A PROPOSAL TO FURTHER INVESTIGATE THE CRETACEOUS-PALEOGENE BOUNDARY SECTION AT DANGYANG HUBEI PROVINCE

The mass extinction of terrestrial dinosaurs is the most important evolutionary event across the Cretaceous-Paleogene boundary.Continental Cretaceous-Paleogene strata are important information carriers of this extinction event.The continental strata of the Cretaceous and Paleogene are well developed and widely distributed in the world.It is unlikely that a single Cretaceous-Paleogene GSSP will satisfy all criteria necessary for an unambiguous and practicable standard of this boundary,and establishing a continental Cretaceous-Paleogene boundary stratotype is essential and its significance and importance are no less than the GSSP.Since the Cretaceous and Paleogene of China are mostly continental deposits and there are many stratigraphic problems concerning the Cretaceous-Paleogene boundary,and since ongoing work to establish stages of continental strata and the Regional Chronostratigraphic Chart of China is being conducted in China,it is imperative to resolve the problems of the Cretaceous-Paleogene boundary in China and to establish the lower boundary of the Paleogene and the Cenozoic of China.Otherwise,the Regional Chronostratigraphic Chart of China would be incomplete.Thus,the establishment of a continental stratotype will have practical values.The continuous biostratigraphic record of the Cretaceous-Paleogene transition and particularly the early Paleocene is scarce in the continental domain,and searching a section suitable for establishing the continental Cretaceous-Paleogene boundary stratotype is very difficult.From the viewpoint of charophytes,the outcrop section of the Paomagang Formation in Dangyang,Hubei Province(Central China),contains the most continuous,abundant and diverse terrestrial biostratigraphic records of the Cretaceous-Paleogene transition,in particular the early Paleocene,known so far in the world.The biostratigraphic record of ostracods in the transition is also very continuous,rich and diverse.Thus,this section meets critical requirements as a candidate for a boundary stratotype.The Dangyang section is the only outcrop section known so far in China that has potential to become a candidate for a global or regional continental stratotype of the Cretaceous-Paleogene(and Mesozoic-Cenozoic)boundary.It is also the best section for establishing the lowermost stage of the Paleogene or the Cenozoic of China.Therefore,the Dangyang section is undoubtedly worth further investigation in greater detail.