摘要
软沉积物变形构造的成因和触发机制是灾变沉积学的一个热点问题。除地震成因外,非地震成因也能够导致软沉积物变形。因此,区分地震成因与非地震成因的软沉积物变形构造是理解其变形过程和地质事件的关键。论文重点讨论了青藏高原东部河湖相沉积中地震成因和非地震成因(暴雨与河流冲刷、风暴浪、洪水、重力碎屑流、崩塌滑坡、落石沉陷、冻融作用等)的软沉积物变形构造,并对其形成特征、环境意义和区别标志作了初步的归纳和分析。此外,对同震的软沉积物变形构造与震后相关的沉积构造关系进行了讨论。初步认为地震成因的软沉积物变形构造,是一种层间的,变形尺度较小(一般为厘米级)的变形构造,并具有侧向连续性和垂向重复性,变形强弱和频率与之到断层的距离存在明显相关性。对青藏高原东部软沉积物变形的成因进行区分,有助于为正确认识该区的地震灾害类型和致灾机理提供重要的基础资料,也可为更全面地认识该区的古地震事件提供新的依据。
The cause and trigger mechanism of the soft sediment deformation structure is a“hot spot”in catastrophic sedimentology.Besides earthquake,non-earthquake genesis can also cause the soft sediment deformation structure.Therefore,the distinction between earthquake caused and non-earthquake caused soft sediment deformation structures is the key to understanding its deformation process and geological events.This paper focuses on discussing the earthquake caused and non-earthquake(rainstorm and fluvial erosion,tempest waves,floods,unevenly loads,gravity debris flows,collapse landslides,rock fall subsidence,freeze/thaw cycles,etc.)caused soft sediment deformation structures in the fluvial-lacustrine sediments,eastern Tibetan Plateau.It also analyzes the distinctive signs and environmental significances of the structures.Then,the relationship between the co-seismic soft sediment deformation structure and the post-seismic sedimentary structure is also discussed.We supposed that the soft sediment deformation structure triggered by earthquake have a small-scale interlayer deformation,which can be traced laterally and repeated vertically.Deformation strength and frequency have an obvious correlation with the distance to the faults.This study provides some basic data and theoretical basis for determining the types and mechanisms of disasters in eastern Tibetan Plateau.It also provides a novel evidence for a more comprehensive understanding of the paleoseismic events in this area.
作者
钟宁
蒋汉朝
李海兵
徐红艳
黄小龙
ZHONG Ning;JIANG Han-chao;LI Hai-bing;XU Hong-yan;HUANG Xiao-long(Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing 100081;Key Laboratory of Deep-Earth Dynamics,Ministry of Land and Resources,Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037;State Key Laboratory of Earthquake Dynamics,Institute of Geology,China Earthquake Administration,Beijing 100029)
出处
《地球学报》
EI
CAS
CSCD
北大核心
2020年第1期23-36,共14页
Acta Geoscientica Sinica
基金
国家自然科学基金项目(编号:41807298
41572346)
中国博士后基金(编号:2019M650788)
中国地质调查局项目(编号:DD20190319
DD20190059)联合资助~~
关键词
软沉积物变形
古地震
地震事件沉积
河湖相沉积
青藏高原东部
soft sediment deformation structure
paleoearthquake
seismics-related deposit
fluvial-lacustrine sediments
eastern Tibetan Plateau
