Integrated geophysical evidence for a new style of continent-continent collision beneath the western Kunlun in the northwestern China   总被引：1，自引：0，他引：1  

Rizheng He    Rui Gao  Qiusheng Li  Ye Guan  Lithosphere Research Center 《地震学报(英文版)》2009,(4):379-387

Along the western Kunlun-Tarim-Tianshan geoscience transect in the northwestern China,an integrated geophysical investigation was carried out. Owing to the abominable natural conditions there,the sounding profile could not cross the whole transect,consequentially,a variety of velocity structures in the transverse and vertical orientations beneath the whole transect were not obtained,such as the case within the western Kunlun orogenic belt. To supply a gap of deep seismic soundings within the western Kunlun ...  相似文献   

Spatial patterns of old, deep-seated landslides: A case-study in the northern Ethiopian highlands   总被引：1，自引：0，他引：1  

M. Van Den Eeckhaut  J. Moeyersons  J. Nyssen  Amanuel Abraha  J. Poesen  Mitiku Haile  J. Deckers 《Geomorphology》2009,105(3-4):239-252

During the last decade, slope failures were reported in a 500 km² study area in the Geba–Werei catchment, northern Ethiopia, a region where landslides were not considered an important hazard before. Field observations, however, revealed that many of the failures were actually reactivations of old deep-seated landslides after land use changes. Therefore, this study was conducted (1) to explore the importance of environmental factors controlling landslide occurrence and (2) to estimate future landslide susceptibility. A landslide inventory map of the study area derived from aerial photograph interpretation and field checks shows the location of 57 landslides and six zones with multiple landslides, mainly complex slides and debris flows. In total 14.8% of the area is affected by an old landslide. For the landslide susceptibility modelling, weights of evidence (WofE), was applied and five different models were produced. After comparison of the models and spatial validation using Receiver Operating Characteristic curves and Kappa values, a model combining data on elevation, hillslope gradient, aspect, geology and distance to faults was selected. This model confirmed our hypothesis that deep-seated landslides are located on hillslopes with a moderate slope gradient (i.e. 5°–13°). The depletion areas are expected on and along the border of plateaus where weathered basalts rich in smectite clays are found, and the landslide debris is expected to accumulate on the Amba Aradam sandstone and upper Antalo limestone. As future landslides are believed to occur on inherently unstable hillslopes similar to those where deep-seated landslides occurred, the classified landslide susceptibility map allows delineating zones where human interventions decreasing slope stability might cause slope failures. The results obtained demonstrate that the applied methodology could be used in similar areas where information on the location of landslides is essential for present-day hazard analysis.  相似文献   

证据权法在三江北段铜金矿床成矿预测中的应用研究   总被引：11，自引：0，他引：11  

徐善法  陈建平  叶继华 《地质与勘探》2006,42(2):54-59

在仔细分析三江北段区域地质成矿背景的基础上,建立了该区的地质、物探、化探、遥感和矿床(点)数据库,优选了36个与铜金矿床有关的证据层.应用证据权模型对该区进行成矿预测研究分析,认为研究区内主要存在8个对铜金矿床形成有利的成矿区,这一研究对三江地区今后的矿产资源预测与评价具有重要的参考价值.  相似文献   

基于SIG的证据权法矿产资源评价及应用   总被引：1，自引：1，他引：0  

揣媛媛  肖克炎  湛邵斌  刘亚剑 《吉林大学学报(地球科学版)》2007,37(1):54-58

阐述了基于SIG的证据权法矿产资源评价体系结构和方法,并以西南三江成矿带为示范区进行了铜矿资源预测评价。示范区分别设置一个主结点和三个省级结点,并在结点服务器上进行了相应的数据与服务的部署。评价结果表明,基于SIG的矿产资源评价很好地解决了空间信息资源共享与应用问题,提高了评价效率,是一种有实用价值的评价新方法。  相似文献   

Evidence on the Koseda coast of Yakushima Island of a tsunami during the 7.3 ka Kikai caldera eruption     

Futoshi Nanayama  Fukashi Maeno 《Island Arc》2019,28(2)

Previous research indicates that Yakushima Island, southwestern Japan, may have been struck by a huge tsunami before or soon after the arrival of the Koya pyroclastic flow during the 7.3 ka caldera‐forming Kikai eruption, but this has not yet been confirmed. This paper describes sedimentological and chronostratigraphic evidence showing that Unit TG, one of three gravel beds exposed on the Koseda coast of northeast Yakushima Island and investigated here, is a tsunami deposit. Unit TG is a poorly sorted, 30 cm thick gravel bed overlying a wave‐cut bench and underlying a Koya pyroclastic flow deposit. Sparse wood fragments in Unit TG were dated at 7 416–7 167 cal year BP. The constituent gravel clasts of Unit TG are similar in composition to those of modern beach and river deposits along the Koseda coast. Unit TG also contains pumice clasts whose chemistry is identical to that of pumice derived from the 7.3 ka eruption at Kikai caldera. The long‐axis orientations and composition of gravel clasts in Unit TG suggest that they were transported by a landward‐travelling high‐particle‐concentration flow, which suggests that Unit TG was deposited by a tsunami run‐up flow during the 7.3 ka Kikai caldera eruption, just before the arrival of the major Koya pyroclastic flow at the Koseda coast. Whether the 7.3 ka tsunami was caused by a volcanic eruption or an earthquake remains unclear, but Unit TG demonstrates that a tsunami arrived immediately before emplacement of a Koya pyroclastic flow.  相似文献   

人地系统远程耦合的研究进展与展望   总被引：4，自引：2，他引：2  

马恩朴  蔡建明  韩燕  廖柳文  林静 《地理科学进展》2020,39(2):310-326

在越发紧密关联的全球化世界中,如何实现可持续发展日益需要跨系统思维和超区域政策。这首先要求致力于可持续发展研究的学科要提升自身对跨区域资源环境问题的洞察力,因此就有必要推动地理学传统研究框架的适应性创新和变革。远程耦合作为聚焦于“远距离人类与自然耦合系统之间社会经济与环境相互作用”的理论框架,有极大的潜力和优势来促进这一理论创新进程。为了缩小国内外在远程耦合领域的研究差距,论文基于文献研究和笔者对远程耦合框架的理解,从远程耦合的理论建构、经验证据、重点研究领域和研究方法4个方面介绍了该理论框架及其应用进展,并提出3个方面的展望来激发新的研究。综述表明,由于远距离人类活动不断增长以及大尺度自然过程与人类活动的相互作用,在远程连接、全球化和城市化维度上均存在大量远程耦合的经验证据;目前学术界对远程耦合框架的应用主要集中于生态系统服务、远程耦合的社会经济和环境影响及土地变化科学3个方面;同时得益于理论操作化的进展,目前开展远程耦合研究已具备较好的方法支持。基于此,论文认为,为应对新兴的现实科学命题,基于远程耦合框架的地理学研究应当在人地关系网络系统的理论创新、远程耦合动力机制和远程耦合的调控工具集3个方面实现突破。  相似文献   

川东北飞仙关组鲕滩储层硫酸溶蚀的证据和模式探讨   总被引：2，自引：0，他引：2  

杨威  魏国齐  金惠  张林  吴世祥  沈珏红 《地球学报》2006,27(3):247-251

川东北飞仙关组鲕滩储层的主要储集空间为溶蚀孔洞,主要由大气淡水溶蚀作用、有机酸溶蚀作用和硫酸溶蚀作用所形成。通过硫酸对灰岩和白云岩溶蚀实验、天然气中硫化氢含量与飞仙关组石膏厚度关系分析、天然气中硫同位素与地层中的硫同位素比较、方解石胶结物的阴离子分析等证据,首次提出了硫酸溶蚀在该储层形成中起很重要的作用。探讨了硫酸溶蚀形成储层的模式。  相似文献   

典型国家专属经济区及大陆架规划文本比较及对中国启示     

陈汉雪  付秀梅  汤慧颖  贾涛  徐伟 《海洋通报》2018,(3):254-263

本文对澳大利亚、加拿大、英国的专属经济区及大陆架规划进展和规划文本进行对比研究,结果显示这三个国家的专属经济区及大陆架规划文本具有覆盖范围全、定期修订、注重生态系统保护和重视利益相关者的共同特点;同时在规划目标、实施力度、财政支持力度以及跟踪保障措施等方面存在差异。这表明专属经济区及大陆架规划制定应该遵循四个基本理论:国土资源安全理论、动态规划理论、可持续发展理论和利益相关者理论;同时应当做好三方面保障工作:法律保障、管理体制保障和文化保障。在此基础上针对我国专属经济区及大陆架规划目前存在的法律体系、管理体制、管理意识困境,提出相关规划编制建议。  相似文献   

俯冲带流体——来自（超）高压变质岩石的证据     

高俊  李继磊  马智佩  Reiner KLEMD 《地质学报》2024,98(3):758-782

俯冲带是地球上岩浆活动、高压—超高压变质作用、中深源地震、壳幔物质交换、元素循环和铜金大规模成矿的集中发生场所。富水流体不仅调控了这些地质作用,而且也深刻影响了全球C、S等挥发分的循环。当蚀变大洋岩石圈及上覆沉积物进入俯冲带中深部（15~300 km）,伴随由葡萄石- 绿纤石相至超高压榴辉岩相的递进变质作用,含水矿物在不同深度的分解造成流体释放为一连续过程。除极端高地温梯度环境之外,大多数俯冲带洋壳释放的流体为富水流体。但,俯冲带不同深度所产生的流体特征有明显差异。出露于全球造山带的高压—超高压变质地体保存了分凝体、脉体、水压致裂角砾岩等流体作用的有力证据,绿辉石、石榴子石、绿帘石等矿物中原生流体包裹体为流体的直接记录。在俯冲带中等深度（＜65 km）,流体是溶质含量很低的含卤化物水溶液,可含CO2-3、SO2-4、HS-等组分,其所含Si、Al、Ca、Mg、Fe、Na主量元素溶质相当于海水中固化物量的2~3倍,并具大离子亲石元素（LILE）、轻元素（B、Li）富集和高场强元素（HFSE）亏损的特点。当深度≥65 km时,流体转化为类似于超临界性质的溶液,含CH4、C2H6、H2S等挥发分,其所含主量元素溶质显著增加,微量元素除LILE等外,还负载相当量的HFSE和过渡族成矿元素。俯冲带65~100 km深度,为富水流体向超临界流体转变的区间。这种流体具有“亚超临界”性质,发生了氧化还原性质和元素溶解能力的渐变,并伴随硬柱石和角闪石的最终耗尽。高压变质岩石及相关脉体的O、Sr、Nd和金属同位素示踪研究表明俯冲带流体的源区多样,有蚀变基性洋壳、地幔橄榄岩和沉积物,并保存了海底热液蚀变作用的印迹。流体以脉冲方式沿网络状裂隙呈隧道式运移和传输,规模可达千米级,时间尺度在数月至数百年。目前通过高压—超高压变质岩的研究对俯冲带流体已经有了深入的了解,但展望未来,该领域依然有诸多争议和科学问题值得探索。  相似文献   

机器学习方法在预测泉水潜在出露位置中的应用     

李慧香  潘云  宫辉力  孙颖 《地球信息科学学报》2021,23(6):1028-1039

泉水出露受到多种因素影响,在传统地质勘查手段之外,各种模型方法及影响因子预测手段,也被越来越多地应用于泉水的研究中.本文尝试利用机器学习的方法进行泉水出露位置的预测研究.根据北京市野外调查,确定了1378个测试样本点,选取了高程、坡度、坡向、地形湿度指数、径流强度指数、距河流距离、距断裂距离、岩性、归一化植被指数及土地...  相似文献