Hanging Rocks Formation
| Hanging Rocks Formation | |
|---|---|
| Stratigraphic range: Ediacaran | |
| Type | Formation |
| Unit of | Maplewell Group |
| Sub-units | Hallgate and Sliding Stone Slump Breccia Members |
| Underlies |
|
| Overlies | Bradgate Formation[2] |
| Thickness | 50 m (164 ft)[1] |
| Lithology | |
| Primary | Tuff |
| Other | Graywacke |
| Location | |
| Region | Leicestershire |
| Country | United Kingdom |
| Type section | |
| Named for | Bradgate Park |
The Hanging Rocks Formation is a geologic formation in Leicestershire, and is the youngest and smallest of the Maplewell Group and the larger Charnian Supergroup which it is a part of. Due to this, and the fact that the rocks are not well exposed at both the top and base,[1] there have been no Ediacaran fossils found to date, unlike the two underlying Bradgate and Beacon Hill Formations.
Dating
[edit]Despite the poor exposure of the formation, scientists were able to collect zircon crystals from the lower parts of the formation, allowing them to perform zircon U-Pb dating, which recovered a date of 556±6.4 Ma, close to the Bradgate Formations top age of 557 Ma. It is noted that the top of the formation is capped at a zircon age of roughly 550 Ma,[1] which is just before the first formations of the Nama assemblage were deposited.
References
[edit]- Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to the Paleobiology Database". Retrieved 17 December 2021.
- ^ a b c d Noble, Stephen R.; Condon, Daniel J.; Carney, John N.; Wilby, Philip R.; Pharaoh, Timothy C.; Ford, Trevor D. (January 2015). "U-Pb geochronology and global context of the Charnian Supergroup, UK: Constraints on the age of key Ediacaran fossil assemblages". Geological Society of America Bulletin. 127 (1–2): 250–265. doi:10.1130/B31013.1.
- ^ a b Moseley, John; Ford, Trevor. "The Sedimentology of the Charnian Supergroup" (PDF). Mercian Geologist.
- ^ McILROY, D.; Brasier, M. D.; Moseley, J. B. (March 1998). "The Proterozoic–Cambrian transition within the 'Charnian Supergroup' of central England and the antiquity of the Ediacara fauna". Journal of the Geological Society. 155 (2): 401–411. doi:10.1144/gsjgs.155.2.0401.