4 845 framework. method Key words Taili ductile shear zone augen-like structure sinistral strike-slipping shearing strain Fry Ma ~

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1 GLOBAL GEOLOGY Vol. 33 No. 4 Dec NNE σ δ Fry LS Fry P545 A doi /j. issn Genesis analysis of augen texture in mylonite of ductile shear zone of Taili in western Liaoning LUO Wei LIU Yong-jiang FANG Bo-wen LI Wei-min JI Qiu-mei LIANG Guo-yu College of Earth Sciences Jilin University Changchun China Abstract Taili area was located at the eastern segment of the northern part of North China Craton belonging to the Shanhaiguan palaeohigh which is the southeastern edge of the subsidence zone of Yanshan in Proterozoic era with a NNE ductile shear zone in this area. The field observation and microscopic analysis indicated that the main constitutions of this ductile shear zone were protomylonite and mylonite in which developed augen-like structures with σ- and δ-type structures. The augen-like structures had sinistral strike-slipping shearing characteristics. The augen-like structures were not just constituted by single feldspar phenocryst and the main origins were that one type of augen-like structures was formed by the elongating shearing deformation and boudin processes of the original narrow felsic veins while the other type was formed by the shearing deformation of the original mineral crystals. According to the finite-strain determination Fry method shearing strain and kinematic vorticity of the deformed rocks within ductile shear zones it was concluded that the shearing strain type was extensional type and mainly in simple shear deformation and the rock type was LS type tectonite. Combining with the results of previous studies it was concluded that since the Mesozoic Taili area underwent intense extensional deformation which related to the subduction of the Pacific Plate. Therefore the ductile shear zone in Taili was formed in the transtension tectonic yongjiang@ jlu. edu. cn

2 4 845 framework. method Key words Taili ductile shear zone augen-like structure sinistral strike-slipping shearing strain Fry Ma ~ 140 Ma ~ 100 Ma 120 ~ 110 Ma km σ δ 2A B σ σ δ 1 7 1C 8 1A 315 ~ ~ ~ ~ 5 NNE 6 1B S -C 2C D ~ 5 cm 10 4

3 A. B. C. A -B. Fig. 1 1 Regional geological map in Taili area of western Liaoning

4 4 847 A. σ B. δ C. D. S -C. Fig. 2 2 Field macroscopic characteristics of ductile shear zone in Taili area 50% ~ 60% 40% ~ 12 50% 16 3A 3B C 3 BLG SR ~ NNE S -C 26 3D

5 A. B. C. D. Af Qtz Bi. Fig. 3 3 Microscopic features of ductile shear zone in Taili area 5D 4A 4B 5E 5F 4C 6 5A 5B 5C 3. 2 δ σ

6 4 849 A. B. C.. Fig. 4 4 Changing process of felsic vein turning into augen porphyroclast

7 A B C D E F Af Qtz Bi Fig. 5 5 Photographs of field and microscope of augen porphyroclast 27

8 Fry Flinn Fry 6 XZ YZ 1 Flinn 6 K 1 K LS LS 4. 2 S -C S -C 34 γ = 2 /tan2θ γ θ θ XZ 2 Fig. 6 Flinn finite strain discrimination diagram 6 Flinn Table 1 1 Measured data of finite strain of ductile deformed rocks in Taili area X /Z Y /Z X /Y Ln X /Y Ln Y /Z k 13TL TL TL TL TL6-14b TL6-16b Table 2 2 Shear strain and kinematic vorticity of ductile shear zone in Taili area θ / γ Wk 13TL TL TL TL TL6-14b TL6-16b

9 J J ZHAI Ming-guo MENG Qing-ren LIU Jian-ming et 1-7. WANG Gen-hou ZHANG Chang-hou WANG Guosheng et al. Geological features of Mesozoic tectonic regime inversion al. Tectonic framework of western Liaoning in eastern North China and implication for geodynam- Province and evolution during Mesozoic J. Geosci ics J. Earth Science Frontiers Wk J / Wk = Wk = 1 Wk = SHAO Ji-an ZHANG Lü-qiao MOU Bao-lei. Transformation of the tectonic regime is a lithospheric scale activi ~ ty J. Geological Bulletin of China / θ Wk Wk = sin 2θ J. D LI Gang LIU Zheng-hong LIU Jun-lai et al. Formation 1 and timing of the extensional ductile shear zones in Yiwulü Mountain area western Liaoning Province North S -C China J. Science in China Ser. D NNE ~ 450 J K 1 LS WANG Qing-long JIN Wei CAI Li-bin et al. Characteristics and genesis of Neoarchean granitic complex in Xingcheng of western Liaoning J. Global Geology D LI Jian. Characteristics of granitic rocks and its geological significance in Taili area of western Liaoning Province master's degree thesis D. Changchun College of Earth Sciences of Jilin University FENG Ming LIANG Hui-she. The introductory tutorial of J. D ZHAI Ming-guo ZHU Ri-xiang LIU Jian-ming et al. The key time of Mesozoic tectonic regime transition in the plate tectonic and Chinese regional geological M. Beijing Geological Publishing House M East North China Mesozoic J. Science in China Ser. HUANG Ji-qing REN Ji-shun. Tectonics and evolution D M of China M. Beijing Science Press

10 4 853 ence J JI Mo HU Ling LIU Jun-lai et al. Dynamic recrystallization and metamorphic conditions of main rock LIN Xiao-hui QIN Zheng-yong. The structural style of forming Yanshan and the western Liaoning J. Geology of Chemical Minerals M. SHRIMP U- Pb J DU Jian-jun MA Yin-sheng ZHAO Yue et al. SHRIMP U- Pb zircon dating of the Yiwulüshan granite 19 Stipp M Stunitz H Heilbronner R et al. Theeastern in western Liaoning and its geological implications J. Tonale fault zone a-natural laboratory forcrystal plastic Geology in China deformation of quartz over a temperature range from to 700 e J. Journal of Structural Geology J LI Gang LIU Zheng-hong XU Zhong-yuan et al. Evidences of syn-extensional emplacement of Yiwulüshan pluton and its geological significance J. Journal of Jilin University Earth Science Edition M Bureau of Geology and Mineral Resources of Liaoning Province. Regional geology of Liaoning Province M. Beijing Geological Publishing House J GUO Hong-zhong ZHANG Zhao-chong. Essential characteristics of Mesozoic volcanic rock in western Liaoning J. Acta Petrologica et Mineralogica Acta Geoscientia Sinica D. J / ZHANG Guo-ren. The Mesozoic intraplate orogeny in REN Ji-shun NIU Bao-gui et al. Tectonic framework and geodynamic evolution of eastern China J. Geoscientific Liaoxi Ph'D dissertation D. Beijing School of Earth Sciences and Mineral Resources of China University of Geosciences Research / Maruyama S Seno T. Orogeny and relative plate mo- tions example of the Japanese Islands J. Tectono- 16. M. physics / ZHONG Zeng-qiu GUO Bao-luo. Tectonite and microstructure M. Wuhan China University of Geology Press J minerals J. Earth Science Frontiers HU Ling. An outline of microstructure geology M. Beijing Geological Publishing House M WANG Yu. The evolution and dynamics of the orogenic belt and the basin in North China since the Mesozoic M. Beijing Geological Publishing House J MA Yin-sheng CUI Sheng-qin WU Gan-guo. Uplift history of Yiwulüshan mountains in West Liaoning J. J MA Yin-sheng CUI Sheng-qin WU Gan-guo. The structural feature of metamorphic core complex in Yiwulüshan mountains West Liaoning J. Acta Geoscientia Sinica J LI San-zhong LIU Jian-zhong ZHAO Guo-chun et al.

11 Key geochronology of Mesozoic deformation in the eastern block of the North China Craton and its constraints on regional tectonics a case of Jiaodong and Liaodong Peninsula J. Acta Petrological Sinica M YANG Zhen-sheng. The method of geological survey and comprehensive research in high-grade metamorphic area WANG Xin-she ZHENG Ya-dong WANG Tao. The M. Beijing Geological Publishing House type of strain and shear action of ductile shear zone in Louzidian of the southern Chifeng in Inner Mongolia 27. J. Science in China Ser. D J MIAO Pei-sen ZHANG Zhen-fu. Ductile shear zones formed by different mechanisms J. Regional Geology of China Ramsay J G. M Stone D Schwerdtner W M. Total strain within a major Ramsay J G. Modern structural geology M. LIU mylonite zone southern Canadian shield J. Journal Rui-xun CHANG Zhi-zhong ZHANG Rong-chang of Structural Geology translated. Beijing Geological Publishing House M ZHENG Ya-dong CHANG Zhi-zhong. Finite strain measurement and ductile shear zones M. Beijing Geological Publishing House Siddans A W Henry B Kligfield R. Finite strainpatterns and their significance in Permian rocks of the Alpes Maritimes France J. Journal of Structural Geology Fry N. Random point distributions and strain measurements in rocks J. Tectonophysics J WANG Yun-bin LIANG Ming-hong HUO Qin-zhi et al. The study of the limit deformation measurement with deformation feldspar in granite areas J. Northwestern Geology J. D 35 Means W D Hobbs B E Lister G S et al. Vorticity and non-coaxiality in progressive deformations J. Journal of Structural Geology Simpson C De Paor D G. Strain and kinematic analysis in general shear zones J. Journal of Structural Geology Weijermars R. The role of stress in ductile deformation J. Journal of Structural Geology Weijermars R. Taylor-mill analogues for patterns of flow and deformation in rocks J. Journal of Structural Ge- ology

km BIF km BIF 6 7 BIF MT 14. MT. Fig. 1 1 Geological sketch map of Hanling -P

km BIF km BIF 6 7 BIF MT 14. MT. Fig. 1 1 Geological sketch map of Hanling -P 35 2 2016 6 GLOBAL GEOLOGY Vol. 35 No. 2 Jun. 2016 1004 5589 2016 02 0495 08 130061 4 MT 53 km N 65 NW 60 NW SE 35 ~ 50 P631 P542. 3 A doi 10. 3969 /j. issn. 1004-5589. 2016. 02. 021 Deep geological features