扬子北缘志留系新滩组震积岩的发现及其地质意义

Discovery and Geological Significance of the Silurian Xintan Formation Seismite Along the North Margin of Yangtze Plate

宁强县黄家坝一带下志留统新滩组上部发育了2层震积岩,其表现形式为震积岩中有微裂缝、微褶皱(液化砂岩卷曲构造)、半塑性角砾岩、碎块-液化均一层。为一个地震活跃期的2次地震事件,是区内首次发现,填补了区内震积岩的空白。该地震事件与板块的裂解有着直接的联系,是早古生代Rodinia超大陆再次发生大规模裂解引起地震活动的结果,是加里东构造运动的有力证据。

Two seismite strata are developed in the upper part of the lower Silurian Xintan Formation around Huangjiaba village, Ningqiang county, which contains many micro cracks, micro folds （coiled structure of liquefied sandstone）, semiplastic breccia and fragment liquefied homogeneous layers and represents two seismic events during a single seismic active period. This is the very first discovery that fills the gap of seismite in the region. The seismic event is directly related to the splitting of plates, and the discovery of seismite offers a powerful evidence for the late Caledonian movement at the end of the early Paleozoic, namely the Rodinia＇s massive splitting in Early Paleozoic caused seismic activities.