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 504.5 million years ago. The top is defined as the first appearance of another trilobite Lejopyge laevigata around 500.5 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, United States.[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 (203 ft) above the base of the Wheeler Formation.[3]
Palaeontology
Arthropods
| Arthropods of the Drumian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| "Stage 3"-Guzhangian | Burgess Shale, British Columbia, Canada; Yuanshan Formation, Chengjiang biota, China | |||
| "Stage 5"-Guzhangian | Phyllopod Bed, Burgess Shale | |||
Dinocarididans
| Dinocarididans of the Drumian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| "Stage 3"-Drumian | Burgess Shale, Canada; China; Wheeler Shale, Utah & Pennsylvania, USA; and Emu Bay, Kangaroo Island, Australia | |||
| "Stage 5"-Guzhangian | Burgess Shale | |||
| Fortunian-Guzhangian | Phyllopod bed, Walcott Quarry, Burgess Shale, British Columbia, Canada; Koscierzyna borehole, Kashubia, Poland | |||
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.[permanent dead link]
- ^ "GSSP for Drumian Stage". Retrieved 12 November 2012.
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