The end of ductile shear deformation of Ningshan fault: Constraint from the activity time of Longbozi shear zone
-
摘要:
南秦岭宁陕断裂镇安段北缘的龙脖子剪切带记录了宁陕断裂带左行走滑韧性剪切变形过程。带内3类石英脉体和方解石脉体的ESR年龄分别为125.6~88.7Ma、56.7~32.9Ma和19.8~14.6Ma。其中第一类产出于构造片理和A型褶皱核部的石英脉体，代表左行走滑韧性剪切变形结束、脆性构造活跃的时代。研究表明，宁陕左行走滑剪切带在晚三叠世早期开始活动，且可能持续到早—中侏罗世。第一类脉体年龄的确定表明，宁陕断裂带左行走滑韧性剪切变形最晚可持续到早白垩世；晚白垩世—始新世，宁陕断裂带以伸展-走滑脆性或韧-脆性剪切变形为主。因此，早白垩世是宁陕断裂带韧性剪切变形向脆性剪切变形转换的关键时期。宁陕断裂带经历了晚三叠世—中侏罗世晚期快速冷却阶段、晚侏罗世—白垩纪缓慢冷却阶段和古近纪以来快速冷却阶段。宁陕断裂带在缓慢冷却晚期（早白垩世）实现韧性剪切变形向脆性剪切变形转换说明，早白垩世也是秦岭造山带陆内变形机制转变的关键时期。
Abstract:Three groups of ESR dating ages were obtained from different vein materials in Longbozi shear zone, i.e., 125.6~88.7Ma, 56.7~32.9Ma and 19.8~14.6Ma. The first type of vein materials sampled from schistosities and A-type fold cores marked the end of left-lateral shear deformation. It has been confirmed that the ductile deformation of Ningshan fault began from the early Late Triassic, and might have lasted to Early-Middle Jurassic. However, the result of the first type of vein material ESR dating shows that Ningshan fault left-lateral ductile shear effect lasted to Early Cretaceous. So Early Cretaceous was the critical period when the ductile shear deformation transformed to brittleness in Ningshan shear zone. Furthermore, Ningshan fault experienced Late Triassic-Middle Jurassic rapid-cooling phase, Late Jurassic-Cretaceous slow-cooling phase, and Paleocene-Quaternary rapid-cooling phase. The strain translation that occurred in the late slow-cooling phase suggests that Early Cretaceous also was the critical period of intracontinental deformation mechanism changing.
-
Key words:
- Longbozi shear zone /
- Ningshan fault /
- left-lateral shear /
- cleavage /
- A-type fold /
- ESR dating
-
-
表 1 龙脖子剪切带多期脉体ESR测年数据
Table 1. Results of multi-period vein materials ESR dating in Longbozi shear zone
类别 产出状态 样品编号 顺磁中心浓度/
1015Sp/gU当量含量/10-6 年龄/Ma 第一类 A型褶皱核部石英脉 12ZS01/SS9 0.227 0.359 125.6±12.0 平行构造片理石英脉 DL01-Ⅱ/R2 0.486 1.059 91.8±9.0 A型褶皱核部石英脉 12ZS02/SS10 0.248 0.559 88.7±8.0 第二类 斜截构造片理石英脉 DL03-Ⅲ/R7 0.261 0.919 56.7±5.6 斜截构造片理石英脉 DL01-Ⅰ/R1 0.196 0.779 50.3±5.0 斜截构造片理石英脉 DL02-Ⅱ/R4 0.157 0.954 32.9±3.2 第三类 斜截构造片理方解石脉 DL02-Ⅲ/R5 0.105 1.059 19.8±2.0 斜截构造片理方解石脉 DL02-Ⅳ/R6 0.077 1.059 14.6±1.4 
下载: 导出CSV
表 2 宁陕断裂带各测年方法获得的年龄与封闭温度/脉体形成温度数据
Table 2. Ages and corresponding closure (forming) temperatures of different dating approaches in Ningshan fault belt
数据类型 年龄/Ma 测年矿物 计时方法 封闭温度/脉体形成温度/C 统计年龄[14-15] 214.4±1.1 锆石 U-Pb >900 212.8±1.6 186.0±4.0 统计年龄[36] 203.0~197.0 全岩 Rb-Sr 500 统计年龄[12] 169.5±2.3 白云母 Ar-Ar 350~400 统计年龄[12, 15] 165.1±2.6 黑云母 Ar-Ar 350~387 162.1±1.3 黑云母 Ar-Ar 350~387 161.1±9.3 黑云母 Ar-Ar 350~387 160.0±17.0 黑云母 Ar-Ar 350~387 实测年龄 125.6±12.0 高温石英脉 ESR ~300 91.849.0 88.7±8.0 实测年龄 56.7±5.6 低温石英脉 ESR ~200 50.3±5.5 32.9±3.2 实测年龄 19.8±9.0 方解石脉 ESR 150~75 14.6±1.4
下载: 导出CSV
-
[1] Ramsay J G, Graham R H. Strain variation in shear belts[J]. Canadian Journal of Earth Sciences, 1970, 7(3):786-836. doi: 10.1139/e70-078
[2] Ramsay J G. Structural Geology. (Book reviews:Folding and fracturing of rocks)[J]. Science, 1968, 160:410 http://cn.bing.com/academic/profile?id=1d9cbe556aab4a65206a3927a3849a02&encoded=0&v=paper_preview&mkt=zh-cn
[3] Sibson R H. Fault rocks and faults mechanisms[J]. Journal of the Geological Society, 1977, 133(1):191-213. http://d.old.wanfangdata.com.cn/NSTLQK/NSTL_QKJJ0229586914/
[4] Ratschbacher L, Hacker B R, Calvert A. Tectonocics of the Qinling (Central China):Tectonostigraphy, Geochronology, and Deformation History[J]. Tectonophysics, 2003, 366(1/2):1-53. http://www.uvm.edu/~lewebb/papers/Ratschbacher%20et%20al%202003.pdf
[5] 张国伟, 程顺有, 郭安林, 等.秦岭-大别中央造山系南缘勉略古缝合带的再认识:兼论中国大陆主体的拼合[J].地质通报, 2004, 23(9/10):846-853. http://dzhtb.cgs.cn/gbc/ch/reader/view_abstract.aspx?file_no=200409155&flag=1
[6] Li S Z, Kusky T M, Wang L, et al. Collision leading to multiplestage large-scale extrusion in the Qinling orogen:Insight from the Mianlue suture[J]. Gondwana Research, 2007, 12(1/2):121-143. https://www.researchgate.net/publication/223091906_Collision_leading_to_multiple-stage_large-scale_extrusion_in_the_Qinling_Orogen_insights_from_the_Mianlue_Suture
[7] Dong Y P, Zhang G W, Neubauer F, et al. Tectonic evolution of the Qinling Orogen, China:Review and synthesis[J]. Journal of Asian Earth Sciences, 2011, 41(3):213-237. doi: 10.1016/j.jseaes.2011.03.002
[8] 王二七, 苏哲, 许光.我国的一些造山带的侧向挤出构造[J].地质科学, 2009, 44(4):1266-1288. doi: 10.3321/j.issn:0563-5020.2009.04.016
[9] 王二七, 孟庆任, 陈智樑, 等.龙门山断裂带印支期左旋走滑运动及其大地构造成因[J].地质前缘, 2001, 8(2):375-384. http://www.cnki.com.cn/Article/CJFDTOTAL-DXQY200102029.htm
[10] Wang T, Pei X Z, Wang X X, et al. Orogen-Parallel Westward Oblique Uplift of the Qinling Basement Complex in the Core of the Qinling Orogen(China):An Example of Oblique Extrusion of Deep-Seated Metamorphic Rocks in a Collisional Orogen[J]. The Journal of Geology, 2005, 113:181-200. doi: 10.1086/427668
[11] 屈红军, 梅志超, 崔智林, 等.南秦岭镇安盆地泥盆纪沉积体系与古地理演化[J].古地理学报, 2001, 4(1):36-37. http://d.old.wanfangdata.com.cn/Periodical/gdlxb200201004
[12] 胡健民, 孟庆任, 陈虹, 等.秦岭造山带内宁陕断裂带构造演化及其意义[J].岩石学报, 2011, 27(3):651-671. http://d.old.wanfangdata.com.cn/Periodical/ysxb98201103006
[13] 李建华, 张岳桥, 董树文, 等.北大巴山凤凰山基底隆起晚中生代构造隆升历史-磷灰石裂变径迹测年约束[J].地质科学, 2010, 45(4):969-986. doi: 10.3969/j.issn.0563-5020.2010.04.004
[14] 李源, 许志琴, 裴先治, 等.秦岭-大别-苏鲁印支造山带连接枢纽的形成时代-来自宁陕断裂带同构造花岗岩锆石U-Pb年代学的限定[J].岩石学报, 2015, 31(12):3595-3607. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=ysxb98201512007
[15] 陈虹, 胡健民, 武国利, 等.南秦岭构造带中段晚中生代陆内变形特征与侧向挤出构造[J].吉林大学学报(地球科学版), 2014, 44(6):1906-1927. http://d.old.wanfangdata.com.cn/Periodical/cckjdxxb201406017
[16] 张国伟, 孟庆任, 赖绍聪.秦岭造山带的结构构造[J].中国科学(B辑), 1995, 25(9):999-1003. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=QK199500247435
[17] 张国伟, 张宗清, 董云鹏.秦岭造山带主要构造岩石地层单元的构造性质及其大地构造意义[J].岩石学报, 1995, 11(2):102-114. http://www.cnki.com.cn/Article/CJFDTOTAL-YSXB199502000.htm
[18] Meng Q R, Zhang G W. Timing of collision of the North and South China blocks:Controversy and reconliliation[J], Geology, 1999, 27(2):123-126. doi: 10.1130/0091-7613(1999)027<0123:TOCOTN>2.3.CO;2
[19] 于在平, 崔海峰.造山运动与秦岭造山[J].西北大学学报(自然科学版), 2003, 33(1):65-69. doi: 10.3321/j.issn:1000-274X.2003.01.019
[20] Dong Y P, Zhang G W, Lai S C, et al. An ophiolitic tectonic mélange first discovered in Huashan area, south margin of Qinling orogenic belt, and its tectonic implications[J]. Science in China (Series D), 1999, 42(3):292-302. doi: 10.1007/BF02878966
[21] 周鼎武, 李文厚, 张云祥, 等.区域地质综合研究的方法与实践——鄂尔多斯盆地-秦岭造山带地质野外实习指导书[M].北京:科学出版社, 2002:136-292.
[22] 李三忠, 张国伟, 李亚林, 等.秦岭造山带勉略缝合带构造变形与造山过程[J].地质学报, 2002, 76(4):469-483. doi: 10.3321/j.issn:0001-5717.2002.04.006
[23] 张二朋, 牛道韫, 霍有光.秦巴及邻区地质构造特征概论[M].北京:地质出版社, 1992:1-291.
[24] 郭洪方.变质岩定向薄片采制及构造要素的测定与分析[J].中国区域地质, 1993, 2:174-178. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=QK000004039342
[25] Yang K F, Yang K G, Ma C Q. Deformation character and ESR dating of Anhua-Xupu fault belts, Xuefeng Mountains[J]. Geotectonicet Metallogenia, 2005, 29(1):84-92.
[26] 梁兴中, 陈继镛, 冯家岷. α石英E'心合断代零点研究[J].核技术, 1993, 16(4):213-216. http://www.cnki.com.cn/Article/CJFDTotal-HJSU199304004.htm
[27] 杨坤光, 梁兴中, 谢建磊, 等. ESR定年:一种确定脆性断层活动年龄的方法原理与应用[J].地球科学进展, 2006, 21(4):430-435. doi: 10.3321/j.issn:1001-8166.2006.04.013
[28] 高钧成, 梁兴中. α石英E'心浓度测量与测年研究[J].核技术, 1995, 18(8):507-508. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=QK199500210321
[29] 姚益民, 修申成, 魏秀玲, 等.东营凹陷下第三系ESR测年研究[J].油气地质与采收率, 2002, 9(2):31-35. doi: 10.3969/j.issn.1009-9603.2002.02.010
[30] 梁兴中, 童运福.古剂量勘查技术[J].物探化探计算技术, 1996, 18(增刊):27-30. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=QK199600551097
[31] 梁兴中, 高钧成.断裂成矿年龄的α石英ESR研究[J].矿物岩石, 1999, 19(2):69-71. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=QK199900416170
[32] 贾丽, 鲍继飞, 尹功明, 等.方解石脉ESR定年信号和测量条件的研究[J].地震地质, 2006, 28(4):668-673. doi: 10.3969/j.issn.0253-4967.2006.04.015
[33] Schwarcz H P, Rink W J. Dating methods for sediments of caves and rock shelters with examples from the Mediterranean region[J]. Geoarchaeology, 2001, 16(4):355-371. doi: 10.1002/(ISSN)1520-6548
[34] Cliff R A. Isotopic dating in metamorphic belts[J]. Journal of the Geological society, 1985, 142:97-110. doi: 10.1144/gsjgs.142.1.0097
[35] Dodson M H, McClellang-Brown E. Isotopic and palaeomagnetic evidence for rates of cooling, uplift and erosion[J]. Geological Society London Memoirs, 1985, 10(1):315-325. doi: 10.1144/GSL.MEM.1985.010.01.26
[36] 张国伟, 张本仁, 袁学诚, 等.秦岭造山带与大陆动力学[M].北京:科学出版社, 2001:221-264.
[37] 陈虹, 胡健民, 武国利, 等.西秦岭勉略带陆内构造变形研究[J].岩石学报, 2010, 26(4):1277-1288. http://d.old.wanfangdata.com.cn/Periodical/ysxb98201004022
[38] Zhang G W, Dong Y P, Lai S C. Mianlue tectonic zone and Mianlue suture zone on southern margin of Qinling-Dabie orogenic belt[J]. Science in China (Series D), 2003, 47(4):300-316. http://cn.bing.com/academic/profile?id=53a384c68f3a1794b9101a29ed394639&encoded=0&v=paper_preview&mkt=zh-cn
[39] Li W, Dong Y P, Guo A L, et al. Sedimentary fill history of the Huicheng Basin in the West Qinling Mountains and associated constraints on Mesozoic intracontinental tectonic evolution[J]. Science China Earth Sciences, 2013, 56:1639-1653. doi: 10.1007/s11430-013-4607-4
[40] Li W, Dong Y P, Guo A L, et al. Geochronology, geochemistry and Sr-Nd-Hf isotopes of mafic dikes in the Huicheng Basin:Constraints on intracontinental extension of the Qinling oroge[J]. Journal of Asian Earth Sciences, 2015, 104:115-126. doi: 10.1016/j.jseaes.2014.11.014
-
图(8)
表(2)
计量
- 文章访问数: 876
- PDF下载数: 5
- 施引文献: 0