Dapingian
The Dapingian is the third stage of the Ordovician and the first stage of the Middle Ordovician. It is preceded by the Floian and succeeded by the Darriwilian. The top of the Floian is defined as the first appearance of the conodont species Baltoniodus triangularis which happened about 470 million years ago. The Dapingian lasted for about 2.7 million years until about 467.3 million years ago.
The Dapingian is named after a village that lies nearby the Dapingian GSSP (Huanghuachang section, in Huanghuachang) where there is also an outcrop of similar rocks, the "Chenjiahe section" (formerly "Daping section") in Chenjiahe. The name was proposed in 2005.
The GSSP of the Dapingian is the Huanghuachang section (30°51′38″N 111°22′26″E / 30.8605°N 111.3740°E), in Huanghuachang, Yichang, China. It is an outcrop of the Dawan Formation. The lower boundary is defined as the first appearance of the conodont species Baltoniodus triangularis in the type section. Radiometric dating has constrained the Floian-Dapingian boundary at 470 million years ago. The exact boundary lies 10.57 m above the base of Dawan Formation.
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