| 伏牛山构造带变质流体脉变形特征及构造意义 |
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| 引用本文： | 任升莲,宋传中,Lin Shoufa,李加好,涂文传,马涛,宫龙,黄鹏,颊建,杨帆,刘乐.伏牛山构造带变质流体脉变形特征及构造意义[J].地质科学,2013,0(3):626-637. |
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| 作者姓名： | 任升莲 宋传中 Lin Shoufa 李加好 涂文传 马涛 宫龙 黄鹏 颊建 杨帆 刘乐 |
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| 作者单位： | 1. 合肥工业大学资源与环境工程学院 合肥 230009;
2. 加拿大滑铁卢大学 加拿大安大略省 N2L 3G1 |
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| 摘 要： | 伏牛山构造带由多条近平行的断裂带和夹持其间的变形岩片组成,洛南-栾川断裂带和瓦穴子-乔端断裂带为其中的两条主要断裂带。这两条断裂带虽遭受多期强烈构造活动的影响,但主造山期的构造特征至今仍然保存完好,并以中深层次的韧性剪切变形为主,形成了典型的糜棱岩和同构造期石英脉。本文从宏观、微观、超微观变形特征及年龄等方面对这些变质流体脉进行了研究,以探讨与其形成密切相关的构造活动特征、年代及其在秦岭造山带和华北板块南缘强变形带中的作用。石英脉中石英颗粒动态重结晶特征总体显示远离剪切带只有少量的膨凸式,靠近断裂带为亚颗粒式,形成核-幔结构,位错特征显示远离剪切带位错密度较小,靠近断裂带较大,位错形态显示瓦乔断裂带以挤压为主,洛南-栾川断裂带以剪切为主。两条断裂带石英脉的变形特征说明它们的糜棱岩化过程均为塑性变形中的晶质塑性变形,形成过程均为挤压在先,剪切在后。所测糜棱岩中石英脉的ESR年龄分别为372.9±30.0 Ma、275.0±20.0 Ma和218.0±20.0 Ma,真实地记录了晚加里东至中-晚海西期北秦岭的构造活动及所受影响。其中372.9±30.0 Ma是宽坪岩块向华北板块下的斜向俯冲汇聚和走滑的年代, 275.0±20.0 Ma是瓦乔断裂带的形成年龄。218.0±20.0 Ma的年龄则反映了华南、华北两大板块印支晚期全面闭合作用在秦岭造山带内部的影响。从以上3个年龄可以看出:北秦岭各构造带自北向南演化,时代上自北向南变新。
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| 关 键 词： | 伏牛山构造带 同构造期石英脉 变质流体脉 同变形分泌 微观、超微观变形 |
| 收稿时间： | 2012-07-01 |
| 修稿时间： | 2012-07-01; |
The deformation characteristics of metamorphic fluid veins and its tectonic significance in Funiushan tectonic belt |
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| Ren Shenglian,Song Chuanzhong,Lin Shoufa,Li Jiahao,Tu Wenchuan,Ma Tao,Gong Long,Huang Peng,Jia Jian,Yang Fan,Liu Le.The deformation characteristics of metamorphic fluid veins and its tectonic significance in Funiushan tectonic belt[J].Chinese Journal of Geology,2013,0(3):626-637. |
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| Authors: | Ren Shenglian Song Chuanzhong Lin Shoufa Li Jiahao Tu Wenchuan Ma Tao Gong Long Huang Peng Jia Jian Yang Fan Liu Le |
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| Institution: | 1. School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009;
2. Department of Earth Sciences, University of Waterloo, Ont., N2L 3G1, Canada |
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| Abstract: | Funiushan tectonic belt is composed of several nearly parallel fault zones and many deformation domains which are separated by the faults.The Luoluan fault and Waqiao fault are two main faults in this area.They are subjected multistage structural activities,but so far the structural characteristic of main orogenic episode is still well preserved,mainly manifested by the middle and deep-seated shear zones with mylonites and syntectonic quartz veins.Macro,micro,ultra micro-deformation characteristic and geochronology of metamorphic fluid veins are studied to explore the characteristics and geochronology of tectonic activity which was closely related to their formation and their effect on Qinling orogenic belt and the southern margin of the north China plate strong deformation zone.The dynamically recrystallized characteristics of the quartz grains in quartz veins indicate a small amount of BLG type away from the shear zone but it changes to SR type and forms the core-mantle structure while near the shear zone.The dislocation density increases from margin to the center of shear zone.The morphology of dislocation also reveals that Waqiao fault belt are formed mainly by compressive stress and Luoluan fault belt are formed mainly by shear stress.The deformation feature of the quartz veins developed in these two fault belts both give evidence of crystalline ductile deformation in mylonitization(compressive stress earlier,shear stress in the latter).Stress on Waqiao fault belt is greater than its on Luoluan fault belt.The ESR ages of quartz veins in mylonite measured as 372.9±30.0 Ma、275.0±20.0 Ma and 218.0±20.0 Ma,which truly recorded tectonic activities in north Qinling tectonic belt in Late Caledonian to the Middle and Late Hercynian and their influence.372.9±30.0 Ma represents the time when the Kuanping group was obliquely subducted beneath north China plate.275.0±20.0 Ma is the formation age of Waqiao fault belt.218.0±20.0 Ma may reflect the effect of the closure between south China and north China plate on north Qinling tectonic belt.From those ages we can see that the north Qinling tectonic belt is evolved gradually from the north to south. |
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| Keywords: | Funiushan tectonic belt Syntectonic quartz veins Metamorphic fluid veins Syntectonic deforming secretion Micro- ultra-micro-deformation |
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