A Guide to English-Language Journals for Geography Education     

《The Journal of geography》2012,111(1):14-23

  相似文献   

胶东金矿研究进展及约束金物质来源的新思路     

李大鹏  程光锁  迟乃杰  李成学 《山东国土资源》2014,30(12)

作为全球最主要的金成矿带之一,胶东地区仅占全国国土面积的0.27%,黄金储量却约占全国的25%,特别是胶西北地区的金矿更是星罗棋布,引起了国内外地质学家的广泛关注,进行了大量的生产和科研工作。该文总结了近年来取得的关于胶东金矿在构造、岩浆、流体及成矿物质、富集机制等方面取得的研究进展,并且针对颇具争议的金成矿物质来源问题,提出了新的研究思路,并初步论证了其可行性。以期抛砖引玉,引起广大地学同仁对此科学问题的关注。  相似文献   

Continuous Measurement of Number Concentrations and Elemental Composition of Aerosol Particles for a Dust Storm Event in Beijing   总被引：1，自引：0，他引：1  

ZHANG Renjian  HAN Zhiwei  SHEN Zhenxing  CAO Junji 《大气科学进展》2008,25(1):89-95

A continuous measurement of number size distributions and chemical composition of aerosol particles was conducted in Beijing in a dust storm event during 21-26 March 2001. The number concentration of coarse particles （ 〉2μm） increased more significantly than fine particles （ 〈2μm） during the dust storm due to dust weather, while the anthropogenic aerosols collected during the non-dust-storm period tended to be associated with fine particles. Elemental compositions were analyzed by using proton-induced X-ray emission （PIXE）. The results show that 20 elements in the dust storm were much higher than in the non-dust-storm period. The calculated soil dust concentration during the dust storm was, on average, 251.8μg m^-3, while it was only 52.1μg m^-3 on non-dust-storm days. The enrichment factors for Mg, A1, P, K, Ca, Ti, Mn, Fe, C1, Cu, Pb, and Zn show small variations between the dust storm and the non-dust-storm period, while those for Ca, Ni and Cr in the dust storm were much lower than those in the non-dust-storm period due to significant local emission sources. A high concentration and enrichment factor for S were observed during the dust storm, which implies that the dust particles were contaminated by aerosol particles from anthropogenic emissions during the long-range transport. A statistical analysis shows that the elemental composition of particles collected during the dust storm in Beijing were better correlated with those of desert soil colleted from desert regions in Inner Mongolia. Air mass back-trajectory analysis further confirmed that this dust storm event could be identified as streaks of dust plumes originating from Inner Mongolia.  相似文献   

Chemical Characteristics of Carbonaceous Aerosols During Dust Storms over Xi＇an in China     

李旭祥  曹军骥  JudithCHOW  韩永明  李顺诚  John  WATSON 《大气科学进展》2008,25(5)

Characterization of carbonaceous aerosols including CC (carbonate carbon), OC (organic carbon), and EC (elemental carbon) were investigated at Xi'an, China, near Asian dust source regions in spring 2002. OC varied between 8.2 and 63.7 μg m-3, while EC ranged between 2.4 and 17.2 μ m-3 during the observation period. OC variations followed a similar pattern to EC and the correlation coeflcient between OC and EC is 0.89 (n=31). The average percentage of total carbon (TC, sum of CC, OC, and EC) in PM2.5 during dust storm (DS) events was 13.6%, which is lower than that during non-dust storm (NDS) periods (22.7%). CC, OC, and EC accounted for 12.9%, 70.7%, and 16.4% of TC during DS events, respectively. The average ratio of OC/EC was 5.0 in DS events and 3.3 in NDS periods. The OC-EC correlation (R2=0.76, n=6) was good in DS events, while it was stronger (R2=0.90, n=25) in NDS periods. The percentage of water-soluble OC (WSOC) in TC accounted for 15.7%, and varied between 13.3% and 22.3% during DS events. The distribution of eight carbon fractions indicated that local emissions such as motor vehicle exhaust were the dominant contributors to carbonaceous particles. During DS events, soil dust dominated the chemical composition, contributing 69% to the PM2.5 mass, followed by organic matter (12.8%), sulfate (4%), EC (2.2%), and chloride (1.6%). Consequently, CC was mainly entrained by Asian dust. However, even in the atmosphere near Asian dust source regions, OC and EC in atmospheric dust were controlled by local emission rather than the transport of Asian dust.  相似文献   

2004年北京秋季大气颗粒物的化学组分和来源特征   总被引：1，自引：0，他引：1  

浦一芬  吴瑞霞 《气候与环境研究》2006,11(6):739-744

2004年9月在北京城区进行了大气颗粒物采样,样品用PIXE方法进行了分析,得到了20种元素的浓度及其谱分布。并对北京颗粒物的谱分布、富集因子和来源进行了分析研究。发现K元素浓度分布呈细粒态单峰谱分布,细粒态K富集因子较高,表明了生物质燃烧的主要贡献。因子分析结果还表明,土壤尘、生物质燃烧、煤烟尘、工业源和汽车尾气排放源对秋季北京局地排放源有明显贡献。  相似文献   

四川盐源西范坪渐新世含矿二长斑岩成因浅析   总被引：1，自引：0，他引：1  

黄景厚  周清  张锦让  王宏  王生伟  朱斯豹  刘宇杰 《地质学报》2019,93(3):622-632

四川盐源西范坪斑岩型铜矿位于扬子板块西南缘,通过对含矿二长斑岩进行锆石U-Pb定年,获得年龄为31.68±0.28 Ma(MSWD=1.2;2σ),表明其形成时代为古近纪渐新世早期,与区内碱性斑岩岩浆活动的高峰期一致。岩石碱度率指数(A.R.)为3.59～3.69,K/N为0.89～1.11,A/NK为1.16～1.24,A/CNK为0.97～1.13,属准铝—过铝质碱性石英二长斑岩;岩石高度富集轻稀土元素,相对亏损重稀土元素,δEu(0.80～0.85)异常不明显,并且富Sr贫Yb(Y),具高Sr/Yb和Sr/Y比值,系典型的埃达克岩。西范坪埃达克质含矿斑岩为印度板块与欧亚大陆板块碰撞造山晚期远程压力释放环境下,拆沉下地壳部分熔融的产物。  相似文献   

亲铜(亲铁)元素含量比值在地球科学中的初步应用实例     

汪在聪  邹宗琪 《矿物岩石地球化学通报》2019,(2):224-236,445

亲铜(亲铁)元素在行星增生演化、核幔分异、地幔岩浆过程、壳幔相互作用以及金属矿床成因等领域具有举足轻重的作用。本文从亲铜元素的地球化学性质出发,介绍了"高维度思维"的亲铜元素含量比值及其在地球科学领域的初步应用:①获得同一份样品中不同亲铜元素含量可在一定程度上降低样品的不均一性(块金效应)对含量比值的影响;②Cu/Ag值可以约束不同高温岩浆过程中硫化物固液状态和亲铜元素地球化学性质,进而认识地幔、洋壳和大陆地壳间的联系;③具有不同分配系数的亲铜元素含量的比值可以鉴别岩浆硫化物饱和史,比如通过亲铜元素的分异约束火星陨石母岩浆的硫化物不饱和演化历史;④依据In-Cd-Zn在硅酸盐地球的含量以及它们的相对亲铜亲铁性质,地球主体增生物质已经消失,不能由陨石代表。  相似文献   

蚀变带元素地球化学成矿预测法——以金龙山微细浸染型金矿为例     

赵利青 《地质与资源》1997,6(3):214-220

金矿化作用伴随围岩蚀变,且多受断裂控制,反映在地球化学上出现某些元素的异常晕.在已发现一定矿(化)体并掌握一般控矿特征的地区,利用已有工程,经科学的组合采样(主要在蚀变带范围内连续拣块采样),分析有关指示元素,总结有关的地球化学指标,建立地球化学预测模式(从元素异常特征或线金属量、地球化学指标或元素比值、逐步回归方程估值等三方面),对已知矿(化)体及外围异常进行地球化学评价研究.这就是蚀变带元素地球化学成矿预测法.该方法在秦岭南坡金龙山微细浸染型金矿上的应用有较好的效果.本方法的预测是半定量或定性的,回归分析估值是近似定量的,同时也是有效的,低成本的.  相似文献   

"数字地球"的体系结构   总被引：14，自引：0，他引：14  

李琦  杨超伟  易善桢 《遥感学报》1999,3(4):254-258

根据我们一年来对“数字地球”的研究,从地理信息与信息技术发展和信息化社会的角度出发,系统地介绍了“数字地球”涉及的研究内容、关键技术、应用前景等问题,比较客观地阐明了“数字地球”的相关内容。  相似文献   

长岛轮渡码头装卸工艺设计     

赵瑞芬 《海岸工程》1999,18(4):59-63

以长岛港轮渡码头装卸工艺设计为例,介绍轮渡码头装卸工艺设计的步骤和内容。  相似文献