The Liaonan metamorphic core complex, Southeastern Liaoning Province, North China: A likely contributor to Cretaceous rotation of Eastern Liaoning, Korea and contiguous areas   总被引：36，自引：0，他引：36  

Junlai Liu  Gregory A. Davis  Zhiyong Lin  Fuyuan Wu 《Tectonophysics》2005,407(1-2):65-80

The Mesozoic Liaonan metamorphic core complex (mcc) of the southeastern Liaoning province, North China, is an asymmetric Cordilleran-style complex with a west-rooting master detachment fault, the Jinzhou fault. A thick sequence of lower plate, fault-related mylonitic and gneissic rocks derived from Archean and Early Cretaceous crystalline protoliths has been transported ESE-ward from mid-crustal depths. U–Pb ages of lower plate syntectonic plutons (ca. 130–120 Ma), ⁴⁰Ar–³⁹Ar cooling ages in the mylonitic and gneissic sequence (ca. 120–110 Ma), and a Cretaceous supradetachment basin attest to the Early Cretaceous age of this extensional complex. The recent discovery of the coeval and similarly west-rooting Waziyu mcc in western Liaoning [Darby, B.J., Davis, G.A., Zhang, X., Wu, F., Wilde, S., Yang, J., 2004. The newly discovered Waziyu metamorphic core complex, Yiwulushan, western Liaoning Province, North China. Earth Science Frontiers 11, 145–155] indicates that the Gulf of Liaoning, which lies between the two complexes, was the center of a region of major crustal extension.Clockwise crustal rotation of a large region including eastern Liaoning province and the Korean Peninsula with respect to a non-rotated North China block has been conclusively documented by paleomagnetic studies over the past decade. The timing of this rotation and the reasons for it are controversial. Lin et al. [Lin, W., Chen, Y., Faure, M., Wang, Q., 2003. Tectonic implication of new Late Cretaceous paleomagnetic constraints from Eastern Liaoning Peninsula, NE China. Journal of Geophysical Research 108 (B-6) (EPM 5-1 to 5-17)] proposed that a clockwise rotation of 22.5° ± 10.2° was largely post-Early Cretaceous in age, and was the consequence of extension within a crustal domain that tapers southwards towards the Bohai Sea (of which the Gulf of Liaoning is the northernmost part). Paleomagnetic studies of Early Cretaceous strata (ca 134–120 Ma) in the Yixian–Fuxin supradetachment basin of the Waziyu mcc indicate the non-rotation of North China and the basin [Zhu, R.X., Shao, J.A., Pan, Y.X., Shi, R.P., Shi, G.H., Li, D.M., 2002. Paleomagnetic data from Early Cretaceous volcanic rocks of West Liaoning: evidence for intracontinental rotation. Chinese Science Bulletin 47, 1832–1837]. Such upper-plate non-rotation supports our conclusion that the lower plates of the Waziyu and Liaonan metamorphic core complexes were displaced ESE-ward in an absolute sense away from the stable North China block, thus contributing to the rotation of Korea and contiguous areas. Rotation is inferred to have affected only the upper crust above mid-crustal levels into which we believe the Jinzhou and Waziyu detachment fault zones flattened. If this is the case, the regional Tan Lu fault that lies between the two core complexes was truncated at mid-crustal depth, since in areas to the south it forms the boundary between the North and South China lithospheric blocks. It is noteworthy that the two extensional complexes lie not far north of the Bohai Bay, the area proposed by Lin et al. [Lin, W., Chen, Y., Faure, M., Wang, Q., 2003. Tectonic implication of new Late Cretaceous paleomagnetic constraints from Eastern Liaoning Peninsula, NE China. Journal of Geophysical Research 108 (B-6) (EPM 5-1 to 5-17)] as the site of the pole of rotation for Korea's clockwise displacement.Lin et al. [Lin, W., Chen, Y., Faure, M., Wang, Q., 2003. Tectonic implication of new Late Cretaceous paleomagnetic constraints from Eastern Liaoning Peninsula, NE China. Journal of Geophysical Research 108 (B-6) (EPM 5-1 to 5-17)] were unaware of the Liaonan and Waziyu mcc's and argued that most of the regional block rotation was post-Early Cretaceous and, in part, early Cenozoic. However, the ca. 130–120 Ma ages of the two Liaoning mcc's and a Songliao basin mcc (Xujiaweizi), the latter discovered only by recent drilling through its younger stratigraphic cover, support our and some Korean coworkers' conclusions that most of the clockwise rotation was Early Cretaceous.  相似文献   

华北地台太古宙地壳生长机制与构造体制转换     

吴福元  葛文春  孙德有  林强 《吉林大学学报(地球科学版)》1995,(3)

Ｓｍ－Ｎｄ同位素研究结果显示，华北地台太古宙构造体制与地壳生长可分为二个发展阶段：２８００Ｍａ以前，地壳以幔源物质垂向增生为主；进入２８００Ｍａ以后，地壳物质开始进入地幔，并以水平运动为主要构造体制，反映板块构造机制在太古宙晚期地质演化中具有十分重要的作用。  相似文献   

辽北太古宙变质岩中的振荡型矿物环带及意义          下载免费PDF全文

吴福元  林强 《岩石矿物学杂志》1993,12(2):126-133

对辽北太古宙层状变质岩系中石榴石、黑云母的成分分析发现,其中存在明显的振荡型矿物环带。对其形成机理的研究表明,这是矿物在结晶过程中由于偏离理想状态而形成的一种非平衡态自组织现象,即耗散结构。矿物内部成分的振荡性并不是由于外界条件的周期变化所造成的,而是体系内部固有属性的反映。这种认识对研究变质作用的动力学过程具有重要的借鉴意义,文中还就这种振荡性矿物环带在变质作用研究中的意义作了进一步的阐述。  相似文献   

中国满洲里－绥芬河地学断面域古生代构造单元及其地质演化   总被引：1，自引：0，他引：1  

Ye Mao  Zhang Shihong  Wu Fuyuan 《吉林大学学报(地球科学版)》1994,(3)

额尔古纳－兴安地体（ＥＴ）、松嫩－张广才岭地体（ＳＴ）、佳木斯地体（ＳＴ）是断面域古生代具有独立发展演化历史的地质构造单元，ＥＴ与西伯利亚地台具有亲缘性，ＳＴ－ＪＴ与华北和西伯利亚地台均无亲缘关系；ＳＴ与ＪＴ、ＥＴ与ＳＴ－ＪＴ分别沿牡丹江和嫩江断裂拼贴，最终形成统一亚洲大陆的一部分。  相似文献   

南水北调漕河渡槽Ⅲ标段桩基13000kN竖向抗压静载试验及分析     

常福远  宋玉才 《岩土工程技术》2007,21(6):315-318

漕河渡槽是南水北调中线工程总干渠上的标志性建筑物,其Ⅲ标段渡槽基础采用桩基形式。桩基施工完毕后,为了检测单桩竖向抗压承载力,采用了以堆锚联合反力装置为反力方式的13 000 kN竖向抗压静载试验,实验结果分析表明,本工程单桩的竖向抗压承载力满足设计要求。  相似文献   

黄土记录的中亚干旱区东部全新世气候与环境演化     

范义姣  马箫忆  刘慧  王树源  杨军怀  陈梓炫  高福元  贾佳  夏敦胜 《冰川冻土》2021,43(3):818-826

选取位于中亚干旱区东部新疆天山地区的两个典型黄土沉积剖面,通过磁学参数（χ_ARM/SIRM）、亮度（L^*）、有机碳/氮同位素（δ¹³C_org和δ¹⁵N）等记录,对研究区内全新世以来的气候环境进行重建。结果表明：早全新世,χ_ARM/SIRM、L^*指示黄土成壤较弱、有机质含量低,δ¹³C_org记录表明区域降水较少,共同反映该时期地表植被覆盖低、相对干旱的气候环境;中晚全新世,χ_ARM/SIRM、L^*和δ¹³C_org记录的湿度逐渐增加,黄土δ¹⁵N偏正变化,指示地表生态系统生产力增强、植被覆盖增加,表明该区域气候适宜期发生在中晚全新世。中亚干旱区东部全新世以来的气候环境特征,与北半球高纬度冰盖、太阳辐射强度的变化密切相关。  相似文献   

中太平洋西部海底沉积物孢粉分析与C14年代测定   总被引：1，自引：0，他引：1  

王永吉  蔡德陵  谢福缘  徐家声  刘新霞  孔繁荣 《海洋学报》1982,4(1):50-62

1978年12月-1979年8月,我国参加了世界气象组织主办的“第一次全球大气试验”.其间,我国科学考察船在中太平洋西部海域进行了海底沉积物调查研究工作.  相似文献   

基于 GIS 的富钴结壳资源量计算系统开发   总被引：1，自引：0，他引：1  

程永寿  冯志勇  殷汝广  张富元 《海洋通报》2007,26(6):85-90

富钴结壳资源量计算和资源评价是大洋富钴结壳矿区圈定工作的重要内容之一。阐述了基于GIS组件MO构建富钴结壳资源量计算系统的主要功能模块组成和设计思路。该系统利用VC采取面向对象的方法编程,设计开发了富钴结壳资源量计算评价程序,实现了地质块段法等多种计算方法。该系统吸纳了资源评价和矿区圈定中水深、丰度、品位和坡度等几个重要评价指标,可方便地实现钴结壳资源量计算,为大洋富钴结壳矿区圈定和矿产资源开发提供依据和参考。  相似文献   

地幔柱构造理论研究若干问题及研究进展   总被引：3，自引：0，他引：3  

赵国春  吴福元 《地质科技情报》1995,14(2):1-6

介绍了目前地幔柱构造理论研究中若干重要问题和最新进展,许多证据显示,地幔柱是严自于核幔边界附近的Ｄ″层发生热扰动并产生地幔柱的热动力源于外地核的不均匀加热作用;一个新启动的地幔柱在穿过整个地幔的缓慢上升过程会形成巨大球状顶冠和狭窄尾柱;地幔柱巨大球状顶冠会导致地壳发生上隆、区域变质作用、地壳深熔作用、构造变形作用和大规模火山作用,形成大陆或大洋溢流玄武岩;地幔柱狭窄尾柱的长期活动会在上覆运动板块上  相似文献   

全面二孩政策对中国人口结构及区域人口空间格局的影响   总被引：3，自引：2，他引：1  

王开泳  丁俊  王甫园 《地理科学进展》2016,35(11):1305-1316

从“单独二孩”到“全面二孩”,近几年中国生育政策的连续调整,不仅引起了社会的强烈反响,而且也将对中国未来的人口结构和空间格局产生重要影响。本文利用人口学的队列元素法对全面放开二孩政策实施后,中国未来总人口及人口结构的变化趋势进行预测,并从地理学的角度分析了全面放开二孩对中国区域人口空间格局的影响。结果表明：①全面放开二孩可以有效延缓中国总人口的递减趋势、老龄化的趋势以及未来劳动人口不断走低的趋势;②全面放开二孩政策前后,中国的区域人口空间分布均呈现东部人口密度最高、中部次之、东北再次、西部最低的总体格局,全面放开二孩将会增加胡焕庸线东南侧的人口密度,中国人口分布东南集聚、西北相对稀疏的格局将会长期存在并进一步加剧;③根据各省全面放开二孩政策后未来15年人口变化强度,可划分为人口快速变化区、人口中速变化区、人口缓慢变化区和人口平稳区。  相似文献