Aeronian
From Handwiki | Aeronian | |
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| 440.8 ± 1.2 – 438.5 ± 1.1 Ma PreЄ
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| Chronology | |
Silurian graphical timeline -444 — – -442 — – -440 — – -438 — – -436 — – -434 — – -432 — – -430 — – -428 — – -426 — – -424 — – -422 — – -420 — – -418 — Subdivision of the Silurian according to the ICS, as of 2021.[3] Vertical axis scale: millions of years ago. | |
| 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 graptolite Monograptus austerus sequens |
| Lower boundary GSSP | Trefawr Track Section, Llandovery, Wales, United Kingdom [ ⚑ ] 52°01′48″N 3°42′00″W / 52.0300°N 3.7000°W |
| GSSP ratified | 1984[4] |
| Upper boundary definition | Just above LAD of the brachiopod Eocoelia intermedia, below FAD of lowest succeeding species Eocoelia curtisi |
| Upper boundary GSSP | Cefn-cerig Road Section, Llandovery, Wales, UK [ ⚑ ] 51°58′12″N 3°47′24″W / 51.9700°N 3.7900°W |
| GSSP ratified | 1984[4] |
In the geologic timescale, the Aeronian is an age of the Llandovery Epoch of the Silurian Period of the Paleozoic Era of the Phanerozoic Eon that began 440.8 ± 1.2 Ma and ended 438.5 ± 1.1 Ma (million years ago). The Aeronian Age succeeds the Rhuddanian Age and precedes the Telychian Age, all in the same epoch.[5]
During the Aeronian the Sedgwickii Event occurred in which graptolite diversity was greatly reduced.[6] This event has been attested in locations such as today's Canada, Libya as well as in La Chilca Formation in Argentina (then part of Gondwana).[6]
GSSP
The GSSP is located in the Trefawr Track section, 500m north of Cwm-coed-Aeron Farm, Wales, United Kingdom .[7] The GSSP lies within the gently-dipping blocky mudstones of the Trefawr Formation, which principally yield abundant and diverse shelly faunas, but also contain enough graptolites to allow recognition of several biozones.[8]
References
- ↑ Jeppsson, L.; Calner, M. (2007). "The Silurian Mulde Event and a scenario for secundo—secundo events". Earth and Environmental Science Transactions of the Royal Society of Edinburgh 93 (02): 135–154. doi:10.1017/S0263593300000377.
- ↑ Munnecke, A.; Samtleben, C.; Bickert, T. (2003). "The Ireviken Event in the lower Silurian of Gotland, Sweden-relation to similar Palaeozoic and Proterozoic events". Palaeogeography, Palaeoclimatology, Palaeoecology 195 (1): 99–124. doi:10.1016/S0031-0182(03)00304-3.
- ↑ "Chart/Time Scale". International Commission on Stratigraphy. http://www.stratigraphy.org/index.php/ics-chart-timescale.
- ↑ 4.0 4.1 Holland, C. (June 1985). "Series and Stages of the Silurian System". Episodes 8 (2): 101–103. doi:10.18814/epiiugs/1985/v8i2/005. http://www.episodes.org/journal/view.html?volume=8&number=2&spage=101&vmd=A#1. Retrieved 15 December 2020.
- ↑ "GSSP Table - All Periods". http://www.stratigraphy.org/GSSP/index.html.
- ↑ 6.0 6.1 Lopez, Fernando Enrique; Kaufmann, Cintia (2023). "New insights on the Silurian graptolite biostratigraphy of the La Chilca Formation, Poblete Norte section, Central Precordillera of San Juan, Argentina: faunal replacement and paleoenvironmental implications". Andean Geology 50 (2). doi:10.5027/andgeov50n2-3617. https://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-71062023000200201&lng=en&nrm=iso&tlng=en.
- ↑ Gradstein, Felix M.; Ogg, James G.; Smith, Alan G. (2004). A Geologic Time Scale 2004. ISBN 9780521786737.
- ↑ "GSSP for Aeronian Stage". http://www.stratigraphy.org/GSSP/Aeronian.html.
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Categories: [Llandovery epoch] [Silurian geochronology]
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