Distal ash fall from the mid-Holocene eruption of Mount Hudson (H2) discovered in the Falkland Islands: New possibilities for Southern Hemisphere archive synchronisation

Cryptotephra deposits (microscopic volcanic ash) are important geochronological tools that can be used to synchronize records of past environmental change. Here we report a distal cryptotephra from a Holocene peat sequence (Canopus Hill) in the Falkland Islands, in the South Atlantic. Using geochemi...

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Bibliographic Details
Published in:Quaternary Science Reviews
Main Authors: Panaretos, P, Albert, PG, Thomas, ZA, Turney, CSM, Stern, CR, Jones, G, Williams, AN, Smith, VC, Hogg, AG, Manning, CJ
Format: Article in Journal/Newspaper
Language:English
Published: Elsevier 2021
Subjects:
Antarctic
Antarctic Peninsula
Canopus
Hudson
Patagonia
Antarc*
Online Access:https://doi.org/10.1016/j.quascirev.2021.107074
https://ora.ox.ac.uk/objects/uuid:4f76422d-0928-4b97-8575-30e2f5c5f591
Description
Summary:Cryptotephra deposits (microscopic volcanic ash) are important geochronological tools that can be used to synchronize records of past environmental change. Here we report a distal cryptotephra from a Holocene peat sequence (Canopus Hill) in the Falkland Islands, in the South Atlantic. Using geochemical analysis (major- and trace-element) of individual volcanic glass shards, we provide a robust correlation between this cryptotephra and the large mid-Holocene explosive eruption of Mt. Hudson in Patagonia, Chile (H2; ∼3.9 ka cal BP). The occurrence of H2 as a cryptotephra in the Falkland Islands significantly increases the known distribution of this marker horizon to more than 1200 km from the volcano, a threefold increase of its previous known extent. A high-resolution radiocarbon chronology, based on terrestrial plant macrofossils, dates the H2 tephra to 4265 ± 65 cal yr BP, suggesting that the eruption may have occurred slightly earlier than previously reported. The refined age and new geochemical reference dataset will facilitate the identification of the H2 tephra in other distal locations. The high concentration of glass shards in our peat sequence indicates that the H2 tephra may extend well beyond the Falkland Islands and we recommend future studies search for its presence across the sub-Antarctic islands and Antarctic Peninsula as a potentially useful chronological marker.

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