A new species of Platanus from the Cenomanian (Upper Cretaceous) in eastern Heilongjiang, China

The stratigraphic division and sequence of the Upper Cretaceous sediments in eastern Heilongjiang Province, China, have been ambiguous and controversial, mainly due to a lack of biostratigraphically useful fossils and related radiometric dating. A new species of angiospermous fossil plant, Platanus heilongjiangensis sp. nov., from Qitaihe in eastern Heilongjiang has been found in sediments conformably above which zircons from a rhyolitic tuff has been dated by U-Pb radiometric methods as 96.2±1.7 Ma, indicating that the Upper Houshigou Formation is of Cenomanian age. This discovery not only provides new data to improve our stratigraphic understanding of the Houshigou Formation, but also shows that Platanus flourished in the early Late Cretaceous floras of the region. This new study also indicates active volcanism taking place in the eastern Heilongjiang region during the Cenomanian of the Late Cretaceous.