龙泉山背斜的地壳缩短与隆升——来自河流阶地变形的证据
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摘要
位于龙门山逆冲推覆构造带东侧的龙泉山背斜,构成了四川前陆盆地的前陆隆起。通过室内航空相片对凯江跨背斜段的地貌面的解译,结合野外考察可知凯江发育3级阶地,其中T1、T2为堆积阶地,T3为基座阶地。在野外用差分GPS测量了阶地的空间坐标信息,同时采集了各级阶地堆积物的测年样本,并经实验分析约束了阶地的形成年龄。另外,对石油地震剖面解译揭示出龙泉山背斜北段地壳缩短和隆升主要是通过褶皱膝折带迁移机制进行的,滑脱层的深度约6km。利用面积守恒准则计算出龙泉山背斜晚更新世以来的地壳缩短速率约为(1.36±0.41)mm/a、隆升速率为(0.64±0.19)mm/a。通过滑脱层的推覆抬升机制形成的龙泉山背斜,给青藏高原东缘变形模式中的逆断层推覆地壳缩短造山增加了证据。
Located at east of the Longmen Mountains Thrust,the Longquan anticline is a foreland uplift of Sichuan foreland basin. Three terraces have formed along the Kaijiang River across the Longquan anticline. According to optically stimulated luminescence(OSL)and \{14C\} samples,the age of the terrace T1 and T2 is 4.6ka and(11.7±0.4)ka,respectively. With growing of the anticline,terrace surfaces deformed obviously,which is characterized by folding scarps.The longitudinal profiles of the terraces at the Kaijiang River have been measured by differential GPS.We interpret the subsurface fault and fold geometries using petroleum seismic reflection profiles,our data suggest that the Longquan anticline grows laterally through kink-band migration and depth-to-detachment is about 6 kilometers.The cumulative shortening along the direction of tectonic transport is estimated to be 0.8km. We can confine that the crustal shortening and the uplift rate in late Pleistocene is(1.36±0.41)mm/a and(0.64±0.19)mm/a. India colliding with Eurasia results in the strong resistance from the South China block against the E to SEE extrusion of Bayan Har block,most of the energy has released in the form of uplifting of Longmen Mountains,and part,by the decollement,has been transferred to form the Longquan anticline.The 12 May 2008 Wenchuan earthquake(MW=7.9)of China occurred in the Longmen Shan thrust belt and is a consequence of the ongoing uplift process of the eastern margin of Tibetan plateau. After the earthquake,stress was reduced on the northern section and increased on the southern section of Longquan Fault.The event clearly illustrates that the Longquan anticline and the Longmen Shan thrust belt is an integral whole.The mechanism of uplift of Longquan Mountains provides some evidence for the orogenic model of brittle crustal thickening in the eastern Tibet Plateau.
引文
①中国石油勘探公司,2008,地震勘探剖面(工作报告)。
    陈社发,邓起东,赵小麟,等.1994.龙门山中段推覆构造带及相关构造的演化历史和变形机制[J].地震地质,16(4):404—421.CHEN She-fa,DENG Qi-dong,ZHAO Xiao-lin,et al.1994.Evolutionary history and deformation mechanism of centralLongmenshan thrust-nappes and related tectonics[J].Seismology and Geology,16(4):404—421(in Chinese).
    邓宾,刘树根,李智武,等.2008.青藏高原东缘及四川盆地晚中生代以来隆升作用对比研究[J].成都理工大学学报:自然科学版,35(4):477—486.DENG Bin,LIU Shu-gen,LI Zhi-wu,et al.2008.A comparative study of the late Mesozoic uplifting in the eastern mar-gin of Qinghai-Tibet Plateau and Sichuan Basin,China[J].Journal of Chengdu University of Technology(Science&Technology Edition),35(4):477—486(in Chinese).
    邓起东,陈社发,赵小麟,等.1994.龙门山及其邻区的构造和地震活动及动力学[J].地震地质,16(4):389—403.DENG Qi-dong,CHEN She-fa,ZHAO Xiao-lin,et al.1994.Tectonics seismicity and dynamics of LongmenshanMountains and its adjacent regions[J].Seismology and Geology,16(4):389—403(in Chinese).
    黄祖智,唐荣昌.1995.龙泉山活动断裂带及其潜在地震能力的探讨[J].四川地震,(1):18—23.HUANG Zu-zhi,TANG Rong-chang.1995.The Longquanshan Fault zone and exploration of potential earthquake ability[J].Earthquake Research in Sichuan,(1):18—23(in Chinese).
    李涛,陈杰,肖伟鹏,等.2011.利用变形河流阶地限定帕米尔北缘木什背斜的地壳缩短、隆升和侧向扩展[J].地震地质,33(2):308—322.doi:10.3969/j.issn.0253-4967.2011.02.005.LI Tao,CHEN Jie,XIAO Wei-peng,et al.2011.Using deformation terraces to confine the shortening,uplift and lateralpropagation of the Mushi anticline,northern margin of the Pamir[J].Seismology and Geology,33(2):308—322(in Chinese).
    刘树根,孙玮,李智武,等.2008.四川盆地晚白垩世以来的构造隆升作用与天然气成藏[J].天然气地球科学,19(3):293—300.LIU Shu-gen,SUN Wei,LI Zhi-wu,et al.2008.Tectonic uplifting and gas pool formation since late Cretaceous epoch,Sichuan Basin[J].Natural Gas Geosicence,19(3):293—300(in Chinese).
    鲁人齐,何登发,Suppe J,等.2010.龙门山中段山前带浅层冲断系统的结构、形成与演化[J].地质科学,(4):997—1010.LU Ren-qi,HE Deng-fa,Suppe J,et al.2010.The structures,formation and evolution of the shallow thrusting system inthe central Longmen Mountains front belt[J].Chinese Journal of Geology,(4):997—1010(in Chinese).
    钱洪,唐荣昌.1997.成都平原的形成与演化[J].四川地震,(3):1—7.QIAN Hong,TANG Rong-chang.1997.On the formation and evolution of the Chengdu plain[J].Earthquake Researchin Sichuan,(3):1—7(in Chinese).
    王伟涛,贾东,李传友,等.2008.四川龙泉山断裂带变形特征及其活动性初步研究[J].地震地质,30(4):968—979.WANG Wei-tao,JIA Dong,LI Chuan-you,et al.2008.Preliminary investigation on deformation characteristics and activ-ity of Longquanshan Fault belt in Sichuan[J].Seismology and Geology,30(4):968—979(in Chinese).
    解朝娣,朱元清,于海英,等.2010.MS8.0汶川地震产生的应力变化空间分布及其对地震活动性的影响[J].中国科学(D辑),40(6):688—698.doi:10.1007/s11430-010-4025-9.XIE Chao-di,ZHU Yuan-qing,YU Hai-ying,et al.2010.Pattern of stress change and its effect on seismicity rate causedby MS8.0Wenchuan earthquake[J].Science in China(Ser D),40(6):688—698(in Chinese).
    徐水森,任寰,宋杰.2006.龙泉山断裂带地震活动性浅析[J].四川地震,(2):21—27.XU Shui-seng,REN Huan,SONG Jie.2006.Primary study on the seismicity along the faults of Longquanshan[J].Earthquake Research in Sichuan,(2):21—27(in Chinese).
    徐锡伟,闻学泽,陈桂华,等.2008.巴颜喀拉地块东部龙日坝断裂带的发现及其大地构造意义[J].中国科学(D辑),38(5):529—542.XU Xi-wei,WEN Xue-ze,CHEN Gui-hua,et al.2008.Discovery of the Longriba Faults,eastern part of the Bayankelatectonic block and its geodynamic implications[J].Science in China(Ser D),38(5):529—542(in Chinese).
    杨晓平,冉勇康,程建武,等.2006.柯坪推覆构造中的几个新生褶皱带阶地变形测量与地壳缩短[J].中国科学(D辑),36(10):905—913.YANG Xiao-ping,RAN Yong-kang,CHENG Jian-wu,et al.2006.Measurement of terrace deformation and crustal short-ening of some renascent fold zones within Kalpin nappe structure[J].Science in China(Ser D),36(10):905—913(in Chinese).
    Charreau J,Avouac J P,Chen Y,et al.2008.Miocene to present kinematics of fault-bend folding across the Huerguosianticline,northern Tianshan(China),derived from structural,seismic,and magnetostratigraphic data[J].Geology,36(11):871—874.
    Chen J,Heermance R,Burbank D W,et al.2007.Quantification of growth and lateral propagation of the Kashi anti-cline,southwest Chinese Tian Shan[J].J Geophys Res,112B03S16.
    Chen S F,Wilson C,Deng Q D,et al.1994.Active faulting and block movement associated with large earthquakes in theMin Shan and Longmen Mountains,northeastern Tibetan plateau[J].Journal of Geophysical Research,99(B12):20—25.
    Daron M,Avouac J P,Charreau J,et al.2007.Modeling the shortening history of a fault tip fold using structural and ge-omorphic records of deformation[J].J Geophys Res,112B03S13.
    Hubbard J,Shaw J H.2009.Uplift of the Longmen Shan and Tibetan plateau,and the2008Wenchuan(M=7.9)earth-quake[J].Nature,458(7235):194—197.doi:10.1038/nature07837.
    Hubert-Ferrari A,Suppe J,Gonzalez-Mieres R,et al.2007.Mechanisms of active folding of the landscape(southern TianShan,China)[J].Journal of Geophysical Research,112(B3):B03S09.
    LavéJ,Avouac J P.2000.Active folding of fluvial terraces across the Siwaliks Hills,Himalayas of central Nepal[J].Journal of Geophysical Research,105(B3):5735—5770.
    Jia D,Li Y,Lin A,et al.2010.Structural model of2008MW7.9Wenchuan earthquake in the rejuvenated LongmenShan thrust belt,China[J].Tectonophysics,491(1-4):174—184.doi:10.1016/j.tecto.2009.08.040.
    Richardson N J,A L Densmore,D Seward,et al.2008.Extraordinary denudation in the Sichuan Basin:Insights fromlow-temperature thermochronology adjacent to the eastern margin of the Tibetan plateau[J].J Geophys Res,113:B04409.doi:10.1029/2006JB004739.
    Scharer K,Burbank D,Chen J,et al.2004.Detachment folding in the southwestern Tian Shan-Tarim foreland,China:Shortening estimates and rates[J].Journal of Structural Geology,26(11):2119—2137.
    Suppe J,Chou G T,Hook S C.1992.Rates of folding and faulting determined from growth strata[A].In:McClay K R(ed).Thrust Tectonics.Chapman&Hall,London.105—121.
    Tapponnier P,Zhiqin X,Roger F,et al.2001.Oblique stepwise rise and growth of the Tibet Plateau[J].Science,294(5547):1671—1677.
    Wilson L F,Pazzaglia F J,Anastasio D J.2009.A fluvial record of active fault-propagation folding,Salsomaggiore anti-cline,northern Apennines,Italy[J].J Geophys Res,114B08403.doi:10.1029/2008JB005984,2009.
    Xu X,Wen X,Yu G H,et al.2009.Coseismic reverse-and oblique-slip surface faulting generated by the2008MW7.9Wenchuan earthquake,China[J].Geology,37(6):515—518.doi:10.1130/G25462A.1.
    Zapata T R,Allmendinger R W.1996.Growth stratal records of instantaneous and progressive limb rotation in the Pre-cordillera thrust belt and Bermejo Basin,Argentina[J].Tectonics,15(5):1065—1083.

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