内蒙古白云鄂博地区基底岩石锆石年代学及对构造背景的指示   总被引：12，自引：7，他引：5  

范宏瑞  杨奎锋  胡芳芳  王凯怡  翟明国 《岩石学报》2010,26(5):1342-1350

白云鄂博地区的克拉通基底岩石主要由糜棱岩化花岗片麻岩(2588±15Ma),正长岩、花岗闪长岩(2018±15Ma)和黑云母花岗片麻岩、含石榴石蓝晶石花岗片麻岩(～1890Ma)等组成,白云鄂博超大型稀土矿床就位于华北克拉通太古代基底之上。太古代克拉通基底在早元古代中晚期(2.0Ga)又经历了一次强烈的碰撞造山运动,造成了闪长质与花岗质岩浆侵位,以及1.9Ga片麻岩相变质事件。  相似文献   

数据同化——它的缘起,含义和主要方法   总被引：31，自引：1，他引：30  

王跃山 《海洋预报》1999,16(1):11-20

我国已进入流体动力学的卫星观测世纪,数据同化（有时叫“四维同化”）,势必成为随之而来的重要课题之一。针对目前人们对这一课题尚无太多了解,从而在实际工作中产生一些混乱,笔者在本文就数据同化的必要性,它的含义,它的开创和现在研究、应用中的主要方法作一比较详细的论述。  相似文献   

兴凯湖花岗杂岩体的锆石U——Pb 年龄及其地质意义   总被引：3，自引：0，他引：3  

杨浩  张彦龙  陈会军  葛文春 《世界地质》2012,31(4):621-630

佳木斯地块东南缘的兴凯湖花岗杂岩体主要由花岗闪长岩、二长花岗岩和正长花岗岩组成,其锆石的LA-ICP-MS U-Pb 测年结果显示,杨田寨南山岩体形成于257 ± 2 Ma,双子山岩体形成于215 ～212 Ma; 花岗岩的时空展布表明,两期花岗质岩浆的就位可能分别与古亚洲洋板块的俯冲作用和后造山伸展进程密切相关。结合本区和黑龙江东部其他花岗质岩石的年龄,揭示了佳木斯地块和兴凯地块在早古生代、二叠纪及三叠纪共同经历了三期大规模岩浆活动,暗示两者具有相同的构造属性,共同组成了同一陆块。  相似文献   

Water quality improvement through five constructed serial wetland cells and its implications on nonpoint-source pollution control     

Z. Jia  S. Tang  W. Luo  Y. Hai 《水文科学杂志》2013,58(16):2946-2956

ABSTRACT

Constructed wetlands can be used for reducing nonpoint-source pollution and providing ecological services in a watershed. This paper presents a field monitoring study on water quality improvement in constructed wetlands of five cells in series. The wetland system covers 59.9 ha, or 0.08% of the watershed area; it diverts 7.3 million m³ (hm³) water (or 4.3% annual flow) from a degraded river. The results showed that the hydraulic retention times (HRT) of the five cells ranged from 5 to 15 days, 18.4% inflow was lost to seepage and increased evapotranspiration (ET) in the wetlands; the wetlands retained 99.1% total suspended solids (TSS), 60.9% total phosphorus (TP), and 54.4% total nitrogen (TN) from the inflow. Major reductions of TSS and TP were observed in the first two large cells that occupied 57% of the total wetland area. The smaller cells did not show advantages over the bigger ones in pollutant retention as reported in some studies. Although significant water quality benefit can be achieved by the constructed wetlands, the increased water loss may be a concern, particularly in dry regions.