藏北日土地区南羌塘乌拉尔统曲地组孢粉化石的发现及意义OA

Dispersed palynomorphs from the Cisuralian Qudi Formation within the South Qiangtang stratigraphic region of Rutog area,northern Xizang,are reported here for the first time.Gymnosperm pollen(80.0%-88.6%)is significantly dominant over pteridophyte spores(11.4%-20.0%),with the bisaccate striate pollen Protohaploxypinus and monosaccate pollen Potonieisporites being the most prominent.This assemblage is designated as the Protohaploxypinus—Potonieisporites Assemblage.It exhibits distinct Sub-Angara floristic characteristics,while also containing the Gondwanan diagnostic taxon Plicatipollenites.This pattern aligns with observations from the Baoshan and Lhasa blocks,indicating shared plant taxa between the Gondwanan and Sub-Angaran realms during the Early Permian.The observed floral mixing likely resulted from Gondwana-affiliated rifted terranes(e.g.,South Qiangtang,Lhasa,and Baoshan blocks),serving as stepping stones for the"island hopping"dispersal of microfloras,such as bisaccate ribbed pollen,following the Early Permian deglaciation.