Discovery of Paleogene palynological assemblages from the Wanbaogou Group-complex in western part of the Eastern Kunlun orogenic belt and its geological significance

The Wanbaogou Group-complex is a suit of mélange aggregation of the Eastern Kunlun orogenic belt, which is divided into two parts, i.e. the exotic blocks and the matrix strata. Based on stromatolite fossils yielded in the exotic blocks, the age of this group-complex was once defined to the Precambrian. Recently, two Paleogene palynological assemblages have been found in samples from the matrix strata of the Upper Part in this group-complex by the authors: in ascending order, the Al- nipollenites-Quercoidites assemblage of Late Eocene and the Caryapollenites-Pinuspollenites as- semblage of Early Oligocene. Those results show that the matrix strata of this mélange were mainly formed in Paleogene, and the event causing mixture should be a Himalayan Movement Phase. This paper is designed to provide some detailed evidence for determining the age of the matrix strata in this group-complex based upon study at the Kunlunqiao Section, which would be of important geo- logical significance for further understanding this group-complex as a suit of mélange aggregation and establishing or improving the stratigraphic framework of the studied region. The new finding will cer- tainly benefit from now on the investigation on geotectonic and sedimentary evolution of Eastern Kunlun.

Wanbaogou Group-complex is a suit of melange aggregation of the EasternKunlun orogenic belt, which is divided into two parts, i.e. the exotic blocks and the matrix strata.Based on stromatolite fossils yielded in the exotic blocks, the age of this group-complex was oncedefined to the Precambrian. Recently, two Paleogene palynological assemblages have been found insamples from the matrix strata of the Upper Part in this group-complex by the authors: in ascendingorder, the Al-nipollenites-Quercoidites assemblage of Late Eocene and theCaryapollenites-Pinuspollenites assemblage of Early Oligocene. Those results show that the matrixstrata of this melange were mainly formed in Paleogene, and the event causing mixture should be aHimalayan Movement Phase. This paper is designed to provide some detailed evidence for determiningthe age of the matrix strata in this group-complex based upon study at the Kunlunqiao Section, whichwould be of important geological significance for further understanding this group-complex as asuit of melange aggregation and establishing or improving the stratigraphic framework of the studiedregion. The new finding will certainly benefit from now on the investigation on geotectonic andsedimentary evolution of Eastern Kunlun.