Active deformation of Chinese Mainland from GPS measurement and numerical simulation

Using discontinue deformation analysis(DDA) method we analyzed the characters of the crustal deformation of Chinese mainland in this study form the velocity field revealed by 308 GPS stations. The result shows that the current N-S compression rate and W-E extension rate of the south Tibetan plateau are 1.40 × 10-8/a and 1.81 × 10-8/a, and that of Tiansan block are 2.59× 10-8/a and 0.62× 10-8/a. The Altyn Tagh is a left-lateral strike slip fault with a current slip rate of 8-12 mm/a, and the clockwise rotating rate of Tarim and Gansun-Qinghai block are -8.7 and -8.1 nrad/a, respectively, with respect to the Eurasia plate. According to the boundary condition of Chinese mainland respect to the Eurasia obtained from the DDA model, a two-dimension discontinuous finite element method(DFEM) model was built. Using this model, we evaluated the relationships between the slipping of Altyn Tagh and the crustal deformation and dynamics of Chinese mainland, and found that the slip of Altyn Tagh has influence on compression of Tibetan plateau, rotating of Tarim basin and Gansun-Qinghai block, the region absorbing the energy generated by the collision of Indio Plate and Eurasia plate, the ability and method of energy transferring toward east and the deformation of both Ordos block and North-China block. Further more, the slip of Altyn-Qiliansan Tagh strongly effects the stress field in most part of north-south seismic belt. The crustal deformation and tectonic activities of Chinese mainland west is mainly caused by the block boundary stress generated by the movement of India Plate, and it also influences some area of the east mainland through slipping along Altyn-Qiliansan Tagh. In some Part of east China and south east of China, the small-scale mantle convection and the effect of denudating can not be ignored.     

Geological and chronological evidence of Indo-Chinese strike-slip movement in the Altyn Tagh fault zone

A set of granitic and amphibole mylonite are exposed in the Altyn Tagh fault zone. The preliminary study shows that these rocks are the product of the syntectonic anatexis in the process of the left-lat- eral strike-slip shear, and are the result of the ductile transpression. There are two types of zircon sorted from the mylonite formed with synshear anatexis. Among them, one is the anatectic long columnar zircon and another is the residual metamorphic sub-rounded columnar zircon. Two groups of age for single zircon measured by ion microprobe (SHRIMP) are obtained: one is 461-547 Ma for the sub-rounded columnar residual metamorphic zircon, and the other is 239-244 Ma for the long-columnar anatectic zircon. This type of zircon is directionally spread in rock, and the long axis direction of its crystal is identical to that of stretching lineation, representing the direction of tectonic stress in the process of the strike-slip. 40Ar-39Ar age of the directional growth hornblende in the same mylonite sample measured is 223-226 Ma. The above geological and chronological data prove that the syntectonic anatexis occurred during Indo-Chinese Epoch, showing that the strong strike-slip movement occurred in the Altyn Tagh fault zone at least as early as Indo-Chinese Epoch.     

阿尔金山北麓晚新生代沉积特征及其对构造活动的响应

阿尔金山北麓晚新生代沉积物比较敏感地记录了阿尔金山构造活动的历史.通过若羌-米兰剖面晚新生代沉积特征表明中新世晚期以来该区沉积环境经历了从湖相到扇三角洲,最后至洪积扇和河流相沉积演化.依据沉积物岩性、沉积物粒度、沉积环境、古流向等的变化以及地层接触关系分析,揭示了阿尔金山晚新生代以来经历的晚中新世-早上新世,晚上新世和中更新世三次重大构造活动的历史.     

阿克塞盆地和肃北盆地中新世沉积特征及其与阿尔金断裂关系的研究

阿克塞盆地和肃北盆地分列于阿尔金断裂两侧,形成于中新世,有人认为它们曾是统一的盆地,在中新世末期由于阿尔金断裂的活动而被分割。然而砂岩成分分析表明,这两个盆地具有不同的物源特征：阿克塞盆地主要以石英和岩屑为主,含有大量的变质岩岩屑;肃北盆地主要以石英和长石为主,含有大量的岩浆岩岩屑。这两个盆地也具有不同的重矿物组合,与阿克塞盆地相比,肃北盆地含有较多的不稳定矿物（绿帘石和角闪石）。两个盆地的形成及演化均受控于阿尔金断裂,但它们最初并非为统一的盆地。推断阿尔金断裂在渐新世开始走滑,并造成阿尔金山隆升,控制阿克塞盆地的沉积;阿尔金断裂的走滑运动造成党河南山抬升,形成了肃北盆地。     

南大别变质块体温压结构的初步探讨

根据对太湖地区大坝附近榴辉岩的峰期变质P-T条件的研究,以及前人对南大别榴辉岩的P-T条件的分析,同时结合榴辉岩的空间分布状态的研究,文章认为南大别变质块体自北向南可分为金刚石、柯石英榴辉岩、石英/柯石英榴辉岩和石英榴辉岩4个变质单元;变质P-T条件总体上显示逐渐降低的趋势,反映了南大别变质块体俯冲时的连续性,而现今榴辉岩的P-T分布型式则代表南大别多板片的折返状态。     

The Jurassic System in SW Japan: review of recent research

The present state of the art in Jurassic oceanicplate stratigraphy in Japan is the result of research over the last two decades. Radiolarian biochronology puts age constraints on the development of fore-arc basin deposits, which cover Permian and Jurassic accretionary complexes of the Outer Zone, facing the Pacific. Special attention is given to the “Torinosu-type” reef-limestone blocks in the Upper Jurassic-Lower Cretaceous fore-arc basin deposits that derived from a shallow-marine continental margin such as the Inner Zone shelf, facing Eurasia. Further progress was achieved in dating and defining sedimentary environments in the Inner Zone Tetori Group. Erosive events during the process of Jurassic accretion are also discussed in relation to the Late Mesozoic geologic and tectonic setting.     

中国地体构造研究进展综述

地体构造理论被应用于中国地质的具体实践已经１５年并取得了丰硕的成果,主要表现在：１．中国境内地体构造的划分,２．地体构造理论上的创新,包括地体定义的完善;板块、微板块、地体、板惩、覆体五者之间的理论甄别,地体的古板块单元重建和古地体古大洋研究;地体拼贴增生和裂解离散的形式和过程,地体运动形成的沉积盆地和能源矿产;３．方法学上的进展,主要有古地磁喾综合地球物理学、微古生物及其对含放射虫硅质岩的新认识