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981.
This paper examines the morphotectonic and structural–geological characteristics of the Quaternary Martana Fault in the Umbria–Marche Apennines fold‐and‐thrust belt. This structure is more than 30 km long and comprises two segments: a N–NNW‐trending longer segment and a 100°N‐trending segment. After developing as a normal fault in Early Pleistocene times, the N–NNW Martana Fault segment experienced a phase of dextral faulting extending from the Early to Middle Pleistocene boundary until around 0.39 Ma, the absolute age of volcanics erupted in correspondence to releasing bends. The establishment of a stress field with a NE–ENE‐trending σ3 axis and NW–NNW σ1 axis in Late Pleistocene to Holocene times resulted in a strong component of sinistral faulting along N–NNW‐trending fault segments and almost pure normal faulting on newly formed NW–SE faults. Fresh fault scarps, the interaction of faulting with drainage systems and displacement of alluvial fan apexes provide evidence of the ongoing activity of this fault. The active left‐lateral kinematic along N–NNW‐trending fault segments is also revealed by the 1.8 m horizontal offset of the E–W‐trending Decumanus road, at the Roman town of Carsulae. We interpret the present‐day kinematics of the Martana Fault as consistent with a model connecting surface structures to the inferred north‐northwest trending lithospheric shear zone marking the western boundary of the Adria Plate. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   
982.
THE EVALUATION AND ANALYSIS OF THE TOURISM RESOURCES IN JILIN PROVINCE   总被引:1,自引:0,他引:1  
This paper comprehensively evaluates and analyzes the tourism resources in Jilin Province,China.And it consists of three parts.The first two parts are on the resources evaluation and analysis.Based on the results of evaluation about the structural and spatial distribution of the tourism resources,it is found that ,the natural resources play fundamen-tal roles in Jilin,while the human and cultural resources are important complementary parts as well .In the spatial distribu-tion analysis,the resources show the characteristic of “six clusters“and “three belts “spatial relations.Four clusters are centered on the cities,which are Changchum,Jilin,Baicheng,Tonghua and Jiˊan;one cluster is around the Changbai Moutains and one cluster nears the frontier at Tumen between China,Russia and P.D.R.Korea.And the three belts are;1)The west belt.It contains Xianghai and Momoge natural protection region.The evident of this zone is its ecologi-cal and ethical tourism resources.2)The middle belt characterized by urban traveling and recreation,including Jilin and Changchum,together with their nearby Nongˊan and Siping.3)The last belt is also the most important one,which is the east zone.It covers the Changbai Mountains,the golden triangles of Tonghua and the Tumen River.This zone is remark-able for its abundant natural landscapes and unique folk-customs.In the last part the concept planning is briefly construct-ed for the tourism resources in Jilin Province according to the above evaluation and analysis.  相似文献   
983.
两郧断裂构造解析与第四纪滑动速率研究   总被引:2,自引:1,他引:1  
根据现场调查、大比例尺地质填图和第四纪年代学测定,利用构造解析法分析总结了两郧断裂的基本构造样式、构造变形序次和离散走滑(拉分)型盆地、汇聚挤压型剪切弯曲等相关构造特征;定量估算出两郧断裂中西段第四纪的滑动速率。  相似文献   
984.
Kongsvegen, a surge‐type glacier in Spitsbergen, Svalbard, shares a tide‐water margin with the glacier Kronebreen. The complex has been in retreat since a surge advance of Kongsvegen around 1948. The surface of Kongsvegen displays suites of deformational structures highlighted by debris‐rich folia. These structures are melting out to form a network of sediment ridges in the grounded terminal area. The structures are also visible in a marginal, 1 km long, 5–20 m high cliff‐face at the terminus. Current models for the evolution of deformational structures at Kongsvegen divide the structures into suites based on their orientation and dip, before assigning a mechanism for genesis based on structure geometry. Interpretation of aerial photographs and field mapping of surface structures suggest that many structures were reorientated or advected during the surge. We suggest that many of the deformational structures highlighted by debris‐rich folia represent reorientated, sediment‐filled crevasses. Some evidence of thrusting is apparent but the process is not as ubiquitous as previously suggested. Many deformational structures also appear to have been offset by more recent structures. Mechanisms of structural development must, therefore, be considered within the context of distinct stages of glacier flow dynamics and multiple surge episodes. Furthermore, evidence for thrusting and folding within the glacier systems of Svalbard has been used as the basis for interpreting Quaternary glacial landforms in the UK. The findings of this paper, therefore, have implications for interpretations of the Quaternary record. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   
985.
李旭  谢艳  殷翅  常军 《世界地震工程》2022,38(1):080-89
目前作为结构健康监测系统核心的损伤识别大多是基于模态参数变化而进行的,但模态参数对局部损坏不敏感,导致损伤识别精度不够。波在结构中的传播状态可以更好地反映局部损伤状况,波动能量可以作为损伤识别的有效指标。为了提高环境激励下结构损伤识别的精度,采用S变换分析了结构输出信号,建立波动能量指标,从而使波动能量指标的使用领域扩展到非平稳信号范围。最后通过三层钢框架试验及弹性分层剪切梁的数值模型对该方法进行了验证,结果表明:该方法不仅能够有效识别结构损伤位置,而且能够识别出损伤程度。  相似文献   
986.
为了研究甘肃寨上金矿南矿带矿体隐伏规律,预测深部找矿远景,基于构造叠加晕找矿方法对该矿床南矿带深部找矿潜力进行探讨。对南矿带32号脉9种金属元素(Au、Ag、As、Bi、Cu、Pb、Sb、W、Zn)的测试数据进行数学地质分析,结果表明Au与As具有较好的相关性,是找矿的指示元素;As与Sb、Cu与Bi的相关系数分别为0.586、0.945,可能与它们在热液上升过程中靠近矿体的头部和尾部有关。基于对矿区9种元素的数学统计分析并与中国金矿床原生晕综合轴向(垂向)分带序列对比,得到寨上矿区理想原生晕分带序列为:As-Sb(前缘晕)→Pb-Ag-Au-Zn-W(近矿晕)→Cu-Bi(尾晕);根据改良的格里戈良分带指数法得到各勘探线轴向分带序列,前、尾晕共存等“反分带”现象的出现表明存在多次热液叠加作用。使用克里金插值法得到衬值晕分带图,显示矿体向东倾覆,含矿热液应从东南向西北运移,剥蚀程度自东向西加强。在野外地质工作的基础上,结合矿区地质特征和元素空间分布规律,建立了南矿带构造叠加晕实用模型。根据原生晕找矿特征标志,32号脉东南部67线深处的有利成矿空间指示有矿,并将其定成预测靶位。通过布设钻孔ZK67-0验证了预测靶位的准确性,表明构造叠加晕实用模型在寨上金矿找矿预测具有可行性。  相似文献   
987.
Tectonic activity occurred during the depositional period of the Enping Formation in the southern Baiyun Sag in the Pearl River Mouth Basin,with a series of synsedimentary faults and a set of large fan delta reservoir bodies developing.There is no data from drilling,cores,etc.for this area,so this paper applies three-dimensional seismic data to study the structural style of the steep slope zone,the seismic facies characteristics of fan deltas,and the source-sink system and sedimentary model of the Enping Formation.The control action of tectonic activity on fan deltaic sedimentary systems is studied by combining interpretation of fault systems,dissection of structural styles,seismic reflection structure,seismic facies geometry,and seismic attribute analysis,together with theoretical analysis of the source-sink deposition process.The Baiyun Sag has experienced tectonic activity since the Eocene,and a series of synsedimentary faults are developed in the southern steep slope zone.Under the common control of multiple large synsedimentary faults,a large ancient gully formed in the steep slope zone in the south,which gradually widened from south to north.The uplift area in the southern part of the sag was exposed for a long time during the deposition of the Enping Formation and consequently suffered weathering and erosion.The resulting sediments were transported through a system of provenance channels composed of slopes and an ancient gully to the depression area,where they were deposited and eventually converged to form a large fan delta.The fan delta presents the overall characteristics of NS strong wedge reflection and EW strong domal reflection—thick in the middle part and thin in the wings.It displays a lobe-shaped distribution on the plane,with the fan root pointing to the south slope.According to differences in reflection intensity from bottom to top,it can be subdivided into three stages of progradational sedimentary bodies—the southern uplift and denudation zone,the large ancient gully,and the fan delta—which together constitute a complete source-sink system.This represents a sedimentary model of progradational fan delta under the overall joint control of the re stricted ancient gully and syndepositional faults.  相似文献   
988.
神东矿区砂岩地层中存在大量的结构面,这种结构面的存在会对岩层的力学性能、超声波传播、破坏形式以及力的传递等都有显著的影响,但是结构面的微观结构及元素特征是其主要原因之一。本文以布尔台煤矿、大柳塔煤矿和补连塔煤矿地层砂岩中的结构面为研究对象,采用FEI-SEM扫描电镜和能谱仪对不同类型结构面的微观结构和元素特征进行了研究。结果表明:神东矿区砂岩中的结构面可以分为两大类(Ⅰ_和Ⅱ),其中Ⅰ_类又可以分为三个亚类(Ⅰ_1、Ⅰ_2、Ⅰ_3);Ⅰ_类主要含有煤,Ⅱ类主要含有白云母。Ⅰ_1和Ⅱ类结构面颗粒感不明显,颗粒边界不清晰,Ⅰ_2和Ⅰ_3类结构面颗粒感比较明显,颗粒边界比较清晰。Ⅰ_1、Ⅰ_2、Ⅰ_3和Ⅱ类型结构面的孔隙直径和裂隙长度(#m)分别为2.1、81.8、8.9、38.8、4.5、143.7和3.8、13.8。Ⅰ_1类结构面主要组成元素是C、O、Si、Al、K、Ti和Fe;Ⅰ_2类结构面主要为C;Ⅰ_3类结构面主要为C、O、Si、Al、K和Mg;Ⅱ类结构面的主要元素有C、O、Si、Al、K和Ti。神东矿区地层中结构面主要元素为C和O,两种类型的微观结构存在差异。研究结果有助于进一步揭示神东矿区顶板动力灾害及台阶下沉等现象。  相似文献   
989.
辽河(岩)群在辽宁省为十分重要的地层,不仅蕴藏着丰富的矿产,还存在诸多有争议的问题,变形期次就是其中重要问题之一.辽河(岩)群中最主要的构造形迹就是东西向展布的区域上透入性面理,它是纵向置换作用形成的,在微观上残留了较多置换过程的痕迹.从辽河(岩)群的的原岩建造来看,它至少经历了类似"大西洋阶段"和"太平洋阶段",不会是夭亡的裂谷.通过全方位构造解析认为,洋盆闭合挤压造山过程是一个漫长的递进变形过程,在这一漫长的递进变形过程中形成的所有构造形迹皆属同一期构造,即辽河(岩)群可归纳为一期构造.  相似文献   
990.
针对基于出行的时空特征分析在解释老年人不同活动出行行为差异上的不足,根据昆明城市老年人407份有效问卷调查和54份追踪访谈,对基于活动的出行行为特征进行分析。采用结构方程模型分析方法,对出行行为特征参数间的关系进行建模计算,得到了属性、活动因素与出行行为以及出行行为各参数间的关联性。研究结果显示:老年人不同活动的出行特征差异显著,与活动密切相关的出行行为特征参数间有较强的关联性,表现为活动对出行方式和出行强度、出发时刻对出行方式、出行方式对出行强度具有较强的影响。  相似文献   
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