SEISMOLOGY AND GEOLOGY ›› 2014, Vol. 36 ›› Issue (3): 896-906.DOI: 10.3969/j.issn.0253-4967.2014.03.026

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ANALYSIS OF ORGANIC COMPONENTS AND ITS EFFECT ON THE FRICTIONAL PROPERTIES OF PINGXI BLACK GOUGE IN YINGXIU-BEICHUAN FAULT OF LONGMENSHAN FAULT ZONE

ZHANG Lei, HE Chang-rong   

  1. State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing 100029, China
  • Received:2013-04-09 Revised:2013-12-12 Online:2014-09-30 Published:2014-09-30

龙门山映秀-北川断裂平溪黑色断层泥中有机质成分分析及对断层摩擦滑动性质的影响

张雷, 何昌荣   

  1. 中国地震局地质研究所, 地震动力学国家重点实验室 100029
  • 作者简介:张雷|男|1985年生|2013年在中国地震局地质研究所获得博士学位|助理研究员|研究方向为高温高压断层力学|电话:010-62009010|E-mail:zhanglei@ ies.ac.cn。
  • 基金资助:

    “十一五”国家科技专项“汶川地震断层科学钻探”项目、地震动力学国家重点实验室自主研究课题(LED2009A01,LED2012A01)共同资助

Abstract:

Through a series of analysis on the black gouge at Pingxi in Yingxiu-Beichuan Fault, we found about 9wt.%organic matter of kerogen type preserved in the black gouge. The gas chromatography mass spectrometry (GC-MS) was applied to the organic matter and five major alkane compounds were identified, namely, n-alkanes (C14-C21), acyclic isoprenoids(pristane and phytane), sterane, terpane and n-alkylcyclohexanes (C10-C21). Based on preliminary analysis on the organic compounds, we conclude that the organic matter in the black gouge should have deposited in a sea facies or in a saline lacustrine reducing environment, with features of long-time storage and high maturity degree. Through contrast experiments between original gouge samples and organic-removed gouge samples, we found that organic matter in the Pingxi black gouge can significantly weaken fault frictional strength and increase its sliding stability.

Key words: Pingxi black gouge of Longmenshan Fault zone, frictional properties, organic matter, kerogen, alkane compounds

摘要:

通过对龙门山映秀-北川断裂平溪黑色断层泥一系列的分析测试,发现黑色断层泥中含有约9wt%的有机质组分,并且属于干酪根类型。通过对有机质的气相色谱质谱分析得到,其中主要的烷烃化合物成分为正构烷烃(C14-C21)、无环异戊二烯烷烃(姥鲛烷和植烷)、甾烷、萜烷和n烷基环已烷(C10-C21)。对有机化合物的初步分析表明,有机质形成于海相或咸水湖泊相的还原环境,并且赋存时间长,有机质成熟度高。通过对比实验发现,黑色断层泥中有机质的出现能够显著地弱化断层的摩擦强度以及提高断层摩擦滑动的稳定性。

关键词: 龙门山断裂带, 黑色断层泥, 摩擦特性, 有机质, 干酪根, 烷烃类化合物

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