金属矿地震散射波场的数值模拟研究   总被引：7，自引：0，他引：7  

孙明  林君 《地质与勘探》2001,37(4):68-70

地震方法用于寻找石油、煤田等沉积层控矿床已取得许多成功经验和大量的成果；对于金属矿可依据微扰理论，通过地震波散射响应的强弱推断矿体。模拟实验结果表明，散射波相干性的好坏与杂乱散射体的不均匀性有关；不均匀性越强，产生的散射相干性就越好。  相似文献   

Cenozoic Sedimentary Sequence in the Kumkal Basin, Xinjiang and New Evidence for the Late Quaternary Uplift of the Qinghai-Tibetan Plateau     

ZHANG Yunxiang  CHE Zicheng  LIU Liang Department of Geoogy  Northwest University  Xi*an   《Continental Dynamics》2001,(2)

1. IntroductionThe Qinghai-Tibetan Plateau is an importantregion for the study of the global change andstructural evolution history). The in-depth knowledgeon its uplift process is the ke}' to understand theformation and development of temporary ph}'sicalenvironment of China or even East Asia. Therefore.a large quantity of researchers have given muchmore attention on this field (Burbank et al.. l982;Fang Xiaornin et al.. 1995f Ruddoman. ]997f AnZhisheng et al.. 1998). The macroscopic e\'o…  相似文献   

贵州瓮安震旦纪陡山沱期磷酸盐化球状化石的新观察   总被引：16，自引：2，他引：16       下载免费PDF全文

尹崇玉  高林志等 《地质学报》2001,75(2):145-150,T001,T002

我国贵州瓮安陡山沱期磷块岩中的磷酸盐化球状化石是近年来受到广泛关注的一类微体化石。对于它们的生物亲缘认识，长期以来存在着动植物之争，特别是近年来一些学者发现，部分磷酸盐化球状化石内部保存了2、4、8、16等几何级数增长的细胞特征，根据化石的大小、细胞排列方式和表面纹饰可与现生甲壳类动物的胚胎比较，认为它们很可能是运动胚胎化石，但另一些学者却持截然不同的观点，认为它们不是动物胚胎化石的观察与研究，同时结合相同层位岩石薄片所发现的大量同类化石微细结构的对比。特别是把磷块岩中的化石与燧石中发现的化石详细比较，对一些磷酸盐化球状化石的归属和亲缘关系进行探讨，研究表明贵州瓮安陡山沱期燧石中发现的化石详细比较，对一些磷酸盐化球状化石的归属和亲缘关系进行探讨。研究表明贵州瓮安陡山沱期磷酸盐化微体化石群具有多样性特征，包含不同门类，是迄今为止全球保存最好的晚新元古代磷酸盐化的化石库。  相似文献   

中国的遗迹化石研究   总被引：1，自引：0，他引：1  

龚一鸣 《矿物岩石》2001,21(3):205-207

中国的遗迹化石在20世纪后期取得了长足的进展，主要表现在三个方面：前寒武纪遗迹化石与后生动物的起源和演化研究，将后生动物遗迹化石记录追索到1500Ma甚至1800Ma左右的元古宙早期；遗迹化石和遗迹组构与沉积环境和层序地层的关系研究，描述了大量的遗迹化石，建立了多种地方性的遗迹相，遗迹组构研究开始渗透到遗迹学研究的众多方面；拓扑遗迹分析，将拓扑学与遗迹学紧密联系，创立了遗迹学研究的新方法。  相似文献   

Malaria and related environmental issues in India: a case study of Aligarh city     

Abha Lakshmi Singh  Atiqur Rahman 《GeoJournal》2001,53(1):89-99

Malaria is one of the most widespread diseases in the world. Endemic malaria no longer occurs in many temperate zones as a result of social and economic improvement. At present malaria is the Third World's most dreaded killer. It kills over 1 million people and causes 300–500 million episodes of illness. In India, malaria-reported deaths have shown an upward trend. In 1955, a drive to eradicate malaria was launched in India. But after initial success it failed and malaria made a comeback. Malarial mosquitoes generally prefer unpolluted natural breeding sites but now they have adapted to the changed urban environment. In this paper, an attempt has been made to examine the occurrence of malaria and related environmental issues in a small town of India. Aligarh city, lying in the shadow of the country's capital New Delhi, was selected as a case study. Data were collected mainly from household surveys with the help of questionnaire interviews. About 2,185 households belonging to different income groups were sampled. The differences in the occurrence of malaria in the different income households (in 87% low, 69% lower-middle, 65% middle, 14% upper-middle, and 5% upper) suggest that most of these differences are related to the environmental conditions existing inside and outside their homes, such as poor drainage system, poor sullage disposal, open blocked drains, waterlogging and indoor water storage in open containers. Commitment both by the Government and local residents is needed to improve the environmental conditions and eradicate malaria.  相似文献   

COMPREHENSIVE PLANNING FOR WATER RESOURCES EXPLOITATION AND WATER POLLUTION CONTROL FOR CHANGLI COUNTY-A CASE STUDY FOR SMALL TOWNS OF CHINA     

Cheng Tianwen  Mou Haisheng 《地理学报(英文版)》1996,(3)

I.EnvironmeotaICharacterishcsofChangliCountyChangliCoLmtyislocatedinthenortheastermendoftheNorthChinaPlain,nexttoBohaiSeaontheeastandthesouthemendofYanshanMountainsontl1enortl1.Luani1emverWhichrunsthroughthecouotyforn1sthewestemandsouthemboundaryoftitiscoastalcounty.ThenorthempartofthecoUnyishillywithaverageheigltrrangingfrom5oto5Oom,andmostportionintheeastemandsouflempartislocatedonthealluvialplainofLuani1eandYirunarivers,inclilungfromnorthwesttosoutieastwiil1heighrangingfrom2to3m.Tl1…  相似文献   

吉林省四平南部下二台群小壳化石的发现及其地质意义     

佟文选  王福泰  任锡钢 《吉林大学学报(地球科学版)》1992,(1)

吉林省四平南部1:5万半拉山门、石岭街、下二台子、叶赫站幅的吉林省境内区调,首次在经过修订的下二台群黄顶子组下部条带状硅质大理岩中,采获丰富的小壳化石,初步确定为3属6种,其中4新种。属于辽北地区新确立的清河镇动物群辐射演化而来的新的动物群。从而,为这套地层的划分对片、时代确定,提供了重要的古生物佐证。  相似文献   

新疆早寒武世玉尔吐斯小壳动物群再研究     

肖兵  段承华 《新疆地质》1992,(3)

新疆乌什—阿克苏地区下寒武统玉尔吐斯组的小壳化石丰富,已描述了近50属90种,包括1个新属,15个新种。计有软舌螺类、似软舌螺类、单板类、腹足类、骨针类及分类位置未定的化石,还有节肢动物门的高肌虫类。按小壳化石在地层纵向出现的次序及其代表性,可将玉尔吐斯组小壳动物群的比石划分为3个带,即1.Anabarites trisulcatus带;2.Cambroclavus-Aurisella带;3.Adyshevitheca-Xinjiangella带。其中1带可与梅树村阶I.Anabarites-Protohertzina带对比;2—3带大致可与梅树村阶Ⅱ.Paragloborilus-Siphogonuchites带—Ⅲ.Sinosachites-Lapworthella带对比。因Aanbarites trisulcatus的发现,证实玉尔吐斯组的下界可与梅树阶的底界对比;玉尔吐斯组顶部发现的高肌虫有别于筇竹寺阶的高肌虫。前者与大量梅树村期小壳动物共生,可以认为梅树村期已经出现高肌虫的先遣分子。  相似文献   

小窑采空区地质灾害综合评价研究     

郝喆 《地质与资源》1992,28(4):394-400

采用物探和钻探相结合的综合勘察方法，获取地质环境的破坏现状和采空区特征.按相关规范要求，预测小窑采空区的影响范围，剖析采空区残留空洞的稳定性，评价采空区的活化潜在威胁，分析采空引起的覆岩三带发育特征，剖析采空区引起的地表移动特征，获取相应地表变形特征参数.  相似文献   

采用小径密抗桩一条龙抢治滑坡的方法及效果     

周颂杰  郭映忠 《四川地质学报》1993,(2)

以往整治滑坡,较多地使用大口径挖孔桩或钻孔灌注抗滑桩,周期长、成本高。川地208队在治理重庆制药五厂已处于危急态势的滑坡中,采用“天平式”控制、勘治结合、快速抢险,用三排小径密抗桩(300mm口径)整治,取得明显成效。实践表明:浅层滑坡采用较小口径的密抗桩,并辅以排水,能达到事半功倍的效果。  相似文献