安徽巢县凤凰山和州组上段Glossifungites遗迹相的成因及其意义

The Genesis and Significance of Glossifungites Ichnofacies at the Upper Member of Hezhou Formation of Lower Carboniferous, Northern Chao County, Anhui

安徽巢县凤凰山剖面和州组上段生物扰动灰岩含丰富的遗迹化石Thalassinoides sp,属于Glossifungites遗迹相,它发育在没有完全石化的间断面上,反映了一种潮间带潮坪的沉积环境。Glossifungites遗迹相的发现,在地层学上证实了巢县以北和州组与黄龙组之间为间断接触,缺失或只存在一部分相当于巢县以南普遍存在的老虎洞组白云岩时代的地层。

The bioturbate limestone at the upper member of Hezhou Formation of Lower Carboniferous in northern Chao County was caused by Thalassinoides sp. which produced at the semiconsolidated, but not fully lithified discontinuity surfaces. It could be attributed to Glossifungites ichnofacies which was formed in the intertidal flat environment. The features of carbonate microfacies and chemical components of the fills in the burrow systems differ from that of the host rock. The former is finely crystaline limestone mainly with crinoidal debris and contains higher clay minerals and dolomite than that of the latter. The latter is biomicrite bearing foraminifer. fusulina, molluscan and crinoidal debris. These differences imply that they were not formed in the same time and environment. The fills were piped in the burrow systems in the next transgression after the halt of deposition. The occurrence of Glossifungites ichnofacies at the uppermost surface of Hezhou Formation could provide a new important stratigraphic information for interpreting the lacking of Laohudong Formation between Huanglong Formation of Upper Carboniferous and Hezhou Formation of Lower Carboniferous here which prevails in southern Chao County.