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Sediment characterization at the equatorial Mid‐Atlantic Ridge from P‐to‐S teleseismic phase conversions recorded on the PI‐LAB experiment

Sediment characterization at the equatorial Mid‐Atlantic Ridge from P‐to‐S teleseismic phase conversions recorded on the PI‐LAB experiment
Sediment characterization at the equatorial Mid‐Atlantic Ridge from P‐to‐S teleseismic phase conversions recorded on the PI‐LAB experiment
Accurate marine sediment characteristics, for example, thickness and seismic velocity, are important for constraining sedimentation rates with implications for climate variations and for seismic imaging of deeper structures using ocean bottom seismic deployments. We analyze P‐to‐S seismic phase conversions from the sediment‐crust boundary recorded by the Passive Imaging of the Lithosphere‐Asthenosphere Boundary (PI‐LAB) experiment to infer the sediment thickness across the Mid‐Atlantic Ridge covering 0‐ to 80‐Myr‐old seafloor. We find Pds‐P delay times of 0.04–0.37 s, or 5‐ to 82‐m thickness. Sediment thickness increases with age. Thickness agrees with global estimates for young (<15–20 Myr) seafloor but is thinner on older lithosphere. Our result may represent a lower limit on sediment thickness, given that several of our stations are on topographic highs. The sedimentation rate decrease observed from 5 to 1.2 mm/kyr at ∼10 Myr suggests a recent increase in productivity related to climate change, eolian dust fluxes, and/or biogenic marine activity.
0094-8276
Agius, Matthew
cb168c8d-0926-4c0d-951c-721fb4cf1ebf
Harmon, Nicholas
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Rychert, Catherine
70cf1e3a-58ea-455a-918a-1d570c5e53c5
Tharimena, Saikiran
9e95dff0-7044-43d4-ac5e-51e72468b719
Kendall, J. Michael
49233af5-e888-4ab8-87b7-d97938f0ed27
Agius, Matthew
cb168c8d-0926-4c0d-951c-721fb4cf1ebf
Harmon, Nicholas
10d11a16-b8b0-4132-9354-652e72d8e830
Rychert, Catherine
70cf1e3a-58ea-455a-918a-1d570c5e53c5
Tharimena, Saikiran
9e95dff0-7044-43d4-ac5e-51e72468b719
Kendall, J. Michael
49233af5-e888-4ab8-87b7-d97938f0ed27

Agius, Matthew, Harmon, Nicholas, Rychert, Catherine, Tharimena, Saikiran and Kendall, J. Michael (2018) Sediment characterization at the equatorial Mid‐Atlantic Ridge from P‐to‐S teleseismic phase conversions recorded on the PI‐LAB experiment. Geophysical Research Letters. (doi:10.1029/2018GL080565).

Record type: Article

Abstract

Accurate marine sediment characteristics, for example, thickness and seismic velocity, are important for constraining sedimentation rates with implications for climate variations and for seismic imaging of deeper structures using ocean bottom seismic deployments. We analyze P‐to‐S seismic phase conversions from the sediment‐crust boundary recorded by the Passive Imaging of the Lithosphere‐Asthenosphere Boundary (PI‐LAB) experiment to infer the sediment thickness across the Mid‐Atlantic Ridge covering 0‐ to 80‐Myr‐old seafloor. We find Pds‐P delay times of 0.04–0.37 s, or 5‐ to 82‐m thickness. Sediment thickness increases with age. Thickness agrees with global estimates for young (<15–20 Myr) seafloor but is thinner on older lithosphere. Our result may represent a lower limit on sediment thickness, given that several of our stations are on topographic highs. The sedimentation rate decrease observed from 5 to 1.2 mm/kyr at ∼10 Myr suggests a recent increase in productivity related to climate change, eolian dust fluxes, and/or biogenic marine activity.

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Accepted/In Press date: 2 November 2018
e-pub ahead of print date: 9 November 2018

Identifiers

Local EPrints ID: 426860
URI: https://eprints.soton.ac.uk/id/eprint/426860
ISSN: 0094-8276
PURE UUID: ddd43d62-593a-408b-b6d3-2643fadb03fd
ORCID for Saikiran Tharimena: ORCID iD orcid.org/0000-0002-1841-1911

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Date deposited: 14 Dec 2018 17:30
Last modified: 14 Mar 2019 01:26

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Author: Matthew Agius
Author: Nicholas Harmon
Author: J. Michael Kendall

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