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1.
《《幕》》2008,31(3):355-355
An "International Workshop on Central Asian Orogenesis and Metallogeny", sup- ported by Department of Science and Tech- nology of Xinjiang Uygur Autonomous Region, the Geosciences Department of the Natural Science Foundation of China, the Bureau of Science and Technology for Resources and Environment, the Chinese Academy of Science, Xinjiang Petroleum Company, and China National Petroleum Corporation, was held in Urumqi, Xinjiang, from 18-24 September, 2007 (hosted by the National 305 Project Office).  相似文献   

2.
During the past ten years graptolite-bearing strata were repeatedly discovered in various localities by the members of the Geological Survey of China, and by the Expedition of the National Peking University and the collections~1 of graptolites were obtained from different horizons (Tremadocian-Valentian).  相似文献   

3.
This paper is supported by the Special Doctoral Grant of the Ministry of Education of China (No. 98049114) and the National Natural Science Foundation of China (No. 49972023).  相似文献   

4.
A geologic workshop on the Qilian Mountains and adjacent region was held by the two sides of the Taiwan Strait from June 1 to June 9, 2000, in Beijing, China. This conference was presided by the Institute of Geology, CAGS, with support of the Committee of the National Natural Science Foundation and the Ministry of Land and Resources. The theme was the material constitution and geologic evolution of the Qilian Mountains and adjacent area. More than 60 experts from the Institutes of Ge…  相似文献   

5.
PREFACE     
The Abstracts of Chinese Geological Literature is edited and published by the National Geological Library of the People's Republic of China with an aim to provide bibliographic information to foreign geological circles on Chinese geological literature.  相似文献   

6.
The materials included in this short paper were collected from Yunnan,Kuangsi,Szechuan,Shensi and Kansu by members of the National GeologicalSurvey of China and men who are interestsd in geology and palaeontology.Brief  相似文献   

7.
PREFACE     
The Abstracts of Chinese Geological Literature is edited and published by the National Geological Library of the People' s Republic of China with an aim to provide bibliographic information to foreign geological circles on Chinese geological literature.  相似文献   

8.
PREFACE     
The Abstracts of Chinese Geological Literature is edited and published by the National Geological Library of the People' s Republic of China with an aim to provide bibliographic information to foreign geological circles on Chinese geological literature.  相似文献   

9.
PREFACE     
The Abstracts of Chinese Geological Literature is edited and published by the National Geological Library of the People' s Republic of China with an aim to provide bibliographic information to foreign geological circles on Chinese geological literature.  相似文献   

10.
In recent years several localities of highly alkaline rocks have been dis-covered in Shansi by the National Geological Survey of China and the Sino-Swedish Research Institute.The results of investigation in this line up to 1927are embodied in the paper:"S  相似文献   

11.
贵州西南部“法郎组”牙形石及其时代   总被引:30,自引:3,他引:27  
杨守仁  刘疆 《地层学杂志》1995,19(3):161-170,198
根据近年牙形石研究,在“法郎组”中从下而上识别了3个牙形石带:1、Neogondolellapolygnathiformis-Neogondolellamaantangensis组合带;2、Neogondolellapolygnatiformis-N-eogondolellatadpole组合带;3、Neogondolellapolygnatiformis带。根据牙形石N.excelsa谱系演化、牙形石发展事件、牙形石分带及其与国内外的牙形石带对比,论证了“法郎组”的时代,“法郎组”可解体为瓦窑组和竹杆坡组,全属晚三叠世卡尼期,而不是拉丁期。  相似文献   

12.
土壤重金属污染具有巨大的生态环境风险和危害。本文以雄安新区西南部(老河头镇、同口镇和芦庄乡)的表层土壤和大宗农作物小麦、玉米为研究对象,在对8种重金属As、Ni、Cu、Cr、Pb、Hg、Cd和Zn含量测试分析的基础上,开展了土壤重金属污染和生态风险评价。结果表明:研究区表层土壤局部存在重金属超标情况,重金属的污染程度依次为:Cd>As>Cu>Zn>Pb>Hg,Cr和Ni土壤环境清洁;研究区表层土壤重金属污染是人为源输入,老河头镇及周边大量有色金属冶炼活动是可能的主要污染源;8种重金属的潜在生态危害程度由强至弱依次为:Cd>Hg>As>Cu>Pb>Zn>Cr>Ni;多金属潜在生态风险指数RI的平均值为252,土壤整体的重金属潜在危害程度为中等风险,其中Cd对潜在生态风险指数RI的贡献最大,且Cd的活性最强,迁移能力强,易被植物吸收。研究成果可为雄安新区的土地利用规划提供重要依据。  相似文献   

13.
This paper reappraises the seismicity of Algeria and adjacent regions. It presents a general view of the geographical structure, the historical development of the seismological station network, some aspects of the effects of past destructive earthquakes, the state of knowledge of the seismicity and the seismic hazard and risk in the region under survey. Magnitude-frequency relationships for different parts of the region studied are presented as well as magnitude-intensity and intensity-attenuation relationships, semi-empirical formula. It also discusses the macroseismic information, the instrumental data and the social and economic implications of earthquakes in the Maghreb region.  相似文献   

14.
大气影响下平顶山膨胀土地表蒸发研究   总被引:1,自引:0,他引:1  
为探索膨胀土的蒸发特征,对平顶山市区膨胀土进行了不同初始含水量土体的室内和室外蒸发试验研究,测试了蒸发过程中土体含水量在不同深度的变化。对室内、外试验结果及其差异性进行了分析,发现室内和室外土样的蒸发强度差别较大,但是蒸发系数相差不大,蒸发系数与土体含水量、含水量梯度有较强的相关性。地表土体接近饱和时,蒸发系数在1上下波动。随着蒸发的持续,蒸发系数随地表含水量降低而下降,含水量梯度随地表含水量的降低而升高。当地表含水量达到残余含水量时,含水量梯度达到极大值,持续蒸发含水量梯度将继续减小。土体蒸发系数与蒸发历时进行拟合,呈较好的对数关系。  相似文献   

15.
黄蜡玉的主要组分为石英,材料特性完全符合玉石的三大标准;美观、耐久、稀少,是品质很好的一种云南玉石新品,与翡翠、软玉相比有相似性或一致性。与我国其他地区所产石英质的京白玉、东陵玉、密玉、贵翠等相比,质地更细腻绵润,颜色更柔和,光泽更亮丽。龙陵黄蜡玉有独特的工艺经济价值,以及很高的科研价值。  相似文献   

16.
Substantial diel (24-h) cycles in dissolved (0.1-m filtration) metal concentrations were observed during summer low flow, winter low flow, and snowmelt runoff in Prickly Pear Creek, Montana. During seven diel sampling episodes lasting 34–61.5 h, dissolved Mn and Zn concentrations increased from afternoon minimum values to maximum values shortly after sunrise. Dissolved As concentrations exhibited the inverse timing. The magnitude of diel concentration increases varied in the range 17–152% for Mn and 70–500% for Zn. Diel increases of As concentrations (17–55%) were less variable. The timing of minimum and maximum values of diel streamflow cycles was inconsistent among sampling episodes and had little relation to the timing of metal concentration cycles, suggesting that geochemical rather than hydrological processes are the primary control of diel metal cycles. Diel cycles of dissolved metal concentrations should be assumed to occur at any time of year in any stream with dissolved metals and neutral to alkaline pH.Electronic Supplementary Material Supplementary material is available for this article if you access the article at . A link in the frame on the left on that page takes you directly to the supplementary material.  相似文献   

17.
《地学前缘》2017,24(3):257-262
Ruby-bearing marbles of the Southern Ural Mountains are developed in the metamorphic perimeter of granites-gneisses domes where high grade metamorphic granitization and diaphthoresis have occurred.Geological research into the development and occurrence of ruby-bearing marbles indicate that they formed as a result of repeated transformation.Their substrate consisted of an organogenous marine limestone containing Visean faunal remains.Intensive Mg metasomatism of limestone during early progressive stages of metamorphism resulted in a substrate of dolomite composition containing faunal remains with a calcite composition.Increased temperature and pressure resulted in metamorphism of early Mg metasomatites,turning them into fine-grained marble containing Visean faunal remains.Tensional stresses near the intrusive domes resulted in dedolomitization of early Mg metasomatites,giving rise to light,coarse-grained calcite marbles having polygonal-grained structure.Such carbonaceous marbles became metamorphosed around the perimeter of granite-gneiss massifs.Their rheological properties allowed for plastic flow in these marbles into areas of tectonic neutrality,forming bodies of rheomorphic marbles,sometimes even among marbled limestone.Relict bodies of Mg metasomatites underwent boudinage and rotation.Flow cleavage occurred in axial blocks of inter-dome structures and in their steep walls.Therefore platy jointing(banding,pseudo-lamination)formed in the marbles.Thickness of the plates is from several millimeters to 2-3m.Calcite underwent recrystallization with extension of grain size in the central parts of plates,sometimes amounting to 15-25cm in cross-section.Ruby-bearing marbles consist of Mg-calcite.The rock is coarse-grained,with a panidiomorphic texture.Schistosity is often observed in the plane of cleavage.Mg-calcite marble occurs among and grades into background calcite marbles,which are controlled by cleavage of flowing.It is supposed that the ruby-bearing Mg-calcite marbles bodies are elongated in the direction of dip.Their formation is caused by recrystallization under the action of rising metamorphogenic fluids at high temperatures and higher pressures(amphibolitic and epidote-amphibolitic facies).Ruby-bearing marbles formed at the end of the prograde stage of metamorphism.The early retrograde stage of metamorphism is defined by a new wave of Mg metasomatism and formation of calcite-dolomitic marbles with a poikiloblastic texture from calcite or Mg-calcite marbles.Usually the boundaries of the bodies are clear,planar,and controlled by cleavage.Studies of small bodies have shown that they are elongated in the direction of dip.Usually they contain pink corundum and/or pink spinel;red corundum is replaced by red spinel.Thus the initial marine limestones were transformed into various marbles and completely lost their primary composition and bedding as a result of metamorphism,deformation,and metasomatic transformation.Ruby-spinel mineralization in marbles is controlled by cleavage.  相似文献   

18.
针对"淹埋深-历时-频率"(S, D, F)阈值研究存在的问题,根据土壤学、植物生态学、系统论、地理系统学说以及反演理论等的相关原理,系统分析了湿地(S, D, F)阈值确定的理论和方法。结果表明:在正常情况下,水饱和至地表的最大地下水埋深、湿地植物主要根系分布层下限和沉水植物分布下界淹水深分别是湿地土壤上界、湿地植被上界和湿地下界的S阈值;D阈值只能通过湿地土壤或湿地植被边界界定在水位过程线上反演,稳定湿地边界的D阈值应取与50%频率值对应的D值或D值的多年平均值,波动湿地边界的D阈值是常数;"非正常情况下"湿地的D阈值应参照湿地水文地貌分类的同一区域子类中"正常情况下"的湿地的D阈值;检验D阈值科学性的标准是利用D阈值确定的湿地水文边界必须与湿地土壤边界或湿地植被边界耦合。  相似文献   

19.
管涌与滤层的研究(Ⅱ): 滤层   总被引:1,自引:0,他引:1  
对管涌和滤层两个相关联问题的研究和发展过程进行了综述和评论;同时也给出了过去的研究成果,并与之进行比较。在滤层研究方面,指出了由平均粒径一点控制到两点和级配曲线多点控制的发展趋势;研究表明:太沙基的滤层规格比较保守,应结合内外水动力学研究砂砾滤层和织物滤层的适用规格。而粘土的滤层设计,关键是看能否发生贯穿性裂缝,其设计思想悬殊;井管滤层的淤堵失效应研究抽洗复苏的良策。  相似文献   

20.
赵亮 《云南地质》2005,24(1):98-107
丽江为滇西北重镇,旅游资源十分丰富,是云南省旅游重点开发区,具有山岳冰川、高原地质生态、大峡谷、丹霞地貌、河流袭夺湾、卡斯特等六大景观类型,誉为地质生态博物馆。加快丽江旅游地质资源的勘查和开发利用,对民族地方经济发展有举足轻重作用。  相似文献   

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