Prodigious submarine landslides during the inception and early growth of volcanic islands

James E Hunt,Ian Jarvis

doi:10.1038/s41467-017-02100-3

Abstract

Volcanic island inception applies large stresses as the ocean crust domes in response to magma ascension and is loaded by eruption of lavas. There is currently limited information on when volcanic islands are initiated on the seafloor, and no information regarding the seafloor instabilities island inception may cause. The deep sea Madeira Abyssal Plain contains a 43 million year history of turbidites among which many originate from mass movements in the Canary Islands. Here, we investigate the composition and timing of a distinctive group of turbidites that we suggest represent a new unique record of large-volume submarine landslides triggered during the inception, submarine shield growth, and final subaerial emergence of the Canary Islands. These slides are predominantly multi-stage and yet represent among the largest mass movements on the Earth’s surface up to three or more-times larger than subaerial Canary Islands flank collapses. Thus whilst these deposits provide invaluable information on ocean island geodynamics they also represent a significant, and as yet unaccounted, marine geohazard.

Highlights

Volcanic island inception applies large stresses as the ocean crust domes in response to magma ascension and is loaded by eruption of lavas
Data of turbidite compositions overlain on the composition of terrestrial volcanics from the Canary Islands and Madeira; volcanic data sourced from the GEOROC database at Max-Plank Institut für Chemie
The turbidites of the present study likely represent the only evidence of these large submarine landslides they represent, as the failure scars are likely infilled by thick accumulations of hemipelagites and subsequent proximal landslide deposits

Summary

Introduction

Volcanic island inception applies large stresses as the ocean crust domes in response to magma ascension and is loaded by eruption of lavas. We investigate the composition and timing of a distinctive group of turbidites that we suggest represent a new unique record of large-volume submarine landslides triggered during the inception, submarine shield growth, and final subaerial emergence of the Canary Islands. These slides are predominantly multi-stage and yet represent among the largest mass movements on the Earth’s surface up to three or more-times larger than subaerial Canary Islands flank collapses. Despite the large emplacement of volcanic mass upon the oceanic crust, the deposition of surficial materials potentially prone to failure and the rapidity of growth, there is Volcaniclastic White calciclastic

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