阿吾拉勒山西段二叠纪火山岩组合与构造环境分析     

姜常义  吴文奎  谢广成  李伍平 《地球科学与环境学报》1992,(4)

阿吾拉勒山体西段发育了厚度巨大的下二叠统火山岩,这些火山岩均属碱性玄武岩系列,以钾质类型为主,钠质类型次之,岩浆演化呈现出跨越B型趋势。这种火山活动是在大陆地壳内部产生的,代表了陆内裂谷演化的早期阶段。在早二叠世末期,由于受到新源运动的影响,这种火山活动被终止了。  相似文献   

星风吸积引起的钡星重元素超丰     

常瑞香  张波  彭秋和 《中国天文和天体物理学报》1997,(3)

首先指出目前星风吸积模型中理论上的不自洽，考虑到δｒ≠０，重新推导轨道参量变化方程，消去了理论上的不自洽．提出一个新模型：首次将星风吸积同内禀ＡＧＢ星核合成模型结合起来计算钡（Ｂａ）星的重元素超丰，并将计算结果与观测值进行了比较．各参量按标准情况取值时，计算结果不太理想．取Ｂｏｎｄｉｈｏｙｌｅ吸积率的０．５倍或取较大的星风速率时，对于较长轨道周期（Ｐ＞１０００天）的Ｂａ星，计算结果与观测值基本符合；而较短轨道周期（Ｐ＜６００天）的Ｂａ星，其重元素超丰机制可能是盘吸积  相似文献   

Quantitative methods in the earth sciences     

A. F?rster  D. F. Merriarn 《Mathematical Geology》1997,29(5):727

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A study on quality of aquatic environment in Tumen River Area     

Zhu Yanming  Li Jinsong  Lu Xueqiang 《中国地理科学(英文版)》1997,8(2):126-135

After the survey of pollution sources, a study on surface water quality assessment and forecast is given by means of grey system method, fuzzy mathematical method and multiple-index method. Based on it, aquatic environment quality features, treatment measures and environmental strategies of the area are proposed. The quality of aquatic environment of 5 rivers in the Tumen River area is studied. The results show that the pollution of surface water is serious; water quality of most rivers is between grade IV and V except the Hunchun River, being higher than grade IV standard; pollution levels of most rivers have been basically controlled except the of Burhatong River, which is deteriorating gradually. Pollutants of the rivers are comparatively regular, mainly are SS, COD, BOD, AR-OH, NH₃-N. The main pollution trades are chemical fibre industry, pulp and paper making industry and mining industry. If the growth rate of gross industrial product is higher than 25 percent under the encouraging-model of regional exploitation, the pollutants’ load will overtake the bearing capacity of aquatic environment. Thus some protection program against pollution must be worked out in order to achieve the harmonious development of economy society and environment. A project from “Studies on Earlier Stage of Regional Development” of the Chinese Academy of Sciences  相似文献   

Isotopic evidence for holocene climatic changes in Bosten Lake, Southern Xinjiang, China     

Zhong Wei  Xiong Heigang 《中国地理科学(英文版)》1997,8(2):176-182

Based on the δ¹³C and δ¹⁸O fluctuation of lacustrine carbonate, CaCO₃ content and sporo-pollen data, a palaeoclimatic history of Bosten Lake during the Holocene has been outlined, several stages of climatic changes are divided, and the following result es are obtained: (1) Palaeoclimatic changes revealed by carbonate isotope around Bosten Lake are basically identical with that revealed by other geological records in Xinjiang. Environmental changes presented apparent Westlies Style model: during cold period, relative humidity increased, δ¹⁸O, δ¹³C and CaCO₃ appeared low; but in warm periods, the dry regime aggravated. (2) The temperature reflected by δ¹⁸O exist evident features being increase in the late period during the Holocene. Together with the δ¹³C, pollen and CaCO₃ analyses, several cold and warm phases which are of broad regional significance can be identified. The warm peaks occurred at about 11.0 ka B.P., 9.4 ka B.P., 7.5 ka B.P., 5.0 ka B.P., 3.0 ka B.P. and 2.0 ka B.P.; the cold peaks at 11.5 ka B.P., 10.5 ka B.P., 8.8 ka B.P., 5.5 ka B.P., 3.3 ka B.P., 2.2 ka B.P. and 1.5 ka B.P.. (3) Several climatic events with the nature of “abrupt climatic changes” are revealed in the periods of 11.0 ka B.P. −10.5 ka B.P., 9.4 ka B.P. −8.8 ka B.P., 5.5 ka B.P. −5.0 ka B.P. and 2.0 ka B.P. −1.5 ka B.P.. (4) The results show that carbonate isotopic record of lacustrine sediment in arid area is very sensitive to climatic changes, and may be play a very important role in understanding the features and mechanism of palaeoclimatic changes.  相似文献   

沂沭断裂带内部王氏组的沉积环境及构造意义          下载免费PDF全文

商玉强  文琼英  张宝政 《山东国土资源》1992,(1)

本文将晚白垩世王氏组的沉积相划分为五类:湖盆陡岸浊积扇相、洪积扇沉积相、滨—浅湖前缘斜坡相、次深湖相、湖湾相。并对其微相特征进行了详细研究。王氏组沉积特征所反映的沂沭断裂带之活动特点是:先为徐缓的脉动,而后是陡然激烈的断陷,故造成了补偿性沉积与超补偿性沉积的叠置。王氏组砂岩平均化学成分表明:马站盆地具弧后盆地性质。  相似文献   

西宁盆地泥石流类型及其防治意见     

洪文之  徐旭 《青海国土经略》1997,(1)

概略地叙述了西宁地区的泥石流形成条件和形成机理,并将西宁地区泥石流划分为稀性泥石流类及泥石质泥石流种类。在此基础上提出防治泥石流灾害的意见。  相似文献   

描述地壳垂直运动过程的一种函数形式     

杨国华  巩曰沐  卢景忠  韩月萍 《大地测量与地球动力学》1995,(1)

本文在已有数据处理方法的基础上，利用近代数值逼近理论，给出了从时空域角度描述地壳垂直运动过程的一种具体的函数解析形式。最后给出了一个实际算例。  相似文献   

一种基于自证明公钥的可公开验证的认证加密方案     

彭银桥  甘元驹  邓锐  彭凌西  陈月峰 《广东海洋大学学报》2005,25(3):73-75

针对现有的基于证书的认证加密方案通信量和计算量大的缺点,提出了基于自证明公钥的可公开验证的认证加密方案。详细阐述了方案的系统初始化、签名生成、消息恢复验证以及公开验证4个阶段,方案的安全性是基于求解离散对数的困难性(DLP)和强单向hash函数(OWFH)的不可逆。该方案在没有签名者的协作下,任何验证者都可验证签名者的诚实性,在验证签名的同时可认证签名者的公钥,因而减少了存储空间、通信量和计算量。  相似文献   

Atmospheric radiative transfer simulation for atmospheric correction of remote sensing data     

Yunfei Bao Shengbo Chen 《东北亚地学研究》2006,9(1):100-108

IntroductionThe radiance leaving the earth-atmosphere sys-tem which can be sensed by a satellite borne ra-diometer is the sum of radiation emission fromtheearth surface and each atmospheric level that aretransmittedtothe top of the atmosphere.The radia-tion emissionfromthe earthsurface andthe radianceof each atmospheric level can be separated fromtheradiance at the top the atmospheric level a satellitemeasured.Thus,the earth surface parameters willbe retrieved from the surface radiance after a…  相似文献