SUMMARY

Cư Brei Formation of Early Devonian age in Kon Tum, South Việt Nam

Thân Đức Duyện, Bùi Phú Mỹ, Tống Duy Thanh

Devonian sediments have been discovered in Kon Tum, South Việt Nam and were preliminary described by Thân Đức Duyện [4] as the Cư Brei Formation (D₁ cb). The formation occurs in a synclinorium of NW–SE direction of 6 km in length and 3 km in width. New abundant fossil collections have been allowing to date the Cư Brei Formation as Early Devonian, and the study in detail of the sections shows that the formation is composed of two parts.

Lower part, 175 m thick, with conglomerate, gritstone conformably lying upon the granodiorite of the second phase of the Diên Bình Complex, grading upward into sandstone, siltstone and argillaceous shale.

 Upper part, 250 m thick, with a talcschist bed grading upward into carbonate sediments – dolomite interbedded with marly shale, sericite schist, argillaceous shale and siltstone.

Abundant stromatoporoids, tabulates, fragmented crinoids and algae were found in the light grey, dark grey limestone of the uppermost member of the section, that enable to refer the Cư Brei Formation to the Lower Devonian.

Ngày nhận bài: 2-8-2004
Người biên tập: Trần Văn Trị