A palynological study on Upper Palaeozoic sediments in the palaeosuture zone area (W. Yunnan, China) and its phytogeographical significance

Abstract

Several important findings of Late Palaeozoic palynomorphs in the different blocks of West Yunnan have been made in the present palynological investigation. The Granulatisporites frustulentus assemblage (Playford, 1976), typically distributed in Gondwana subcontinent, has been found in Sipaishan, Gengma. It could be roughly divided into the Grandispora spiculifera assemblage (Tournaisian) and the Anapiculatisporites largus - Lycospora pusilla (Visean) assemblage respectively, which have been correlated with those in West Europe and Australia. An attempt has been made to correlate these Gengma assemblages to the standard West Europe miospore zones of BP, PC(?) and Pu. Some Early Permian miospores have been recovered in Haibang, Ali and Kongshuhe, Tengchong respectively. The miospores found in Haibang are characterized by some Carboniferous relict genera, such as Lycospora, Densosporites, but dominated by Protohaploxypinus, Striatopodocarpites, which are the typical representatives in Gondwana palynological province. Jayantisporites pseudozonatus and Microhaculispora tentula, typically distributed in the Lower Permian of the Collie Basin, Western Australia, and Karoo Basin in South Africa, have been found in Kongshuhe, Tengchong. Therefore, it is obvious that the Gondwana microflora had once arrived in Tengchong and even in the Changning-Menglian belt in West Yunnan during Early Carboniferous and Early Permian. In Simao block, North Hemisphere palynomorphs were dominated in Late Carboniferous Namurian section and Late Permian Dengkong section without the mixture of Gondwana-type palynomorphs.

The miospore similarities of western Yunnan with both West Europe and Australia in Early Carboniferous and with Australia solely in Early Permian indicate that West Yunnan was perhaps located much further to the west (Early Carboniferous) and south than the previous continent reconstruction. Such a miospore conclusion seems to coincide with the palaeomagnetic data analysis.