Discovery of the Cretaceous sporopollen assemblage in the matrix strata of the Wanbaogou Group-complex in the East Kunlun orogenic belt, China.

Abstract: The Wanbaogou Group-complex is a mélange in the East Kunlun orogenic belt, which is composed of two parts: exotic blocks of various ages and matrix strata. On the basis of stromatolite fossils in the exotic blocks, the age of this group-complex was once assigned to the Precambrian Jixianian-Qingbaikouan. According to the field survey and research, 50 genera and 12 species of Paleogene late Eocene to mid-early Oligocene sporopollen found in the matrix strata of the group-complex at the Kunlunqiaonan section were for the first time reported in 2005. In the same year, 22 genera and 15 species of Paleogene Oligocene sporopollen were found in the Wanbaogou section—the naming site of this group-complex—were also reported. What are reported in this paper are 43 genera (sp. Incert.) and 19 species of late Early Cretaceous-early Late Cretaceous sporopollen found by the authors in the matrix strata of this group-complex and the Cretaceous Cicatricosisporites-Schizaeoisporites-Triporopollenites assemblage is named. The discovery of the sporopollen is of great geological significance for further defining the age of this group-complex and analyzing its paleoenvironment and the formation and evolution of the East Kunlun orogenic belt.