Aeronian

Aeronian
440.8 ± 1.2 – 438.5 ± 1.1 Ma
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Chronology
Etymology
Name formalityFormal
Usage information
Celestial bodyEarth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unitAge
Stratigraphic unitStage
Time span formalityFormal
Lower boundary definitionFAD of the graptolite Demirastrites triangulatus
Lower boundary GSSPHlásná Třebaň section, Czech Republic
49°55′23″N 14°12′43″E / 49.9230°N 14.2119°E / 49.9230; 14.2119[4]
Lower GSSP ratified2024[5][6]
Upper boundary definitionFAD of the graptolite Spirograptus guerichi
Upper boundary GSSPEl Pintado section, Seville, Spain
37°59′07″N 5°55′43″W / 37.9853°N 5.9285°W / 37.9853; -5.9285[4]
Upper GSSP ratified2024[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 440.8 ± 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.[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]

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

  1. ^ 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.
  2. ^ 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.
  3. ^ "Chart/Time Scale". www.stratigraphy.org. International Commission on Stratigraphy.
  4. ^ a b "Global Boundary Stratotype Section and Point". International Commission of Stratigraphy. Retrieved 3 August 2024.
  5. ^ a b "Silurian Telychian and Aeronian stage GSSPs have been relocated". stratigraphy.org. International Commission on Stratigraphy. Retrieved 1 March 2024.
  6. ^ 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.
  7. ^ 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)
  8. ^ "GSSP Table - All Periods". International Commission on Stratigraphy. Retrieved 2018-09-15.
  9. ^ 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.
  10. ^ Gradstein, Felix M.; Ogg, James G.; Smith, Alan G. (2004). A Geologic Time Scale 2004. ISBN 9780521786737.
  11. ^ "GSSP for Aeronian Stage". International Commission on Stratigraphy. Retrieved September 15, 2018.


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