Aeronian
Silurian graphical timeline | ||||||||
−444 — – −442 — – −440 — – −438 — – −436 — – −434 — – −432 — – −430 — – −428 — – −426 — – −424 — – −422 — – −420 — – −418 — |
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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.[4]
GSSP
The GSSP is located in the Trefawr Track section, 500m north of Cwm-coed-Aeron Farm, Wales, UK.[5] 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.[6]
Palaeontology
Agnathans
Agnathans of the Aeronian | ||||
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Taxa | Presence | Location | Description | Images |
Rhuddanian-Telychian | It had an elongated body and a dorsal fin and an anal fin near the back third of its body. |
Cephalopods
Cephalopods of the Aeronian | ||||
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Taxa | Presence | Location | Description | Images |
Dapingian-Homerian | The shallow seas of Laurentia, Baltica and Siberia.[7] | Head was soft muscular tissue at the opening of hard cone-like shell. |
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". www.stratigraphy.org. International Commission on Stratigraphy.
- ^ "GSSP Table - All Periods". International Commission on Stratigraphy. Retrieved 2018-09-15.
- ^ 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.
- ^ Frey, R.C. 1995. "Middle and Upper Ordovician nautiloid cephalopods of the Cincinnati Arch region of Kentucky, Indiana, and Ohio" (PDF). U.S. Geological Survey, p.73