沧口断裂断层泥石英颗粒微形貌特征及其年代学意义

Micro-morphology characteristics and chronology implications of the gouge quartz of Cangkou fault

利用扫描电镜对胶州湾东岸段沧口断裂断层泥中的石英颗粒进行微形貌特征观察与统计。结果表明:胶州湾东岸段沧口断裂最新活动时代为中更新世至晚更新世,未见全新世以来的活动迹象;该段沧口断裂自上新世以来至晚更新世有3期活动,分别为第一期上新世,第二期早更新世,第三期中更新世至晚更新世。总体来说,自上新世至晚更新世,沧口断裂活动性呈明显减弱的趋势。断层泥石英微形貌所反映的沧口断裂最新活动时代与前人测年结果基本一致,所反映的沧口断裂自上新世至晚更新世活动性明显减弱的趋势与山东胶东半岛NE-NNE向断裂活动性在第四纪晚期迅速减弱的趋势一致。

In this paper,the micromorphology characteristics of quartz particles in the gouge of Cangkou fault in eastern Jiao-zhou Bay were observed and statistically analyzed using scanning electron microscope.The statistical results of quartz micromor-phology show that the latest active age of Cangkou fault is from the Middle Pleistocene to the late Pleistocene,and there is no evi-dence of activity since the Holocene.From Pliocene to late Pleistocene,Cangkou fault experienced three periods of activity,the first period is Pliocene,the second period is early Pleistocene,and the third period is Pleistocene to late Pleistocene.In general,from Pliocene to late Pleistocene,the Cangkou fault activity showed a significant weakening trend.The main active age of Cangkou fault was from Pliocene to early Pleistocene,with the most intense activity in Pliocene and slight weakening in early Pleistocene.In late Pleistocene,the Cangkou fault activity weakened rapidly,and no obvious signs of activity have been observed since Holocene.The latest activity age of Cangkou fault reflected by the micromorphology of mud and stone is basically consistent with the previous dating results.And the significant weakening trend of Cangkou fault activity from Pliocene to late Pleistocene is consistent with the rapid activity weakening trend of NE-NNE fault during the late Quaternary in Jiaodong Peninsula,Shandong Province.