南海北部陆缘新生代玄武岩地球化学特征及成因

南海盆地及周缘地区新生代玄武岩对揭示南海盆地的演化历史至关重要,然而这些玄武岩的成因还存在争议。本文研究了位于南海北部陆缘的海南岛临高县多文组玄武岩岩石地球化学和矿物地球化学特征,并探讨其成因和构造背景。多文组玄武岩主要由橄榄石、单斜辉石、斜长石、斜方辉石、铬尖晶石和铁钛氧化物等组成。橄榄石Fo值变化于55.5～71.1之间,Ni的含量较低,Fe/Mn比值较高。铬尖晶石Cr^#值为74.1～82.7,Mg^#值为45.5～63.8, Ti的含量较高。斜方辉石Mg^#值为63.9～79.6,单斜辉石为66.0～80.6。单斜辉石稀土配分曲线富集MREE,亏损LREE和HREE,呈拱形分布。斜长石以中-拉长石为主(Ab_{36.56～52.78}),富集LREE、Ba、Sr和Eu。铁钛氧化物的TiO₂含量为50.19%～51.46%。多文组玄武岩原始岩浆的主量和微量元素组成与夏威夷、峨眉山、塔里木等玄武岩组成一致,地幔源区包含了辉石岩的成分,而且其地幔潜在温度(>1400℃)和氧逸度(Δ...     

倾斜固体潮对我国若干地震的触发作用浅析

本文研究了我国历史与现今中强以上地震的发震时刻与倾斜固体潮的关系。结果表明,地震发震时刻位于震中区当天倾斜固体潮的峰值时段上。孤立型地震的发震时刻往往与震中区倾斜固体潮极大值对应;原地重复发生的地震,其发震时刻所处的倾斜固体潮背景相同;逼近地震与主震发震时刻的倾斜固体潮背景相同的占70%;大震后有60%的强余震与主震发震时刻的倾斜固体潮背景相同。据此,成功地预报了门源6.4级地震后的较大余震。     

Finite Element Analysis of Crossing Flow in an Intersected Fracture by Penalty Function Formulation

On the basis of Navier-Stokes equation, a digital analogue of crossing flow is carried out by means of finiteelement analysis performed through penalty function formulation. The results of the digital analogue are ingood agreement with that of the previous hydraulic physical simulation. They both demonstrate the effect of"deflection flow" occurring at the fracture intersection that the fracture-water crossing flow deflects △q intothe wide fracture.     

关于我国的盐溶角砾岩

盐溶角砾岩可分为溶解-崩塌角砾岩和塑变-交代角砾岩两种类型。它们的主要鉴定特征是分布的层位稳定、角砾成分单一,而且无例外地均和易溶蒸发盐岩伴生。我国主要成盐期的地层中,均有盐溶角砾岩分布,不过发育的程度和特点略有不同。     

金沙江—澜沧江—怒江地区金矿类型及成矿条件

金沙江-澜沧江-怒江地区是中国重要的贵金属、有色金属成矿远景区之一。金矿类型繁多,主要有:蛇绿混杂岩中的构造蚀变岩型;与中酸性岩浆侵入活动有关的多金属石英脉型;构造破碎带中的微细浸染型;碳酸盐岩层构造裂隙中的混成热液型;与次火山岩有关的热液型;火山热泉型和海底火山喷流沉积-热液改造型。成矿时间集中于中新生代。矿床和矿体主要受线型构造控制。岩浆活动在金的成矿过程中有不同程度影响。金矿基本属浅成、中低温热液型。蚀变作用普遍强烈。成矿物质及热液具多源性。     

山地制度建设试验与思考

本试验针对怀化地区山地制度建设问题,通过建立山地档案制度,使山地产权制度、使用权流转制度和山地开发管理制度更趋规范化、科学化,消除由于流转不规范而影响山地开发的隐患,对促进山地的集中,规模开发和利用,提高山地生产力取得了明显的成效。     

CHANGE OF CLIMATE AND ITS INFLUENCE ON THE CROPPING SYSTEM IN CHINA

Tne global change of climate and its influence on the cropping system in China have been investigatedin this paper.It is found that the temperature was increased during the last decade and the precipitationdecreased in northern China and increased in southern China during the last 30 years.The sea level hasbeen rising by about 21—26 cm in the coastal areas south of 30°N in China during the last 100 years.The most of results as simulated by the general circulation models(GCMs)show that the temperature increasewould amount to about 2°—4°C in the most parts of China and precipitation and soil moisture might bedecreased in northern China and increased in sourthern China due to doubling of carbon dioxide(CO_2).The effects of doubled CO_2 on growth period and climatic yield capability in China have been estimatedroughly.It is shown that the regions of the growth period in China would be moved northward about fivedegrees latitude and the climatic yield capability might be increased by about 10％ in the most parts of China.