从奥陶系顶底界线研究新进展谈岩石地层单位的跨时性

NOTES ON THE DIACHRONISM OF LITHOSTRATIGRAPHIC UNTIS IN THE LIGHT OF THE ADVANCES IN THE STUDIES OF THE CAMBRIAN-ORDOVICIAN AND THE ORDOVICIAN-SILURIAN BOUNDARIES

This paper discusses certain advances in the study of the Cambrian-Ordovician boundary and the Ordovician-Silurian boundary from Wuning County (Jiangxi Province), Ningguo County and Shitai County (South Anhui Province), Xixiang County (South Shaanxi Province). It is better to place the Cambrian-Ordovician boundary at the base of the Tremadocian Stage. Some lithostratigraphic units in different areas cross the Cambrian-Ordovician boundary. The author plases the Ordovician-Silurian boundary at the base of the Glyptograptus persculptus zone temporarily. Some lithostratigraphic units cross the Ordovician-Silurian boundary as well. It is needless to change the definition of the lithostratigraphic units. They (lithostratigraphic units) can cross the boundary between two neighbouring systems or two series or two erathems.