安徽铜陵新桥铜-硫-铁-金矿床中石英闪长岩和辉绿岩锆石SHRIMP年代学及其意义   总被引：48，自引：3，他引：48       下载免费PDF全文

王彦斌刘敦一  蒙义峰曾普胜杨竹森  田世洪 《中国地质》2004,31(2):169-173

对安徽铜陵新桥铜-硫-铁-金矿床区内的石英闪长岩和辉绿岩中的锆石分别进行了SHRIMP精确定年研究,石英闪长岩中锆石206Pb/238U年龄为(140.4±2.2)Ma,辉绿岩中锆石的年龄较复杂,其中发现了元古代锆石颗粒,其锆石207Pb/206Pb年龄为(2261±14)Ma,(1612±8)Ma,(919±12)Ma,(831±17)Ma。另外还有一组早古生代年龄的锆石,锆石206Pb/238U年龄为(443±13)Ma。以上这些新资料说明该区可能存在元古代基底的信息,且燕山期岩浆活动对本区成矿具有重要意义。  相似文献   

大兴安岭地区浅覆盖层对地面伽马能谱测量的影响   总被引：1，自引：2，他引：1  

刘菁华  王祝文  郝立波  田钢 《物探与化探》2004,28(2):111-113

讨论在大兴安岭地区进行地质填图中浅覆盖层对伽马能谱测量的影响问题。通过放射性元素的取样分析、岩石—土壤的矿物分析以及实测剖面分析,得知了伽马能谱测量的影响因素,从而为应用伽马能谱测量解决地质填图中的问题提供了依据。  相似文献   

Discovery of Pyrrhotite-Chalcopyrite-Bearing Amphibole Megacrysts in Tongling Area, Anhui Province   总被引：1，自引：0，他引：1  

QinXinlong DuYangsong TianShihong H.K.Lee YinJingwu S.J.Kim 《中国地质大学学报(英文版)》2004,15(1):36-45

Some pyrrhotite-chalcopyrite-bearing amphibole megacrysts (including pyroxene megacrysts) were discovered in Mesozoic augite diorite-porphyrite at Caoshan in Tongling area, Anhui Province. The amphibole megacrysts, belonging mainly to pargasite and magnesiohastingsite, are characteristic of the amphibole composition derived from mantle and crystallized in lower crust. In general, the aggregates of pyrrhotite-chalcopyrite take the shapes of cylinder and sphere. Three occurrences have been recognized in the amphibole megacrysts: parallel linear, bunchy and scattered. The unique cylinder-like shape of the aggregates and remarkable Ni-poor sulfides in Caoshan are distinctively different from the spherical Ni-rich sulfides in pyroxene megacrysts and any other kinds of megacrysts. In terms of composition, the amphibole megacrysts and their sulfides in Caoshan are similar to those in the pyroxenite xenoliths in Qilin, Guangdong Province. In terms of origin, the pyrrhotite-chalcopyrites as exsolution products resulted from the subsolidus re-equilibration of sulfide solid solution within amphibole megacrysts.amphibole megacrysts were first discovered inside and outside China. This discovery is important for the study of regional magma evolution and its associated mineralizations and ore sources as well.  相似文献   

松嫩平原湿地植被对生境干-湿交替的响应   总被引：9，自引：0，他引：9  

田迅  卜兆君  杨允菲  郎惠卿 《湿地科学》2004,2(2):122-127

扎龙湿地和向海湿地水分布存在不均一性，生境中有“干-湿”交替过程。选取“干-湿”界面上沼泽植被与草甸植被共存的群落片断分别设置15个固定样方，生长季内4个月观测结果表明：扎龙湿地和向海湿地生境旱生化时羊草为优势种群，湿生化时芦苇为优势种群，芦苇沼泽群落和羊草草甸群落随生境“干-湿”交替过程相互演替，演替过程既受生境水分波动的影响，又由优势种群内在生物学特性决定。  相似文献   

海岸带临港工业、海运物流与全球化大生产的探讨   总被引：5，自引：0，他引：5  

田汝耕  张振克  朱大奎 《世界地理研究》2004,13(2):1-8

海岸带是世界人口密集、经济发达的地带，在全球经济一体化和全球化大生产中具有重要的地位。近半个世纪以来，海岸带临港工业迅速崛起并持续高速发展，依托海港建设、大型船舶运输发展起来的临港工业和海运物流，在跨国公司的运作下形成了现代意义上的全球化大生产。这种生产方式使资源贫乏的日本快速发展成发达国家；深圳赤湾临港工业区成为中国高效益工业的典范。本文着重讨论了海岸带经济建设中大力发展临港工业对地区、国家和全球经济的影响，指出中国21世纪应大力开发利用海岸带港湾资源、重点建设全球化大生产的大进大出的基地，建立若干个具有国际竞争力的海岸带产业中心，推动国民经济持续、快速发展。  相似文献   

预应力锚索技术在大型水库除险加固工程中的应用          下载免费PDF全文

呼咏  孙志峰  田野 《探矿工程》2004,31(9):46-47,50

介绍了无粘结预应力锚固技术在吉林省二龙山水库除险加固工程中的应用。对造孔、编索、下索、张拉等工艺进行了详细介绍。  相似文献   

Impact of land-cover and climate changes on runoff of the source regions of the Yellow River     

LI Daofeng  TIAN Ying  LIU Changming  HAO Fanghua 《地理学报》2004,14(3):330-338

After dividing the source regions of the Yellow River into 38 sub-basins, the paper made use of the SWAT model to simulate streamflow with validation and calibration of the observed yearly and monthly runoff data from the Tangnag hydrological station, and simulation results are satisfactory. Five land-cover scenario models and 24 sets of temperature and precipitation combinations were established to simulate annual runoff and runoff depth under different scenarios. The simulation shows that with the increasing of vegetation coverage annual runoff increases and evapotranspiration decreases in the basin. When temperature decreases by 2oC and precipitation increases by 20%, catchment runoff will increase by 39.69%, which is the largest situation among all scenarios.  相似文献   

近20年华北地电阻率异常空间演化及强震短期前兆判别标志研究     

郑文俊  田山  邵永新 《中国地震》2005,21(2):260-268

开展了华北地电阻率异常参数提取的研究，以1980—2001年的异常参数为输入进行了全时空扫描，并对其动态图像演化做全面分析，由此提取出华北地区5级以上地震的地电阻率短期前兆的判别标志。为了进行初步检验，本文依上述判别标志对华北近年地电阻率动态图像做了对比分析。  相似文献   

采空区二维超声波物理模型实验研究     

赵家福  田钢  石战结  王者江 《吉林大学学报(地球科学版)》2005,(Z1)

由于对资源矿产的过度开采使得矿山地区(尤其是煤矿)出现了采空区,从而引起地表塌陷等地质灾害。为了深入了解地震方法在采空区调查中的应用效果,从超声波物理模型实验研究出发,论述了物理模型的原理和制作,研究了采空区的地震波场特征,并利用W inse is软件对所采集的二维超声波实验数据进行了处理。由叠偏剖面推断的采空区的位置与实际模型相符,从而验证了超声波采空区物理模型试验是有效的、可信的;同时可以为实际探测采空区提供进一步的理论依据。  相似文献   

Fractionation mechanism of stable isotope in evaporating water body     

ZHANG Xinping  TIAN Lide  LIU Jingmiao 《地理学报》2005,15(3):375-384

Under Rayleigh equilibrium condition, stable isotopic ratio in residual water increases with the decrease of the residual water proportion f exponentially, and the fractionation rate of stable isotopes is inversely proportional to temperature. However, under kinetic evaporation condition, the fractionation of stable isotopes is not only related to the phase temperature but also influenced by the atmospheric humidity and the mass exchange between liquid and vapor phases. The ratio δ in residual water will not change with f after undergoing evaporation of a long time for great relative humidity. The rate that the evaporating water body reaches isotopic steady state is mainly dependent on the relative humidity in atmosphere. The analysis shows that the actual mean linear variety rates, about -30.0, of the δ18O in residual water versus the residual water proportion at Nagqu and Amdo stations are consistent with the simulated process under temperature of 20 oC and relative humidity of 50%. The distillation line simulated under Rayleigh equilibrium condition is analogous to the global meteoric water line (MWL) as the temperature is about 20 oC. Under non-equilibrium condition, the slope and constant values of distillation line are directly proportional to temperature and relative humidity. According to the basic data, the simulated distillation line is very consistent with the actual distillation line of Qinghai Lake.  相似文献