Rain shower on a Cambrian mudflat  

五亿年前的阵雨:来自寒武纪雨痕的证据

作　　者：Wei Liu Xingliang Zhang Liang Duan Chao Chang Xi Liu 刘伟;张兴亮;段亮;常超;刘茜(Shaanxi Key Laboratory of Early Life and Environments,State Key Laboratory of Continental Dynamics,Department of Geology,Northwest University,Xi’an 710069,China;Northwest University Museum,Xi’an 710069,China)

机构地区：[1]Shaanxi Key Laboratory of Early Life and Environments,State Key Laboratory of Continental Dynamics,Department of Geology,Northwest University,Xi’an 710069,China [2]Northwest University Museum,Xi’an 710069,China

出　　处：《Science Bulletin》2022年第24期2522-2525,M0003,共5页科学通报（英文版）

基　　金：supported by the National Natural Science Foundation of China(41890843,41902007,and 41621003);the Natural Science Basic Research Plan in Shaanxi Province of China(2022JCDW5-01);the Program of Introducing Talents of Discipline to Universities(the 111 Project,D17013)。

摘　　要：Raindrop imprints,as an ephemeral structure on the surface of loose or semi-consolidated sediments exposed to air,are charac-terized by a central depression surrounded by an external rim.These imprints are useful in interpreting the paleoenvironment and paleoclimate[1,2].One of the most fascinating is the applica-tion of raindrop imprints to estimate the paleo-air density[3.4].下雨是自然界最常见的现象之一.雨滴在重力作用下撞击到半固结的泥质沉积物表面时所形成的环形凹坑,称之为雨痕.通常而言,只有在干旱或半干旱环境下偶发的阵雨所形成的雨痕才有可能保存下来,因此具有重要的环境指示意义.本文报道了扬子地块北缘距今约5.1亿年前保存在寒武纪泥坪中的凹状压痕,通过与现代雨痕、冰雹痕、空气逃逸构造等相似结构的比对,确认它们是寒武纪的雨痕.这些雨痕完美记录了寒武纪半干旱泥坪环境中的一次强烈的空气对流现象,生动展现了一幅寒武纪阵雨天气的场景.

关 键 词：空气对流 泥质沉积物 雨痕 相似结构 半干旱环境 寒武纪 

分 类 号：P534.41[天文地球—古生物学与地层学] P532[天文地球—地质学]