滇西九顶山斑状花岗岩LA-ICP-MS锆石U-Pb定年及地球化学特征   总被引：1，自引：0，他引：1  

刀艳 《地质与勘探》2014,50(3):533-542

九顶山斑状花岗岩产于扬子板块西缘与金沙江-哀牢山深大断裂构造带东侧交会部位,是矿区内复式小杂岩体群中出露面积最大的岩体。岩体斑晶含量约占30%,主要由正长石、斜长石、石英和少量的黑云母、角闪石等组成;基质为中细粒的石英、斜长石和正长石等组成,副矿物主要有磷灰石和锆石等。斑状花岗岩中锆石U-Pb年龄为34.7±0.6 Ma,为喜马拉雅早中期(始新世)的产物。斑状花岗岩具有高钾富碱高铝的特征,属碱性-碱钙性,高钾钙碱性系列-钾玄岩系列,大部分落入A型花岗岩区域。斑状花岗岩轻稀土富集、重稀土亏损(La/Yb)N=28.90~42.28,负Eu异常(δEu=0.69~0.93)不明显,富集大离子亲石元素Rb、Ba、U、Th和亏损高场强元素Nb、Ta、Zr、Hf。通过斑状花岗岩地球化学特征、图解判别等的综合研究,认为九顶山斑状花岗岩是壳幔混合成因,形成于青藏高原新生代碰撞造山-造山期后拉张的构造环境。  相似文献   

新疆04井水位突降异常的机理分析   总被引：3，自引：3，他引：0  

王道  卢静芳  许秋龙  高小其 《内陆地震》2001,15(2):104-113

通过04井地下不动力学条件和地球化学环境的综合分析，探讨了井水位突降异常变化的基本特征和相邻两并含水层孔隙压力动态的关系及相互作用过程。4b井喷（溢）水卸压是04井水位突降的直接原因。当04井的水位升高，水头高度达到并超过4b井井口的高度时，4b井开始喷水卸压，水头损失造成孔隙压力的降低而形成降落漏斗，造成04井水位突然下降，一旦4b井喷水停止，04井水位又开始上升并逐步恢复到正常水位高度。在04井水位持续突降变化阶段，可通过统计突降过程参数（如突降发生的频度、两次突降异常之间的时长等）判别地震前兆异常。  相似文献   

Three‐dimensional indoor network accessibility auditing for floor plan design          下载免费PDF全文

Thi Hong Diep Dao  Jean‐Claude Thill 《Transactions in GIS》2018,22(1):288-310

Built environments have played an increasingly important and complex role in contemporary cities in the face of the significant number of discretionary and non‐discretionary event‐based activities that take place indoors, and the great variety of three‐dimensional designs that indoor spaces have grown to assume. However, intelligent tools that can assist designers to achieve high accessibility, particularly for large and complex buildings, are still underdeveloped. This article presents an innovative custom computer‐based design tool, dubbed FloorplanAAU (floor plan accessibility auditing), that couples GIS data modeling, indoor traversable network accessibility analysis, and interactive three‐dimensional visualization for built environments, to interactively evaluate and audit floor plans for high accessibility. The proposed method contributes to the success of applying GIS and transportation geography concepts to establish computational tools toward intelligent design and assessment of built environments.  相似文献   

Change in carbon flux (1960–2015) of the Red River (Vietnam)     

Thi Phuong Quynh Le  Nhu Da Le  Viet Nga Dao  Emma Rochelle-Newall  Thi Mai Huong Nguyen  Cyril Marchand  Thi Thuy Duong  Thi Xuan Binh Phung 《Environmental Earth Sciences》2018,77(18):658

Global riverine carbon concentrations and fluxes have been impacted by climate and human-induced changes for many decades. This paper aims to reconstruct the longterm carbon concentrations and carbon fluxes of the Red River, a system under the coupled pressures of environmental change and human activity. Based on (1) the relationships between particulate and dissolved organic carbon (POC, DOC) or dissolved inorganic carbon (DIC), and suspended sediments (TSS) or river water discharge and on (2) the available detailed historical records of river discharge and TSS concentration, the variations of the Red River carbon concentration and flux were estimated for the period 1960–2015. The results show that total carbon flux of the Red River averaged 2555?±?639 kton C year^?1. DIC fluxes dominated total carbon fluxes, representing 64% of total, reflecting a strong weathering process from carbonate rocks in the upstream basin. Total carbon fluxes significantly decreased from 2816 kton C year^?1 during the 1960s to 1372 kton C year^?1 during the 2010s and showed clear seasonal and spatial variations. Organic carbon flux decreased in both quantity and proportion of the total carbon flux from 40.9% in 1960s to 14.9% in 2010s, reflecting the important impact of dam impoundment. DIC flux was also reduced over this period potentially as a consequence of carbonate precipitation in the irrigated, agricultural land and the reduction of the Red River water discharge toward the sea. These decreases in TSS and carbon fluxes are probably partially responsible for different negatives impacts observed in the coastal zone.  相似文献   

Three-dimensional,time-dependent modeling of rainfall-induced landslides over a digital landscape: a case study     

The Viet Tran  Massimiliano Alvioli  Giha Lee  Hyun Uk An 《Landslides》2018,15(6):1071-1084

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冷龙岭活动断裂的滑动速率研究   总被引：20，自引：0，他引：20       下载免费PDF全文

何文贵  刘百篪  袁道阳  杨明 《地震工程学报》2000,22(1):91-98

根据对冷龙岭断裂重点地段的野外调查,研究了该断裂的几何特征及浮雕劝速率。结果表明：该断裂为一条全新世活动断层,由一组近于平行的次级断裂所组成。按总体特征可将该断裂分为３段,中更新世以来各时代的断裂平均滑动速率分别为：中更新世：２．１４～４．６４ｍｍ／ａ,晚更新世：２．８６～４．０７ｍｍ／ａ,全新世：３．３５～４．６２ｍｍ／ａ,全新世以来该断裂平均垂直滑动速率为０．３８ｍｍ／ａ。  相似文献   

天山地震活动区地下水同震、震后效应的研究   总被引：1，自引：0，他引：1  

王道 《内陆地震》2000,14(3):252-259

前言一个完整的地震过程应当包括震前孕育、震时发生和震后调整全过程。研究震时、震后效应对认识震源形成及前兆异常演变过程 ,预报后续地震 (强余震、强震群、相关地震和成组地震 )以及评定地震烈度和灾害都具有重要意义。作者收集分析了中国新疆、哈萨克斯坦、吉尔吉斯斯坦、乌兹别克斯坦、塔吉克斯坦、土库曼斯坦等天山地震活动区 1 970年以来 48次地震 ( M≥ 5 .0 )、35 0多项地下水地震异常资料。研究表明 :地下水动力学和水文地球化学参数不仅在震前表现出明显的前兆异常变化 ,而且在震时和震后异常效应也十分普遍和强烈。震时、震…  相似文献   

新疆04井水位固体潮加卸载响应比的研究     

陈玲  王道  张洪斌 《内陆地震》2000,14(1):71-77

根据加卸载响应比理论,利用１９９０～１９９７年新疆０４井水位动态观测资料,分析了井水位对地球固体潮汐的响应。通过彼尔采夫滤波、气压和水位相关分析,剔除水位长趋势变化和气压的影响,计算出井水位固体潮体应变的响应率,合理地选取加载和卸载的时段,得出水位固体潮加卸载响应比,其值为１左右。水位固体潮加卸载响应比变化特征为年变平稳、幅度小,在中强地震活动时出现比值短期增高现象,异常大多出现在震前１～３个月内  相似文献   

Numerical investigation of the effect of seasonal variations of depthof-closure on shoreline evolution     

Xuan Tinh Nguyen  Minh Thanh Tran  Hitoshi Tanaka  Trung Viet Nguyen  Yuta Mitobe  Cong Dien Duong 《国际泥沙研究》2021,36(1):1-16

The current study presents the effects of seasonal variations in the depth-of-closure(Dc)on shoreline evolution using a numerical,one-line shoreline model.Beach erosion of the southern beach of the Nha Trang Coast,which is located in south central of Vietnam,is selected as the study area.This study area is immensely influenced by the tropical monsoon climate that has a clear pattern of large waves in the northeast monsoon season and calm waves in the non-monsoon season.The analysis of the long-term measured shoreline variations from a video-camera system has found a strong correlation of these variations to the monsoon-dominated wave characteristics in the Nha Trang Bay.Therefore,a new approach for determining the depth-of-closure with consideration of the seasonal wave climate changes is purposed in the current study.By implementing this new approach into a numerical,one-line shoreline model,it is found that the seasonal variations of Dc appear to better describe the periodical shoreline evolution due to the monsoon-dominated wave characteristics for the Nha Trang Coast.Such important findings are considered to commonly apply for monsoon-dominated coastal regions in general.These findings are useful information not only for scientific readers but also for the coastal authorities and managers in order to make better countermeasure plans against this kind of erosion mechanism in the future.  相似文献   

大别山锆石喇曼光谱初步研究   总被引：3，自引：0，他引：3  

程昊  陈道公  汪相  吴元保 《地球化学》2002,31(4):383-388

对北大别地区的鹿吐石，道士冲和南大别地区的三祖,双河片麻岩锆石进行了激光喇曼探针，背散射电子显微镜（BSE）观察了U，Th等微量元素的组成分析，发现锆石喇曼光谱波数和半高宽都能指示其蜕晶化程度，而大多数情况下B1g(v3)峰更特征些。单颗粒锆石内部BSE图像与喇曼光谱能完全对应。通过锆石微区微量元素和喇曼探针分析发现，半高宽和Th/U比正相关，这是由于岩浆锆石在变质过程中不同程度的重结晶作用造成的。锆石重结晶人用是变质岩中锆石年龄和化学组成变化的主要原因。三祖寺片麻岩可能曾经遭受过燕山期的热事件扰动。  相似文献