郯庐断裂带中桃源韧性剪切带剪切温压条件及锆石U-Pb分析

发布时间：2018-07-09 22:41

本文选题：郯庐断裂带 + 桃源韧性剪切带　；参考：《岩石学报》2016年03期

【摘要】：郯庐断裂带西侧的桃源韧性剪切带位于合肥市肥东县浮槎山的东麓,是郯庐断裂带的重要组成部分。左旋平移现象十分经典,走向北北东,垂直于大别造山带展布,带内大量发育高温糜棱岩。综合剪切带内基质的矿物组合、变形机制及电子探针分析结果,本文得出该韧性剪切带的变形温度为550~650℃,压力在0.5GPa左右,属高温中压变质环境,剪切深度大概在20km左右,后期抬升至地表。剪切带内不同岩石分别给出了~0.8Ga、~2.0Ga、~2.5Ga的锆石U-Pb基底年龄。推断0.8Ga和2.0Ga年龄具有华南板块的特征,而2.5Ga年龄岩石兼具有华南和华北板块的属性,仍无法判断其具体来自哪个板块。此外,剪切带内发育的同构造弱变形伟晶岩脉测得年龄为129Ma,指示郯庐断裂带肥东段在129Ma仍在进行左行剪切活动,但剪切强度已大幅衰减。
[Abstract]:The Taoyuan ductile shear zone on the west side of the Tanlu fault zone is located in the eastern foothill of Fucha mountain in Feidong County, Hefei. It is an important part of the Tanlu fault zone. The left lateral movement is very classic, moving toward the north to the East, perpendicular to the Dabie orogenic belt and a large number of high temperature mylonite in the belt. The mineral assemblage, deformation mechanism and electricity in the comprehensive shear zone The results of subprobe analysis show that the deformation temperature of the ductile shear zone is 550~650 C, the pressure is about 0.5GPa, and it belongs to the high temperature medium pressure metamorphic environment. The shear depth is about 20km, and the later period is raised to the surface. The different rocks in the shear zone give ~0.8Ga, ~2.0Ga, and 2.5Ga zircon U-Pb base age respectively. It is concluded that 0.8Ga and 2.0Ga age are obtained. The characteristics of the Southern China plate, while the 2.5Ga age rocks have both the Southern China and the North China plate properties, are still unable to determine which plate it comes from. In addition, the isomorphic and deformable pegmatite veins developed in the shear zone measured the age of 129Ma, indicating that the eastern section of the tan Lu fault zone is still in the left shear activity in 129Ma, but the shear strength is large. Amplitude attenuation.
【作者单位】：合肥工业大学资源与环境工程学院;
【基金】：国家自然科学基金项目(41272222;41072161) 博士点基金中国地质调查局科研项目(1212011220243)联合资助
【分类号】：P542.3;P597.3

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