首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
利用氢氧稳定同位素(δD、δ18O)和放射性同位素氚(T)分析了金川矿区不同水体间的水力联系,初步判断了井巷排水的主要补给源,研究结果表明:金川矿区井巷排水是深部基岩裂隙水和经过蒸发效应的大气降水混合的产物,不同地段排水中生产水与深部基岩裂隙水比例不同,深部基岩裂隙水比例16%~83%,生产水比例84%~17%;井巷排水主要为上世纪60年代或70年代补给的充填析出水。  相似文献   

2.
科学钻探是一项技术含量高的高科技科学工程,也是一项庞大而又复杂的系统工程,它的实施离不开新技术革命,新技术革命是科学钻探的技术基础,随着新技术革命的不断发展,必将促进科学钻探向更快更好更深的方向前进。  相似文献   

3.
安徽月山矿田硅、氦、氖同位素地球化学研究   总被引:2,自引:1,他引:2  
对安徽月山矿田硅、氦、氖同位素组成研究表明 ,月山岩体是玄武质岩浆结晶分异和同化混染的产物 ,矿床的硅来自岩浆熔 流分离作用形成的岩浆热液 ,成矿流体中的氦来自地壳和地幔两个端员。成矿过程中发生了富含放射性成因氦的演化大气降水与岩浆热液的混合。  相似文献   

4.
略论塔里木古生代盆地演化   总被引:11,自引:0,他引:11  
浪良杰 《现代地质》1997,11(1):14-20
依据所处板块构造位置和地球动力学环境,提出塔里木古生代盆地演化经历了震旦—泥盆纪和石炭—二叠纪两个完整的开合旋回。第一旋回自震旦纪开始张裂形成大陆裂谷,寒武—奥陶纪伸展为被动大陆边缘,志留—泥盆纪俯冲消减,泥盆纪晚期碰撞闭合,时间跨度达400Ma以上。第二旋回表现为石炭—二叠纪弧后拉张—弧后造山事件,延续仅约100Ma。  相似文献   

5.
相山地区如意亭剖面火山建造特征   总被引:4,自引:0,他引:4  
对如意亭剖面鹅湖岭组与打鼓顶组的界线进行了重新厘定,对早晚两个火山活动旋回火山岩的化学成分,稀土配分特征进行了比较,得出两旋回火山岩系属同一岩浆源的不同阶段演化产物的认识,同时,指出了两旋回间及早旋回与基底之间的界面是相山火山塌陷中的两个滑脱面,它们分别被花岗斑岩和流纹英安斑岩所侵位,构成了相山火山塌陷盆地东北部及西北部的半球状构造。  相似文献   

6.
在前文对祁连山地区水汽输送进行分析的基础上, 应用刘国纬的水文循环大气过程模型, 研究了同期祁连山地区的大气水循环变化特征. 结果表明: 祁连山地区区域总降水量在过去51 a中表现为缓慢增加的趋势, 境外输送水汽对于当地降雨的贡献呈减小趋势, 局地蒸发产生的水汽对于当地降水的贡献增加, 表现为21世纪初期由局地蒸发产生的降水量比1960年代增加33.0 mm; 水文外循环系数表现为明显的下降趋势, 表明境外输送水汽在祁连山地区水文循环中的作用降低; 与之相反, 水文内循环系数呈明显的上升趋势, 表明由蒸发产生的降水使区域水循环加强. 祁连山地区水汽滞留时间表现出明显的下降趋势, 反映出祁连山地区的水汽更新速率加快, 水汽利用效率提高. 区域温度升高是该地区蒸发量增加的主要原因之一; 区域径流量的增加是降水量增多与冰川冻土带融水共同作用的结果, 其中冰川冻土融水的作用更加明显.  相似文献   

7.
Igor Vrišer 《GeoJournal》1993,31(4):373-377
Agrarian economy on the territory of a new European state, ie Slovenia (the NW part of former Yugoslavia) has undergone substantial transformations over the past 150 years. The changes were particularly intense after World War II when the Yugoslav Communist Party came to power in former Yugoslavia. Under its influence an extensive redistribution of property (ie expropriations) was carried out, as well as reorientation of production and a thorough social transformation. After the independent state of Slovenia was established in 1991 (Slovenia, 1992) and the capitalist system was reintroduced, the agrarian economy of this area has had to face certain far-reaching problems which are crucial for the future development of the new state.  相似文献   

8.
A. C Vigarié 《GeoJournal》1992,26(4):477-481
Iberian great maritime discoveries had been a good opportunity for some other European countries to try to build a new maritime geopolicy. In the French kingdom, traders and merchant adventurers worked strongly to carry home gold, spices and other riches from newly discovered lands. But during the 16th century, French kings, thoroughly engaged in the Italian wars, had no real ocean policy, no maritime geostrategy. They came late in 17th century to build a new colonial empire, too late perhaps to give new directions or new impulses to some large trends of history.  相似文献   

9.
北祁连山石居里沟富铜矿床成矿特征   总被引:11,自引:1,他引:11  
杨合群  李文渊 《地质与勘探》2000,36(6):20-22,31
讨论北祁连山石居里沟富铜矿床成矿特征,通过分析认为:成矿环境为中奥陶世弧后扩张脊,容矿岩石为蛇绿岩套上部火山岩或火山-沉积岩系,矿体赋存部位受海底裂隙系统的控制,含矿热液起源于海水与玄武岩在高温下的反应,成矿金属元素主要来自火山岩,矿化剂硫来自二者。  相似文献   

10.
通过对位于东亚季风区中东部与西部边缘的两个高分辨率黄土剖面记录的对比研究,发现它们不仅捕捉到了20个Dansgaard Oeschger事件与6个Heinrich事件,而且黄土记录与GRIP冰芯记录的这些快速气候波动基本上是同步的。暗示在整个末次冰期,东亚季风气候同样存在千年—百年尺度上的快速波动。所不同的是,西面的沙沟剖面对这些快速气候波动的反应比东面的王官剖面敏感。结合末次冰期中国黄土记录的先前研究结果,我们发现,自西向东Dansgaard Oeschger旋回的幅度逐渐变小,推测这主要是由西风与东亚夏季风共同作用所造成的。  相似文献   

11.
为了更为精细地刻画出川西坳陷中段中侏罗统上沙溪庙组的古地理和砂体展布特征,笔者以高分辨率层序地层学理论为指导,建立了研究区上沙溪庙组高分辨率层序地层学划分方案,并进行了高分辨率层序地层格架的搭建。在此基础上以中期旋回层序为编图单元,进行了系统的古地理和砂体展布特征研究。发现川西坳陷中段中侏罗统上沙溪庙组可以划分为1个长期和4个中期(M1,M2,M3,M4)沉积期。M1和M2沉积期,研究区以发育曲流河三角洲—湖泊沉积体系为特征;M3和M4沉积期,研究区转变为以发育冲积扇—冲积平原—辫状河三角洲—湖泊沉积体系为特征,砂体的展布主要分布于两个地区:大邑—温江地区和中江地区,前者砂体主要发育于M1,M3,M4 3个中期旋回,后者砂体主要发育于M1,M2,M3 3个中期旋回。  相似文献   

12.
The Carpinteria State Beach is a little known public park in Carpinteria, near Ventura, California, USA. Miocene‐age conglomerates and sandstone bluffs along the Pacific Ocean beachfront have featured continual natural oil seeps since the Pleistocene epoch. While not as famous as the La Brea Tar Pits of downtown Los Angeles, the park is the only public beach in North America where such a geological phenomenon is readily seen. Long used by the Chumash Indians for the asphaltum used to waterproof their seagoing canoes, asphaltum came into general use in the late nineteenth century. The beach is the former site of an industrial plant, devoted to removing and processing the asphaltum to yield many commercial products. Before it became a state park it served as a travel camp and a camp for World War II GIs suffering from battle fatigue.  相似文献   

13.
王鹏 《地质与勘探》2013,49(3):429-436
本文详细研究了辽西二道沟金矿的矿化特征、矿石结构、构造和主要载金矿物黄铁矿,在此基础上分析讨论了成矿温度、热液活动期次和活动方向。研究表明二道沟金矿的形成经历了热液期和表生期,热液期又分为石英-黄铁矿阶段、石英-多金属硫化物阶段、石英-碳酸盐阶段;且可能存在多期次的热液活动,每一期热液相互叠加改造,成矿热液早期温度较高,大于450℃,但金属矿物大量沉淀时温度较低,在150~300℃,属中低温成矿。金在Ⅲ、Ⅴ号矿脉中的分布在水平方向和垂直方向都存在明显不均匀性,金品位高值区从上向下都有向南东方向发展的趋势,指示成矿热液可能来自南东方向。本文详细研究了二道沟金矿Ⅲ、Ⅴ号脉金的富集规律,对于指导矿山生产及资源勘查具有重要的指导意义。  相似文献   

14.
On the occurrence of the celebration of the Fiftieth An-niversary for the establishm ent of the People’s Republic ofChina,we contribute this paper entitled“Developm ent of Ge-ological Science in China in the Twentieth Century”.Thiscomes out from a review of the newly published book aboutthe history of geological disciplines:“Fifty Years of Geologi-cal Science in China”.The draftof the paper was formed aftera discussion between the authors.It deals with the existingstate of geologica…  相似文献   

15.
新疆可可塔勒铅锌矿床同位素地球化学研究   总被引:5,自引:0,他引:5  
同位素资料表明,可可塔勒铅锌矿床成矿时代为早泥盆世,与下泥盆统海相火山岩系年代一致;矿石铅主要来自于活动造山带,与弧盆系火山岩有关,属幔壳混合铅;矿石的硫源与赋矿围岩或后期脉状矿石的硫源存在明显的差异,前者属细菌成因硫和海水硫酸盐还原硫的混合,后者属深部火山硫或岩浆硫;主成矿期的成矿介质水主要是海水,可能有少量大气降水加入,后期矿化则以混合岩浆水为主。矿床形成属海底火山喷气-沉积迭加改造型矿床。  相似文献   

16.
China has suffered from severe earthquake disasters in recent years. In order to explore the impact of severe earthquakes on public risk perception on different time scales, four surveys were conducted twice each after the severe Wenchuan and Yushu earthquakes. t tests were performed between two consecutive surveys to explore the change of public risk attitudes. The results demonstrated that after the two severe earthquakes, the public seismic risk acceptance has increased over time, and the comparison between pre- and post-Yushu earthquake illustrated that the severe disaster had more impact on vulnerable population such as females, children and low-income people. Moreover, linear regression models were employed to find the determining factors of public acceptance towards earthquake risks. It was discovered that the public perceived earthquake effect had significant negative relationship with seismic risk acceptance, and public trust towards local government had positive relationship with the risk acceptance. This study could help government to gain better understanding of public mental status and take more effective disaster preparedness measures when preventing and responding to a severe earthquake.  相似文献   

17.
Cizmic I 《GeoJournal》1996,38(4):431-436
Croatia ranks among those parts of Europe which have taken very high part in all forms of emigration flows in almost all periods of the last few centuries. The emigration from Croatia was caused by different reasons, such as historical, political, national, religious, social and other. It started in the 16th century and has been going on more or less intensively in different historical periods up to now. The first emigrations were caused by Turkish invasion, and those from the later periods came as a result of economical, social and political circumstances in which population of Croatia lived at the time. About 500,000 people had emigrated from Croatia in the period from the end of the century up to World War I. Most of them went to the USA. World War I had made a break in the mass emigration. After the war the emigrant problem came up again, but with some essential changes which were the consequences of the war. World War II stimulated a greatwave of emigration from Croatia. Emigration occurred either voluntarily or involuntarily. For the entire period 1948–1981, statistics show that modern overseas emigration from Croatia totalled roughly 140,000 persons. Finally, we would like to emphasize that the problem of emigration was and is still actual for the Croatian nation, especially in view of the fact that emigration from Croatia did not stop and continues up to this day. As a result today two million and half Croatian immigrants and their descendants live abroad.  相似文献   

18.
红舍克铝土矿由沉积型及风化堆积型二类。沉积型铝土矿由越北古陆中的岩浆岩、变质岩经长期剥蚀、风化后,经长距离搬运沉积而成,受基底、古岩溶地貌、沉积环境和沉积相的控制。堆积矿床属于表生第四纪岩溶堆积型,不但与岩性、气候、构造、地形地貌关系密切,亦与沉积型矿床有直接因果联系。  相似文献   

19.
以1990、 2000、 2010年3期Landsat TM影像为土地利用基础数据, 结合1990年以来的社会经济资料和反映气候变化的气温、 降水数据, 对1990年以来阿克苏河流域绿洲土地利用变化进行了分析. 结果表明: 1990-2010年期间, 耕地、 建设用地以单向转入为主, 耕地对绿洲"扩张"贡献最大, 前期(1990-2000年)的贡献率为129.1%, 后期(2001-2010年)的贡献率提高到142.5%; 草地、 水域以单向转出为主, 草地对绿洲"萎缩"贡献最大, 前期的贡献率是-39.8%, 后期是-34.8%; 其次是水域, 前期对绿洲的贡献率是-1%, 后期是-9.3%; 河漫滩、 林地、 湿地在前期对绿洲的"扩张"贡献率分别是7.5%、 0.3%和5.1%, 后期对绿洲的"萎缩"贡献率分别是-2.4%、 -0.02%和-0.4%. 近20 a来流域绿洲规模整体上持续扩张. 通过分析绿洲土地利用驱动力系统可以看出, 绿洲土地利用类型变化主要受人类活动影响, 气候变化起基础性作用.  相似文献   

20.
黑河流域观测通量的空间代表性研究   总被引:7,自引:0,他引:7  
地表湍流通量包括显热通量和潜热通量,它的准确测定对天气气候预报、农业节水和水资源管理等意义重大。目前应用较为广泛的通量测量技术有涡动相关仪(EC)和大孔径闪烁仪(LAS),前者是单点观测,观测范围通常只有几百米;后者近年来得到长足的发展,可以观测从几百米到十几公里尺度上的区域湍流通量。建立了EC和LAS通量解析足迹模型,详细介绍了足迹模型的理论依据和建立方法,并对二者模型的异同进行了阐释。在黑河流域遥感—地面观测同步试验中,以高寒与干旱区伴生的黑河流域为试验区,包括寒区水文试验、森林水文试验和干旱区水文试验,使用足迹模型分别分析了临泽草地站、阿柔冻融观测站的EC、LAS观测通量的源区,结合风向变化规律,对二者通量观测差异进行分析解释;分析了盈科灌区绿洲站、大野口关滩森林站的EC观测数据,以及阿柔冻融观测站的EC、LAS观测数据,选择具有代表性的月份,进行观测站点的空间代表性分析。结果表明:对通量观测站点进行空间代表性分析是十分必要的,可得到观测站点通量源区的时空变化特征,同时足迹模型在通量观测数据的分析中有很大的实用价值,可为今后通量观测数据的应用提供参考。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号