The Upper Famennian and Tournaisian Rugosa and stratigraphy of Viet Nam
Fauna Rugosa i stratygrafia osadów górnofameńskich i turnejskich w Wietnamie
NGUYEN DUC KHOA
Institute of Geology and Mineral Resources, Hanoi, Vietnam
Abstract: Upper Famennian and Tournaisian deposits are present in the eastern, northern and western parts of North Viet Nam and in the northern part of Central Viet Nam. Argillaceous and siliceous limestone are the predominant lithologies. Transitional deposits of Devonian/Carboniferous age are represented by the Halong, Toctat, Bancai, Phongnha and Sebanghieng Formations. The Rugosa from Halong, Phongnha and Sebanghieng Formations have not previously been described. Of necessity, some of them have been identified only as Rugosa gen. indet. This is an endemic fauna, similar in some ways to the deep-water fauna from the Shaodong Formation of southern China. The Rugosa from the Chernyshinella Zone (Upper Tournaisian) are also been described here. Two new genera: Fedorowskia and Cobaiphyllum, both from the Quasiendothyra Zone have been recognised. Cystophrentis, which is very common in Viet Nam, is present in the Halong and Sebanghieng Formations. Dematophyllum is typical of the Chernyshinella-Dainella Zones. Two Rugosa Assemblage Zones: Cystophrentis-Cobaiphyllum Ass. Zone (Middle Famennian to Early Tournaisian) and the Pseudouralina-Fedorowskia Ass. Zone (Middle and Late Tournaisian) have also been determined.
Key words: Rugosa, systematic, stratigraphy, Famennian, Tournaisian, Vietnam
