Abundant and diverse trace fossils occur in the littoral-neritic sediments recording an Early Devonian transgression in South China. The well-exposed Ganxi section is located in the Longmen Mountain 100 km northwest of Chendu, Sichuan. The Lower Devonian strata are dominated by sandstones, siltstones, muddy shales, limestones, bioclastic limestones, and muddy limestones. About thirteen ichnogenera were systematically described, including Arenicolites, ?Balanoglossites, Chondrites, Cylindrichnus, Diplocraterion, Planolites, Palaeophycus, Phycodes, Rhizocorallium, Rusophycus, Skolithos, Thalassinoides, and Zoophycos. Six trace fossil associations under different sedimentary environments have been recognized as follows: the Skolithos and Diplocraterion-Skolithos associations mainly consist of domichnia derived from a high-energy zone of the foreshore to upper shoreface; the Rusophycus-Phycodes association is characterized by fodinichnia and cubichnia generated in a lower-energy zone of the upper shoreface; the Chondrites-Palaeophycus association mainly consists of domichnia, chemichnia, and fodinichnia as indicators of the lower-energy and suboxic conditions of a coastal lagoon; the Rhizocorallium association includes feeding and dwelling burrows formed in a lower-energy zone of the upper offshore enriched with food; and the Zoophycos association is characterized by fodinichnia and pascichnia as indicators of the lower offshore frequently influenced by storm waves. The entire sequence shows several transgressive-regressive cycles from the Lochkovian to Pragian and much storm influence in the Emsian.
ZHANG, LI-JUN and ZHAO, ZHAO
"Lower Devonian trace fossils and their paleoenvironmental significance from the western Yangtze Plate, South China,"
Turkish Journal of Earth Sciences: Vol. 24:
4, Article 2.
Available at: https://journals.tubitak.gov.tr/earth/vol24/iss4/2