昆明二村下奥陶统红石崖组顶部Cruziana rugosa遗迹化石群落的沉积环境和生态特征

Cruziana及其相关的遗迹化石是由底栖三叶虫在沉积物表面停歇、爬行所留下的遗迹,一般认为产于潮下带至浅海陆棚环境,具有古水深指示意义。然而,本文通过对昆明民富二村下奥陶统红石崖组顶部含Cruziana rugosa遗迹化石群落层位的沉积环境分析却发现,Cruziana rugosa遗迹化石群落的沉积环境为潮上带—潮间带,说明三叶虫可以在短暂暴露环境中活动。三叶虫的这种适应性活动可能为节肢动物从海洋走向陆地做好了进化准备。

Trace Fossil Community Cruziana rugosa, sedimentary environment and ecological characteristics in the top of the Early Ordovician Hongshiya Formation in Erchun, Kunming

Cruziana and its related trace fossils usually were formed on sediment surface by benthic trilobite resting and creeping in subtidal zone to neritic continental shelf area,which could indicate ancient water depth. In this paper, the sedimentary environment analysis on the trace fossil community Cruziana rugosa in the top of the Early Ordovician Hongshiya Formation in Erchun, Kunming neritic continental, Yunnan Province shows that the sedimentary environment of trace fossil community Cruziana rugosa occurrs from the supratidal zone to the intertidal zone, indicating that trilobites could live in the short-term exposuring environment. This adaptive activity of trilobites may be the evolution preparation for the arthropods advancing from the ocean to the land.