CAMBRIAN STRATIGRAPHY AT PAIBI, HUNAN PROVINCE, CHINA: GSSP AND REFERENCE SECTION FOR THE BASE OF THE FURONGIAN SERIES AND THE PAIBIAN STAGE

摘要

Two sections, one exposing the upper Aoxi and Huaqiao formations, and the other exposing the upper Huaqiao Formation through the Lower Ordovician, are present in the vicinity of the village of Paibi, Huayuan County, Hunan Province (Figs. 1-3). The two sections are separated by a large valley that follows a fault plane trending nearly perpendicular to the strike of the sections. The two sections are referred to as the Paibi section, which exposes the lower stratigraphic interval, and the Paibi-2 section, which exposes the upper stratigraphic interval. Some stratigraphic overlap occurs between the upper part of the Paibi section and the lower part of the Paibi-2 section. In these two sites we will primarily examine the lithology of the middle part of the Huaqiao Formation. That part of the formation differs from the middle part of the Huaqiao Formation at Wangcun in having more limestone debris beds, which are interpreted to have been deposited in a slope environment. We will also examine the stratigraphic interval containing the Furongian/Paibian GSSP (Fig. 2). We will not examine other intervals of the Huaqiao Formation, nor the Lower Ordovician (Tremado-cian) part of the section, at this locality.