Aeronian
| Aeronian | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chronology | |||||||||||||
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| 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 Demirastrites triangulatus | ||||||||||||
| Lower boundary GSSP | Hlásná Třebaň section, Czech Republic 49°55′23″N 14°12′43″E / 49.9230°N 14.2119°E[4] | ||||||||||||
| Lower GSSP ratified | 2024[5][6] | ||||||||||||
| Upper boundary definition | FAD of the graptolite Spirograptus guerichi | ||||||||||||
| Upper boundary GSSP | El Pintado section,
Seville, Spain 37°59′07″N 5°55′43″W / 37.9853°N 5.9285°W[4] | ||||||||||||
| Upper GSSP ratified | 2024[5][7] | ||||||||||||
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 440.5 ± 1.0 Ma and ended 438.6 ± 1.0 Ma (million years ago). The Aeronian Age succeeds the Rhuddanian Age and precedes the Telychian Age, all in the same epoch.[8]
During the Aeronian the Sedgwickii Event occurred in which graptolite diversity was greatly reduced.[9] 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).[9]
It was also from this time that the first gnathostomates appeared, represented by the genera Qianodus and Fanjingshania.
GSSP
The GSSP is located in the Trefawr Track section, 500m north of Cwm-coed-Aeron Farm, Wales, UK.[10] 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.[11]
References
- ^ Jeppsson, Lennart; Calner, Mikael (June 2002). "The Silurian Mulde Event and a scenario for secundo—secundo events". Earth and Environmental Science Transactions of the Royal Society of Edinburgh. 93 (2): 135–154. doi:10.1017/S0263593300000377. eISSN 1755-6929. ISSN 1755-6910. LCCN 2007237265. OCLC 184982680. S2CID 129308139.
- ^ Munnecke, Axel; Samtleben, Christian; Bickert, Torsten (June 5, 2003). "The Ireviken Event in the lower Silurian of Gotland, Sweden-relation to similar Palaeozoic and Proterozoic events". Palaeogeography, Palaeoclimatology, Palaeoecology. 195 (1–2): 99–124. Bibcode:2003PPP...195...99M. doi:10.1016/S0031-0182(03)00304-3. eISSN 1872-616X. ISSN 0031-0182. LCCN 65009956. OCLC 1761774. S2CID 129353726. Retrieved December 12, 2025.
- ^ "International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy. December 2024. Retrieved October 23, 2025.
- ^ a b "Global Boundary Stratotype Section and Point". International Commission of Stratigraphy. Retrieved 3 August 2024.
- ^ a b "Silurian Telychian and Aeronian stage GSSPs have been relocated". stratigraphy.org. International Commission on Stratigraphy. Retrieved 1 March 2024.
- ^ Štorch, Petr. "Formal proposal for a new Global Boundary Stratotype Section and Point (GSSP) for the Aeronian Stage at Hlásná Třebaň, Czech Republic" (PDF). International Commission on Stratigraphy. Retrieved 16 April 2024.
- ^ Gutierrez-Marco, Juan Carlos (August 2022). "SILURIAN TREASURES IN SPANISH UNESCO GLOBAL GEOPARKS. Silurian Times, 29 (for 2021), 16-21. -Aparecido en 2022-". doi:10.13140/RG.2.2.13314.15044. Retrieved 1 March 2024.
{{cite journal}}: Cite journal requires|journal=(help) - ^ "GSSP Table - All Periods". International Commission on Stratigraphy. Retrieved 2018-09-15.
- ^ a b 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.
- ^ Gradstein, Felix M.; Ogg, James G.; Smith, Alan G. (2004). A Geologic Time Scale 2004. ISBN 9780521786737.
- ^ "GSSP for Aeronian Stage". International Commission on Stratigraphy. Retrieved September 15, 2018.