四川省西昌盆地上三叠统白果湾组地球化学特征及其意义   总被引：2，自引：2，他引：0       下载免费PDF全文

白宪洲  文龙  王玉婷  伏国通 《中国地质调查》2017,4(2):51-58

对四川省西昌盆地上三叠统白果湾组碎屑岩的主量元素、微量元素、稀土元素进行综合研究,得出其主量元素具有富SiO₂、CaO、P₂O₅,贫Al₂O₃、TFe₂O₃、MgO、Na₂O、K₂O的特征; 微量元素具有富Zr、Cs、Th、U等特征; 稀土元素总量相对较高,轻重稀土元素分馏明显,轻稀土较重稀土相对富集,具有中等负铕异常。白果湾组物源区为长英质岩区,属于被动大陆边缘区; 白果湾期的气候经历了湿润→干旱→湿润→干旱的变化过程; 成分成熟度总体偏低,呈现高→低→高→低的变化规律,与CIA变化趋势呈负相关。本次研究为该区晚三叠世环境演化研究提供了基础资料。  相似文献   

Newly developed technique and analysis solution to accelerate consolidation of ultrasoft soil     

Chen Geng  Shi Jiangwei  Chen Long 《Marine Georesources & Geotechnology》2017,35(2):292-299

Plastic vertical drainage is widely used in vacuum preloading for soft soil treatment. However, plastic vertical drainage has a number of disadvantages such as it only provides drainage paths in vertical directions and the distribution of soil strength is not uniform. A new technique, prefabricated vertical–horizontal drainage, was developed in this study to shorten the consolidation time of ultrasoft soil. Using one vertical drainage tube and four horizontal drainage tubes, prefabricated vertical–horizontal drainage provides drainage paths not only in vertical but also in horizontal directions. An analytical solution was derived to calculate the degree of soil consolidation when using the prefabricated vertical–horizontal drainage technique. Field tests were conducted to evaluate the effectiveness of prefabricated vertical–horizontal drainage and to verify the proposed analytical solution. It was found that consolidation time of soft clays using prefabricated vertical–horizontal drainage was 50% lower than plastic vertical drainage. Moreover, the average undrained shear strength of soil treated by the prefabricated vertical–horizontal drainage technique was approximately 30% larger than that treated by the plastic vertical drainage technique. The degree of soil consolidation estimated from the proposed analytical solution showed good agreement with field measurements. This implies that the proposed analytical solution can be used to directly estimate the degree of consolidation when the soil is treated by prefabricated vertical–horizontal drainage.  相似文献   

大兴安岭北段偃尾山铜银矿床流体包裹体与矿床成因类型研究     

韩龙 《地质与勘探》2017,53(3):445-455

偃尾山铜银矿床是大兴安岭北段呼中-塔源成矿带内新发现的中小型矿床。矿床围岩蚀变呈面状分布,主要蚀变类型为硅化、碳酸盐化、黄铁矿化、伊利石化、高岭石化和绢云母化。热液成矿期可分为三个阶段:成矿早期石英-黄铁矿阶段(含少量黄铜矿)、主成矿期石英-斑铜矿-黄铜矿-辉铜矿(含铜硫化物)阶段和成矿晚期石英-碳酸盐-萤石阶段(含少量方铅矿和闪锌矿)。该矿床流体包裹体主要为富液相包裹体,也有少量纯气相包裹体,未见含子矿物包裹体。主成矿阶段流体包裹体均一温度为155℃~342℃,峰值集中在160℃~230℃,冰点温度在﹣3.3℃~﹣0.3℃,盐度为0.53%NaC_(leqv)~5.41%Na Cleqv;流体成分以K~+、Na~+、SO_4~(2-)为主,含少量Ca~(2+)和Cl~-,气相成分以H_2O为主,含少量的CO_2;流体δ~(18)O在-11.8‰~-13.72‰之间,δD变化范围在-105‰~-137‰之间。总体上,成矿流体为低温低盐度流体,流体来源主要是大气降水,成矿流体和矿床蚀变-矿化特征显示本矿床可能为高硫型浅成低温热液矿床。流体压力的突然降低可能是成矿物质沉淀的主要机制。偃尾山矿床可能代表了区域上同时代一种新的矿床类型,后续深入研究将有助于认识该区域成矿规律和找矿方向。  相似文献   

1951-2014年内蒙古地区气温、降水变化及其关系   总被引：2，自引：0，他引：2  

李虹雨  马龙  刘廷玺  杜艳霞  刘明 《冰川冻土》2017,39(5):1098-1112

内蒙古地域辽阔,气候复杂多变,研究气候因子变化对生态环境建设、水资源开发利用有一定借鉴意义。利用内蒙古地区及周边70个气象站点1951-2014年气温和降水资料,采用中心聚类、气候倾向率等方法,对气温、降水变化特征及其关系做了分析。结果表明：空间上平均、最低、最高气温年（季）变化均随纬度升高而降低,降水量与此趋势相反。各类气温年际变化均呈上升趋势,最低气温增温速率最快,西、中、东部气候倾向率分别达到0.427℃·（10a）^-1、0.442℃·（10a）^-1、0.395℃·（10a）^-1。各类气温在春、冬季增温明显,总体表明最低气温对气候变暖所做贡献最大。降水量年际波动较大,但总体趋势不明显。春季降水量呈缓慢增长趋势,其中中部增长速率最快[1.583 mm·（10a）^-1],夏季呈减少趋势。年降水量与年际各类气温均呈负相关,各分区年、季（除个别夏季）降水量与三类气温除个别阶段呈一致变化趋势外,其他年际呈反对称变化。气温不断升高,降水量的减少,使得研究区气候不断向暖干化趋势发展。  相似文献   

Unmanned aerial vehicle based remote sensing method for monitoring a steep mountainous slope in the Three Gorges Reservoir,China     

Haifeng Huang  Jingjing Long  Haiyu Lin  Lei Zhang  Wu Yi  Bangjun Lei 《Earth Science Informatics》2017,10(3):287-301

Monitoring has been considered to be the most effective means of preventing and mitigating geo-hazards. Unmanned aerial vehicle (UAV) based remote sensing has been proven to be a viable method for monitoring relatively flat areas, but has typically encountered challenges on steep mountainous slopes. The Qinglingou Slope, which is located at the head of the Three Gorges Reservoir, China, was selected as a case study, and a UAV-based remote sensing method was applied to monitor this steep mountainous slope. The UAV, which was equipped with a camera, was used to acquire images on May 10 and Sept. 13, 2015. At the same time, a plan for establishing and measuring a detailed network of ground control points (GCPs) and check points was carefully designed and implemented, according to the local conditions. Georeferenced digital surface models (DSMs) and digital orthophotos were obtained by photogrammetric processing. Based on the results, a simple and quick method that identified and quantified slope deformation by calculating and analyzing the changes in the DSMs was developed. The results showed that the UAV-based remote sensing method was rapid, safe and effective, and it could be valuable for monitoring a large number of steep mountainous slopes in the Three Gorges Reservoir.  相似文献   

政区多粒度时空对象建模及其Geodatabase实现     

程星华  胡迪  俞肇元  龙毅  周如财 《地球信息科学学报》2017,19(9):1228-1237

全空间信息系统是将现实世界抽象为由多粒度时空对象组成的数据世界,对动态且复杂的现实世界中的各类时空实体对象进行表达、分析等。时空数据模型是时态地理信息系统（TGIS）核心,在一些特定领域上取得了较好的应用效果,对时空对象的时态信息进行了一定程度的表达,但仍旧无法完整地描述时空对象的变化以及联系。本文在分析时空数据模型的研究现状和存在问题的基础上,以全空间多粒度时空对象建模为指导思想,以北京近百年来的政区演变为例,分析了政区的基本特征,进而将政区看作是多粒度时空对象,探索了多粒度时空对象的建模方法,对政区进行了多粒度时空对象表达,并采用可视化表达的方法进行了实验验证。结果表明：多粒度时空对象建模能较好地反映政区的空间特征、属性特征和时间特征,反映其在时空上的演变过程以及便于更好地支持时空对象的查询、分析和可视化表达等。  相似文献   

Simulation of morphological development of soil cracks in Yuanmou Dry-hot Valley region,Southwest China   总被引：2，自引：0，他引：2  

Donghong Xiong  Dongchun Yan  Yi Long  Xiaoning Lu  Jianning Han  Xueqin Han  Liangtao Shi 《中国地理科学(英文版)》2010,20(2):112-122

Soil cracking is an important process influencing water and solutes transport in the Yuanmou Dry-hot Valley region of Southwest China. Studying the morphological development of soil cracks helps to further reveal the close relationship between the soil cracking process and water movement in such semi-arid regions. Here we report regular changes on surface morphology of soil cracks with decreasing water in four different soils (Typ-Ustic Ferrisols,Ver-Ustic Ferrisols,Tru-Ustic Vertisols and Typ-Ustic Vertiso...  相似文献   

广义线性高程拟合法在物探中的应用     

滕龙  朱红兵  高卫华 《火山地质与矿产》2010,(3):209-215

地球物理勘探工作需要三维坐标为其定位,尤其是重力勘探,对高程有较高的要求。作为一种先进的现代化测量技术,GPS能实时提供高精度的平面坐标,但因其使用W G S-84坐标系统,高程为大地高,没有实际的地球物理意义。地球物理勘探用的是正常高,故GPS测量的大地高无法直接使用。若联测高程,不仅增加工作难度,时间成本和经济成本也将大大增加。本文以长江中下游某些地区地球物理矿产勘查为例,介绍利用广义线性拟合法来获取高程。该模型不仅能对拟合结果进行评价,亦能评价模型参数的优劣。  相似文献   

Study on Potential Strong Earthquake Risks Around the Mabian Area,Southern Sichuan     

Yi Guixi  Wen Xueze  Zhang Zhiwei  Long Feng  Ruan Xiang  Du Fang 《中国地震研究》2010,24(4):478-490

Based on seismic data from the regional network for the last 34 years,we analyzed the present fault behavior of major fault zones around the Mabian area,southern Sichuan,and identified the risky fault-segments for potential strong and large earthquakes in the future.The method of analysis is a combination of spatial distribution of b-values with activity background of historical strong earthquakes and current seismicity.Our results mainly show:(1) The spatial distribution of b-values indicates significant heterogeneity in the studied area,which reflects the spatial difference of cumulative stress levels along various fault zones and segments.(2) Three anomalously low b-value areas with different dimensions were identified along the Mabian-Yanjin fault zone.These anomalies can be asperities under relatively high cumulated stress levels.Two asperities are located in the north of Mabian county,in Lidian town in western Muchuan county,and near Yanjin at the south end of the fault zone.These two areas represent potential large earthquake seismogenic sites around the Mabian area in the near future.Besides them,the third relatively smaller asperity is identified at southern Suijiang,as another potential strongearthquake source.(3) An asperity along the southwestern segment of the Longquanshan fault zone indicates the site of potential moderate-to-strong earthquakes.(4) The asperity along the segment between Huangmu town in Hanyuan county and Longchi town in Emeishan city on Jinkouhe-Meigu fault has potential for a moderate-strong earthquake.  相似文献   

体波谱振幅相关系数法在肥东地震序列震后判定中的应用   总被引：2，自引：1，他引：1  

刘泽民  刘东旺  夏仕安  徐鑫  龙爱军  缪鹏 《地震地磁观测与研究》2010,31(5):13-16

地震直达体波记录的观测谱包含震源、传播路径和台站信息,而发生在同一震源区的不同地震,如:序列地震,在同一地震台站的记录,受传播路径影响基本相同,地震台站的场地响应、仪器响应也完全相同。因此,序列地震体波观测零频谱的相关系数直接反映震源辐射图型因子的相似性,即震源机制解的相似性。将该方法用于2009年安徽肥东地震序列,与传统方法计算的震源机制解作比较,结果显示,谱振幅相关系数法能反映序列地震震源机制解的变化过程。  相似文献