Unit 3: Paleozoic Floras in Vietnam and the adjacent areas: implication for connection between Indochina and Sino-Vietnam composite terranes

Nghiêm Nhật Mai

Paleontological & Stratigraphical Association of Vietnam.

No. 6 Pham Ngu Lao Str., Hoan Kiem Dist., Hanoi, Vietnam

Received: 14/6/2019

Accepted: 25/9/2019

Abstract: In Vietnam and adjacent areas, Early Devonian to Early Cretaceous terrestrial plant fossils were found in many places. The first Early Devonian plant Zosterophyllum is found in Indochina and in Sino-Vietnam composite terrane (including the North Bac Bo Vietnam, Yangtze and Cathaysian terranes of South China Block which is separated from the Indochina Block by Song Ma suture zone to the Southwest).  Middle and Late Devonian plants were evolved to a higher level by the presence of Lycophyta representatives. The late Early Carboniferous flora, sharing Cathaysian affinity, was represented by Stigmaria rugulosa, Pecopteris aspera, Rhodeopteridium sp. cf. tenuis, and Lepidodendron sp. and was found in Laos, Thailand, Malaysia and South China. The presence of the aforementioned plants implies a landmass connection between the Indochina and Sino-Vietnam composite terranes since that time. This flora thrives in a hot and humid climate condition that favors coal seam formation. During Late Permian time, Cathaysian plant assemblages (especially that of Gigantopteris nicotinaefolia) were widespread in South and East Asia.

Keywords:  Plant fossils, Terrestrial plant, Gondwana, Cathaysia flora, Hon Gai Flora