Biostratigraphic Study Of Late Carboniferous-early Permian Spores And Pollen From The Tengchong And Baoshan Blocks, Western Yunnan, China

This study collected 123 rock samples from the the Kongshuhe Formation of the Tengchong Block and Dingjiazhai Formation of the Baoshan Block, and separated spores and pollen from them. The identified spores and pollen were classified into 51 genera and 80 species. Based on a summary of research into the Gondwana Realm and an analysis of spore and pollen assemblages from the Kongshuhe and Dingjiazhai formations, both formations appear to be characterized by Gondwanan spores and pollen, such as Microbaculispora ten tula, Horriditriletes tereteangulatus, Vestigisporites gondwanensis, Marsupipollenites striatus and Gnetaceaepollenites sinuosus.Gondwana micro-flora have features that distinguish them clearly from the micro-geoflorae of other plates. The majority of this region has been studied. Most areas of the Gondwana Realm have been studied by Palynomorph, including Australia, Antarctica, India, South America, South Africa, Yemen and Oman. The spores and pollen from those areas have certain similarities, but they are not the same. The most widespread characteristic is the successive emergence and development of monosaccate pollen, cheilocardoid spores (e.g. Microbaculispora), Cycadopites, striate and non-striate bisaccate pollen. The Baoshan, Tengchong and Lhasa blocks are recognized as Gondwana-derived blocks.This paper considers the emergence sequences for gymnospermous pollen and fern spores, the variety of species and their biodiversity, and correlates these with related factors. It is concluded that the upper strata of the Upper Kongshuhe Formation are Late Asselian to Early Sakmarian in age, and that the lower strata are Late Gzhelian to Early Asselianin age. Whereas, the upper strata of the Dingjiazhai Formation can be dated to Late Sakmarian to Early Artinskian, and the lower strata to Late Asselian to Early Sakmarian.The lower strata of the Upper Kongshuhe Formation in the Datang Section of the Tengchong Block is characterized by low biodiversity and a small number of spores and pollen, with bisaccate pollen almost absent. The cheilocardoid spore Microbaculispora tentula is dominant. The most frequent pollen are monosaccate Plicatipollenites spp. and Vestigisporites gondwanensis. There is no Cycadopites cymbatus in this formation. This formation can therefore be dated as Late Asselian to Early Sakmarian.Microbaculispora tentula increases in the upper strata of the Upper Kongshuhe Formation (Datang Section). Calamospora microrugosa accounts for a significantly high proportion of the total spores and pollen. There are some bisaccate pollen, such as Alisporites spp and Protohaploxypinus rugatus. Converrucosisporites confluens shows a significant percentage content. It is concluded that the upper strata are thus Late Asselian to Early Sakmarian in age.The spore and pollen assemblage of the Shangcaiyuan Section is very similar to that of the Upper Kongshuhe Formation of the Datang Section. Its age is therefore most likely to be Late Asselian to Early Sakmarian.Lycopsids are the main spores found in the lower part of the Dingjiazhai Formation at the Woniusi Section of the Baoshan Block. Punctatisporites gretensis is common and Cycadopites cymbatus appears. The age is thus inferred as Late Asselian to Early Sakmarian.The percentage of pollen is higher than spores in the upper part of the Dingjiazhai Formation of the Wafang Section. Striate and non-striate bisaccate pollen dominate this section, e.g. Weylandites magmus, Vittatina, Tiwariasporites simplex, Striatopodocarpites fusus, Striatopodocarpites cancellatus, Striatoabieites multistriatus, Scheuringipollenites ovatus, Scheuringipollenites maximusetc. The age of these strata is most probably Late Sakmarian to Early Artinskian.Vertical variation of spores and pollen from the Tengchong and Baoshan blocks and the corresponding vegetation indicates the two blocks experienced climate amelioration with temperature rise from glacial to interglacial stage. The Baoshan block maintained a different palynomorph composition from Tengchong block suggests different climate and vegetation in the two blocks in late Asselian to early Sakmarian.