Offshore evidence for volcanic landslide post Last Glacial Maximum at sub-Antarctic Heard Island, southern Indian Ocean

Jodi M. Fox; Sally J. Watson; Trevor J. Falloon; Rebecca J. Carey; Joanne M. Whittaker; Erica A. Spain; Robert A. Duncan; Richard J. Arculus; Millard F. Coffin

doi:10.30909/vol.08.01.3150

Offshore evidence for volcanic landslide post Last Glacial Maximum at sub-Antarctic Heard Island, southern Indian Ocean

Jodi M. Fox, Sally J. Watson^*, Trevor J. Falloon, Rebecca J. Carey, Joanne M. Whittaker, Erica A. Spain, Robert A. Duncan, Richard J. Arculus, Millard F. Coffin

^*Corresponding author for this work

Research School of Earth Sciences

Research output: Contribution to journal › Article › peer-review

Abstract

Heard Island, an active sub-Antarctic intraplate volcanic island on the Kerguelen Plateau, is mostly covered by glaciers. The amphitheatre shaped summit of the active volcanic centre, Big Ben (2813 m), has been interpreted to be the product of a significant volcanic landslide. Here we present the first offshore geomorphological and geological evidence supporting a volcanic landslide on Big Ben, including: (1) the seafloor to the southwest of Heard resembling a landslide deposit, covering at least 467 km², (2) the spatial correlation between the onshore landslide scar and the offshore deposit and (3) the consistency in lithologies and compositions of rocks sampled from the deposit with the onshore in situ lithologies. ⁴⁰Ar/³⁹Ar geochronology constrains the maximum age of the volcanic landslide to 18.0 ± 1.4 ka, post the Last Glacial Maximum. Finally, we assess the risk of volcanic landslide at Heard Island in the future.

Original language	English
Pages (from-to)	31-50
Number of pages	20
Journal	Volcanica
Volume	8
Issue number	1
DOIs	https://doi.org/10.30909/vol.08.01.3150
Publication status	Published - Jan 2025

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@article{c038f7f9a050493fa1ba09e1cab777ee,

title = "Offshore evidence for volcanic landslide post Last Glacial Maximum at sub-Antarctic Heard Island, southern Indian Ocean",

abstract = "Heard Island, an active sub-Antarctic intraplate volcanic island on the Kerguelen Plateau, is mostly covered by glaciers. The amphitheatre shaped summit of the active volcanic centre, Big Ben (2813 m), has been interpreted to be the product of a significant volcanic landslide. Here we present the first offshore geomorphological and geological evidence supporting a volcanic landslide on Big Ben, including: (1) the seafloor to the southwest of Heard resembling a landslide deposit, covering at least 467 km2, (2) the spatial correlation between the onshore landslide scar and the offshore deposit and (3) the consistency in lithologies and compositions of rocks sampled from the deposit with the onshore in situ lithologies. 40Ar/39Ar geochronology constrains the maximum age of the volcanic landslide to 18.0 ± 1.4 ka, post the Last Glacial Maximum. Finally, we assess the risk of volcanic landslide at Heard Island in the future.",

keywords = "40Ar/39Ar, Debris avalanche, Glacier, Intraplate, Kerguelen, Sector collapse",

author = "Fox, {Jodi M.} and Watson, {Sally J.} and Falloon, {Trevor J.} and Carey, {Rebecca J.} and Whittaker, {Joanne M.} and Spain, {Erica A.} and Duncan, {Robert A.} and Arculus, {Richard J.} and Coffin, {Millard F.}",

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month = jan,

doi = "10.30909/vol.08.01.3150",

language = "English",

volume = "8",

pages = "31--50",

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TY - JOUR

T1 - Offshore evidence for volcanic landslide post Last Glacial Maximum at sub-Antarctic Heard Island, southern Indian Ocean

AU - Fox, Jodi M.

AU - Watson, Sally J.

AU - Falloon, Trevor J.

AU - Carey, Rebecca J.

AU - Whittaker, Joanne M.

AU - Spain, Erica A.

AU - Duncan, Robert A.

AU - Arculus, Richard J.

AU - Coffin, Millard F.

PY - 2025/1

Y1 - 2025/1

N2 - Heard Island, an active sub-Antarctic intraplate volcanic island on the Kerguelen Plateau, is mostly covered by glaciers. The amphitheatre shaped summit of the active volcanic centre, Big Ben (2813 m), has been interpreted to be the product of a significant volcanic landslide. Here we present the first offshore geomorphological and geological evidence supporting a volcanic landslide on Big Ben, including: (1) the seafloor to the southwest of Heard resembling a landslide deposit, covering at least 467 km2, (2) the spatial correlation between the onshore landslide scar and the offshore deposit and (3) the consistency in lithologies and compositions of rocks sampled from the deposit with the onshore in situ lithologies. 40Ar/39Ar geochronology constrains the maximum age of the volcanic landslide to 18.0 ± 1.4 ka, post the Last Glacial Maximum. Finally, we assess the risk of volcanic landslide at Heard Island in the future.

AB - Heard Island, an active sub-Antarctic intraplate volcanic island on the Kerguelen Plateau, is mostly covered by glaciers. The amphitheatre shaped summit of the active volcanic centre, Big Ben (2813 m), has been interpreted to be the product of a significant volcanic landslide. Here we present the first offshore geomorphological and geological evidence supporting a volcanic landslide on Big Ben, including: (1) the seafloor to the southwest of Heard resembling a landslide deposit, covering at least 467 km2, (2) the spatial correlation between the onshore landslide scar and the offshore deposit and (3) the consistency in lithologies and compositions of rocks sampled from the deposit with the onshore in situ lithologies. 40Ar/39Ar geochronology constrains the maximum age of the volcanic landslide to 18.0 ± 1.4 ka, post the Last Glacial Maximum. Finally, we assess the risk of volcanic landslide at Heard Island in the future.

KW - 40Ar/39Ar

KW - Debris avalanche

KW - Glacier

KW - Intraplate

KW - Kerguelen

KW - Sector collapse

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DO - 10.30909/vol.08.01.3150

M3 - Article

AN - SCOPUS:85217476412

SN - 2610-3540

VL - 8

SP - 31

EP - 50

JO - Volcanica

JF - Volcanica

IS - 1

ER -

Offshore evidence for volcanic landslide post Last Glacial Maximum at sub-Antarctic Heard Island, southern Indian Ocean

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