极地乌拉尔砂金矿的形成和分布规律     

Н.Г.Патык-Кара  А.Г.Щевелев  周伯桃  董智慧 《黄金地质》1993,(3)

本文对极地乌拉尔西坡科日姆砂金矿区砂矿的构造地貌环境、地貌中砂矿的原岩位置及其切割水平、夷平面和风化壳的完整性、潜蚀喀斯特、河谷网系的发育阶段、第四纪冰川作用等地质地貌背景和矿床基本特征以及该区砂金矿的主要类型进行了全面论述。  相似文献   

Magnetic Fabric of Late Devonian Metasedimentary Rocks from Longyan,Southwestern Fujian,China     

Zhai Yongjian Maurice K. SeguinDepartment of Geology  Laval University  Quebec  Canada GIK PZhou Yaoxiu Dong JinmingInstitute of Aero - Geophysical Center  Beijing 《中国地质大学学报(英文版)》1993

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太平洋海啸警报系统     

帕拉拉斯-卡拉扬尼斯  卢玉真 《国际地震动态》1987,(7)

历史背景在所有自然灾害中海啸是最可怕、最复杂的现象,并能造成巨大的人员伤亡与财产损失。从有记录的历史以来,这种巨大的海啸波在全世界一些海岸地区造成了很大的破坏。在人类社会上,海啸影响可追溯到有历史记载的公元前1480年,即当地中海东部的古希腊克里特岛米诺斯文化,由于桑托林岛火山喷发引起的巨大海啸被扫除的时候。在已发生很多这种巨大海啸波的太平洋,历史记载虽然简  相似文献   

观赏“星雨”     

黄立!--- 《天文爱好者》2000,(1)

观赏“星雨”$天津市大港石化@黄立!4-33-1-40130027...  相似文献   

The Effects of Land Uses on Purplish Soil Erosion in Hilly Area of Sichuan Province, China     

LIU Gangcai    ZHANG Jianhui  TIAN Guanglong  WEI Chaofu College of Resources  Environment  Southwest Agriculture University  Chongqing  China Institute of Mountain Hazard  Environment  Chinese Academy of Science & Water Resources Ministry  P. O. Box  Chengdu  Sichuan  China Research  Development Department  Metropolitan Water Reclamation District of Greater Chicago  W. Pershing Road  Cicero  IL -  USA 《山地科学学报》2005,2(1):68-75

1 Introduction Food grain productivity of dry land per capitahas declined significantly during the past fewdecades (Parr et al. 1990). Bowman et al. (1990)and Blaikie (1985) indicated that the greatest lossin productivity comes from soil loss, withsecondary effects from loss of nutrients due toreduced organic matter and increased soil bulkdensity. Soil erosion has major ecological andeconomic consequences in densely populatedChina, particularly, in a large agriculture province,Sichuan…  相似文献   

征订启事     

本刊年征订工作业已开始。本刊委托天津市全国非邮发报刊《联订服务部》办理订阅事宜。定价每册.元  全年订价.元。凡需订阅者请将订刊款通过邮局或银行汇款至下列地址即可：　　邮政编码：　　地址：天津市大寺泉集北里别墅号户头全称：天津市河西区联合征订服务部帐 号：-　　开户银行：工商行天津市尖山分理处电 话： 《天文学进展》2000,18(3):191

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古巴蛇绿岩侵位     

J.  L.  Cobiella  -  Reguera  耿春雁 《海洋地质》2006,(4):37-58

根据岩性和构造特征，古巴划分出三套含蛇绿岩的构造单元：1）北部蛇绿岩带，混杂岩复合体沿古巴岛延伸长度超过1000km；2）白垩纪火山弧建造的变质岩基底；3）中古巴南部Escambray（Guamuhaya）高压变质地块中的构造片体。现有年龄分析资料表明，古巴现存洋壳年代为晚中生代，形成于两种不同的构造背景；1）晚侏罗世-纽康曼期，北美大陆及其南部大陆的漂移造成的小盆地；2）北美被动大陆边缘与阿普第-阿尔必（Aptian—Albian）期火山弧之间形成的俯冲带上部（suprasubduction）边缘盆地。Escambary（Cuamuhaya）地块中生代变质沉积岩中的蛇纹岩片体和高压角闪石形成于一小型洋盆关闭期间．时代很可能为阿尔必（Albian）期。火山弧岩层的变质岩基底来自于上侏罗统-纽康曼阶洋壳，并在中自垩世火山弧形成期间发生变质。北部蛇绿岩带可能来自上述小盆地，以及俯冲边缘盆地的，并自晚白垩世坎佩尼（Campanian）期至始新世中期发生多次侵位。古巴不同的蛇绿岩类型代表了南北美大陆之间泛古陆解体后形成的洋壳的残余物（加勒比洋盆原型）。文章提出并讨论了一种可能的板块构造模型。  相似文献   

RS AND GIS-BASED FOREST FIRE RISK ZONE MAPPING IN DA HINGGAN MOUNTAINS     

YIN Hai-wei  KONG Fan-hua    LI Xiu-zhen 《中国地理科学(英文版)》2004,14(3):251-257

1INTRODUCTIONForests are one of the major natural resources that per-form important environmental and recreational func-tions (COSTANZA and GROOT, 1997). It is well known that forests can absorb atmospheric carbon, maintain a certain degree of humidity in atmosphere, regulate rainfall, moderate temperature, and restrain soil erosion, etc. (AURELIA, 2003). So, the health of a forest in any given area is a very important indicator of the ecological conditions. But fire is the great…  相似文献   

LUCC and Accompanied Soil Degradation in China from 1960''''s to 1990''''s   总被引：1，自引：0，他引：1  

JIANG Qigang 《东北亚地学研究》2002,(1)

This paper tries to qualitatively analyze land use and cover changes (LUCC) and accompanied soil degradation in China, the data of World Atlas of Agriculture in 1969, Land Cover Data of Asia in 1992 and Global Assessment of Human Induced Soil Degradation in 1992, etc. have been used. From 1960' s to 1990's, the area of forestland had increased, ara-ble land and paddy as well as grassland had significantly decreased in China. The major type of soil degradation is due to wa-ter erosion, which is widely distributed especially in Loess Plateau and in Southeast and Southwest China, this happened in forestland, grassland and arable land and mainly resulted from deforestation. The secondary type is wind erosion, which is mainly distributed in Northwest China, it happened in arable land and grassland and was caused by overgrazing. Chemical deterioration is distributed in North and Northwest China, which happened in paddy, arable land and grassland. Physical de-terioration only concentrated in local area in North  相似文献   

The Effect of Tide on the Global Climate Change   总被引：1，自引：0，他引：1  

YANG Xuexiang  CHEN Zhen  CHEN Dianyou 《东北亚地学研究》2002,(1)

The differential rotation between the solid and fluid spheres caused by tidal force could explain the 1500 to 1800 - year cycle of the worlds temperature. Strong tide increases the vertical and horizontal mixing of water in the oceans,dra-wing the cold Pacific water from the depths to the surface and the warm water from the west to the east, where it cools or warms the atmosphere above, absorbs or releases CO2 to decrease or increase greenhouse effect and to make La Nina or El Nino occur in the global. The moons declination and obliquity of the ecliptic affect the tidal intensity. The exchange of tidal energy and tide -generating force caused by the sun, moon and major planets makes the earths layers rotate in different speeds. The differenti-al rotation between solid and fluid of the earth is the basic reason for El Nino and global climate change.  相似文献