京西鸡毛洞的发现及其意义     

吕金波  孙永华  李铁英 《地质通报》1999,18(2)

新发现的鸡毛洞属岩溶洞穴,位于北京市房山区佛子庄乡北窖村。据洞中现存的文物资料记载,早在唐朝（公元６７０～７３３年）已经是当地居民经常活动和栖息的场所。该洞穴不仅在岩溶地质学和考古学方面有重要的研究价值,而且具有建成一个新的旅游景点的良好前景  相似文献   

浅谈广西岩溶石山区人畜饮用水改水工作     

钱小鄂 《南方国土资源》1999,12(2):35-38

广西是我国著名的岩溶区,年降水在１０００ｍｍ以上,但由于独特的地貌及水文地质条件,区内旱季人畜饮用水十分困难,特别是岩溶峰丛洼地谷地。另一方面,该区地下水资源又十分丰富,如何合理开发利用地下水资源就成为解决人畜饮用水乃至农村可持续发展的重要课题。  相似文献   

Temperature dependence of magnetic hysteresis properties, and thermoremanent and anhysteretic remanent magnetization of stress-controlled synthetic 1125  m titanomagnetite (Fe_2.3Ti_0.7O₄) particles     

A. Zitzelsberger  & E. Schmidbauer 《Geophysical Journal International》1999,136(3):505-518

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重庆市黔江县小流域综合治理效益评估     

周麟 《山地学报》1999,17(1):76-80

通过对治理和非治理的两个条件相似的小流域的对比分析进行综合治理效益评估,结果表明：治理小流域减洪减沙效益及农作物增产增收效益显著。这将为西南山区类似条件的小流域综合治理提供一定的示范作用。  相似文献   

Slope-gully erosion relationship in small catchments of the middle reaches of the Yellow River     

CHEN Hao 《地理学报(英文版)》1999,(2)

1introductionThetopiconslope-gUllyerosionretahonshipinsmallCatclunentSofthendddiereaChesoftheYellowhiverhaslongbeenconcernedbyscienhstsinreleVantdepartmentSasthere~hresultwouldprovidescienuncbasisforop~erosioncontrolteChniqueanddeCisionmaking.AlthoughnumerousfieldStUdiesonedmentso~sinasmallCatchmentinthecoddlereachesoftheYellowmyerhavebeendriedcuLyetcurrentviewPOintSweredrawnduetodifferentresearchmethodsappliedTheproblemofsedimentsourcesonasmallcatClunentinthecoddlereachesoftheYellowhiv…  相似文献   

小导管预注浆技术   总被引：1，自引：0，他引：1       下载免费PDF全文

杨刚  于海营  寇俊峰 《探矿工程》1999,(2):19-21

在围岩自稳能力差或无自稳能力地层中开挖隧道及地下工程,提出了预注浆机理与分类、参数选择,材料选择与配比等关键问题进行综述,展示了注浆在工程中应用的广阔前景。  相似文献   

山西省首届青年科学大会论文论朔州神头岩溶泉水的保护及开发     

王枝堂  阎文胜 《华北地质矿产杂志》1998,13(2):164-169

神头岩溶泉水域广阔、岩溶构造极发育,形成闻天然的地下水库。由于水资源极其丰富、水质又好,故为雁北地区能源发展的主要基础,为使区内能源工业及经济持续、高速发展,必须对岩溶水实行保护性开发利用,降低地表水流失,监测地下水位的升降,确保岩溶泉水补排转化的平衡及神头泉区自然排放的清洁泉湖环境。  相似文献   

鸡毛菜叶龄估算模式及其应用     

李军  杨秋珍  汪治澜 《气象》1998,24(4):50-53

根据对不同播种期鸡毛菜的抽样测定资料,采用植物生长模型结合鸡毛菜生产期间９￣２５℃的有效积温对叶龄进行估算,叶龄估算的绝对误差在０．５叶之内。  相似文献   

An overview of the geology of the Transvaal Supergroup dolomites (South Africa)   总被引：1，自引：0，他引：1  

P. G. Eriksson  W. Altermann 《Environmental Geology》1998,36(1-2):179-188

 In the Neoarchaean intracratonic basin of the Kaapvaal craton, between approximately 2640 Ma and 2516 Ma, two successive stromatolitic carbonate platforms developed. Deposition started with the Schmidtsdrif Subgroup, which is probably oldest in the southwestern part of the basin, and which contains stromatolitic carbonates, siliciclastic sediments and minor lava flows. Subsequently, the Nauga formation carbonates were deposited on peritidal flats located to the southwest and were drowned during a transgression of the Transvaal Supergroup epeiric sea, around 2550 Ma ago. This transgression led to the development of a carbonate platform in the areas of the preserved Transvaal and Griqualand West basins, which persisted for 30–50 Ma. During this time, shales were deposited over the Nauga Formation carbonates in the southwestern portion of the epeiric sea. A subsequent period of basin subsidence led to drowning of the stromatolitic platform and to sedimentation of chemical, iron-rich silica precipitates of the banded iron formations (BIF) over the entire basin. Carbonate precipitation in the Archaean was largely due to chemical and lesser biogenic processes, with stromatolites and ocean water composition playing an important role. The stromatolitic carbonates in the preserved Griqualand West and Transvaal basins are subdivided into several formations, based on the depositional facies, reflected by stromatolite morphology, and on intraformational unconformities; interbedded tuffs and available radiometric age data do not yet permit detailed correlation of units from the two basins. Thorough dolomitisation of most formations took place at different post-depositional stages, but mainly during early diagenesis. Partial silicification was the result of diagenetic and weathering processes. Karstification of the carbonate rocks was related to periods of exposure to subaerial conditions and to percolation of groundwater. Such periods occurred locally at the time of carbonate and BIF deposition. Main karstification, however, probably took place during an erosional period between approximately 2430 Ma and 2320 Ma. Received: 15 September 1996 · Accepted: 12 May 1998  相似文献   

沈阳市方形广场地下通道工程施工技术          下载免费PDF全文

寇俊峰  方德平 《探矿工程》1998,(5):52-53

通过地下通道施工实例,介绍了小导管超前注浆预加固的施工及注浆材料、注浆参数的确定方法。  相似文献