Palynological assemblages from Hongguleleng Formation of Western Junggar, Northwest China and their correlation with conodont zonation

Abstract

The Upper Devonian Hongguleleng Formation is a significant stratigraphic unit near the Frasnian/Famennian and Devonian/Carboniferous boundaries of the Kazakhstan Paleoplate. However, its age is still under debate. A new palynostratigraphic analysis was conducted at the Gennaren section to provide a more accurate biostratigraphic assignment. In this study, we identified 43 species belonging to 26 spore genera, including those in open nomenclature. Despite the poor preservation of the palynofloras, the spore taxa were categorized into two assemblages. Assemblage I is established at the lower part of the lower member of the Hongguleleng Formation, containing Cornispora varicornata, cf. Auroraspora pseudocrista, and Cyrtospora cristifera. Assemblage II is from the upper part of the lower member of the Hongguleleng Formation, including Grandispora cornuta, Grandispora famennensis var. famennensis, Grandispora cf. famennensis var. minutus, Grandispora microseta, and Rugospora radiata. These assemblages are compared with the Western European DV Oppel Zone (lower-middle Famennian), and the GF to VCo Oppel zones. The assemblages are equivalent to the conodont crepida–rhomboidea and marginifera to Lower trachytera zones (middle-upper Famennian).