Induan | |||||||||||||||||||||||
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Chronology | |||||||||||||||||||||||
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Etymology | |||||||||||||||||||||||
Name formality | Formal | ||||||||||||||||||||||
Usage information | |||||||||||||||||||||||
Celestial body | Earth | ||||||||||||||||||||||
Regional usage | Global (ICS) | ||||||||||||||||||||||
Time scale(s) used | ICS Time Scale | ||||||||||||||||||||||
Definition | |||||||||||||||||||||||
Chronological unit | Age | ||||||||||||||||||||||
Stratigraphic unit | Stage | ||||||||||||||||||||||
Time span formality | Formal | ||||||||||||||||||||||
Lower boundary definition | FAD of the Conodont Hindeodus parvus | ||||||||||||||||||||||
Lower boundary GSSP | Meishan, Zhejiang, China 31°04′47″N 119°42′21″E / 31.0798°N 119.7058°E | ||||||||||||||||||||||
Lower GSSP ratified | 2001[6] | ||||||||||||||||||||||
Upper boundary definition | Not formally defined | ||||||||||||||||||||||
Upper boundary definition candidates | FAD of the Conodont Neospathodus waageni | ||||||||||||||||||||||
Upper boundary GSSP candidate section(s) | Mud (Muth) village, Spiti valley, India[7] |
The Induan is the first age of the Early Triassic epoch in the geologic timescale, or the lowest stage of the Lower Triassic series in chronostratigraphy. It spans the time between 251.9 Ma and 251.2 Ma (million years ago).[8] The Induan is sometimes divided into the Griesbachian and the Dienerian subages or substages.[9] The Induan is preceded by the Changhsingian (latest Permian) and is followed by the Olenekian.
The Induan is roughly coeval with the regional Feixianguanian Stage of China.
Tozer1965
was invoked but never defined (see the help page).