From Handwiki | Aeronian | |
|---|---|
| 440.8 ± 1.2 – 438.5 ± 1.1 Ma | |
| Chronology | |
| 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]
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]
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Categories: [Llandovery epoch] [Silurian geochronology]