Two Permian-Triassic boundary sections (Lung Cam and Nhi Tao) in shallow marine carbonates from northern Vietnam, near the border between Vietnam and China, were studied for major and trace elemental variations as well as carbon and oxygen isotopic compositions. At the Nhi Tao section, we observe a continuous transition from Late Permian limestones, siliceous limestones and microbial limestones (Dong Dang Formation) to Early Triassic limestones and dolomitic limestones (Hong Ngai Formation). At the Lung Cam section, a thin layer of shale (the uppermost part of the Dong Dang Formation-Late Permian) separates carbonate layers of the Dong Dang Formation (Late Permian) from those of the Hong Ngai Formation (Early Triassic).
