河北省白石山中元古代地震遗迹的发现  

Discovery of Mesoproterozoic seismites at Baishi Mountain,Hebei Province and its geological significance

作　　者：梁定益[1] 宋志敏[1] 赵崇贺[1] 聂泽同[1] 

机构地区：[1]中国地质大学地质公园(地质遗迹)调查评价研究中心,北京100083

出　　处：《地质通报》2002年第10期625-631,共7页Geological Bulletin of China

摘　　要：在河北省涞源县白石山构造峰林游览路线上,中元古界雾迷山组(距今10～14亿年间)第二段地层下部,发现“震动坍塌巨角砾岩”(震积岩)。“巨角砾岩”受两条同沉积期正断层控制,是由两侧断崖上坍塌的岩块瞬时地在水下形成的。这是目前所知最早的震积岩(古地震遗迹)。根据震积岩的规模与两条正断层的断陷程度推测,白石山古地震的强度大体相当里氏6级以上,是华北中元古代地震灾变事件濒发期的具体表现。白石山距古太行山深断裂不足10km,白石山震积岩、同沉积期正断层与古太行山断裂带均呈NNE向延伸,推断当时白石山地区处在古太行山断裂带活动的影响范围内。Seismically collapsed megabreccias(seismites)have been found in the lower part of the Second Member of the Mesoproterozoic Wumishan Formation(1.0-1.4Ga ),along the tour route of the Baishi Mountain tectonic'peak forest'in Laiyuan County,Hebei Province.These megabreccias are controlled by two synsedimentary normal faults and formed instantaneously subaqueously from collapsed fault-cliff rocks.According to the scale of the seismites and the degrees of down-faulting of the two faulting,it is estimat-ed that the strength of the Baishi Mountain earthquake may have reached magnitude8±of the Richter scale.The earthquake was a concrete manifestation of the stage of repeated occurrence of Mesoproterozoic seismic catastrophic event in North China.As Baishi Mountain is less than10km from the ancient Tai-hangshan deep fault and the Baishi Mountain seismites extends in a NNE direction as is the case with its synchronous normal fault and Taihangshan deep fault,it is inferred that then at that time the Baishi Mountain area might have been within the influence of the activity of the Taihangshan fault zone.

关 键 词：震积岩 中元古界雾迷山组 古太行山断裂 白石山 河北 地震遗迹 

分 类 号：P315.2[天文地球—地震学]