Zhepure Fm

The naming section is located south of Gongzha Village on the north slope of the western Zhepure Mountains, Dingri County, Tibet, and the reference section is located at the Zongpu River north of the seat of Gangba County, Tibet. Named by the Scientific Expedition of the Chinese Mountaineering Party in 1962.

The Zhepure Formation is a sequence of alternating shale and limestone overlying the limestone of the Zongpu Fm, its top being not seen. It is lithologically divided into two members: Lower member, gray, thick-bedded and nodular limestone and yellowish green shale and marlstone, 144 m thick; Upper member, only exposed in the Gangba area, mainly green mudstone-shale, with thin-bedded limestone and siltstone, 136 m thick.

It yields abundant foraminifera and small quantities of ostracods, bivalves and algae. From below upward two foraminifera assemblages may be distinguished. In the lower part there occurs the Orbitolites-Fasciolites assemblage and the main elements are Orbitolites complanatus and Fasciolites oviculus. This fauna is best developed in the Gangba area and appears in the lower member of this formation. The fossils are concentrated to form layers of “Orbitolites limestone” and “Fasciolites limestone” (in the Dingri area the assemblage is Assilina-Nummulites and the representative forms are Assilina granulosa and Nummulites atacicus). In the upper part there occurs the Globorotalia-Globigerina assemblage and the representative forms are Globorotalia spinulosa and Globigerina ouachitaensis. This assemblage is only found in the lower part of the upper member of this formation in the Gangba area. In its upper part the benthic small foraminifera Miliola rostrata and Schlumbergerina alveoliniformis are also found.

This formation belongs to neritic deposits in an open platform and restricted platform environments.