SUMMARY

Reviewing the stratotype of Chang Pung Formation at  Hà Giang Province

       Phạm Kim Ngân, Trần Hữu Dần,
 Lương Hồng Hược, Trần Văn Trị

The Chang Pung - Nho Quế River section has been considered as the stratotype of Chang Pung Formation. It is composed of limestone, dolomitic limestone, oolitic limestone intercalated with shale, siltstone and sandstone containing abundant Late Cambrian Trilobites and Brachiopods. The faunal sequence is as follows (in ascending order): 1) Cyclolorenzella tonkinensis - Blackwelderia sp. - Drepanura premesnili, 2) Billingsella tonkiniana, 3) Prochuangia mansuyi,  4) Irvingella sp. - Pagodia sp., 5) Prosaukia angulata - Haniwa sp., 6) Dictyella   mansuyi - Tsinania sp., 7) Calvinella walcotti - Eoorthis sp. In the Chang Pung section, the Calvinella walcotti zone occurs in Tông Qua Chải village and then in Seo Thèn Pả village that shows a repeat of some members of this section. So, the thickness of Chang Pung Formation is only 805 m, that is smaller than in former description.

Ngày nhận bài: 9-6-2004
Người biên tập: Tống Duy Thanh