Developing a South Pacific tephra framework: Initial results from a Samoan Holocene sequence
Developing a South Pacific tephra framework: Initial results from a Samoan Holocene sequence
Tephra preserved in sediments form useful isochronous marker layers, linking disparate geological, palaeoenvironmental and archaeological records. The application of tephrochronology is greatly enhanced through the detection of macroscopically invisible tephra (cryptotephra). Here, we identify two discrete cryptotephra in Samoan lake sediments, the first identification of cryptotephra in the region outside of New Zealand. Geochemical data suggest one ash layer is from a local Samoan source, providing the first data on an eruption of this age, adding to knowledge of the local volcanic record. The second has a distinctive rhyolitic glass composition, which matches either that of Raoul Island in the Kermadec Arc (1800 km south of Samoa), or two currently submarine volcanoes in the Tongan Arc, ‘Volcano F’ and Lateiki/Metis Shoal (550 and 700 km south of Samoa, respectively). In all possible source cases, this points to a regionally significant eruption of a Kermadec–Tongan volcano at ca. 10 000 a bp. The study marks the first step in the establishment of a South Pacific tephra framework that can be used to answer questions about the synchronicity of changes in hydroclimate, vegetation and early Polynesian migration patterns, as well as providing more information on the volcanic history of Pacific island volcanoes.
Holocene, Kermadec–Tongan volcano, Samoa, South Pacific, tephra
806-815
Bourne, Anna J.
73d7d57c-19a0-4648-93b6-436fc94bc598
Sear, David A.
ccd892ab-a93d-4073-a11c-b8bca42ecfd3
Langdon, Peter G.
95b97671-f9fe-4884-aca6-9aa3cd1a6d7f
Cronin, Shane J.
f26c3e96-3286-410d-822b-0948e853647d
August 2023
Bourne, Anna J.
73d7d57c-19a0-4648-93b6-436fc94bc598
Sear, David A.
ccd892ab-a93d-4073-a11c-b8bca42ecfd3
Langdon, Peter G.
95b97671-f9fe-4884-aca6-9aa3cd1a6d7f
Cronin, Shane J.
f26c3e96-3286-410d-822b-0948e853647d
Bourne, Anna J., Sear, David A., Langdon, Peter G. and Cronin, Shane J.
(2023)
Developing a South Pacific tephra framework: Initial results from a Samoan Holocene sequence.
Journal of Quaternary Science, 38 (6), .
(doi:10.1002/jqs.3519).
Abstract
Tephra preserved in sediments form useful isochronous marker layers, linking disparate geological, palaeoenvironmental and archaeological records. The application of tephrochronology is greatly enhanced through the detection of macroscopically invisible tephra (cryptotephra). Here, we identify two discrete cryptotephra in Samoan lake sediments, the first identification of cryptotephra in the region outside of New Zealand. Geochemical data suggest one ash layer is from a local Samoan source, providing the first data on an eruption of this age, adding to knowledge of the local volcanic record. The second has a distinctive rhyolitic glass composition, which matches either that of Raoul Island in the Kermadec Arc (1800 km south of Samoa), or two currently submarine volcanoes in the Tongan Arc, ‘Volcano F’ and Lateiki/Metis Shoal (550 and 700 km south of Samoa, respectively). In all possible source cases, this points to a regionally significant eruption of a Kermadec–Tongan volcano at ca. 10 000 a bp. The study marks the first step in the establishment of a South Pacific tephra framework that can be used to answer questions about the synchronicity of changes in hydroclimate, vegetation and early Polynesian migration patterns, as well as providing more information on the volcanic history of Pacific island volcanoes.
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Bourne et al JQS 2023
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Accepted/In Press date: 12 March 2023
e-pub ahead of print date: 17 April 2023
Published date: August 2023
Additional Information:
Funding Information:
This work would not have been possible without the guidance, kindness and support of a number of key colleagues from Samoa, including: Taule'ale'ausmai Laavasa Malua and the late Niualuga Evaimalo from the Ministry of Natural Resources and Environment (MNRE) Division of Environment and Conservation, Government of Samoa, who worked with us on providing permissions. We are indebted to Josie Hill, Lucy, Tinifu, Solomano, Ai and Georgia Eves who all provided field assistance. We thank Dr Chris Hayward for his assistance with the use of the electron microprobe at the Tephrochronology Analytical Unit, University of Edinburgh. The Explorers Club Exploration Fund Grant, Gilchrist Expedition Grant and Royal Geographical Society (with the Institute of British Geographers) Monica Cole Grant assisted with travel to Samoa. A special mention to Jon Hassall who originally worked on Lake Lanoto'o for his PhD, funded under an NERC Studentship (to J. Hassall). We acknowledge the support of the NERC Radiocarbon Facility NRCF010001 and specifically dates provided under allocation numbers 2004.0416, 1799.0414 and 1900.0415.
Funding Information:
This work would not have been possible without the guidance, kindness and support of a number of key colleagues from Samoa, including: Taule'ale'ausmai Laavasa Malua and the late Niualuga Evaimalo from the Ministry of Natural Resources and Environment (MNRE) Division of Environment and Conservation, Government of Samoa, who worked with us on providing permissions. We are indebted to Josie Hill, Lucy, Tinifu, Solomano, Ai and Georgia Eves who all provided field assistance. We thank Dr Chris Hayward for his assistance with the use of the electron microprobe at the Tephrochronology Analytical Unit, University of Edinburgh. The Explorers Club Exploration Fund Grant, Gilchrist Expedition Grant and Royal Geographical Society (with the Institute of British Geographers) Monica Cole Grant assisted with travel to Samoa. A special mention to Jon Hassall who originally worked on Lake Lanoto'o for his PhD, funded under an NERC Studentship (to J. Hassall). We acknowledge the support of the NERC Radiocarbon Facility NRCF010001 and specifically dates provided under allocation numbers 2004.0416, 1799.0414 and 1900.0415.
Publisher Copyright:
© 2023 The Authors Journal of Quaternary Science Published by John Wiley & Sons Ltd.
Keywords:
Holocene, Kermadec–Tongan volcano, Samoa, South Pacific, tephra
Identifiers
Local EPrints ID: 476782
URI: http://eprints.soton.ac.uk/id/eprint/476782
ISSN: 0267-8179
PURE UUID: aacb0f2d-8bc7-40c8-8897-9e0e67556679
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Date deposited: 15 May 2023 17:16
Last modified: 17 Mar 2024 02:45
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Author:
Anna J. Bourne
Author:
Shane J. Cronin
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