Identifying the source of unknown volcanic eruptions in Late Antiquity

Informations projet

VEILA

N° de convention de subvention: 800204

DOI

10.3030/800204

Projet clôturé

Date de signature de la CE 10 Avril 2018

Date de début 1 Février 2019

Date de fin 9 Mars 2021

Financé au titre de

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Coût total

€ 183 454,80

Contribution de l’UE

€ 183 454,80

Coordonné par

THE CHANCELLOR MASTERS AND SCHOLARS OF THE UNIVERSITY OF CAMBRIDGE
United Kingdom

Periodic Reporting for period 1 - VEILA (Identifying the source of unknown volcanic eruptions in Late Antiquity)

Période du rapport: 2019-02-01 au 2021-01-31

Résumé du contexte et des objectifs généraux du projet

It has been suggested that extended cooling episodes known as the Late Antique Little Ice Age (LALIA, 6th-7th centuries) and Little Ice Age (LIA, 15th-19th centuries) contributed to major societal reorganisations across Eurasia, such as human migrations, spread and demise of empires and political upheavals. If correct, there is now evidence to implicate volcanism in the triggering of two episodes of centennial-scale cooling (LALIA and LIA) and societal impact in the Northern hemisphere during the Holocene. However, most of the sources of these eruptions remain to date, unknown. This project aimed to locate and characterise tephra in polar ice and equatorial sediment cores and correlate them to possible volcanic sources of Holocene eruptions in order to constrain the role of volcanism in centennial-scale climate forcing.

The methodologically innovative strategies in tephrochronology developed in this framework aimed to correlate polar ice core records to an annually-layered tropical palaeoclimate record for the first time. This will be a crucial proof-of-concept for future studies, further back in time, that may address the timing and mechanisms of global climate teleconnections within such a precisely-dated framework. The results of the proposed research will provide a better understanding of the role of volcanism in centennial-scale climate forcing during the Holocene, giving insights into the impacts of future eruptions on our societies already dealing with the consequences of climate change.

This project aimed to locate and characterise tephra in polar ice and equatorial sediment cores and correlate them to possible volcanic sources of key eruptions in order to constrain the role of volcanism in centennial-scale climate forcing during the Holocene. The outputs will provide insights into the impacts of future eruptions on our societies already dealing with the consequences of climate change.

Travail effectué depuis le début du projet jusqu’à la fin de la période considérée dans le rapport et principaux résultats atteints jusqu’à présent

Pumice rock samples from a major medieval eruption at Tofua volcano were prepared, analysed, and compared with analysis of pumice rocks collected in a giant tsunami deposit found in the Tonga archipelago. The geochemical correlation of the mid-15th century megatsunami that triggered a sudden demographic fall and a series of cultural upheavals with the Tofua caldera-forming eruption were unsuccessful. This co-investigation led to a publication now accepted in Frontiers in Earth Science journal entitled 'Bridging Legends and Science: The Kingdom of Tonga Devastated by a Large Tsunami in the 15th Century'.

Before the March 2020 lockdown, CV established a collaboration with Prof. Joe McConnell from the Desert Research Institute (USA), and localised particles of potentially volcanic origin in B54 Antarctica ice cores for the 4.2 ka BP and 682 CE eruptions. Samples were received in November 2020, just before the second lockdown. They have not been extracted nor analysed yet.
CV also initiated a collaboration with Dr. J.L. Fernandez Turiel from the Institute of Earth Sciences J. Almera - CSIC (Spain) to analyse volcanic glass from the 4.2 ka Cerro Blanco eruptive products. Samples have not been analysed yet.

The project has been catastrophically disrupted during the covid-19 pandemic, with the closure of the Department of Geography of the University of Cambridge from 23 March 2020. The extremely restricted reopening of the laboratories from October 2020 has prevented research strategy development, preparation, and analysis of the samples with a key collaborator of the project (Prof. Christine Lane).
No significant conclusions of the action have been drawn at present, but the research activities have resumed with the complete reopening of the labs in October 2021. CV has secured a five-year lectureship at Cambridge and remains affiliated to the Department of Geography for research activities.

Progrès au-delà de l’état des connaissances et impact potentiel prévu (y compris l’impact socio-économique et les conséquences sociétales plus larges du projet jusqu’à présent)

Given the unprecedented disruption of the project caused by the covid-19 pandemic, the successive UK lockdowns, and the closure of the Cambridge Geography department, very little progress was achieved on the project, and the potential impacts cannot be reported for now.

The unsuccessful correlation of the Tofua eruption with the volcanic debris found in the mid-15th century Tonga megatsunami discards Tofua volcano as a likely source of the 1458 CE unknown eruption recorded in ice cores during the Little Ice Age. One of the largest volcanically induced climate anomalies of the last millennium remains a mystery.