Environment and Age of the Upper Devonian–Carboniferous Zhulumute and Hongguleleng Formations, Junggar Basin, NW China: Ichnological and Palynological Aspects

Two Upper Devonian and Lower Carboniferous sections, namely the Bulongguoer (Hongguleleng Formation) and Haer (Heishantou Formation, Namu Member) of the Junggar Basin, Central Asian Orogenic Belt, have been studied in ichnological and palynological terms. The deposits, mostly unbioturbated or poorly bioturbated, with poorly diversified trace fossils, suggest unfavourable conditions for the burrowing benthic community during the Late Devonian and Early Carboniferous. The main factor governing the growth of the bioturbating population was rapid sedimentation of fine‐grained volcanic material which buried benthic fauna, as documented by tempestites. Within the Bulongguoer section, the presence of the miospores Teichertospora torquata and Grandispora gracilis enabled identification of the broad Teichertospora torquata‐Grandispora gracilis Miospore Zone from the transitional Frasnian/Famennian interval. Identification of more accurate palynostratigraphical levels (DE and CZ miospore Zones) is tentative only. On the basis of palynofacies, samples from the lower part of the Bulongguoer section indicate deposition in more proximal conditions, whereas samples from the top of the section indicate deposition in a more distal environment. Within the Haer section, due to bad preserved organic, only general stratigraphic indication on Tournaisian was possible.