X-RAY DIFFRACTION ANALYSIS RESULT OF CO-SEISMIC FAULT GOUGE IN CARBON MUDSTONE AT OUTCROPS OF BAJIAOMIAO AND SHENXIGOU IN HONGKOU

doi:10.3969/j.issn.0253-4967.2012.01.003

Abstract

Abstract:

The co-seismic surface ruptures of the May 12,2008 Wenchuan earthquake in Bajiaomiao and Shengxigou were developed mainly at the outcrops of carbon mudstones of Xujiahe formation of Triassic system. The black color and textures of co-seismic gouge are similar to old gouge and bed rock. We excavated trenches along the surface ruptures and collected samples of wall rock, fault breccia, old fault gouge and co-seismic gouge. All samples were analyzed quantitatively by X-ray diffraction. The main rock-forming minerals and clay minerals of co-seismic gouge are similar to old gouge, but their content is different, which shows the co-seismic gouge was formed based on old gouge. The wall rock and fault breccias adjacent to co-seismic gouge are carbon mudstones. The mineral composition and texture of the fault zone are obviously simpler than that of the northern part of the surface ruptures of Yinxiu-Beichuan Fault. The major minerals of co-seismic gouge are quartz and clay minerals, containing a few amount of feldspar, without calcite; a small amount of dolomite was found in co-seismic gouge at Shenxigou, and the content of dolomite is much lower than that in bed rock and old gouge. The marked character of new gouge is abundant in clay minerals, and the content of clay minerals decreases in turn from co-seismic gouge to old fault gouge, fault breccia and wall rock. The main clay minerals are illite and illite/smectite (I/S) mixed layer, containing a few amount of chlorite; a few kaolinite was found in co-seismic gouge of Shenxigou, the bed rock and gouge of Bjiaomiao did not contain kaolinite. Mineral characters of co-seismic gouge are different from old gouge. The old gouge contains calcite and dolomite, and the co-seismic gouge contains a few amount of dolomite and without calcite; the old gouge does not contain illite. However, for co-seismic gouge, mineral characters are different between black and white gouges, the content of illite in black gouge is higher than that in white gouge. In this study, the main clay minerals are I/S mixed layer, illite and chlorite, which is similar with San Andreas Fault and Chelunpu Fault. However, kaolinite content is extremely low in this fault, only trace kaolinite was found in the co-seismic gouge of Shenxigou. The high content of I/S in co-seismic gouge shows that the rich K+fluid participated in the seismic fault slip. All of these characters show that minerals of co-seismic fault gouge in this study are somewhat different with that of San Andreas Fault and Chelunpu Fault.

Key words: Wenchuan earthquake, co-seismic gouge, X-ray diffraction quantitative analysis, clay mineral

摘要：

5.12汶川地震同震地表破裂带在虹口八角-深溪沟一带主要出露于三叠系须家河组的炭质泥岩中,同震断层泥在颜色、结构上与老断层泥和围岩类似。通过开挖探槽,系统采样,采用粉晶X射线衍射定量分析方法,研究了同震地表破裂带的围岩、断层角砾岩、老断层泥和新断层泥的矿物成分特征。同震断层泥的主要成分为石英和黏土矿物,含微量长石和白云石;断层泥的显著特征为高黏土矿物含量,从同震断层泥、老断层泥、角砾岩到围岩黏土矿物含量依次降低,黏土矿物以伊利石和伊蒙混层为主,含微量绿泥石和高岭石,矿物组成明显比地表破裂带北段同震断层泥简单。不同颜色的同震断层泥成分略有不同,黑色断层泥中伊利石含量明显高于白色断层泥;老断层泥中含有方解石和白云石,而同震断层泥不含方解石,只含微量白云石。同震断层泥中伊蒙混层高含量表明,在本次地震错动中有富含K的流体参与。

关键词: 汶川地震, 同震断层泥, 粉晶X射线衍射定量分析, 黏土矿物

CLC Number:

P315.2

DANG Jia-xiang, ZHOU Yong-sheng, HAN Liang, HE Chang-rong, CHEN Jian-ye, DANG Xin-zeng, YANG Xiao-song. X-RAY DIFFRACTION ANALYSIS RESULT OF CO-SEISMIC FAULT GOUGE IN CARBON MUDSTONE AT OUTCROPS OF BAJIAOMIAO AND SHENXIGOU IN HONGKOU[J]. SEISMOLOGY AND GEOLOGY, 2012, 34(1): 17-27.

党嘉祥, 周永胜, 韩亮, 何昌荣, 陈建业, 党新增, 杨晓松. 虹口八角庙-深溪沟炭质泥岩同震断层泥的X射线衍射分析结果[J]. 地震地质, 2012, 34(1): 17-27.

References

党嘉祥,周永胜,陈建业,等.2012.汶川地震地表破裂带北段基岩同震断层泥的矿物成分特征［J］.岩石学报,(出版中).
DANG Jia-xiang,ZHOU Yong-sheng,CHEN Jian-ye,et al.2012.Mineral characters of co-seismic fault gouge in the northern part of surface ruptures of the Wenchuan earthquake［J］.Acta Petrologica Sinica,(in press)(in Chinese).
付碧宏,王萍,孔屏,等.2008.四川汶川5.12大地震同震滑动断层泥的发现及构造意义［J］.岩石学报,24(10): 2237-2243.
FU Bi-hong,WANG Ping,KONG Ping,et al.2008.Preliminary study of coseismic fault gouge occurring in the slip zone of the Wenchuan M_S 8.0 earthquake and its tectonic implications［J］.Acta Petrologica Sinica,24(10): 2237-2243(in Chinese).
韩亮,周永胜,陈建业,等.2010.汶川地震基岩同震断层泥结构特征［J］.第四纪研究,30(4): 745-758.
HAN Liang,ZHOU Yong-sheng,CHEN Jian-ye,et al.2010.Structural characters of co-seismic fault gouge in bedrocks during the Wenchuan earthquake［J］.Quaternary Sciences,30(4): 745-758(in Chinese).
何宏林,孙昭民,魏占玉,等.2008.汶川M_S 8.0地震地表破裂带白沙河段破裂及其位移特征［J］.地震地质,30(3): 658-673.
HE Hong-lin,SUN Zhao-min,WEI Zhan-yu,et al.2008.Rupture of the M_S 8.0 Wenchuan earthquake along the Baishahe River［J］.Seismology and Geology,30(3): 658-673(in Chinese).
黄思静.1990.混层伊利石-蒙脱石的鉴定及其成岩意义［J］.岩相古地理,5: 23-29.
HUANG Si-jing.1990.Identification and diagenetic significance of interstratified illite-montmorillonite series［J］.Sedimentary Facies and Palaeogeography,5: 23-29(in Chinese).
王萍,付碧宏,张斌,等.2009.汶川8.0级地震地表破裂带与岩性关系［J］.地球物理学报,52(1): 131-139.
WANG Ping,FU Bi-hong,ZHANG Bin,et al.2009.Relationships between surface ruptures and lithologic characteristics of the Wenchuan M_S 8.0 earthquake［J］.Chinese Journal of Geophysics: 52(1): 131-139(in Chinese).
徐锡伟,闻学泽,叶建青,等.2008.汶川M_S 8.0地震地表破裂带及其发震构造［J］.地震地质,30(3): 597-629.
XU Xi-wei,WEN Xue-ze,YE Jian-qing,et al.2008.The M_S 8.0 Wenchuan earthquake surface ruptures and its seismogenic structure［J］.Seismology and Geology,30(3): 597-629(in Chinese).
张培震,徐锡伟,闻学泽,等.2008.2008年汶川8.0级地震发震断裂的滑动速率、复发周期和构造成因［J］.地球物理学报,51(4): 1066-1073.
ZHANG Pei-zhen,XUi Xi-wei,WEN Xue-ze,et al.2008.Slip rates and recurrence intervals of the Longmenshan active fault zone,and tectonic implications for the mechanism of the May 12 Wenchuan earthquake,2008,Sichuan,China［J］.Chinese Journal of Geophysics,51(4): 1066-1073(in Chinese).
周张健.1994.蒙脱石伊利石化的控制因素、转化机制及其转化模型的研究综述［J］.地质科技情报,13(40): 41-46.
ZHOU Zhang-jian.1994.Summary of the studying for illitization of the smectite on its controlling factors,transformation mechanism and models［J］.Geological Science and Technology Information,13(40): 41-46(in Chinese).
Buatier M D,Peacor D R,O'neil J R.1992.Smectite-illite transition in Barbados accretionary wedge sediments: TEM and AEM evidence for dissolution/crystallization at low temperature［J］.Clays and Clay Minerals,40(1): 65-80.
Burchfiel B C,Royden L H,Vander Hilst R D,et al.2008.A geological and geoghysical context for the Wenchuan earthquake of 12May 2008,Sichuan,People's Republic of China［J］.Journal of Geophysical Research,18(7): 4-11.
Chen W M D,Tanaka H,Huang H J,et al.2007.Fluid infiltration associated with seismic faulting: Examining chemical and mineralogical compositions of fault rocks from the active Chelungou Fault［J］.Tectonophysics,443: 243-254.
Hashimoto Y,Sakaguchi A,Tanaka H.2007.Characteristics and implication of clay minerals in the northern and southern parts of the Chelungou Fault,Taiwan［J］.Tectonophysics,443: 233-242.
Liechti R,Zoback MD.1979.Preliminary analysis of clay gouge from a well in the San Andreas Fault zone in central California .In: Proceedings of Conference Ⅷ: Analysis of Actual Fault Zones in Bedrock.Geol Surv Open File Rep U S,79-1239: 268-275.
Lin A M,Maruyama T,Kobayashi K.2007.Tectonic implications of damage zone-related fault-fracture networks revealed in drill core through the Nojima fault,Japan［J］.Tectonophysics,443: 161-173.
Logan J M,Higgs N G,Friedman M.1981.Laboratory studies on natural gouge from the U S Geological Survey Dry Lake Valley No.1 Well,San Andreas Fault zone .In: Carter N L,et al.(eds).Mechanical Behavior of Crustal Rocks.The Handin Volume,Geophys Monogr Ser,AGU Washington,D C,24: 121-134.
Pollastro R M.1993.Considerations and applications of the illite/smectite geothermometer in hydrocarbon-bearing rocks of Miocene to Mississippian age［J］.Clays and Clay Minerals,41(2): 119-133.
Pusch R,Karnland O.1996.Physico/chemical stability of smectite clays［J］.Engineering Geology,41: 73-85.
Tanaka H,Fujimoto K,Ohtani T.2001.Structural and chemical characterization of shear zones in the freshly activated Nojima Fault,Awaji Island,southwest Japan［J］.Journal of Geophysical Research,106(B5): 8789-8810.
Velde B,Vasseur G.1992.Estimation of the diagenetic smectite to illite transformation in time-temperature space［J］.American Mineralogist,40: 629-643.
Vrolijk P,Van Der Pluijm B A.1999.Clay gouge［J］.Journal of Structural Geology,21: 1039-1048.
Wu F T,Blatter L,Roberson H.1975.Clay gouges in the San Andreas Fault system and their possible implications［J］.Pure and Applied Geophysics,113: 87-95.
Wu F T.1978.Mineralogy and physical nature of clay gouge［J］.Pageoph,116: 655-689.
Xu X W,Wen X Z,Yu G H,et al.2009.Coseismic reverse-and oblique-slip surface faulting generated by the 2008 M_W 7.9 Wenchuan earthquake,China［J］.Geology,37(6): 515-518.
Xu Z Q,Ji S C,Li H B,et al.2008.Uplift of the Longmenshan range and the Wenchuan earthquake［J］.Episodes,31(3): 291-301.

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