依兰-伊通断裂新构造活动规律分析  

Analysis on neotectonic activity of the Yilan-Yitong fault

作　　者：翟明见 朱光[1] 刘备[1] 顾承串[1] 张帅[1] 林少泽[1] 宋利宏[1] 

机构地区：[1]合肥工业大学资源与环境工程学院,合肥230009

出　　处：《地质科学》2016年第2期594-618,共25页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家自然科学基金项目（编号：41472186）和中国地质调查局项目（编号：1212011120099）资助.

摘　　要：作为郯庐断裂带北段主干的依兰一伊通断裂，其新构造活动性与活动规律仍然存在不同的认识。本次工作通过详细的野外调查，发现该断裂内活断层广泛存在，由东、西两支北东走向的主干活断层构成，沿着古近纪地堑边界断层发育。这些活断层主要呈破碎型结构，多为逆右行平移活动。通过对这些活断层一系列实测擦痕反演应力场，显示它们多是在东西向挤压中活动的，而现今应力场转变为北东东-南西西向区域性挤压。依据本次野外观察与14C定年，并结合前人定年结果与近代地震分布，表明依兰-伊通西支活断层的最新活动时代为全新世与晚更新世相间，而东支活断层的最新活动时代主要为早一中更新世。依兰-伊通断裂内活断层显示了明显的差异性活动，表现为西支的活动强度明显大于东支，西支的最新活动时代皆晚于东支，沿走向上活动性强、弱相间与最新活动时代不断变化，以及近代地震活动不均一分布。它们沿走向上的分段性、差异性活动主要是因为被一系列北西向断层切断所致。Neotectonic activity and history of the Yilan-Yitong fault, a main branch of the northern segment of the Tan-Lu fault zone remain controversial. Our detailed field investigation demonstrates that active faults are widely present in the Yilan-Yitong fault. They are composed of two main NE-striking active faults called the eastern and western active faults respectively and developed along boundary faults of the Paleogene graben. The active faults mainly show the crashed-type texture and reverse dextral slip. Stress inversion from many fault-slip data of the active faults show that Quaternary activity of the faults took place under the E-W compression that transformed into NEE-SWW compression at present. Our field observation and ＇4C dating, in combination with previous dating results and earthquake distribution, suggest that the most recent periods of activity on the western active fault show alternation of Holocene and Late Pleistocene whereas those on the eastern active fault are dominated by Early-Middle Pleistocene. The active faults in the Yilan-Yitong fault present differential activities that show more intense activity on the western fault than on the eastern one, younger activity on the western fault, alternation of intense and weak activity, change in the most recent periods of activity along their strike as well as inhomogeneous distribution of earthquakes. Segmentation and differential activities of the faults along their strike mainly result from cutting of NW- striking faults on them.

关 键 词：依兰-伊通断裂 活断层 运动学 应力场 最新活动时代 

分 类 号：P542[天文地球—构造地质学]