Drumian
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39°30′42″N 112°59′29″W / 39.5117°N 112.9915°W The Drumian is a stage of 3rd series of the Cambrian. It succeeds still unnamed 5th stage of the Cambrian and precedes the Guzhangian. The base is defined as the first appearance of the trilobite Ptychagnostus atavus around Template:Geologic Ages Inline million years ago. The top is defined as the first appearance of another trilobite Lejopyge laevigata around Template:Geologic Ages Inline million years ago.
The GSSP is defined in the Drumian section (39°30′42″N 112°59′29″W / 39.5117°N 112.9915°W) in the Drum Mountains, Millard County, Utah, USA.[2] The stage was also named after the Drum mountains. The section is an outcrop of the Wheeler Formation, a succession of calcareous shales. The precise base of the Drumian is a laminated limestone 62 m above the base of the Wheeler Formation.[3]
References
- ^ "International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy. September 2023. Retrieved November 10, 2024.
- ^ Babcock, Loren E.; Richard A. Robison; Margaret N. Rees; Shanchi Peng; Matthew R. Saltzman (2007). "The Global boundary Stratotype Section and Point (GSSP) of the Drumian Stage (Cambrian) in the Drum Mountains, Utah, USA" (PDF). Episodes. 30 (2): 85–95. Retrieved 14 September 2012.
- ^ "GSSP for Drumian Stage". Retrieved 12 November 2012.
| Preceded by the Proterozoic Eon |
Phanerozoic Eon | |||||||||||
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| Paleozoic Era | Mesozoic Era | Cenozoic Era | ||||||||||
| Cambrian | Ordovician | Silurian | Devonian | Carboniferous | Permian | Triassic | Jurassic | Cretaceous | Paleogene | Neogene | 4ry | |
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