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Insights into exhumation and mantle hydration processes at the Deep Galicia margin from a 3D high-resolution seismic velocity model

Insights into exhumation and mantle hydration processes at the Deep Galicia margin from a 3D high-resolution seismic velocity model
Insights into exhumation and mantle hydration processes at the Deep Galicia margin from a 3D high-resolution seismic velocity model
High-resolution velocity models developed using full-waveform inversion (FWI) can image fine details of the nature and structure of the subsurface. Using a 3D FWI velocity model of hyper-thinned crust at the Deep Galicia Margin (DGM) west of Iberia, we constrain the nature of the crust at this margin by comparing its velocity structure with those in other similar tectonic settings. Velocities representative of both the upper and lower continental crust are present, but there is no clear evidence for distinct upper and lower crustal layers within the hyper-thinned crust. Our velocity model supports exhumation of the lower crust under the footwalls of fault blocks to accommodate the extension. We used our model to generate a serpentinization map for the uppermost mantle at the DGM, at a depth of 100 ms (~340m) below the S-reflector, a low-angle detachment that marks the base of the crust at this margin. We find a good alignment between serpentinized areas and the overlying major block bounding faults on our map, suggesting that those faults played an important role in transporting water to the upper mantle. Further, we observe a weak correlation between fault heaves and serpentinization beneath the hanging-wall blocks, indicating that serpentinization was controlled by a complex faulting during rifting. A good match between topographic highs of the S and local highly serpentinized areas of the mantle suggests that the morphology of the S was affected by the volume-increasing process of serpentinization and deformation of the overlying crust.
2169-9356
Boddupalli, Bhargav
20ded581-d378-4ab3-862e-c6f54a717701
Minshull, Timothy
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Bayrakci, Gaye
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Lymer, Gael
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Klaeschen, Dirk
d406ea22-0de4-441a-960b-1824c9f68cdd
Reston, Tim
d6885e2c-a42d-4d59-ae40-220a0a0116b4
Boddupalli, Bhargav
20ded581-d378-4ab3-862e-c6f54a717701
Minshull, Timothy
bf413fb5-849e-4389-acd7-0cb0d644e6b8
Bayrakci, Gaye
338e9d78-0c2c-4104-8592-475bcde31ae3
Lymer, Gael
86546640-b4dc-42e9-9117-10de95f1e91d
Klaeschen, Dirk
d406ea22-0de4-441a-960b-1824c9f68cdd
Reston, Tim
d6885e2c-a42d-4d59-ae40-220a0a0116b4

Boddupalli, Bhargav, Minshull, Timothy, Bayrakci, Gaye, Lymer, Gael, Klaeschen, Dirk and Reston, Tim (2022) Insights into exhumation and mantle hydration processes at the Deep Galicia margin from a 3D high-resolution seismic velocity model. Journal of Geophysical Research: Solid Earth, 127, [e2021JB023220].

Record type: Article

Abstract

High-resolution velocity models developed using full-waveform inversion (FWI) can image fine details of the nature and structure of the subsurface. Using a 3D FWI velocity model of hyper-thinned crust at the Deep Galicia Margin (DGM) west of Iberia, we constrain the nature of the crust at this margin by comparing its velocity structure with those in other similar tectonic settings. Velocities representative of both the upper and lower continental crust are present, but there is no clear evidence for distinct upper and lower crustal layers within the hyper-thinned crust. Our velocity model supports exhumation of the lower crust under the footwalls of fault blocks to accommodate the extension. We used our model to generate a serpentinization map for the uppermost mantle at the DGM, at a depth of 100 ms (~340m) below the S-reflector, a low-angle detachment that marks the base of the crust at this margin. We find a good alignment between serpentinized areas and the overlying major block bounding faults on our map, suggesting that those faults played an important role in transporting water to the upper mantle. Further, we observe a weak correlation between fault heaves and serpentinization beneath the hanging-wall blocks, indicating that serpentinization was controlled by a complex faulting during rifting. A good match between topographic highs of the S and local highly serpentinized areas of the mantle suggests that the morphology of the S was affected by the volume-increasing process of serpentinization and deformation of the overlying crust.

Text
JGR Solid Earth - 2022 - Boddupalli - Insights Into Exhumation and Mantle Hydration Processes at the Deep Galicia Margin - Version of Record
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Accepted/In Press date: 24 June 2022
Published date: 2 July 2022

Identifiers

Local EPrints ID: 468476
URI: http://eprints.soton.ac.uk/id/eprint/468476
ISSN: 2169-9356
PURE UUID: 0963855b-4c94-4e6e-a702-929d93302499
ORCID for Timothy Minshull: ORCID iD orcid.org/0000-0002-8202-1379

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Date deposited: 16 Aug 2022 16:38
Last modified: 17 Aug 2022 01:36

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Contributors

Author: Bhargav Boddupalli
Author: Gaye Bayrakci
Author: Gael Lymer
Author: Dirk Klaeschen
Author: Tim Reston

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