Structural Styles of the Longmenshan Thrust Belt and Evolution of the Foreland Basin in Western Sichuan Province, China   总被引：7，自引：0，他引：7  

Liu Hefu  Liang Huishe  Cai Liguo  Shen Fei China University of Geosciences  Beijing Jiang Minxi 《《地质学报》英文版》1994,68(4):351-372

The Longmenshan thrust system consists of two major groups of structural styles according to the depth of their involvement: basement thrusts-compressional fault blocks; fold-thrust system in the cover. In cross-section, the Longmenshan structural belt is divided into 5 zones. The propagation of the Longmenshan thrust system is piggy-back due to pushing at the early stage and overstep due to gravity sliding at the late stage. Balanced cross-sections and palinspastic reconstruction reveal that the total sliding displacement of the thrust system amounts to 120 km. The tectonic evolution of the Tethys domain in western Sichuan has experienced 5 stages: continental break-up; ocean-continent subduction ; continent-arc collision; orogenic thrusting; uplift of western Sichuan.  相似文献   

规则球粒堆积体的孔隙度   总被引：2，自引：0，他引：2       下载免费PDF全文

郭仁炳 《地球科学》1994,19(4):503-503

以椭球堆积体为模型，求出圆球、扁球、长球、椭球４种堆积体的理论孔隙度极值相同，并导出了政府孔隙度的通式。认为理论孔隙度的大小仅与规则球粒的排列方式有关，当某一规则球粒堆积体受压而使该规则球粒变形为另一种规则球粒时，只要排列方式不变，其理论孔隙度也不变。  相似文献   

天山两侧前陆冲断系构造样式与前陆盆地演化   总被引：77，自引：2，他引：77       下载免费PDF全文

刘和甫  梁慧社 《地球科学》1994,19(6):727-741

天山造山带呈Ｗ结构，由Ｖ形结构的南天山和北天山复合而成，两者具有不同的造山模式。南天山自震旦纪开始张裂，扩展为被动大陆边缘和洋盆，在志留－泥盆纪时俯冲，延续至石炭纪碰撞，旋回时限达４００Ｍａ以上，应属威尔逊旋回造山模式。北天山应自泥盆纪开始弧后扩张，形成泥盆－石炭纪边缘海小盆。在石炭纪晚期闭合，旋回时限约１００Ｍａ，应属于孤后造山模式，前陆褶皱－冲断带的变形主要分为两期：早期由于楔冲作用所产生的薄  相似文献   

塔北地区变形样式及其分布规律   总被引：23，自引：3，他引：23       下载免费PDF全文

张光亚  陈发景 《地球科学》1994,19(6):755-768

塔北地区包括库车前陆盆地和塔北前陆克拉通地区两大变形带，在库车前陆盆地，垂向上，主要受滑脱层发育及其展布、构造地层组合及岩层埋深等因素控制，深层一般为被动顶板双冲构造及断变褶皱，中层三角带、冲起构造，浅层为断展，滑脱及底辟褶皱；横向上，与挤压应力大小、地层岩石力学性质、滑脱层发育程度等相关，自造山带前缘向前陆克拉通方向，褶皱一般由紧闭，不对称或倒转变为平缓，开阔，并由断变，断展褶皱变为滑脱褶皱；变  相似文献   

塔里木盆地北部构造样式   总被引：10，自引：0，他引：10       下载免费PDF全文

严俊君  黄太柱 《地球科学》1995,20(3):264-270

塔里木盆地北部发育５种典型的构造样式；基底卷入型压性逆冲构造组成、盖层滑脱型逆冲－褶皱构造组合、隐刺穿刺底檗同幅度褶皱构造组合及张性正断层组合，无论是构造变形时间还是组合分布，在塔北均呈现规律变化，其变形特征及发布受如下３个地质因素控制：（１）区域挤压作用；（２）岩性条件的差异：（２）先期构造格局。  相似文献   

鞍山附近“樱桃园组”的构造样式及其时代讨论          下载免费PDF全文

刘如琦  蔡一廷  张宝华 《地质科学》1987,(1):24-38

本文区分了“樱桃园组”岩石在元古主构造旋回的三幕变形,详细描述了各幕SFL组合和按区段进行了投影。主变形幕D₁的构造最发育,F₁控制着本区的岩性分布。构造序列及样式变化显示由高塑性向脆性的变形格式。本组与下伏的太古鞍山群变粒岩在构造序列、样式和变质相上都有显著差异,过去许多地质学家把二者混划为一个单位,统名“鞍山群”,属太古宙。但本组与上覆的辽河群(上元古)的构造样式和变质相却相似,故其时代相当于早元古Ferrian期。  相似文献   

Hydrogen recombination lines near 327 MHz−II: A Galactic plane survey with a 2°×6′ beam     

D. Anish Roshi  K. R. Anantharamaiah 《Journal of Astrophysics and Astronomy》2001,22(1):81-119

In a previous paper we presented a low-resolution (2°×2°) survey of radio recombination lines (RRLs) at 327 MHz in the longitude rangel=330° to 0° to 89°. In this paper, we present the results of a higher resolution (2°×6′) survey of RRLs from seven 2°-wide fields and two 6°-wide fields in the same longitude range. Observations were made using the Ooty Radio Telescope (ORT). A total of 252 spectra that were obtained are presented. RRLs were detected in almost all the individual positions within the fields withl<35° and at several individual positions within the fields in the longitude rangel=35° to 85°. Detailed analysis of the data towards the field centered at G45.5+0.0, shows that the line emission consists of discrete zones of ionized gas. The angular extent of these zones are likely to be one degree or more corresponding to a linear size of >110 pc at the kinematic distance.  相似文献   

肃南县羊露河上游似鞍山式铁矿地质特征及找矿方向   总被引：5，自引：0，他引：5  

张国成 《地质找矿论丛》2005,20(Z1):129-130

羊露河上游铁矿位于北祁连西段加里东褶皱带西段.铁矿体赋存于下元古界长城系上岩组含铁角闪片岩中,含矿层位严格受地层层位控制,矿石构造具有同生沉积特征,并显示了热液富集作用特点,具"似鞍山式"铁矿成因特征,矿石品位较高,盲矿体存在的可能性较大,因此具有重要的找矿意义.  相似文献   

Structural style and deformation mechanism of the southern Dabashan foreland fold-and-thrust belt, central China     

Li Zhiwu  Liu Shugen  Luo Yuhong  Liu Shun  Xu Guoqiang 《Frontiers of Earth Science》2007,1(2):181-193

The Daba Mountains define the southern margin of the East Qinling orogenic belt, and form the boundary of the Sichuan basin in the north and northeast. The Daba Mountains can be divided into two structural belts by the NW-striking Chengkou fault, namely the northern Dabashan thrust-nappe belt and the southern Dabashan foreland fold-and-thrust belt. The southern Dabashan fold-and-thrust belt is a southwestward extruding thin-skinned thrust wedge, showing obvious belted change in deformation style and deformation intensity along the dip direction, and can be divided further into three sub-belts, i.e. the imbricate thrust sub-belt characterized by imbricate stepped-thrust sheets, the thrust-fold sub-belt characterized by the combination of the equally-developed thrusts and related folds, and the detachment-fold sub-belt characterized by box folds and closed overturned-isoclinal folds on the outcrops. Several kinds of structures have been recognized or inferred, including imbricate thrust system, passive-roof duplex (triangle zone), fault-related folds, back-thrust system and pop-up structure. The NE-SW compressive stress from the Qinling orogenic belt and detachment layers in the covering strata are the two most important determinants of deformation style. After the collision between the North China block and Yangtze block at the end of the Middle Triassic, the northward intracontinental subduction along the southern edge of the Qinling orogenic belt was initiated, which led to the corresponding southward thrusting in the upper crust. The thrusting propagated towards the foreland through the Jurassic and extended to the southernmost part of the southern Daba Mountains around the end of the Early Cretaceous, with thrusting deformation to be preferentially developed along major detachment layers and progressing upwards from the Lower Sinian through the Lower Cambrian and Silurian to Middle-Lower Triassic. Translated from Geotectonica et Metallogenia, 2006, 30(3): 294–304 [译自: 大地构造与成矿学]  相似文献   

基于前传式网络逼近的太平洋副热带高压活动的诊断预测   总被引：13，自引：1，他引：13  

张韧 《大气科学》2001,25(5):650-660

基于前传式神经网络BP算法(BackpropagationNeuralNetwork)和回归模型,探讨了西太平洋副高面积指数同赤道东太平洋海温及赤道纬向风之间非线性分类和映射逼近的建模方法和效果比较.结果表明,前传式网络,特别是回归网络预报模型具有较好拟合精度和预报效果及比较实用的预报时效.  相似文献