中国中奥陶世岩相古地理   总被引：18，自引：10，他引：8       下载免费PDF全文

冯增昭  彭勇民  金振奎  鲍志东 《古地理学报》2003,5(3):263-278

本文是中国早、中、晚寒武世和早奥陶世岩相古地理诸文的继续。在笔者等的华北地区、华南地区和西北地区寒武纪和奥陶纪定量岩相古地理研究及编图成果的基础上,结合其他地区（主要是蒙兴地区、昆仑秦岭地区、西藏地区、海南岛地区和台湾地区）的地质资料,编制出了中国中奥陶世岩相古地理图,并撰写出本文。华北地区、华南地区和西北地区的研究程度较高,其岩相古地理图和文字论述都是定量的。其他地区的研究程度较低,其岩相古地理图和相应的文字论述则是定性的和概略性的。中国中奥陶世岩相古地理的基本格局仍和早奥陶世的一样为“两槽和三台相间分布”。两槽即天山北山蒙辽吉槽地和昆仑秦岭槽地,三台即准噶尔蒙兴台地、塔里木柴达木华北台地和西藏华南台地。但是这些古地理单元及其次级古地理单元的特征却与早奥陶世的有所不同或大不相同。  相似文献   

我国古地理学的形成、发展、问题和共识   总被引：23，自引：17，他引：6       下载免费PDF全文

冯增昭 《古地理学报》2003,5(2):129-141

古地理是研究地质历史时期和人类历史时期的自然地理特征的科学,有重要的地学理论意义和生产实践意义,还与人类赖以生存的古今地理环境密切相关。我国古地理学来源于地层学、地史学、大地构造学、古生物学、沉积岩石学、自然地理学、第四纪地质学、考古学、人类历史地理学等,因此就相应地产生和形成了地层古地理学(或地史古地理学)、构造古地理学、生物古地理学、岩相古地理学(或沉积古地理学)、自然地理古地理学、第四纪古地理学、人类历史古地理学等分支学科。有许多类型的古地理图,如构造古地理图、生物古地理图、岩相古地理图、示意的或定性的古地理图、定量的古地理图、不同比例尺的古地理图、当今界限的古地理图、非当今界限的古地理图等。古地理图是古地理研究的集中表现,是古地理学的生长点。我国的古地理学有4个主要的发展趋势,即从单一到综合,从定性到定量,从手工作图到计算机作图,从理论到应用。《古地理学报》的创刊和开始进入我国科技期刊的先进行列是我国古地理学发展历史中的一件大事。2002年12月香山科学会议第197次学术讨论会围绕“多信息的古地理重建”这个主题,通过充分的讨论和争鸣,对我国古地理学的发展前景达到了共识,即根据多学科的、多层圈的、多时代的、第一手为主的和定量为主的信息资料,编制从长城纪到第四纪以及人类历史时期的、各种比例尺兼有的、既有地学理论意义又能为生产实践和人类生存环境的维护和改善服务的、综合各古地理学分支学科之长的古地理图,是时候了。这是一个巨大的工程。让我们共同努力,为促使这一有重大历史意义和现实意义的宏伟目标的早日实现而奋斗。  相似文献   

阿尔金北缘地区剥离断层控矿和金矿成因——以大平沟金矿床为例   总被引：5，自引：0，他引：5  

陈宣华  杨风  王小凤  陈柏林  陈正乐  王克卓 《吉林大学学报(地球科学版)》2002,32(2):122-127

阿尔金北缘大平沟金矿床是近年来在阿尔金山地区新发现的首例岩金矿床。为了阐明其矿床地质特征及其成因,采用构造解析与矿主档学研究相结合的方法。结果表明,（1）金矿物主要为金－银系列矿物,成色在915－946之间,金含量与K2O、Fe2O3呈正相关关系;（2）变粒岩、强片理化变粒岩、含金石英脉和无矿化纯净石英脉的稀土元素配分型式具有相似性;（3）主要成矿期温度范围198－290℃,为中温热液矿床;（4）成矿深度为1.77-2.68km;（5）氢氧同位素组成具有以岩浆水为主的特征。由此认为,大平沟金矿床是受阿尔金北缘断裂－剥离断层控制的金矿床,是该地区金矿找矿的方向。  相似文献   

Toxic contaminants and their biological effects in coastal waters of Xiamen,China. II. Biomarkers and embryo malformation rates as indicators of pollution stress in fish   总被引：3，自引：0，他引：3  

Klumpp DW  Humphrey C  Huasheng H  Tao F 《Marine pollution bulletin》2002,44(8):761-769

Baseline information is presented on embryo malformation rate and biomarkers in fish as indicators of sub-lethal stress caused by pollution in coastal waters of Xiamen, PR China. Fish and eggs were sampled from several areas in Xiamen coastal waters (Xiamen Harbour, Maluan and Tongan Bays and East Channel), where varying levels of pollutant input have been documented. Comparative sampling was done at a "cleaner" reference site at Dongshan Island. Embryonic malformation rates, which indicate general water quality, varied with location and species of fish, and exceeded background levels for unpolluted waters (assumed approximately 5%) by up to eightfold at some sites. Generally, sites around Xiamen Harbour show signs of poor water quality having highest mean levels of embryo deformity (20-30%) and these decreased towards open waters (Tongan Bay, Eastern Channel) where abnormalities approached background levels. An indication that toxic contaminants may be having a localised effect in the region, particularly in the harbour was reinforced by the biomarker assays. However, activities of the biomarkers ethoxyresorufin O-deethylase (EROD) and glutathione S-transferase in fish livers indicate no clear pattern, and there is no evidence that fish from the four sampling areas have been more or less exposed to PAHs and other compounds that induce these biomarkers. Antioxidant biomarkers (glutathione peroxidase, catalase, superoxide dismutase, and reduced glutathione) suggest that exposure to xenobiotics appears to be lowest in Dongshan and Maluan and highest in the harbour and Tongan. Inhibition of acetylcholinesterase in fish muscle indicated possible effects by organophosphate and carbamate pesticides in Xiamen waters and these effects may be greatest in the area of the harbour.  相似文献   

田玉在中国古玉器中的地位     

白峰  吴瑞华 《岩石矿物学杂志》2002,21(Z1):8-12

中国和田玉的开发利用历史悠久,在中国古玉器中地位显著.从新石器时代晚期开始到清代,和田玉一直是中国古玉器的主要玉材;而和田玉又具有其他产地软玉无法比拟的颜色,具有独特的羊脂白色;用和田玉制成的玉器,是中国传统玉文化的主要载体,具有不可复制的惟一性.  相似文献   

澜沧-耿马Ms7.6级地震前兆综合加权信息量的变化     

张昭栋  张华  冯志军 《大地测量与地球动力学》2000,20(4):71-77

在地震综合信息量的基础上,改进了地震前兆异常的出现概率的计算方法,得到地震前兆综合加权信息量.利用"地震预报专家系统"的思想对每一异常事件进行综合评估.考虑到异常的可靠性、有效性、显著性及相互关联性,给予不同的权重,以每一异常事件的最可能发震时间来估算异常出现的概率,计算了澜沧-耿马地震的地震前兆综合加权信息量,并对这种信息量变化的特点进行了分析.  相似文献   

积极推动“数字海南”建设     

何锋 《地理信息世界》2000,(4)

海南省具有得天独厚的发展优势,“数字地球”是实现整体可持续发展的重要保障,将有力推进全省信息化的进程,促进经济发展。  相似文献   

Preliminary study on assessment of nutrient transport in the Taihu Basin based on SWAT modeling     

Lai Geying  Yu Ge  Gui Feng 《中国科学D辑(英文版)》2006,49(1):135-145

With the Taihu Basin as a study area, using the spatially distributed and mechanism-based SWAT model, preliminary simulations of nutrient transport in the Taihu Basin during the period of 1995:_2002 has been carried out. The topography, soil, meteorology and land use with industrial point pollution discharge, the loss of agricultural fertilizers, urban sewerage, and livestock drainages were all considered in the boundary conditions of the simulations. The model was calibrated and validated against water quality monitoring data from 2001 to 2002. The results show that the annual total productions of nitrogen (TN) and phosphorus (TP) into Lake Taihu are 40000t and 2000t respectively. Nutrient from the Huxi Region is a major resource for Lake Taihu. The non-point source (surface source) pollution is the main form of catchment sources of nutrients into Lake Taihu, occupied TN 53% and TP 56% respectively. TN and TP nutrients from industrial point pollution discharge are 30% and 16%, and sewerage in both forms of point source and non-point source are TN 31% and TP 47%. Both the loss of agricultural fertilizers and livestock drainages from the catchment should be paid more attention as an important nutrient source. The results also show that SWAT is an effective model for the simulation of temporally and spatially nutrient changes and for the assessment of the trends in a catchment scale.  相似文献   

裂隙岩质边坡地下水渗流数值模拟     

刘建军  卢正  江峰 《地下水》2006,28(1):26-28

本文从反倾向岩质高边坡的渗流特征和渗流普遍规律出发,根据渗流力学知识,建立数学模型,通过渗流数值模拟计算分析了渗透压力、水头变化规律以及对岩质边坡稳定性的影响.  相似文献   

Preliminary study on assessment of nutrient transport in the Taihu Basin based on SWAT modeling   总被引：4，自引：0，他引：4  

LAI Geying  YU Ge  GUI Feng 《中国科学D辑(英文版)》2006,49(Z1)

With the Taihu Basin as a study area, using the spatially distributed and mechanism-based SWAT model, preliminary simulations of nutrient transport in the Taihu Basin during the period of 1995-2002 has been carried out. The topography, soil, meteorology and land use with industrial point pollution discharge, the loss of agricultural fertilizers, urban sewerage, and livestock drainages were all considered in the boundary conditions of the simulations. The model was calibrated and validated against water quality monitoring data from 2001 to 2002. The results show that the annual total productions of nitrogen (TN) and phosphorus (TP) into Lake Taihu are 40000t and 2000t respectively. Nutrient from the Huxi Region is a major resource for Lake Taihu. The non-point source (surface source) pollution is the main form of catchment sources of nutrients into Lake Taihu, occupied TN 53% and TP 56% respectively. TN and TP nutrients from industrial point pollution discharge are 30% and 16%, and sewerage in both forms of point source and non-point source are TN 31 % and TP 47%. Both the loss of agricultural fertilizers and livestock drainages from the catchment should be paid more attention as an important nutrient source. The results also show that SWAT is an effective model for the simulation of temporally and spatially nutrient changes and for the assessment of the trends in a catchment scale.  相似文献