星子群变质核杂岩的特征及其地质意义   总被引：8，自引：0，他引：8  

项新葵  许建华 《矿产与地质》1993,7(6):401-407

中生代末—新生代初,由于地壳伸展导致的构造剥离使星子—庐山地区前寒武纪结晶基底的星子群以变质核杂岩的构造形式出露地表.星子群为角闪岩相片岩、变粒岩、斜长片麻岩、斜长角闪岩,原岩为正常沉积的泥砂质岩石和拉斑系列的基性火山岩以及二者的过渡类型.星子群的出现证实了“江南古陆”也存在双层结构的前寒武纪变质基底.  相似文献   

洪镇变质核杂岩及其成矿意义   总被引：8，自引：1，他引：8  

李德威 《大地构造与成矿学》1993,17(3):211-220

位于长江中下游地洼区中的洪镇地区出露了变形变质的元古界结晶基底,并伴有主动侵位的燕山期花岗岩。在结晶基底与侏罗系至第三系基本没有变形变质的“稳定盖层”之间的“活动盖层”中可划分出三个滑脱剥离系,它们分别山元古界与寒武系、泥盆系与石炭系、中三叠统月山组与铜头尖组三个主剥离断层及其上盘相关的正断层系组成。本区包括变质杂岩核、基底剥离断层、“活动盖层”和“稳定盖层”的构造组合。具有不同于科迪勒拉型变质核杂岩的结构特征,称之为陆内伸展型变质核杂岩。它表现出上地幔隆升和中,上地壳多层次拆离、减薄,并控制了燕山期中酸性岩浆岩体的侵位方式和层状多金属矿床的分布、形态和成矿机理。  相似文献   

Metamorphic Core Complexes and Its Significance in the Continental Crustal Evolution     

Song Honglin Wei Bize 《中国地质大学学报(英文版)》1990,(1)

Metamorphic core complexes are a basic structural pattern related toextensional tectonics.Several characteristics of different scales of metamorphiccore complexes in the Fangshan and Yunmengshan(Beijing),Zhongtiaoshan(Shanxi),and Dengfong(Henan)are examined.A three-layer model formetamorphic core complexes is suggested.The conclusion is that metamorphiccore complexes are the result of multiphase intracontinental crustal extensionsand are an important tectonic pattern.which exposes the basementmetamorphic rocks to the ground surface in the intracontinental cover.  相似文献   

The analysis of disk core from the Maoping 800 m bore hole     

阮小平  李方全 《地震学报(英文版)》1994,(2)

Ｔｈｅ　ａｎａｌｙｓｉｓ　ｏｆ　ｄｉｓｋ　ｃｏｒｅ　ｆｒｏｍ　ｔｈｅ　Ｍａｏｐｉｎｇ　８００　ｍ　ｂｏｒｅ　ｈｏｌｅ（阮小平）（李方全）ＴｈｅａｎａｌｙｓｉｓｏｆｄｉｓｋｃｏｒｅｆｒｏｍｔｈｅＭａｏｐｉｎｇ８００ｍｂｏｒｅｈｏｌｅ￥Ｘｉａｏ－Ｐｉｎｇ...  相似文献   

国外对LGM以来深海岩心与冰岩心若干研究进展   总被引：1，自引：0，他引：1  

任国玉 《地球科学进展》1994,9(1):33-37

介绍了近十年来国外LGM阶段以来深海岩心和冰岩心研究的主要成果，评述了这些工作对过去全球环境演变研究的重要意义。  相似文献   

祁连山敦德冰芯氧同位素剖面的古气候信息探究   总被引：10，自引：2，他引：10  

卫克勤  林瑞芬 《地球化学》1994,23(4):311-320

冰芯δ~（１８）Ｏ剖面的古气候研究一直是基于大气降水同位素组成的温度效应，即冰芯δ~（１８）Ｏ值与气温呈正相关关系。我国大气降水的同位素组成研究结果表明，在亚洲季风区，由于夏季风带来贫重同位素的暖湿气团，使得季风气候区夏季雨水的δｓ值低于冬季的δｗ值，δｓ－δｗ＜０，正好和温度效应预测的相反。因此，我国季风气候区冰芯的δ~（１８）Ｏ曲线主要反映古季风的盛衰进退，即冰芯的低δ~（１８）Ｏ值对应的是夏季风盛行，气候转暖，降水量增加，夏季风前锋北移；冰芯的高δ~（１８）Ｏ值则对应夏季风强度减弱，气候转冷，降水量减少，夏季风前锋南移。用上述季风气候模式解释敦德冰芯的百年、千年、万年三个不同时间尺度的δ~（１８）Ｏ剖面，所得结果与已知的全新世古气候事件吻合。根据敦德冰芯δ~（１８）Ｏ剖面提供的古气候信息，全新世大致可分成三段四期：１０６００－７１００ａＢ．Ｐ．为早全新世，与末次冰期相比，夏季风逐渐增强，气候转暖；７１００－４０００ａＢ．Ｐ．为中全新世的前期，夏季风盛行，气候暖湿；４０００－１７００ａＢ．Ｐ．为中全新世的后期，此时夏季风退缩，气候偏干冷；１７００ａＢ．Ｐ．至今为晚全新世，其间１７００－７００ａＢ．Ｐ．夏季风强度  相似文献   

A case study in surface mining simulation with special reference to the problem of model evaluation     

D. B. Ogbonlowo  Y. J. Wang 《Geotechnical and Geological Engineering》1987,5(2):109-119

Summary This paper discusses the framework for modelling and analysing the materials handling aspects of a conventional contour mine as related to the smaller to medium-size coal mining companies. Special emphasis is placed on model evaluation. The methodology employed consists of: (a) using the surface geometry of the area to be stripped for developing the equations that are used for analysing the critical factors affecting pit layout, (b) effecting engineering and graphical layout of the mine, (c) collecting — through time studies — and analysing equipment characteristic data, (d) constructing the model, and (e) evaluating the model. The results show that the graphical approach for model construction and evaluation is fast, accurate, and reliable.  相似文献   

N2O measurements of air extracted from antarctic ice cores: Implication on atmospheric N2O back to the last glacial-interglacial transition     

D. Zardini  D. Raynaud  D. Scharffe  W. Seiler 《Journal of Atmospheric Chemistry》1989,8(2):189-201

A method has been developed for determining the N₂O concentrations of air bubbles trapped in ice cores. The air is removed by cutting ice samples of about 45 cm³ with a rotating knife, under pure nitrogen. About 2 cm³ of the gas extracted from the ice is analyzed. The N₂O concentrations are measured by gas chromatography, using electron capture detection with a detection limit of approximately 1 ppbv. The accuracy of the analysis is lower than 6%.This method has been used to analyze 34 Antarctic ice samples. Twelve air samples are from the D57 core and date approximately from AD 1600 and 1900. Data indicate a concentration of about 270 ppbv approximately 400 years ago, and of about 293 ppbv for the beginning of the 20th Century. The other samples have been taken from the Dome C core and date back to the time period extending from the Holocene to the Last Glacial Maximum. The results obtained for the Holocene period are in very good agreement with the concentrations measured for the pre-industrial time from the D57 core and indicate that, during the Holocene period, atmospheric N₂O mixing ratios may have remained fairly constant. The value observed during the last climatic transition suggest a slight increase in the N₂O concentrations when the climate was warming up. The results obtained on samples formed during the Last Glacial Maximum show high scattering which is best explained by the bad quality of this part of the core.  相似文献   

伸展构造与铀成矿作用   总被引：6，自引：1，他引：6  

余达淦 《铀矿地质》1994,10(3):129-137

伸展构造理论的兴起是建立在近代构造地质学理论基础之上。变质核杂岩构造模式的研究，对伸展构造理论的发展起到了重要的促进作用。伸展构造环境中的铀矿田（区）成矿规律的深入研究，必须采用变质核杂岩构造模式重新认识，铀矿化的形成与伸展构造作用下的岩浆岩体系关系密切。  相似文献   

Sediment records of persistent organic pollutants （POPs） in relation to regional economic development： A comparison study in both Pearl River Delta and Yangtze River Delta, China     

Gan ZHANG Lingli GUO Guoqing LIU Jun LI Zhangdong JIN Shihua QI Xiangdong LI 《中国地球化学学报》2006,25(B08):188-189

Persistent organic pollutants （POPs） are semi-volatile chemicals that are toxic to wildlife and human. Typical POPs include most organochlorine pesticides （OCPs）, polycyclic aromatic hydrocarbons （PAHs）, polychlorobiphenyls （PCBs）, polybrominated biphenyl ethers （PBDEs）, etc. Most POPs are hydrophobic, capable of accumulating and existing for a long time in the sediments. Well preserved, laminated sediment layers hence can serve as archives for POP pollution history in the sediment pool. Rapid economic growth has taken place since the early 1980s in most parts of China, of which the Yangtze River Delta, the Pearl River Delta and the Pan-Bohai Bay took the lead. Along with the brilliant regional economic development, the environmental quality has been severely deteriorated. For a more sustainable economic and social development, it is of vital need to understand the relationship between regional economic development and environmental pollution.  相似文献