论博格达俯冲撕裂型裂谷的形成与演化   总被引：66，自引：23，他引：43  

顾连兴  胡受奚等 《岩石学报》2001,17(4):585-597

博格达裂谷带位于准噶尔与吐－哈两个前寒武纪地块之间,呈东－西走向,东端与克拉麦里－哈尔里克泥盆－石炭纪火山弧呈大角度相交。该 裂谷于早－中石炭世启动和沉降,在盆地中堆积了巨厚的陆源碎屑岩夹双峰式火山岩。裂谷的闭合发生于中石炭世末至晚石炭世。在裂谷闭合后区域构造由挤压向拉张的转折时期,发生了以辉绿岩为主的侵入活动,并伴有少量中－酸性分异产物。博格达裂谷东、西两段的演化特征有着显著差异。东段早石炭世就已开始裂离,裂离过程的火山岩以玄武岩为主,仅有少量流纹岩,裂谷盆地强烈沉降,形成深海－半深海环境,裂谷在中石炭世末至晚石炭世初即已闭合,裂谷岩系因强烈褶皱,与上覆二叠系呈明显角度不整合,显示了“突变”式闭合特征。与此不同的是,西段至中石炭世才开始明显裂离,裂离过程的火山岩以英安岩和流纹岩为主,玄武岩量较少,火山－沉积岩系均形成于浅海环境,裂谷至晚石炭世末才发生闭合,裂谷岩系因未发生强烈褶皱,故与上覆二叠系为平行不整合接触,显示了“渐变”式闭合特征。该裂谷的形成是古亚洲洋壳向先存的准－吐－哈陆块斜向俯冲,将其东南端撕裂的产物,因而可称为俯冲撕裂型裂谷。演化过程沿走向的明显不均一性是这类裂谷的重要特点。  相似文献   

湘南多金属矿集区的圈定及深大断裂构造在成矿中的控制作用     

唐朝永  张南锋  周兴良  刘利生 《矿产与地质》2007,21(5):538-541

湘南多金属矿集区是一个世界级的多金属矿集区，包含有三条有色多金属亚成矿带。其成矿活动与深大断裂带关系密切，深大断裂为深部成矿物质提供了构造通道条件，控制了矿集区内多金属亚成矿带的形成和分布，深大断裂的交汇部位则控制了大型、超大型矿床（田）的产出。  相似文献   

Andean evolution at the Guañacos and Chos Malal fold and thrust belts (36°30′–37°s)     

Andrs Folguera  Víctor A. Ramos  Toms Zapata  Mauro G. Spagnuolo 《Journal of Geodynamics》2007,44(3-5):129-148

The Andes between 36°30′ and 37°S represent a Cretaceous fold and thrust belt strongly reactivated in the late Miocene. Most of the features that absorbed Neogene shortening were already uplifted in the late Cretaceous, as revealed by field mapping and confirmed by previous fission track analysis. This Andean section is formed by two sectors: a western-inner sector generated by the closure of the upper Oligocene-lower Miocene intra-arc Cura Mallín basin between the middle and late Miocene (Guañacos fold and thrust belt), and an eastern-outer sector, where late Triassic-early Jurassic extensional depocenters were exhumed in two discrete phases of contraction, in the latest early Cretaceous and late Miocene to the Present, respectively (Chos Malal fold and thrust belt). Late Miocene deformation has not homogeneously reactivated Cretaceous compressive structures, being minimal south of 37°30′S through the eastern-outer sector (southern continuation of the Chos Malal fold and thrust belt). The reason for such an inhomogeneous deformational evolution seems to be related to the development of a late Miocene shallow subduction regime between 34°30′ and 37°45′S, as it was proposed in previous studies. This shallow subduction zone is evidenced by the eastward expansion of the arc that was accompanied by the eastern displacement of the orogenic front at these latitudes. As a result, the Cretaceous fold and thrust belt were strongly reactivated north of 37°30′S producing the major topographic break along the Southern Central Andes.  相似文献   

中国三大地带经济增长差异的系统分析   总被引：24，自引：2，他引：24  

吴殿廷 《地域研究与开发》2001,20(2):10-15

中国的城乡差异是独特的，以人均GDP作为衡量标准来描述区域差异和进行国际比较不甚确切，文章以统计数据为基础 ，在考察了三大地带农民人均纯收入和城市居民可支配收入差异的基础上，对1978-1998年20年间三大地带经济不平衡发展作了系统分析，通过定量计算得结论；三大地带之间的差距虽然明显，但不可怕，造成三大地带经济增长差异的原因，除了历史基础和自然条件以外，首先是投入强度（尤其是人均外商直接投资额），其次是出口能力和经济体制（所有制结构），产业结构和社会文化因素也有一定影响。为缓解三大地带的差距，并保证国家整体经济实力的持续增强，近期的投资重点应放在中部地带，尤其是中部城市。  相似文献   

天山北坡前山带景观分布特征的遥感研究   总被引：13，自引：0，他引：13  

程维明  周成虎  汤奇成  姚永慧  张百平 《地理学报》2001,56(5):541-548

在前人研究前山带的基础上，借助地理信息系统技术与遥感图像处理技术，结合野外实地考察和遥感影像数据，论述了天山北坡前山带的形成，同时从遥感影像上定量分析了前山带构造带的分布规模和分布特征，阐述了前山带各类各类景观单元对区域气候气候河川径流，绿洲发展，土地利用和土地覆被以及生态环境等综合影响。  相似文献   

中国热带,亚热带西部地区热量带的划分   总被引：3，自引：0，他引：3  

庞庭颐 《地理学报》1996,51(3):224-229

我国热带，亚热带西部地区山多，高原广，垂直地带性的影响，给热量带的划分带来了困难，因为垂直气候都具有在该地区纬向气候带的基础上衍生而生的，因此，亚热带西部地区热量带的划分也应以纬向地带性为主，基带气候为中亚热带的云贵高原和金沙江河谷仍应归属于中亚热带，青藏高原破坏了纬向地带性规律，其东侧应有一条亚热带西界，这一界线应是北、中、南亚热带遇到青藏高原后的中断界线，而不是北、中、南亚热带与青藏高原寒气候  相似文献   

东天山觉罗塔格成对金矿带及其形成的构造背景     

谢才富  李华芹  常海亮 《吉林大学学报(地球科学版)》1999,29(3):232-237

通过地质、地球化学及同位素年代学等方法,研究总结了东天山觉罗塔格地区金矿的基本特征和各类型金矿间的相互关系。发现该区的中深成热液金矿（包括韧性剪切带型及岩浆热液型）和浅成热液金矿分带相邻产出;前者受康古尔—黄山缝合线为主体的推覆隆起带控制,后者受推覆带后侧的石英滩—雅满苏同碰撞伸展带（喜马拉雅型伸展带）控制;成矿时代相互对应,都形成于碰撞造山期（２９５～２４４ Ｍａ）。将这样的两个矿带统称为成对金矿带。  相似文献   

The Pindos Fold-and-thrust belt (Greece): inversion kinematics of a passive continental margin   总被引：1，自引：0，他引：1  

Konstantinos?Skourlis  Theodor?DoutsosEmail author 《International Journal of Earth Sciences》2003,92(6):891-903

Continuous exposure in the Pindos mountain chain (Greece) and the detailed stratigraphic measurements in the area enable us to construct eight balanced cross sections across the Pindos Fold-and-thrust belt (PFTB) and to approach quantitatively some parameters which controlled foreland evolution. The 160-km-wide passive continental margin of the Apulian continent in Greece was progressively shortened from east to west at rates of 6 mm/year between the Early Oligocene and Late Eocene. From the rear to the frontal part of the wedge, fault-bend folds, duplexes and imbricates were formed, while strain was partitioned into faulting (~34%), layer parallel shortening (~23%) and buckling (~9%). Foreland subsidence and internal deformation of the orogenic wedge are strongly affected by two parameters of equal importance: the thrust load of the overthrusted microcontinents and the rigidity of the underthrusted Apulian passive margin. Changes in the thickness of the pre-orogenic sediments and reactivated transform faults induced salients. During the Lower Miocene, the orogenic wedge in the Peloponnese suffered additional uplift and westward gravitational gliding induced by the intracontinental subduction of the Palaeozoic rift zone of the Phyllite-Quartzite Series, which was reactivated and returned to the earths surface during the Hellenic orogeny.  相似文献   

早期碰撞造山过程与板块构造：前寒武纪地质研究的机遇和挑战   总被引：3，自引：0，他引：3  

李江海  侯贵廷  刘守偈 《地球科学进展》2006,21(8):843-848

普遍认为修正后的板块构造模式仍适用于新太古代地质研究，但是早期板块构造过程与后期有明显差异，包括陆块规模、造山带类型、碰撞造山过程等。典型碰撞造山带在地史上的初次形成具有划时代的构造演化意义，涉及典型板块构造初始发生过程、最早超级大陆拼合、威尔逊旋回及板块碰撞造山过程等方面。华北中部保留一条近南北向的碰撞造山带（2 600~2 500 Ma BP），保留特征的巨型复式褶皱、不同层次推覆构造、蛇绿岩混杂带等。围绕华北中部造山带及其25亿年重大构造热事件的研究，对认识华北早期构造演化及其超大陆再造具有重要意义，也是早期板块构造研究的关键突破口之一，开展其不同地壳层次构造变形及其前陆盆地的研究，将深化早期板块边界及其造山过程的科学认识。  相似文献   

Mineralogical and geochemical study of a newly discovered mafic granulite, northwest China: Implications for tectonic evolution of the Altay Orogenic Belt   总被引：5，自引：0，他引：5  

Han-Lin  Chen  Zi-Long  Li  Shu-Feng  Yang  Chuan-Wan  Dong  Wen-Jiao  Xiao  Yoshiaki  Tainosho 《Island Arc》2006,15(1):210-222

Abstract A mafic granulite body was newly discovered in the Altay Orogenic Belt, northwest China. The rocks comprise a suite of coarse‐grained and fine‐grained granulites. Orthopyroxenes (hypersthenes) in the rocks have high X_Mg and low Al₂O₃ contents, whereas clinopyroxenes have low TiO₂ and Al₂O₃ contents. Amphiboles and biotites have a high Mg/(Mg + Fe²⁺) ratio and low contents of F and Cl. The peak metamorphic pressure–temperature (P–T) conditions are estimated as 750–780°C and 6–7 kbar, and retrograde P–T conditions are in the range of 590–620°C and 2.3–3.7 kbar, indicating significant decompression. Metamorphic reactions and P–T estimates define a clockwise P–T path. Geochemically, the rocks are high in Mg/(Mg + Fe) and Al₂O₃, depleted in U, Th, K and Rb, and characterized by light rare earth element enrichment and a weak positive Eu anomaly. The Altay mafic granulite shows depleted Nb, P and Ti contents in the mid‐oceanic ridge basalt normalized spider diagram. The geochemical characteristics suggest that the protolith of the Altay mafic granulite was calc‐alkaline basalt and andesite with an island‐arc affinity. The rock has a high ¹⁴³Nd/¹⁴⁴Nd ratio with ?Nd(0) > 0, indicating derivation from a mantle‐depleted source. In the present study, a two‐stage model for the evolution of the Altay mafic granulite is proposed: an early stage in which calc‐alkaline basalt and andesite with island‐arc affinity were subducted into a deeper level of the crust and subjected to granulite‐facies metamorphism generating the mafic granulite, followed by the later stage exhumation of the system into the upper crust by the late Paleozoic thrusting.  相似文献