Details

Autor(en) / Beteiligte

• Devey, C.W.
• Greinert, J.
• Boetius, A.
• Augustin, N.
• Yeo, I.

Titel

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

Ist Teil von

• Marine geology, 2021-10, Vol.440, p.106548, Article 106548

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2021

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• 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. •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.