大陆层控构造论盆－山系与造山带成因及演化新模式

大陆构造以受中地壳塑性层控制的盆－山系和冲叠造山带厚皮构造为主要构造类型，而与中生代以来才出现的受软流层控制的大洋岩石圈板块构造截然不同。由上地壳正断层上盘断陷盆地和下盘断隆山所组成的盆－山系，与地球自转速度逐渐变慢派生不同性质水平力和重力的共同作用有关。当地球自转速度突然变化时，将派生强烈的侧压力，使升降幅度较大、具有侧向应变空间的断陷盆地与断隆山之间的上地壳发生冲叠运动，盆－山系由此演变成冲叠造山带。后者对前者存在着严格的继承关系，服从于“升降－冲叠律”。中生代以来的盆－山系和冲叠造山带有的是板块活动产物     

Geochemical constraints on the petrogenesis of basalts from eastern Jiangnan orogen, South China

The basalts crop out widely in the eastern part of late Proterozoic Jiangnan orogen. In terms of their petrographical and geochemical characteristics, they can be divided into two distinct types: low- and high-Ti. basalts. They crystallized from the magmas derived from the depleted upper mantle differing in partial melting degree. Project supported by the National Natural Science Foundation of China.     

秦岭造山带地壳构造与楔入成山

横穿秦岭的河南叶县至湖北南漳的反射地震剖面揭示，秦岭造山带地壳由一系列由南向北楔入到中地壳的鳄鱼式构造所组成。南北溱岭上地壳分别形成南秦岭和北秦岭推覆系。北秦岭推覆系是组成基底的地壳沿脆转换面拆离冲叠形成的一个推覆系，可以分出栾川推覆体，瓦穴子推覆体，二郎坪推覆体及朱夏推覆体。     

Timing and geochemical characters of the Sanchazi magmatic arc in Mianlüe tectonic zone, South Qinling

The Sanchazi mafic-ultramafic complex in Mianlue tectonic zone, South Qinling can be subdivided into two blocks, i.e. Sanchazi paleo-magmatic arc and Zhuangkegou paleo-oceanic crust fragment (ophiolite). The Sanchazi paleo-magmatic arc is mainly composed of andesite, basaltic and basalt-andesitic gabbro (or diorite), andesitic dyke, plagiogranite and minor ultramafic rocks, which have typical geochemical features of island arc volcanic rocks, such as high field strength element (e.g. Nb, Ti) depletions and lower Cr, Ni contents. The Light rare earth element (LREE) and K enrichments of these rocks and zircon xenocrystals of 900 Ma from plagiogranite suggest that this magmatic arc was developed on the South active continental margin of the South Qinling micro-continent. The U-Pb age of (300 ± 61)Ma for zircons from plagiogranite indicates that the Mianlue paleo-oceanic crust was probably subducted underneath the South Qinling micro-continent in Carboniferous. This is consistent with the formation time (309Ma) of the Huwan eclogite originating from oceanic subduction in Dabie Mountains, suggesting that the Mianlue paleo-ocean probably extended eastward to the Dabie Mountains in Carboniferous. The high-Mg adakitic rocks in Sanchazi paleo-magmatic arc suggest that the subducted oceanic crust was relatively young (＜25Ma) and hot.     

Structural features and petroleum geology of the fold-thrust belt in the southern Tarim basin, China

The west Kunlun fold-thrust belt (WKFTB) and the Altun fold-thrust belt (AFTB) are respectively located in the southern margin of the Tarim basin, NW China. The analyses of typical structures and regional dynamics of the fold-thrust belts reveal their different structural and petroleum features and mechanisms. WKFTB differs from AFTB by abundant fault-related folds and triangles zones, and was formed by northward extrusion of the west Kunlun orogen. AFTB was affected synchronously by northward extrusion of the Altun orogen and the sinistral strike-slipping of the Altun Fault, so it is characterized by the minor scale and the monotonous structural styles. The Aqike anticline and the Aqike fault, of which the strikes are orthogonal to the strike of the fold-thrust belts, are regarded as the adjustive structures between both of the fold-thrust belts. The oil-gas pools of WKFTB develop mainly in the faulted-related anticline traps, but the oil-gas pools of AFTB develop mainly in the low fault-block and anticlines traps related with the paleo-uplifts. There are different exploration countermeasures for both of the fold-thrust belts.     

Change of crustal gravitational potential energy in the Taiwan orogen by the Chi-Chi earthquake sequence

The active convergence between the northwest corner of the Philippine Sea Plate and the southeast margin of the Eurasian Plate has given rise to the Taiwan mountain-building and produced numerous earthquakes. Among the earthquakes, the 1999 Chi-Chi earthquake is the largest one recorded in the century. In this study, we examine the crustal gravitational potential energy (GPE) change in the Taiwan orogen caused by the Chi-Chi earthquake sequence, which was catalogued by the regional broadband seismometer array for a whole year. As a result, we find that the crust was going up and down randomly during the earthquake sequence, but an overall cumulative gain of the crustal GPE, +1.82×10¹⁶ J, was rapidly achieved in 1 month after the main shock. The crustal GPE was nearly still afterwards and reached +1.90×10¹⁶ J in 1 year. Spatially, although the main surface faulting has occurred in western Taiwan, the crustal GPE gain is mainly distributed in central Taiwan at the area where the existing crustal GPE is high and the existing lithospheric GPE is relatively low. The crustal GPE loss by the Chi-Chi earthquake sequence can also be observed and is generally distributed at both sides of the crustal GPE gain area. The crustal GPE gain mainly found in central Taiwan corroborates that the uplift of the Taiwan orogen is principally taking place in central Taiwan, rather than in the more hazardous western Taiwan.     

秦岭造山带岩浆岩地球物理场特征

根据不同类型岩浆岩的岩石密度、磁性的不同,通过重磁异常分离、延拓、求导、异常的彩色编码及重、磁特征信息的复合处理等,按重磁反映的岩浆岩带所处的构造单元部位、岩浆系列特征以及与矿带的时空关系,将秦岭造山带划分为2带和7个群段.     

山西五台地区系舟山逆冲推覆构造地质特征

系舟山逆冲推覆构造带位于中生代燕山造山带的西南端，分布于系舟山掀斜向斜的北西翼，形成于晚侏罗世晚期，空间上由一系列近平行排列的逆冲断裂组成，剖面上表现为侧幕展布的犁式逆冲断裂所构成的前陡、后缓的单冲式叠瓦状构造。主体由北西向南东方向逆冲．逆冲扩展方式为前展式，运移距离大于5．8km。推覆构造中应力状态在横、纵向上呈现有规律的变化，根带以挤压为主的高角度逆冲断裂及复杂多级褶皱为主；中带以单剪为主，形成叠瓦状构造；锋带挤压作用增强，发育反冲断层和不对称褶皱。随着挤压应力的松弛减弱，山前形成规模较大的正断层。     

An Eocene/Oligocene blueschist‐/greenschist facies P–T loop from the Cycladic Blueschist Unit on Naxos Island,Greece: Deformation‐related re‐equilibration vs. thermal relaxation

Geothermobarometric and geochronological work indicates a complete Eocene/early Oligocene blueschist/greenschist facies metamorphic cycle of the Cycladic Blueschist Unit on Naxos Island in the Aegean Sea region. Using the average pressure–temperature (P–T) method of thermocalc coupled with detailed textural work, we separate an early blueschist facies event at 576 ± 16 to 619 ± 32°C and 15.5 ± 0.5 to 16.3 ± 0.9 kbar from a subsequent greenschist facies overprint at 384 ± 30°C and 3.8 ± 1.1 kbar. Multi‐mineral Rb–Sr isochron dating yields crystallization ages for near peak‐pressure blueschist facies assemblages between 40.5 ± 1.0 and 38.3 ± 0.5 Ma. The greenschist facies overprint commonly did not result in complete resetting of age signatures. Maximum ages for the end of greenschist facies reworking, obtained from disequilibrium patterns, cluster near c. 32 Ma, with one sample showing rejuvenation at c. 27 Ma. We conclude that the high‐P rocks from south Naxos were exhumed to upper mid‐crustal levels in the late Eocene and early Oligocene at rates of 7.4 ± 4.6 km/Ma, completing a full blueschist‐/greenschist facies metamorphic cycle soon after subduction within c. 8 Ma. The greenschist facies overprint of the blueschist facies rocks from south Naxos resulted from rapid exhumation and associated deformation/fluid‐controlled metamorphic re‐equilibration, and is unrelated to the strong high‐T metamorphism associated with the Miocene formation of the Naxos migmatite dome. It follows that the Miocene thermal overprint had no impact on rock textures or Sr isotopic signatures, and that the rocks of south Naxos underwent three metamorphic events, one more than hitherto envisaged.     

全球早古生代造山带(Ⅱ):俯冲-增生型造山

全球早古生代增生造山带极其发育,主要分布在古亚洲洋南北两侧、Iaeptus洋南侧、Rheic洋北侧和环冈瓦纳大陆地带,其中原特提斯洋封闭的产物主要发育在中国境内,大量微陆块在早古生代可能都是冈瓦纳北缘的俯冲-增生带中的重要组成。增生造山带中组成复杂,具有沟-弧-盆体系、海山、洋壳等残存记录,尤以榴辉岩发育为特征,增生造山成为早古生代古亚洲洋和特提斯洋构造体系的显著独特特征。早古生代末中亚早古生代造山带多为微陆块增生造山阶段,沟-弧-盆体系发育,具有增生-软碰撞造山的特点,发生时限较晚,为早古生代末;原特提斯洋中的西昆仑、东昆仑、柴达木北缘、南阿尔金、北阿尔金与北祁连、北秦岭等围限或夹杂的微陆块在早古生代具有相同的增生造山过程,整体是向南俯冲线性增生到冈瓦纳大陆北缘,现今多次重复是早古生代弯山构造所致。400 Ma左右,南部古特提斯洋和北部勉略带的打开,导致其北漂,经复杂变形改造,它们现今为一巨型弯山构造横亘在中国中部,对中国构造格局影响最为重要。