Drumian
39.5117°N 112.9915°W The Drumian is a stage of the Miaolingian Series of the Cambrian. It succeeds the Wuliuan 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.
| Drumian | ||||||||||||||||||||||||||||||||||||||
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| Name formality | Formal | |||||||||||||||||||||||||||||||||||||
| Name ratified | 2006[2] | |||||||||||||||||||||||||||||||||||||
| Former name(s) | Cambrian Stage 6 | |||||||||||||||||||||||||||||||||||||
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| Celestial body | Earth | |||||||||||||||||||||||||||||||||||||
| Regional usage | Global (ICS) | |||||||||||||||||||||||||||||||||||||
| Time scale(s) used | ICS Time Scale | |||||||||||||||||||||||||||||||||||||
| Definition | ||||||||||||||||||||||||||||||||||||||
| Chronological unit | Age | |||||||||||||||||||||||||||||||||||||
| Stratigraphic unit | Stage | |||||||||||||||||||||||||||||||||||||
| First proposed by | Babcock et al., 2006[3] | |||||||||||||||||||||||||||||||||||||
| Time span formality | Formal | |||||||||||||||||||||||||||||||||||||
| Lower boundary definition | FAD of the Trilobite Ptychagnostus atavus | |||||||||||||||||||||||||||||||||||||
| Lower boundary GSSP | Drumian section, Wheeler Shale, Utah, U.S.A. 39.5117°N 112.9915°W | |||||||||||||||||||||||||||||||||||||
| Lower GSSP ratified | 2006[2] | |||||||||||||||||||||||||||||||||||||
| Upper boundary definition | FAD of the Trilobite Lejopyge laevigata | |||||||||||||||||||||||||||||||||||||
| Upper boundary GSSP | Luoyixi section, Luoyixi, Guzhang, Hunan, China 28.7200°N 109.9647°E | |||||||||||||||||||||||||||||||||||||
| Upper GSSP ratified | 2008[4] | |||||||||||||||||||||||||||||||||||||
The GSSP is defined in the Drumian section (39.5117°N 112.9915°W) in the Drum Mountains, Millard County, Utah, United States.[5] 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.[6]
References
- "Chart/Time Scale". stratigraphy.org. International Commission on Stratigraphy.
- Babcock, Loren; Robison, Richard; Rees, Margaret; Peng, Shanchi; Saltzman, Matthew (June 2007). "The Global boundary Stratotype Section and Point (GSSP) of the Drumian Stage (Cambrian) in the Drum Mountains, Utah, USA". Episodes. 30 (2): 85–89. doi:10.18814/epiiugs/2007/v30i2/003. Retrieved 13 December 2020.
- Babcock, Loren; Robinson, Richard; Rees, Margaret; Shanchi, Peng; Saltzman, Matthew. "PROPOSED GLOBAL STANDARD STRATOTYPE-SECTION AND POINT FOR THE DRUMIAN STAGE (CAMBRIAN)". International Subcommission on Cretaceous Stratigraphy. International Subcommission on Cambrian Stratigraphy. Retrieved 13 December 2020.
- Peng, Shanchi; Babcock, Loren; Zuo, Jingxun; Lin, Huanling; Zhu, Xuejian; Yang, Xianfeng; Robison, Richard; Qi, Yuping; Bagnoli, Gabriella; Chen, Yong’an (March 2009). "The Global Boundary Stratotype Section and Point (GSSP) of the Guzhangian Stage (Cambrian) in the Wuling Mountains, Northwestern Hunan, China". Episodes. 32 (1): 41–55. doi:10.18814/epiiugs/2009/v32i1/006. Retrieved 13 December 2020.
- 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. doi:10.18814/epiiugs/2007/v30i2/003. Retrieved 14 September 2012.
- "GSSP for Drumian Stage". Retrieved 12 November 2012.
