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251.
Systematic studies of the ophiolites and associated volcanics stretching more than 1500 km from the Derni-Nanping-Pipasi-Kangxian area in the west to the Qingshuihe area of the south Dabie Mountains in the east indicate the existence of a suture zone (the Mianl(u)e suture)and a vanished paleo-ocean basin (the Mianlue paleo-ocean basin) in the region. From west to east, ophiolitic melange associations distribute discontinuously along the suture. Rock assemblages include ophiolite, island arc and oceanic island rock series. The Mianlue paleo-ocean basin experienced its major formation and expending episode during the Carboniferous-Permian period. The finding of the suture zone and the paleo-ocean basin is tectonically significant in timing the collision between the North China-Qinling and Yangtze blocks and determining the formation and evolution of the Qinling orogenic belt. 相似文献
252.
ZHANG Guowei Dong Yunpeng Lai Shaocong GUO anlin Meng Qingren Liu Shaofeng CHENG Shunyou Yao Anping ZHANG Zongqing PEI Xianzhi Li Sanzhong 《中国科学D辑(英文版)》2004,47(4)
The Mianlue tectonic zone (Mianlue zone), an ancient suture zone in addition to theShangdan suture in the Qinling-Dabie orogenic belt, marks an important tectonic division geo-logically separating north from south and connecting east with west in China continent. To de-termine present structural geometry and kinematics in the Mianlue tectonic zone and to recon-struct the formation and evolution history involving plate subduction and collision in theQinling-Dabie orogenic belt, through a multidisciplinary study, are significant for exploring themountain-building orogenesis of the central orogenic system and the entire process of the majorChinese continental amalgamation during the Indosinian. 相似文献
253.
254.
青藏线冻土地球物理模型的建立 总被引:3,自引:1,他引:3
通过对青藏线冻土勘探综合物探资料的分析 ,建立了 2种有代表性的冻土地球物理模型 ,此模型的建立不仅有助于野外冻土资料的判释 ,而且对今后冻土物探工作有一定的指导意义。 相似文献
255.
大别山北部漫水河灰色片麻岩的锆石UPb年龄及其地质意义 总被引:11,自引:2,他引:11
北大别杂岩主要由灰色片麻岩和斜长解闪岩组成。通过对大别山北部霍山漫水河花岗闪长片麻岩的锆石U-Pb年龄测定,得到中元古代、早三叠世和晚侏罗世3组年龄数据。中元古代的年龄老于灰色片麻岩集中在新元古代的锆石U-Pb上交点年龄,指示漫水河北部片麻岩中有古老锆石捕掳晶;早三叠世年龄指示该片麻岩中有印支期变质作用形成的锆石;晚侏罗世年龄表明灰色片麻岩中有燕山早期形成的岩浆锆石。根据北大别杂岩的构造背景、变质作用及地球化学特征,认为北大别杂岩中的部分灰色片麻岩形成于燕山早期的花岗闪长岩,它们可能源自或混染了经过早三叠世变质作用的扬子陆块俯冲基底。本文的结果表明,北大别杂岩既不是形成于白垩纪的岩浆杂岩,也不完全是形成于新元古代的TTG岩系,其中的部分灰色片麻岩为形成于燕山早期的花岗闪长岩,即在白垩纪大规模岩浆作用前的燕山早期,北大别曾有过一次岩浆作用。 相似文献
256.
Wang Lian Yao Yuedong Wang Kongjie Adenutsi Caspar Daniel Zhao Guoxiang Lai Fengpeng 《Natural Resources Research》2021,30(6):4825-4841
Natural Resources Research - Multi-objective well control optimization, which considers simultaneous optimization of more than one objective, has become an essential tool for efficient intelligent... 相似文献
257.
258.
青藏高原北部新生代火山岩的成因机制 总被引:24,自引:0,他引:24
Based on the electron probe
analyses result of the minerals and the bulk rock composition of the Cenozoic volcanic
rocks from Yumen and Hoh Xil lithodistricts on the Qinghai-Tibet Plateau, the forming
conditions including temperature and pressure of those rocks are studied.According to the
thermodynamics calculation result of the mineral-melt equilibrium,the depth of the
asthenosphere superface (about 75~130km) for the northern part of the Qinghai-Tibet
Plateau during Cenozoic era is suggested. Finally, this paper indicates that the Cenozoic
volcanic rocks in the northern part of the Qinghai-Tibet Plateau mainly consist of
shoshonite series.Their forming temperature is 630~1039℃ and forming pressure is
between 2.3~4.0 GPa and formed in the intracontinental orogenic belt,where the primary
magma was originated from a particular enriched upmantle and accreted crust-mantle belt or
directly originated from asthenosphere superface by partial melting of pyrolite. 相似文献
259.
Jian-Ke Qiang Kai Lu Qian-Jiang Zhang Kai-Feng Man Jun-Ying Li Xian-Cheng Mao Jian-Qing Lai 《应用地球物理》2017,14(1):1-9
We used high-pass filtering and the Fourier transform to analyze tidal gravity data prior to five earthquakes from four superconducting gravity stations around the world. A stable gravitational perturbation signal is received within a few days before the earthquakes. The gravitational perturbation signal before the Wenchuan earthquake on May 12, 2008 has main frequency of 0.1–0.3 Hz, and the other four have frequency bands of 0.12?0.17 Hz and 0.06?0.085 Hz. For earthquakes in continental and oceanic plate fault zones, gravity anomalies often appear on the superconducting gravimeters away from the epicenter, whereas the stations near the epicenter record small or no anomalies. The results suggest that this kind of gravitational perturbation signals correlate with earthquake occurrence, making them potentially useful earthquake predictors. The far-field effect of the gravitational perturbation signals may reveal the interaction mechanisms of the Earth’s tectonic plates. However, owing to the uneven distribution of gravity tide stations, the results need to be further confirmed in the future. 相似文献
260.
利用乌什台数字化前兆形变观测资料,分析乌什MS 4.5级地震前乌什台水管倾斜仪、洞体应变仪数据变化情况。通过对比分析发现:地震前,洞体应变仪北南分量数据曲线正常,东西分量数据曲线加速拉张,05:14-20:32拉张幅度达到7.40×10-7,7月19日5时至20日16时乌什洞体应变仪东西分量快速拉张了9.20×10-7;7月19日5-19时,水管倾斜仪北南分量数据曲线正常,东西分量数据曲线反向西倾7.13ms,且05:59-06:06、07:36-07:46、18:42-18:56数据掉格,水管倾斜仪异常结束后1小时,在洞体应变仪异常过程中发生了乌什MS 4.5级地震。水管仪东西分量震前反向西倾,洞体应变仪东西分量震前拉张加速,短临异常明显,且2套形变观测震前异常时间同步性较好。 相似文献