A structural synthesis of the Proterozoic Arabian-Nubian Shield in Egypt   总被引：3，自引：0，他引：3  

R. O. Greiling  M. M. Abdeen  A. A. Dardir  H. El Akhal  M. F. El Ramly  G. M. El Din Kamal  A. F. Osman  A. A. Rashwan  A. H. N. Rice  M. F. Sadek 《International Journal of Earth Sciences》1994,83(3):484-501

Detailed structural geological and related studies were carried out in a number of critical areas in the Proterozoic basement of eastern Egypt to resolve the structural pattern at a regional scale and to assess the general characteristics of tectonic evolution, orogeny and terrane boundaries. Following a brief account of the tectonostratigraphy and timing of the orogenic evolution, the major structural characteristics of the critical areas are presented. Collisional deformation of the terranes ended about 615-600 Ma ago. Subsequent extensional collapse probably occurred within a relatively narrow time span of about 20 Ma (575 – 595 Ma ago) over the Eastern Desert and was followed by a further period of about 50 Ma of late to post-tectonic activity. The regional structures originated mainly during post-collisional events, starting with those related to extensional collapse (molasse basin formation, normal faulting, generation of metamorphic core complexes). Subsequent NNW-SSE shortening is documented by large-scale thrusting (towards the NNW) and folding, distributed over the Eastern Desert, although with variable intensity. Thrusts are overprinted by transpression, which was localized to particular shear zones. Early transpression produced, for example, the Allaqi shear zone and final transpression is documented in the Najd and Wadi Kharit-Wadi Hodein zones. Two terrane boundaries can be defined, the Allaqi and South Hafafit Sutures, which are apparently linked by the high angle sinistral strike-slip Wadi Kharit-Wadi Hodein shear zone with a tectonic transport of about 300 km towards the W/NW. In general, the tectonic evolution shows that extensional collapse is not necessarily the final stage of orogeny, but may be followed by further compressional and transpressional tectonism. The late Pan-African high angle faults were reactivated during Red Sea tectonics both as Riedel shears and normal faults, where they were oriented favourably with respect to the actual stress regime.  相似文献   

晚期海西运动在塔里木盆地北部油气藏形成中的作用   总被引：2，自引：0，他引：2  

康志宏  魏历灵 《新疆地质》1994,(4)

海西晚期，塔里木板块总体为挤压背景。有资料表明，该时期存在两次性质差异较大的构造运动：早二叠世末期和晚二叠世末期构造运动。前期运动以火山活动、海防变迁为特征；后期以沉积构造格局改变、褶皱、断裂活动为特征，并叠置于前期构造之上。晚期海西运动最终定型的古隆起控制了油气聚集指向，形成的古生代坳陷和中新代坳陷控制着油源区展布，造成了众多的、具有捕获油气能力的圈闭类型。断裂和区域性不整合面为油气运移提供了通道，而且对油气再分布及破坏亦有一定影响。  相似文献   

中酸性侵入岩氧化钾平面分布规律及其与地壳厚度的关系   总被引：1，自引：0，他引：1  

吴珍汉 《地质科技情报》1995,14(2):57-62

燕山地区中生代陆内造山作用强烈，形成数百个中生代中酸性侵入体。本区侵入岩的氧化钾分布具有南北分区、东西分带的特征。燕山北区中酸性侵入岩Ｋ２Ｏ含量普遍较高，平均为５．０％，而燕山南区中酸性侵性岩Ｋ２Ｏ含量平均为４．０％，统计分析表明，燕山陆内造山带中生代中酸性侵入岩氧化钾与地壳厚度呈线性相关，；地壳厚度是决定燕山地区中生代侵入岩氧化钾空间分布的主要因素，与板块边缘岛弧带火山岩氧化钾空间分布的主要制药  相似文献   

Metabasites with eclogite facies relics from Variscides in Sardinia,Italy: a review     

M. Franceschelli  M. Puxeddu  G. Cruciani  D. Utzeri 《International Journal of Earth Sciences》2007,96(5):795-815

Metabasites with eclogite facies relics occur in northern Sardinia as massive to strongly foliated lenses or boudins embedded within low- to medium-grade rocks (Anglona) and migmatites (NE Sardinia). U–Pb zircon dating yielded 453 ± 14, 457 ± 2 and 460 ± 5 Ma as the protolith ages; 400 ± 10 and 403 ± 4 Ma have been interpreted as the ages of the HP event and 352 ± 3 and 327 ± 7 Ma as the ages of the main Variscan retrograde events. A pre-eclogite stage is documented by the occurrence of tschermakite, zoisite relics within garnet porphyroblasts (Punta de li Tulchi) and an edenite–andesine inclusion within a relict kyanite porphyroblast (Golfo Aranci). Four main metamorphic stages have been distinguished in the eclogite evolution: (1) eclogite stage, revealed by the occurrence of armoured omphacite relics within garnet porphyroblasts. The Golfo Aranci eclogites also include kyanite, Mg-rich garnet and pargasite; (2) granulite stage, producing orthopyroxene and clinopyroxene–plagioclase symplectites replacing omphacite. At Golfo Aranci, the symplectitic rims around relict kyanite consist of sapphirine, anorthite, corundum and spinel; (3) amphibolite stage, leading to the formation of amphibole–plagioclase kelyphites between garnet porphyroblasts and pyroxene–plagioclase symplectites and to the growth of cummingtonite on orthopyroxene. Tschermakite to Mg-hornblende, plagioclase, cummingtonite, ilmenite, titanite and biotite are coexisting phases; (4) greenschist to sub-greenschist stage, defined by the appearance of actinolite, chlorite, epidote ss, titanite, sericite and prehnite. The following P–T ranges have been estimated for the different stages. Eclogite stage 550–700°C; 1.3–1.7 GPa; granulite stage 650–900°C; 0.8–1.2 GPa, clustering in the range 1.0–1.2 GPa; amphibolite stage 550–740°C; 0.3–0.7 GPa; greenschist stage 300–400°C; 0.2–0.3 GPa. Comparable ranges characterise the other Variscan massifs in Europe; eclogite stage: T = 530–800°C; P from 0.7–1.1 to 1.7 ± 0.3 GPa; granulite stage T = 760–870°C and P from 1.1–1.4 to 7.2–9.9 GPa, clustering around 1.0–1.2 GPa. Whole-rock chemistry: Sardinian eclogites are N- to T-MORB; European ones N- to E-MORB or calc-alkaline.  相似文献   

造山带构造研究中几个重要学术概念问题的讨论   总被引：1，自引：0，他引：1  

张长厚  吴正文 《地质论评》2002,48(4):337-344

简要分析和评述了造山带构造研究中的几个重要学术概念问题：造山带，造山带类型、造山作用和造山过程、造山带构造格局、造山作用模式。指出不宜将造山带定义直接与板块边缘构造位置和板块间相互作用联系在一起；造山作用和造山带不仅出现在板块之间相互作用的地带，而且可以出现在远离板边界的地方－－即所谓板内造山带。强调了板内造山带研究的重要性，提出了确定板内造山的主要依据，指出在造山带分类、造山带构造山带。强调了板内造山带研究的重要性，提出了确定内造山带的主要依据，指出在造山带分类、造山带构造格局和造山作用过程中应充分注意内造山带的客观存在，以及板内造山带成因动力机制研究中需要着重考虑的重要方面。  相似文献   

秦岭造山带基础地质研究新进展   总被引：18，自引：11，他引：18       下载免费PDF全文

杨志华郭俊锋  苏生瑞李　勇苏春乾  张传林黑爱芝　梁　云 《中国地质》2002,29(3):246-256

“八五”－“九五”期间秦岭的多项研究中，主要取得以下新认识：①创立了抽拉－逆冲岩片构造新理论，丰富和发展了岩石圈板块或壳块运动方式的多样性；②发现了东西向的秦岭造山带从显生宙以来有南北向的隆升带和沉积盆地，特别是太白、宝鸡－佛坪－汉南隆升带的发现，将从根本上改变秦岭乃至中国中东部构造格架的认识；③南北向沉积盆地转变为东西向造山带的Ⅱ型造山带，深部构造岩片抽拉－逆冲推覆在中（新）生代陆相沉积盆地之上所形成的Ⅲ型造山带，为地壳表层增添了两种新型的造山带；④提出秦岭造山带中存在3类沉积盆地，3种盆－山转换，3个发展阶段及3种型式（Ⅰ、Ⅱ、Ⅲ）的造山带；⑤重新厘定商丹带、勉略带和二郎坪带的构造属性、形成时代，首次提出秦岭受3种体制，4个发展阶段的新观点，由抽拉构造形成的陆内造山带是秦岭最重要的划时代发展阶段；⑥提出立交桥式结构观点；⑦发现了一批前震旦系变质地层结晶岩系，重新厘定了一些地层的时代，特别是西秦岭、西成铅锌矿田中元古代地层的发现和超大型厂坝矿床产于其中，有重大的理论和实际意义；⑧提出准浊流态流体的新概念；⑨提出中国和秦岭大地构造发展演化的新全球动力学理论。  相似文献   

喜马拉雅运动：对川滇交界区古地理重建的制约和楚雄盆地的改造   总被引：10，自引：2，他引：10  

吴根耀  马力  许效松  徐克定 《古地理学报》2001,3(2):3-10

简述了喜马拉雅运动三大变形幕的运动学特征并分析了在楚雄地区的反映。在剥去喜马拉雅运动的改造、把攀西地堑系和滇中海槽复原到建造时的位置后（楚雄盆地视作相对原地的），以“盆”“山”耦合的思路重塑了古特提斯分支洋盆的演化及这些盆地的发育。川滇交界区尽管发生燕山运动，印支期建立起来的“盆”“山”耦合关系直至喜马拉雅运动才脱耦。分析了脱耦的各种表现及第四纪内继承的新构造运动对盆地保存和油气成藏的不利因素。  相似文献   

深部天然核反应堆——一种可能的山脉隆升动力源   总被引：3，自引：0，他引：3       下载免费PDF全文

匡耀求  张本仁等 《地质论评》2001,47(2):119-128

板块碰撞造山模式难以解释造山作用在时间上的“滞后”和在空间上的“差位”现象，大量研究表明山脉隆升的动力来自深部，因此，探索深部地质过程的物理和化学机制及其导致的能量再分配是认识山脉隆升动力学机制的关键，若干线索表明地幔中的核反应中可能在岩石圈动力学演化过程中起过不可忽视的作用，通过分析U，Th等元素的地球化学性质及其在深变质过程中的行为，认为伴随板块俯冲发生的陆壳物质向地幔的再循环有可能在办流圈顶部形成富含U，Th,K等放射性亲石元素和碳质（石墨）的地质体，通过理论上的论证和对Oklo天然核反应堆遗迹的反演表明这些地质体可能有一部分具备了形成石墨核反应堆的条件。这种反应堆在亚临界状态下的断续运行有可能为其上方岩石圈中的岩浆作用提供热源，进入超临界状态时将可能导致深部核爆炸，成为地震，火山爆发和岩石圈破裂的动力来源，据此建立的山脉隆升的动力学初步模式，可以解释造山带的形成，高原的隆升，深源地震及其前兆的成因和金刚石及其相关岩石地壳浅部置位的机制。  相似文献   

燕山式板内造山作用在北京西山的   总被引：6，自引：0，他引：6  

赵温霞 《地质科技情报》2001,20(2):23-26

尽管在造山模式、成因机制方面存在分歧，但板内造山作用及其表现特征在现阶段业已引起众多学者的关注并进行了深入研究。受到燕山式板内造山带研究思路和成果的启示，经对比研究认为，北京西山地区在大地构造位置、大地构造属性及大地构造演化等方面具有板内造山的特征；逆冲推覆构造、变质核杂岩及独特的区域构造组合样式等构成了该区燕山式板内造山的基本地质构造要素；基于北京西山的地质实践，提出了对用板内造山的观点在该区深入研究若干新方向。  相似文献   

A Special Orogenic-type Rare Earth Element Deposit in Maoniuping, Sichuan, China: Geology and Geochemistry   总被引：8，自引：0，他引：8  

Denghong WANG  Jianmin YANG  Shenghao YAN  Jue XU  Yuchuan CHEN  Guangping PU  Yaonan LUO 《Resource Geology》2001,51(3):177-188

Abstract: The Maoniuping REE deposit is the second largest light rare earth elements deposit in China, explored recently in the northern Jinpingshan Mountains, a Cenozoic intracontinental orogenic belt in southwestern China. It is a vein-type deposit hosted within, and genetically related to, carbonatite-alkalic complex. Field investigation and new geochemical data of the carbonatites from the carbonatite-alkalic complex support an igneous origin for the Maoniuping carbonatites and related REE mineralization. Carbonatite itself carries rare earth elements which were enriched by hydrothermal solution.
It is known that most of the REE deposits related to carbonatite-alkalic complexes were formed in relatively stable tectonic setting such as cratonic or rifting environment. The Maoniuping deposit, however, was formed during the processes of Cenozoic orogeny. Although the Maoniuping deposit is located in the north sector of the Panxi paleo-rift zone, the rift had been closed before early Cenozoic and evolved into an intracontinental orogenic belt, i.e., the Jinpingshan Orogen, which was formed since later Mesozoic to early Cenozoic. Geochronological and geochemical data also prove that the Maoniuping REE deposit was formed in an intracontinental orogenic belt instead of rift system or stationary block.
The Maoniuping REE deposit is similar to the Mountain Pass REE deposit in many respects such as the high contents of bastnaesite and barite, the low content of niobium, and the common occurrence of sulfides. The discovery of the Maoniuping deposit and other REE deposits during the past two decades suggest a good potential for prospecting REE deposits along the alkalic complex belt located on the eastern side of the Qinghai–Xizang–West Sichuan Plateau.  相似文献