Environmental significance of Palaeogene gastropod fossils in the southern margin of the Junggar Basin

Gastropod fossils, mostly of small individuals, are abundant in the Palaeogene strata in the Sikeshu Depression on the southern margin of the Junggar Basin. The main groups are bithyniids and other prosobranchs. We studied the taxonomy and taphonomy of the gastropod assemblages of the Ziniquanzi Formation in the Sikeshu Depression. The gastropods inhabited muddy-bottom and shallow-water environments in a river floodplain and riverside setting. The results of this study are useful for recognising the Cretaceous-Palaeogene boundary, and demonstrate that the lake ecosystem had recovered from the end-Cretaceous mass extinction.