中国科学院南京地质古生物研究所机构知识库

In this issue, Rowland & Hicks advocate a nomenclature for the four epochs of the Cambrian Period that carries over the terms Early, Middle, and Late Cambrian from previous usage (but with new definitions) and introduces a non-geographically-based term, Ichnocambrian, for the earliest Cambrian epoch. The terms Lower/Early, Middle, and Late/Upper Cambrian are confusing because they connote the second, third, and fourth epochs/series of the period/system, and because each is defined in a way that is different from traditional definitions of those intervals. The use of these terms will ultimately lead to confusion between older concepts of Early Middle, and Late Cambrian and newer, refined concepts of the epochs. The philosophy of the International Subcommission on Cambrian Stratigraphy for establishing a clear subdivision of the Cambrian on a global scale is unambiguous: stratigraphic terms previously in use lack global applicability and should not be adopted as chronostratigraphic/ geochronologic units in the developing global stratigraphic chart of the Cambrian. Moreover, all series and stage names should be GSSP (stratotype section)-based.