Devonian spores from an intra-oceanic volcanic arc, West Junggar (Xinjiang, China) and the palaeogeographical significance of the associated fossil plant beds

Devonian spores were systematically studied from four sections (251 Hill, G217 Highway, Hujiersite and Gannaren) in West Junggar, North Xinjiang, China. All four sections belong to, or are equivalent to, the Upper Member of the Hujiersite Formation, from which abundant plant macrofossils have also been reported. These spores enable us, for the first time, to date these fossil plant beds as from late Emsian to Frasnian in age. The plant localities are all from a Devonian volcanic terrain and have a lycopsid-dominant flora. These lycopsid plants have near global Devonian distributions and are hence the most mobile elements among the contemporary floras. In the upper part of the sequence (Givetian/Frasnian) very rare progymnosperms (both spores and some megafossils) were found. The West Junggar shows a different palynological assemblage from that of the East Junggar and is palaeogeographically significant