Étude gravimétrique de la ceinture archéenne de roches vertes de Kuhmo (Finlande orientale)     

Mohammed Jaffal  Jean-Pierre Lefort  Azzouz Kchikach 《Comptes Rendus Geoscience》2003,335(12):881-887

The Kuhmo greenstone belt (Eastern Finland) is mainly formed by mafic volcanic rocks and metasediments. Although the geological observations indicate that this belt appears as a supracrustal synform overlying a gneissic basement, its deep structures are actually unknown. The present gravity study intends to provide a better understanding of these structures. Interpretation of gravity anomalies of the Kuhmo belt, using two-dimensional modelling suggests that the structures of the belt are controlled by granitoids diapirs. Most of the calculated models show that the belt displays in section pocket-like shapes (purses) terminated by a gully-shape close to the surface. This particular geometry corroborates the hypothesis of a gravitational formation with the heavy volcanic material sinking in a light sialic crust. To cite this article: M. Jaffal et al., C. R. Geoscience 335 (2003).  相似文献   

一种新型绘图软件在气象中的应用初探   总被引：4，自引：1，他引：4       下载免费PDF全文

张秀丽  徐桂荣等 《气象科学》2002,22(2):223-229

介绍了Vis5D可视化软件在微机上的运行环境和安装过程，Vis5D系统的三维图形分析、显示功能及各种图形浏览模式，描述了Vis5D系统可接受的数据格式，给出了将CrADS格式的数据文件转换为v5d格式的方法。并利用该系统对MAPS数值模式的输出产品进行了初步的可视化试验。  相似文献   

Influence de la microporosité sur le piégeage du gaz dans un milieu poreux naturel     

Karine Suzanne  Joël Billiotte 《Comptes Rendus Geoscience》2004,336(12):1071-1078

Trapped-gas content in natural porous media, also called residual gas saturation (Sgr), corresponds to the imbibition end-point. To define the parameters controlling Sgr, two parameters were studied: the influence of rock characteristics (on 400 sandstone samples) and initial gas saturation (Sgi), on the basis of 60 experimental curves between Sgr and Sgi. Based on an extensive experimental database, this study establishes the dominant influence of microporosity on trapped gas saturation, and indirectly that of the contained clays. To cite this article: K. Suzanne, J. Billiotte, C. R. Geoscience 336 (2004).  相似文献   

北天山山前乌鲁木齐—乌苏地区的构造变形特征   总被引：2，自引：0，他引：2  

陶明信 《新疆地质》1990,(4)

北天山山前乌鲁木齐—乌苏地区的构造变形,是在挤压兼左行剪切作用下形成的.根据皱皱构造的排列组合、地层组成、变形强度及构造线等特征,将本区划分为五个构造带,分属于两个构造系.其中小渠子构造带的成因与博格达山活动相关,属于另一个构造系.其四余个构造带组成独立的玛纳斯构造系,叠加在燕山期构造之上.  相似文献   

Mechanical　analysis　of　en　echelon　structure　and　its　significance　of　controlling　earthquakes   总被引：1，自引：0，他引：1  

谢新生  阮小平 《地震学报(英文版)》1994,(1)

ＭｅｃｈａｎｉｃａｌａｎａｌｙｓｉｓｏｆｅｎｅｃｈｅｌｏｎｓｔｒｕｃｔｕｒｅａｎｄｉｔｓｓｉｇｎｉｆｉｃａｎｃｅｏｆｃｏｎｔｒｏｌｌｉｎｇｅａｒｔｈｑｕａｋｅｓＸｉｎ－ＳｈｅｎｇＸＩＥ（谢新生）ａｎｄＸｉａｏ－ＰｉｎｇＲＵＡＮ（阮小平）（Ｉｎｓｔｉｔ...  相似文献   

Mechanical analysis of en echelon structure and its significance of controlling earthquakes     

Xin-Sheng Xie  Xiao-Ping Ruan 《地震学报(英文版)》1994,7(1):55-65

The paper deals with the mechanical origin and rules ofen echelon folds and their secondary fractures by means of elastic stability theory and nonlinear fracture criterion. Obtains the quantitative relations amongen echelon angles ofen echelon folds, ratios of boundary stresses anden echelon pitches of shear zone under an action of general boundary forces (tension shear, pure shear or compression shear). As an applied example, the paper researches the displacement field, stress field, distortion energy distribution, state of secondary fractures and energy released by fracturing ofen echelon fold structure developed at the east foot of Taihang Mountain. The results of research show that maximum principal (compressive) stresses, maximum shear stresses, high value area of distortion energy are in the nuclear parts ofen echelon folds. In these parts compressive fractures were easily developed in approximately parallel with fold axis. So it is verified that the secondary fracture ofen echelon folds is a mechanism controlling a strong earthquake.  相似文献   

Les auditeurs polonais des cours de minéralogie de René Just Haüy au Muséum national d'Histoire naturelle,Paris     

Radosław Tarkowski  Piotr Daszkiewicz 《Comptes Rendus Geoscience》2006,338(11):809-814

The paper analyses a list of thirty-four Poles, listeners to the mineralogy lectures given by R.-J. Haüy at MNHN in Paris. These students played an important role in the history of Polish Earth Sciences (S. Staszic and F. Drzewiński), but also in other scientific fields (J. Markowski, I. Ab?amowicz, F. Drzewiński, M.A. Paw?owicz, J.K. Skrodzki, E.K. Nowicki), and even in political and cultural life of Poland (A. Downarowicz, J. Weyssenhoff, S. Plater, J. Bieliński, F. Potocki). This paper presents later relations between R.-J. Haüy and his Polish students. A possibility of the Poles' attendance to mineralogy lectures given at other Parisian scientific institutions, like the ‘École des mines’ and the ‘College de France’, is also discussed. To cite this article: R. Tarkowski, P. Daszkiewicz, C. R. Geoscience 338 (2006).  相似文献   

准噶尔—天山—北山蛇绿岩:对中亚造山带西南缘洋陆格局演化的制约     

高俊  江拓  王信水  李继磊  翟庆国  胡培远  钱青 《地质科学》2022,57(1):1-42

准噶尔、天山和北山52个蛇绿岩的地质特征、地球化学性质和同位素年代学资料系统集成研究表明它们可以分为14条蛇绿(混杂)岩带。绝大多数蛇绿岩呈"岩块+基质"的混杂岩型式沿重要断裂带(构造线)线状分布,少数蛇绿岩以构造岩片叠置方式面状产出。混杂岩的基质有蛇纹岩(碳酸盐化蛇纹岩)和糜棱岩化细碎屑岩两类,岩块既有地幔橄榄岩、基性杂岩和基性火山岩等蛇绿岩组分,也有其它非蛇绿岩组分岩石。堆晶岩出露局限,典型席状岩墙群没有发育。这些蛇绿岩可归类为SSZ(Supra-Subduction Zone)和MORB(Mid-Ocean Ridge)两种类型,前者玄武岩具大离子亲石元素(LILE)富集和高场强元素(HFS)亏损特征,后者不显示该特点;洋岛玄武岩(OIB)既可出现在SSZ型蛇绿混杂岩中,也可为MORB型的组成部分;SSZ型蛇绿混杂岩辉长岩和玄武岩比MORB型具有相对更富集的Sr-Nd同位素组成,但部分形成于弧后(间)盆地的SSZ型蛇绿岩与MORB型一致,具有近亏损地幔的Sr-Nd同位素组成。已确认的最老蛇绿岩为西准噶尔572 Ma玛依勒,次之为北山542~527 Ma月牙山—洗肠井和西准噶尔531 Ma唐巴勒,最年轻蛇绿岩为325 Ma北天山巴音沟和321 Ma北山芨芨台子。根据蛇绿岩证据,结合近年来中亚造山带古地磁、岩浆岩、高压—超高压变质岩和构造地质方面的进展,可以推断埃迪卡拉纪末期—早寒武世,古亚洲洋已达到一定规模宽度,发育洋岛和洋内弧;早古生代时期,多岛洋格局发育至鼎盛期,一系列弧地体分别归属哈萨克斯坦微陆块周缘的科克切塔夫—天山—北山线性弧、成吉思弧、巴尔喀什—西准噶尔弧体系和西伯利亚南部大陆边缘弧体系;晚古生代时期,古亚洲洋于石炭纪末期闭合,增生杂岩和弧地体组成哈萨克斯坦拼贴体系和蒙古拼贴体系两个巨型山弯构造。  相似文献   

洋板块地层学的概念、模式、组成及失序变化^*          下载免费PDF全文

许淑梅  孔家豪  李三忠  舒鹏程  马慧磊  崔慧琪 《古地理学报》2022,24(1):1-10

着重介绍了洋板块地层的概念、模式、组成及失序变化特征。造山带混杂岩和大陆边缘增生复合体是经历俯冲碰撞消亡后的古洋沉积记录,利用微体古生物地层学和同位素年代学方法可以重建造山带混杂岩和大陆边缘增生复合体的原始地层。洋板块地层(学)是用来描述沉淀在洋壳基底之上的沉积岩和火成岩序列的术语,其开始于洋中脊形成,终止于该洋中脊被移入到汇聚边缘增生楔。从造山带混杂岩中重建的古大洋地层的基本组成大体相似,但因大洋岩石圈的岩浆背景不同,造成不同时期和不同类型的洋板块地层组成也会有差异。在前人研究成果的基础上, 笔者通过对不同类型洋板块地层进行分类,介绍了如何从经历碰撞造山过程的增生造山带进行洋板块地层的重建。引入“洋板块地层学”概念的主要目的在于通过对因俯冲增生而消亡的具有洋壳基底的构造洋盆和边缘海盆地的地层单元进行重建,恢复已消失洋的地层组成单元,这对造山带地层解析、造山带构造古地理恢复、重大构造变革期古地理学研究和板块重建等都将起到积极的促进作用。  相似文献   

识别断层活动和失稳的热场标志——实验室的证据   总被引：5，自引：0，他引：5  

马瑾  马少鹏  刘培洵  刘力强 《地震地质》2008,30(2):363-382

利用一套双向伺服系统对含压性和张性雁列断层的标本进行变形实验,实验中应用红外热像仪和接触式测温仪同步记录岩石变形过程中热红外辐射的亮度温度场和温度场的变化;使用数字CCD相机同步采集标本表面的数字图像,并利用数字散斑方法对采集到的图像进行分析得到位移场和应变场的演化过程。实验结果表明:1)在断层贯通前压性雁列岩桥区温度最高,而张性雁列岩桥区温度最低;数字散斑结果显示压性岩桥区平均应变最高,而张性岩桥区平均应变最低。温度场对两类雁列断层在岩桥区相反的受力状态有清晰的响应,可以为判断断层应力状态提供标志。2)雁列断层经历了从岩桥区应力积累、破坏到断层失稳错动两个变形阶段,升温机制也由应变升温变为摩擦升温;伴随升温机制的转变,在岩桥区观测到断层失稳错动前的破坏降温、温度快速起伏以及升温脉冲等现象,是观测失稳前兆的最佳部位。3)在雁列岩桥区裂纹端点附近观测到升温脉冲,表现为温度快升快降,随后即出现断层带的快速升温。升温脉冲现象可能与裂纹端部的应力奇异集中和破裂扩展引起的应力释放有关。裂纹端部的扩展是断层失稳错动的条件,随后断层带的升温正是断层失稳错动造成的。断层带开始升温发生在失稳前2～3s内,岩桥区的降温发生在失稳  相似文献