罗布泊荒漠地区湖泊蒸发盐资源的形成及环境演化

通过地球卫星遥感资料和地面调查以及化学测试等综合研究, 证实罗布泊地区存在大型现代液体钾盐矿床. 用钻探材料及系统分析方法重建了20 ka BP以来湖泊沉积序列和环境物性柱剖面, 用天然水体五元体系稳定相图讨论了古湖泊湖水及现代湖水的饱和流结晶路线及成盐成矿演化趋势. 结果证明, 液体钾盐矿床的分布及成钾成矿环境受现代地壳运动作用下新生地堑构造系统的控制.     

科尔沁沙地西北缘生态地质环境评价

采用层次分析法对科尔沁沙地西北缘地质环境、生态环境、社会环境进行分析, 构建一套以适应农牧业发展为目标层的评价指标体系, 并计算区域生态地质环境质量的综合指数, 对生态地质环境状况进行评价. 通过对评价结果统计认为: 生态环境较比地质环境、社会环境对整个评价结果的影响更大, 其中土地质量是最主要因素; 研究区所有的评价单元中有86%处于中等及偏下的水平. 该研究结果对正确认识研究区生态地质环境具有重要的意义.     

渤海渤中A区断层差异输导及控藏作用分析

渤中A区位于渤海海域的渤南低凸起北部斜坡带,前期勘探重点为潜山与古近系,而新近系的含油气性日益引起重视.从油气输导体系研究入手,明确了断层垂向输导油气是新近系成藏的关键,通过断层样式、断层活动性的分析,认为背形负花状构造及断层活动差异共同控制新近系差异成藏,并指示构造脊部位是油气优势的运移方向.另外,利用分形几何学原理,对研究区断层分形特征进行研究,构造脊部位断层分形分维数值较高,表明构造脊部位油气运移效率较高,佐证了常规方法的论断且对断层输导体系进行半定量-定量的评价.近期钻井在构造脊部位的新近系有良好发现,证实了断层输导分析的正确性.     

浙西北二叠,三叠纪浊积岩系及其大地构造意义

对浙西北上二叠统长兴组，大隆组及下三叠统政棠组沉积特征，生物生态等的研究表明，长兴组，大隆组和政棠组为一套浊积岩系沉积，沉积背影为一向东南倾斜的被动大陆边缘，印支期造山作用使其发生了强烈的前陆褶皱－冲断变形，岩石地球化学分析结果表明在浊积岩沉积时期，推测可能存在的部分来来源于晚元古代岛弧和晚元古代造山带的物源。     

Stratigraphy and depositional setting of slurry and contained (reflected) beds in the Marnoso‐arenacea Formation (Langhian‐Serravallian) Northern Apennines,Italy

This work presents the stratigraphy and facies analysis of an interval of about 2500 m in the Langhian and Serravallian stratigraphic succession of the foredeep turbidites of the Marnoso‐arenacea Formation. A high‐resolution stratigraphic analysis was performed by measuring seven stratigraphic logs between the Sillaro and Marecchia lines (60 km apart) for a total thickness of about 6700 m. The data suggest that the stratigraphy and depositional setting of the studied interval was influenced by syndepositional structural deformations. The studied stratigraphic succession has been subdivided into five informal stratigraphic units on the basis of how structurally controlled topographic highs and depocentres, a consequence of thrust propagation, change over time. These physiographic changes of the foredeep basin have also been reconstructed through the progressive appearance and disappearance of thrust‐related mass‐transport complexes and of five bed types interpreted as being related to structurally controlled basin morphology. Apart from Bouma‐like Type‐4 beds, Type‐1 tripartite beds, characterized by an internal slurry unit, tend to increase especially in structurally controlled stratigraphic units where intrabasinal topographic highs and depocentres with slope changes favour both mud erosion and decelerations. Type‐2 beds, with an internal slump‐type chaotic unit, characterize the basal boundary of structurally controlled stratigraphic units and are interpreted as indicating tectonic uplift. Type‐3 beds are contained‐reflected beds that indicate different degrees of basin confinement, while Type‐5 are thin and fine‐grained beds deposited by dilute reflected turbulent flows able to rise up the topographic highs. The vertical and lateral distribution of these beds has been used to understand the synsedimentary structural control of the studied stratigraphic succession, represented in the Marnoso‐arenacea Formation by subtle topographic highs and depocentres created by thrust‐propagation folds and emplacements of large mass‐transport complexes.     

柴北缘锡铁山韧性剪切带的基本特征及其形成时代

在柴北缘锡铁山地区元古宇达肯大坂群与奥陶系滩涧山群之间发育一条呈NW向展布的基底韧性剪切带。本文对该韧性剪切带中的宏观构造(鞘褶皱、不对称褶皱、塑性流变组构、S-C组构、旋转碎斑系、构造透镜体、粘滞型石香肠构造)和糜棱岩微观构造(云母鱼构造、压力影构造、动态重结晶、雪球状旋转构造、波状消光和云母扭折)特征作了详细的研究。对锡铁山基底韧性剪切带中花岗质糜棱岩进行白云母Ar-Ar同位素测年,获得坪年龄为398±4 Ma,等时线年龄为399±4 Ma,二者基本一致,代表了锡铁山基底韧性剪切带的形成时间。综合上述特征判断,锡铁山韧性剪切带是一条由元古宇达肯大坂群向SW斜向逆冲所形成的右行逆冲韧性剪切带,该韧性剪切带与早古生代柴达木地块向NE斜向俯冲碰撞造山作用有关,并可能导致了超高压变质体折返到浅部地壳层次。同样,该韧性剪切带的存在,也对锡铁山铅锌矿起到了十分重要的后期构造控制作用。     

DF1-1底辟区构造应力场及渗流场演化的数值模拟研究

DF1-1底辟区是莺歌海盆地内超压流体最活跃的地带之一.超压流体的活动直接受控于构造应力及其形成的不同类型的断裂和裂隙构成的输导系统.从底辟区大规模流体垂向活动以及幕式活动的特征来看, 流体流动的动力主要是由于垂向压差的存在以及渗流场变化引起的局部应力场(包括热应力场) 的作用所致.在详细研究底辟区的构造及流体活动关系的基础上, 对底辟区构造应力场及渗流场的演化进行了模拟.结果显示: 构造运动引起的应力场决定了DF1-1底辟区油气沿主要断裂系走向迁移的总趋势, 在底辟区流体从底辟的两侧向其中心运移, 由底辟体中向上运移为主; 高压流体产生的热应力控制局部应力场状况及油气运移方向, 驱动流体向底辟体顶部运移, 当热应力值过大时有可能改变应力场状况以及油气运移总趋势.      

Decentralized ℋ︁∞ controller design for large‐scale civil structures

Complexities inherent to large‐scale modern civil structures pose many challenges in the design of feedback structural control systems for dynamic response mitigation. With the emergence of low‐cost sensors and control devices creating technologies from which large‐scale structural control systems can deploy, a future control system may contain hundreds, or even thousands, of such devices. Key issues in such large‐scale structural control systems include reduced system reliability, increasing communication requirements, and longer latencies in the feedback loop. To effectively address these issues, decentralized control strategies provide promising solutions that allow control systems to operate at high nodal counts. This paper examines the feasibility of designing a decentralized controller that minimizes the ??_∞ norm of the closed‐loop system. ??_∞ control is a natural choice for decentralization because imposition of decentralized architectures is easy to achieve when posing the controller design using linear matrix inequalities. Decentralized control solutions are investigated for both continuous‐time and discrete‐time ??_∞ formulations. Numerical simulation results using a 3‐story and a 20‐story structure illustrate the feasibility of the different decentralized control strategies. The results also demonstrate that when realistic semi‐active control devices are used in combination with the decentralized ??_∞ control solution, better performance can be gained over the passive control cases. It is shown that decentralized control strategies may provide equivalent or better control performance, given that their centralized counterparts could suffer from longer sampling periods due to communication and computation constraints. Copyright © 2008 John Wiley & Sons, Ltd.     

Assessment and prioritization of soil erosion triggering factors using analytical hierarchy process and Taguchi method

The main aims of this study are assessing some factors which affect the soil erosion process and evaluating the results of an analytical hierarchy process(AHP) method using the Taguchi method. Firstly, the weights for those factors and levels affecting soil erosion were determined by the AHP method. The determination of weights was based on the opinions of academic researchers, experts, middle managers,and members of the Soil and Water Research Centers in Iran. Secondly, an L32 Taguchi orthogona...