Proposal and prospects for the global Lower-Middle Cambrian boundary

摘要: Abstract In recent years paleontologists have been working on the global stratotype section and standard point (GSSP) for Lower-Middle Cambrian boundary in North America, China, Morocco, Spain Russia. Continually, they suggest potential first appearance datum (FAD) of Middle Cambrian, such as Oryctocephalus indicus, Ovatoryctocara granulata, Acadoparadoxides mureroensis, Hupeolenus Arthricocephalus chauveaui being relevant to boundary. There are only a few trilobites distributed widely enough Early connection, so virtually no trilobite(s) can act FAD Cambrian. The easily identified indicus is three realms Its position linked extinction old species coevolution new ones. It appears be comparatively good continuous unbroken Wuliu (Ba...