How volcanically active is an abyssal plain? Evidence for recent volcanism on 20 Ma Nazca Plate seafloor.

Devey, Colin W. , Greinert, Jens , Boetius, Antje, Augustin, Nico and Yeo, Isobel (2021) How volcanically active is an abyssal plain? Evidence for recent volcanism on 20 Ma Nazca Plate seafloor. Open Access Marine Geology, 440 . Art.Nr. 106548. DOI 10.1016/j.margeo.2021.106548.

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Supplementary data:



• Evidence for young volcanism has been found on 20Ma oceanic crust in the Peru Basin.

• This volcanism appears unrelated to hotspot or petit-spot activity and as such represents a new type of intraplate volcanism.

• The volcanism may be linked to seismically slow shallow mantle beneath the Nazca plate.

• Intraplate tension does not seem to be the trigger for the volcanism.

The abyssal plains are generally assumed to be geologically inactive parts of the ocean plate interiors where processes (such as pelagic sedimentation or manganese crust and nodule formation) occur at very slow rates. In terms of intraplate volcanic activity, almost all is assumed to occur at hotspots, leading to little exploration in other intraplate regions. The Peru Basin is an abyssal plain known to host Mn-nodule fields. We present remotely-operated underwater vehicle (ROV) investigations of a small seamount adjacent to such a Mn-nodule field on 20Ma Nazca Plate crust, showing that it appears to have been recently volcanically and hydrothermally active. The seamount lies 1600km east of the nearest spreading axis (East Pacific Rise) and 600km from both the Galapagos Plateau (to the north) and the subduction zone off Peru (to the east), making off-axis, hotspot or petit-spot processes unlikely as a cause of the volcanism. The shallow mantle below the Nazca (and conjugate Pacific) Plate shows globally anomalous low seismic shear-wave velocities, perhaps reflecting higher-than-normal amounts of melt in the mantle below this region which may provide a source for the magmas. Our own regional mapping work and literature sources highlight several similar sites of probable young volcanism elsewhere in the Peru Basin which may also be related to this anomaly. The Nazca abyssal plain may be much more geologically active than previously thought. If so, this could have wider implications for, among other things, chemosynthetic ecosystem connectivity.

Document Type: Article
Keywords: Volcanism, Intraplate, Peru Basin, Non-hotspot
Research affiliation: OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-MG Marine Geosystems
OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-MG Marine Geosystems > DeepSea Monitoring
OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-MUHS
Corresponding Author:
Corresponding Author Name
Devey, Colin
Devey, Colin W. (Devey, Colin)
Main POF Topic: PT8: Georesources
Refereed: Yes
Open Access Journal?: No
Publisher: Elsevier
Related URLs:
Projects: JPIO-MiningImpact
Date Deposited: 28 Jul 2021 11:57
Last Modified: 08 Feb 2023 09:31

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