从中下三叠统膏盐特征看中下扬子早印支运动     

胡光明  张亚金  周雁 《地质科学》2010,45(3):734-744

中下扬子早-中三叠世膏盐层是对早印支运动的沉积响应,本文从膏盐的成因、中下扬子膏盐层位的差异、沉积环境的变迁、膏盐的厚度变化和产状特征、沉积中心和沉降中心的分布等方面,分析早印支运动的表现形式。中下扬子早-中三叠世依次出现陆棚台地(碳酸盐岩)、潟湖—潮坪(白云岩与膏盐)和滨海(碎屑岩),这种大规模海退,正是早印支运动表现为构造抬升的结果。抬升过程中,残留海水在炎热干燥的气候条件下蒸发形成膏盐层,而中扬子的膏盐层位比下扬子低,据此推测中扬子先于下扬子与华北板块碰撞而抬升。平面上,现今构造格局(主要由中印支—早燕山运动形成复向斜、复背斜和推覆构造)的坳陷区主要为白云岩与(硬)石膏互层或石膏夹少量白云岩或云质石膏,膏盐层厚度大,现今构造的隆坳过渡区主要为石膏假晶、含膏云岩、石膏质白云岩、白云岩夹石膏等,膏盐层厚度小,而膏盐的厚度和产状与沉积时的水深和地势直接相关;另外,地层等厚图显示膏盐层主要分布于当时的沉降中心。这些沉积特征显示膏盐沉积时的地势与现今隆坳相间的构造地貌存在一定程度的吻合,说明膏盐沉积时的地层已经发生了轻微的褶皱变形(未见角度不整合和地层缺失)。  相似文献   

火成岩储层物性特征及其影响因素——以松辽盆地南部英台断陷龙深1井区为例   总被引：1，自引：0，他引：1  

仲维维  卢双舫  张世广  黄文彪  邵明礼  王立武 《沉积学报》2010,28(3):563-571

利用大量储层实验资料,分析英台断陷龙深1井区的火成岩储层物性参数及非均质性的定量评价参数,研究结果表明:火成岩储层物性在空间上变化大,非均质性强。这使得对火成岩有效储层的预测变得困难,本次研究通过成像测井、室内岩石薄片鉴定及铸体薄片分析,探讨各种因素对火成岩储集空间的形成和改造的作用机理和过程,指出岩性是其它因素对火成岩储集物性产生影响的基础,火成岩亚相是物性的主要控制因素,成岩作用及构造作用是影响物性的重要因素,从而使得对火成岩有效储层的预测有章可循。  相似文献   

准噶尔盆地南缘新生代构造特征及其与砂岩型铀矿成矿作用初析   总被引：5，自引：0，他引：5  

陈正乐  鲁克改  王果  陈柏林  王国荣  郑恩玖  崔玲玲  丁文君 《岩石学报》2010,26(2):457-470

准噶尔盆地南缘盆山结合部中新生界沉积巨厚,新生代变形强烈,是研究新盆山耦合的理想场所,也是我国砂岩型铀矿找矿的远景区段。本文在综合前人资料和野外观测分析基础上,根据新生代构造活动特征,将准噶尔盆地南缘划分为博格达山前和西部断褶带两个构造分区,博格达山前以强烈的逆冲推覆为特征,发育多条活动的逆冲推覆断裂; 乌鲁木齐以西至乌苏南的西部断褶带则发育三-四排的褶皱-逆冲断裂构造带。对采自博格达山前逆冲推覆断裂带内的方解石和断层泥,利用电子自旋共振测年手段,推测博格达山前的富康-吉木萨尔断裂带和北三台断裂带分别在0.7~1Ma和0.25Ma期间,经历了一期重要的逆冲推覆作用。结合盆地南缘砂岩型铀矿的展布规律及其成矿条件的分析,探讨了新生代构造运动对砂岩型铀矿成矿的控制作用,认为西部断褶带的第一排构造带具有较好的成矿前景,而博格达山前由于新生代构造活动强烈而相对成矿不利,为此提出了准噶尔盆地南缘砂岩型铀矿成矿“构造优先权”的构造控矿模式,进而指出了区域找矿的优选区段。  相似文献   

“Twenty years is yesterday”: Science, multinational mining, and the political ecology of trust in New Caledonia     

Leah S. Horowitz 《Geoforum》2010,41(4):617-626

To date, the scholarly literature has insufficiently investigated the micropolitical ecology of trust, the ways that different interests and expectations within a community can differentially mediate trust relationships between members of that community and an exogenous institution. This study explores the complexities of, and intra-community disagreements about, Kanak villagers’ decisions about whether to trust information provided by, or seemingly in support of, a multinational mining project in southern New Caledonia (South Pacific). An indigenous protest group challenged the company’s claims that the construction and operation of a refinery would have no harmful effects on local ecosystems. The company construed this opposition as stemming from fear based in ignorance, to which the solution lay in the provision of technical information. However, villagers disagreed as to whether this information was reliable. Meanwhile, many project employees joined the protest group. I argue that this seeming irony may be explained by examining the role of affiliation - defined here as a sense of solidarity with a group, and the desire to maintain that relationship - in establishing trust. Culturally-informed expectations of long-term social relationships and the reciprocal power these entailed, and concerns about long-term economic security, played a large role in determining which affiliations people chose to privilege, which in turn influenced which “scientific” information they chose to trust. Ultimately, I argue for the usefulness of a deeper understanding of relationships between trust, affiliation, and expectations of long-term social and economic relations in analyzing lay persons’ evaluations of science.  相似文献   

Study on the action of the active earth pressure by variational limit equilibrium method     

Li Xinggao  Liu Weining 《国际地质力学数值与分析法杂志》2010,34(10):991-1008

Within the framework of limiting equilibrium approach, the problem of active earth pressure on rigid retaining wall is formulated in terms of the calculus of variations by means of Lagrange multipliers. It is transcribed as the functional of extreme‐value problem by two undetermined function arguments, and is further transformed into determining the minimax solution of restrained functions incorporating the geometrical relations of the problem. The function of (fmincon) in the optimization toolbox of MATLAB 6.1 can be used to find the minimax solution. Computation results show there exist two kinds of modes of failure sliding along plane surface and rotating around log‐spiral cylinder surface when the soil behind the walls reaches the critical active state. The magnitude of active earth pressure in the case of translational mode is less than that in the case of rotational mode. The location of action point of earth pressure in the case of translational mode is at or below $\frac{1}{3}$ height of the wall, and in the case of rotational mode, is above $\frac{1}{3}$ height of the wall. Preliminary study indicates a pair of numbers by two theoretical modes can be regarded as an interval estimation of active pressure. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

四川盆地喜马拉雅期地应力场演化对油气运移聚集影响   总被引：2，自引：0，他引：2  

祁林  韩永辉 《四川地质学报》1992,(3)

根据四川盆地及邻区的新构造运动,天然发震机制、石油钻探、人工地震,构造圈闭形态变异及交切关系、储层或油气藏压力、卫星遥感信息解译等多方面资料综合分析得出,喜马拉雅三幕构造运动区域主压应力方向变化很大,早幕和晚幕运动为NE-SW向,中幕运动为NW-SE向。晚幕运动形成的北西向新油气构造圈闭,与中幕运动形成的北北东向及燕山中幕形成的北东东向含油气构造圈闭或油气藏复合叠加,形成了一大批复合背斜构造圈闭的油气藏,也是四川盆地油气勘探最佳远景区。  相似文献   

河南南部的燕山运动     

张瑞胜  许卫国  周世全 《华南地质与矿产》2010,(2):53-59,65

燕山运动是我国东部的一次强烈而重要的构造变动,在河南南部形成了一系列坳陷、断陷,堆积了一套特殊的类磨拉石沉积建造,发育强烈的褶皱和断裂,并有大规模的岩浆喷发和侵入活动,蕴含了丰富的矿产。燕山运动可分早、晚两期5幕,各幕强弱表现不同。早期Ⅰ、Ⅱ幕主要发生在大别山一带,以隆升与小规模岩浆侵入活动为主;晚期Ⅲ幕以火山活动局部发育岩浆侵入活动为特征;Ⅳ幕为断裂、岩浆活动发育,是重要的成矿期;Ⅴ幕使盆地由断陷转入坳陷发育阶段,造成白垩系与三叠系之间普遍不整合或假整合接触。分析认为,燕山期发生的太平洋板块与欧亚板块相互作用及印度板块对中国的推挤,使中国东部始终处于一种以挤压为主局部拉伸的构造应力场中。  相似文献   

长江源区新构造运动特征分析     

赵洪菊  贾小龙  王永贵  马兴华  王国良  辛元红  黄勇  郑长远 《西北地质》2010,43(1):60-65

基于笔者在长江源区野外调查所取得的大量实际资料,结合前人研究成果,运用构造解析法,分析了长江源区新构造运动的特征,认为长江源区第四纪以来的构造运动十分强烈,新构造运动除以整体性、差异性和阶段性隆升的垂直运动外,还表现出以地壳缩短-推覆褶皱和断裂-块体走向滑动为主的水平运动,运动过程既表现出继承性复活,又有一定的改造性和新生性,新构造运动塑造了长江源区的地貌-水系格局。  相似文献   

东胜矿区哈拉沟井田地质灾害危险性评估     

秦国建 《中国煤炭地质》2010,(4):54-58

在详细调查研究区内地质灾害现状的情况下,对采煤引起的覆岩破坏、地表变形等进行了预测,并采用模糊综合评判二次评价模型对地质灾害危险性进行了综合预测。结果表明,研究区地质灾害现状不发育,但井下采矿工程对地面建筑物的危险性大,易引发崩塌、地裂缝、地面塌陷等灾害;预测地质灾害危险大区分布于井田北部、东部和南部,危险性中等区则位于井田中部。预测结果对于矿井的安全生产具有一定的指导意义。  相似文献   

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柴洪洲  崔岳  翟天增  明锋 《大地测量与地球动力学》2009,29(4):74-78

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