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Seismic imaging of a mid-lithospheric discontinuity beneath Ontong Java Plateau

Seismic imaging of a mid-lithospheric discontinuity beneath Ontong Java Plateau
Seismic imaging of a mid-lithospheric discontinuity beneath Ontong Java Plateau
Ontong Java Plateau (OJP) is a huge, completely submerged volcanic edifice that is hypothesized to have formed during large plume melting events ?90 and 120 My ago. It is currently resisting subduction into the North Solomon trench. The size and buoyancy of the plateau along with its history of plume melting and current interaction with a subduction zone are all similar to the characteristics and hypothesized mechanisms of continent formation. However, the plateau is remote, and enigmatic, and its proto-continent potential is debated. We use SS precursors to image seismic discontinuity structure beneath Ontong Java Plateau. We image a velocity increase with depth at 28±4 km consistent with the Moho. In addition, we image velocity decreases at 80±5 km and 282±7 km depth. Discontinuities at 60–100 km depth are frequently observed both beneath the oceans and the continents. However, the discontinuity at 282 km is anomalous in comparison to surrounding oceanic regions; in the context of previous results it may suggest a thick viscous root beneath OJP. If such a root exists, then the discontinuity at 80 km bears some similarity to the mid-lithospheric discontinuities (MLDs) observed beneath continents. One possibility is that plume melting events, similar to that which formed OJP, may cause discontinuities in the MLD depth range. Plume–plate interaction could be a mechanism for MLD formation in some continents in the Archean prior to the onset of subduction.
mid-lithospheric discontinuity, Ontong Java Plateau, anomalous lithosphere, SS precursors, viscous root
0012-821X
62-70
Tharimena, Saikiran
9e95dff0-7044-43d4-ac5e-51e72468b719
Rychert, Catherine
70cf1e3a-58ea-455a-918a-1d570c5e53c5
Harmon, Nicholas
10d11a16-b8b0-4132-9354-652e72d8e830
Tharimena, Saikiran
9e95dff0-7044-43d4-ac5e-51e72468b719
Rychert, Catherine
70cf1e3a-58ea-455a-918a-1d570c5e53c5
Harmon, Nicholas
10d11a16-b8b0-4132-9354-652e72d8e830

Tharimena, Saikiran, Rychert, Catherine and Harmon, Nicholas (2016) Seismic imaging of a mid-lithospheric discontinuity beneath Ontong Java Plateau. Earth and Planetary Science Letters, 450, 62-70. (doi:10.1016/j.epsl.2016.06.026).

Record type: Article

Abstract

Ontong Java Plateau (OJP) is a huge, completely submerged volcanic edifice that is hypothesized to have formed during large plume melting events ?90 and 120 My ago. It is currently resisting subduction into the North Solomon trench. The size and buoyancy of the plateau along with its history of plume melting and current interaction with a subduction zone are all similar to the characteristics and hypothesized mechanisms of continent formation. However, the plateau is remote, and enigmatic, and its proto-continent potential is debated. We use SS precursors to image seismic discontinuity structure beneath Ontong Java Plateau. We image a velocity increase with depth at 28±4 km consistent with the Moho. In addition, we image velocity decreases at 80±5 km and 282±7 km depth. Discontinuities at 60–100 km depth are frequently observed both beneath the oceans and the continents. However, the discontinuity at 282 km is anomalous in comparison to surrounding oceanic regions; in the context of previous results it may suggest a thick viscous root beneath OJP. If such a root exists, then the discontinuity at 80 km bears some similarity to the mid-lithospheric discontinuities (MLDs) observed beneath continents. One possibility is that plume melting events, similar to that which formed OJP, may cause discontinuities in the MLD depth range. Plume–plate interaction could be a mechanism for MLD formation in some continents in the Archean prior to the onset of subduction.

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More information

Accepted/In Press date: 17 June 2016
Published date: 15 September 2016
Keywords: mid-lithospheric discontinuity, Ontong Java Plateau, anomalous lithosphere, SS precursors, viscous root
Organisations: Ocean and Earth Science, Geology & Geophysics

Identifiers

Local EPrints ID: 397601
URI: http://eprints.soton.ac.uk/id/eprint/397601
ISSN: 0012-821X
PURE UUID: 6513f8a8-91bc-4618-8744-3ce1722ed5c9
ORCID for Saikiran Tharimena: ORCID iD orcid.org/0000-0002-1841-1911
ORCID for Nicholas Harmon: ORCID iD orcid.org/0000-0002-0731-768X

Catalogue record

Date deposited: 30 Jun 2016 15:44
Last modified: 27 Apr 2022 02:07

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