川东北三叠系雷口坡组与须家河组界线微球粒的发现

The discovery of the micropellets from the Triassic Leikoupo FormationXujiahe Formation boundary in northeastern Sichuan

摘要: 在川东北地区三叠系雷口坡组与须家河组地层界线处首次发现微球粒。这些微球粒呈单球体,形状为实心圆球状,直径3~4μm。微球粒成分为硅质球,可见溶蚀结构,推测研究区在中、晚三叠世之交可能发生过陨击事件,为研究四川盆地三叠纪海陆演变、生物更替提供了一种新的研究思路。

Abstract: The micropellets are recognized for the first time from the Triassic Leikoupo Formation-Xujiahe Formation boundary in northeastern Sichuan. These micropellets occur as single solid rounded pellets with the diameters from 3 to 4 μm, and compositionally they display the siliceous pellets in which the corrosion structures and textures are visible. It is probable that the meteorite-impact events once took place around the Triassic Leikoupo Formation-Xujiahe Formation boundary in northeastern Sichuan. The discovery of the micropellets in the study area may inspire some new approaches to fathom the terrestrial-marine transition and biotic succession during the Triassic in the Sichuan Basin.