天门山震旦系/寒武系界线事件沉积序列的初步观察与对比分析

湖南省早寒武世石煤层的铱异常发现之后,人们纷纷从地球化学方面推测一次陨石撞击事件的可能性。本文进一步分析了天门山晚震旦世—早寒武世的沉积构造特征,与Ｅｌｔａｎｉｎ小行星撞击Ｂｅｌｌｉｎｇｓｈａｕｓｅｎ海形成的各个沉积单元对比,认为天门山上震旦统灯影组—下寒武统牛蹄塘组是一个完整的海洋撞击事件沉积序列。应进一步在武陵山区寻找这次撞击事件的发生地点,确定陨石撞击坑。这对寻找撞击型金刚石矿具有重要意义。

OBSERVATION AND COMPARISON OF THE SEDIMENTARY SEQUENCE RELATING TO AN EVENT AT THE SINIAN / CAMBRIAN BOUNDARY IN TIANMENG MOUNTAIN

After discovery of iridium anomaly in Early Cambrian stone coal in Hunan province, scientistsbegan to guess the possibility of a meteorite impact event from geochemical aspects. This article haspresented a further analysis of sedimentary structures of Late Sinian to Early Cambrian age inTianmeng Mountain and has given a comparison between the Tianmeng Mountain sedimentary se-quence and the recognized five sedimentary units from the Eltanin asteroid impacted at theBellingshausen Sea. It is found that the deposits from the Late Sinian Dingyin Formation to the EarlyCambrian Liutitang Formation are a rounded sedimentary sequence relating to a possible asteroidimpacted in an ocean environment. As it is of important significance to the formation of impact-typediamond, it is worth searching for the impacting site in the Wulingyuan area, and finding out theimpacted crater.