider nonlinear behavior as well. A software application has been specifically developed to implement the proposed methodology, using modern object‐oriented design and programming. The developed software is utilized in a simple example, and the computed results are compared with the corresponding analysis results obtained from a commercial general‐purpose software application that uses typical contact elements for the simulation of impacts. A discussion follows on the advantages and capabilities of the proposed methodology and the developed software. Copyright © 2013 John Wiley & Sons, Ltd.     

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