Research Advance of Shrub Dendrochronology in the Cold and Arid Regions of China     

Shengchun Xiao  Xiaomei Peng  Aijun Ding  Quanyan Tian  Chao Han 《地球科学进展》1986,35(6):561-567

Along with the booming of dendrochronology in China, the woody species for the tree-ring study have expanded gradually from tree species to the shrub and dwarf shrub species in the last decades. The zonal woody species in the vast alpine mountains, arid desert areas and arid regions in China are mostly shrubs and semi-shrubs, which is very important to understand the process of regional evolution, environmental protection and ecological recovery. In this paper, the shrub species which have been studied on tree rings in cold and arid areas of China were collected and sorted, and the fundamental research advances were presented, which include the shrub tree ring identification, radial growth characteristics, and chronology construction by different parameters. The applications of shrub dendrochronology to the subjects in eco-response, paleoclimate reconstruction, hydrological process, ecological study of artificial forest and ecological restoration were also presented. The prospect of shrub dendrochronology in the future was also discussed.  相似文献   

Reef-controlled Mineral Deposits in Southern China     

Zeng Yunfu  Tian Hongjun 《《地质学报》英文版》1989,63(3):241-252

Reef-controlled mineral deposits in southern China are divided into three types in this paper based on the relative importance of organic reefs in the ore-forming processes; they are: the direct type, indirect type, and passive type. The case histories of several typical deposits are discussed. In studying reef-controlled deposits, more attention should be paid to the function of synsedimentary faults in reef construction and mineralization and the importance of oil-gas palaeoreservoirs in reef rocks for the formation of sulfide deposits, in addition to analysing the favourable sedimentary facies of mineralization.  相似文献   

测距三角高程导线技术规格探讨     

赵吉先  田养权 《华东地质学院学报》1989,12(3):71-80

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我国首次发现方锑金矿   总被引：1，自引：1，他引：1  

苑保钦  田澍章 《矿物学报》1989,9(4):312-314

方锑金矿在我国湖南平江杨山庄金矿床中首次发现。共生矿物有:自然金、辉锑矿、自然锑、毒砂、黄铁矿、车轮矿等。颗粒极细小,直径为0.02—0.05mm,灰黑色,暗淡光泽,不透明,无解理,显微硬度211—246kg/mm~2(20g)。反射色为白色,均质,反射率:63.29(405nm),63.04(480nm),63.00(546nm),62.57(589nm),61.86(656nm)。三个不同颗粒方锑金矿电子探针分析结果:Au 43.04,43.01,42.96;Sb 56.96,56.99,57.04。化学式;Au_(0.93)Sb_2。X射线粉晶分析主要谱线:3.34(60),2.99(70),2.722(60),2.362(70),2.010(100)。  相似文献   

一些地区的地声特征及其作为地震前兆的可能性          下载免费PDF全文

田时秀  孔繁永  李金锡  高景来 《地震工程学报》1985,7(4):20-27

本文收集了河北卢龙、昌黎,辽宁营口,四川成都,山东莒县和山西介休等地的地声观测资料。对这些资料进行分析处理,得到了它们的频谱特性和其他特性。最后对声源的机制及其作为地震前兆的可能性作了扼要的讨论。  相似文献   

第三纪惠民盆地的沉积相和沉积大地构造演化   总被引：4，自引：0，他引：4       下载免费PDF全文

黄家宽  田兴有  陈昌明  陈景山  陈瑞君  李琍  王素民  时华星  李桂华  曹海燕 《地质科学》1985,(4):342-353

山东惠民盆地中所堆积的厚达7000米的第三系地层,主要是陆源碎屑沉积,其次是碳酸盐沉积。解释这些沉积物的沉积环境,显然有助于预测盆地中有利的生、储油相带。我们在分析多项指相标志的基础上,首先总结了主要沉积相的沉积序列和沉积模式,然后概略地描述了不同时期盆地中沉积相的展布,最后将盆地的构造演化与沉积特征相结合,进行沉积大地构造方面的探索。  相似文献   

Approximately-Balanced Drilling in Daqing Oilfield     

XiaBairu ZhengXiuhua LiGuoqing TianTuo 《中国地质大学学报(英文版)》2004,15(1):128-132

The Daqing oilfield is a multilayered heterogeneous oil field where the pressure are different in the same vertical profile causing many troubles to the adjustment well drillings. The approximatelybalanced drilling technique has been developed and proved to be efficient and successful in Daqing oilfield. This paper discusses the application of approximately-balanced drilling technique under the condition of multilayered pressure in Daqing oilfield, including the prediction of fornmtion pressure, the pressure discharge technique for the drilling well and the control of the density of drilling fluid.  相似文献   

滑坡可视化地面模型   总被引：2，自引：0，他引：2  

田金华  池秀文  夏元友 《岩土工程技术》2004,18(3):144-146,153

简述了滑坡可视化地面模型的构建及可视化方法。介绍了可视化软件IDL的功能和特点。利用IDL中的TRIANGULATE函数和TRIGRID函数相结合 ,建立了基于Delaunay三角网的规则格网地面模型。最后 ,论述了滑坡可视化地面模型研究的意义。  相似文献   

关于重力大地水准面精度的探讨   总被引：1，自引：2，他引：1  

田晋  暴景阳  刘雁春 《测绘信息与工程》2005,30(3):42-44

从移去恢复法原理以及局部大地水准面精化残差拟合两个角度,分别得到了重力大地水准面精度估计的直接法与间接法,并通过实例分析了两种方法的误差评定结果。  相似文献   

北京山区农业气候资源系统的模糊综合评判   总被引：1，自引：0，他引：1  

田志会  郭文利  赵新平  王志华  郑大玮 《山地学报》2005,23(4):507-512

为了定量分析北京山区农业气候资源,利用山区1 km^2小网格的气候资料,应用农业气候适宜度理论、模糊数学和因子分析等方法,通过5项农业气候指标与山区栽培植物生长发育条件之间隶属函数的建立及其权重的确定,分别计算山区各网格点的农业气候资源指数、效能指数和利用系数,并在GIS的支持下建立了它们的栅格图.结果表明：北京山区以平谷、密云、怀柔南部等东北部地区的农业气候资源系统较为优良,无论是气候资源总量还是其匹配状况以及利用率都是本地区最高的;与之相反,西北部和海拔较高的山区,不仅农业气候资源总量贫乏,而且光、热、水资源的匹配程度较差,导致农作物对资源的利用率较低;此外,房山东南部和昌平南部等地区气候资源总量较为丰富,但受水资源的限制,光、热、水资源的匹配程度较差,致使当地气候资源利用率较低.  相似文献