Investigating ultra-low velocity zones in the southern hemisphere using an Antarctic dataset
Given limited seismic coverage of the lowermost mantle, less than one-fifth of the core-mantle boundary (CMB) has been surveyed for the presence of ultra-low velocity zones (ULVZs). Investigations that sample the CMB with new geometries are therefore important to further our understanding of ULVZ or...
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ftleedsuniv:oai:eprints.whiterose.ac.uk:157318 2023-05-15T13:45:14+02:00 Investigating ultra-low velocity zones in the southern hemisphere using an Antarctic dataset Hansen, SE Carson, SE Garnero, EJ Rost, S Yu, S Ishii, M 2020-04-15 text https://eprints.whiterose.ac.uk/157318/ https://eprints.whiterose.ac.uk/157318/7/1-s2.0-S0012821X20300856-main.pdf en eng Elsevier https://eprints.whiterose.ac.uk/157318/7/1-s2.0-S0012821X20300856-main.pdf Hansen, SE, Carson, SE, Garnero, EJ et al. (2 more authors) (2020) Investigating ultra-low velocity zones in the southern hemisphere using an Antarctic dataset. Earth and Planetary Science Letters, 536. 116142. p. 116142. ISSN 0012-821X cc_by_nc_nd_4 CC-BY-NC-ND Article NonPeerReviewed 2020 ftleedsuniv 2023-01-30T22:27:13Z Given limited seismic coverage of the lowermost mantle, less than one-fifth of the core-mantle boundary (CMB) has been surveyed for the presence of ultra-low velocity zones (ULVZs). Investigations that sample the CMB with new geometries are therefore important to further our understanding of ULVZ origins and their potential connection to other deep Earth processes. Using core-reflected ScP waves recorded by the recently deployed Transantarctic Mountains Northern Network in Antarctica, the current study aims to expand ULVZ investigations in the southern hemisphere. Our dataset samples the CMB in the vicinity of New Zealand, providing coverage between an area to the northeast, where ULVZ structure has been previously identified, and another region to the south, where prior evidence for a ULVZ was inconclusive. This area is of particular interest because the data sample across the boundary of the Pacific Large Low Shear Velocity Province (LLSVP). The Weddell Sea region near Antarctica is also well sampled, providing new information on a region that has not been previously studied. A correlative scheme between a large database of 1-D synthetic seismograms and the observed ScP data demonstrates that ULVZs are required in both study regions. Modeling uncertainties limit our ability to definitively define ULVZ characteristics but also likely indicate more complex 3-D structure. Given that ULVZs are detected within, along the edge of, and far from the Pacific LLSVP, our results support the hypothesis that ULVZs are compositionally distinct from the surrounding mantle and are not solely related to partial melt. ULVZs may be ubiquitous along the CMB; however, they may be thinner in many regions than can be resolved by current methods. Mantle convection currents may sweep the ULVZs into thicker piles in some areas, pushing these anomalies toward the boundaries of LLSVPs. Article in Journal/Newspaper Antarc* Antarctic Antarctica Weddell Sea White Rose Research Online (Universities of Leeds, Sheffield & York) Antarctic Weddell Sea Transantarctic Mountains Pacific New Zealand Weddell |
institution |
Open Polar |
collection |
White Rose Research Online (Universities of Leeds, Sheffield & York) |
op_collection_id |
ftleedsuniv |
language |
English |
description |
Given limited seismic coverage of the lowermost mantle, less than one-fifth of the core-mantle boundary (CMB) has been surveyed for the presence of ultra-low velocity zones (ULVZs). Investigations that sample the CMB with new geometries are therefore important to further our understanding of ULVZ origins and their potential connection to other deep Earth processes. Using core-reflected ScP waves recorded by the recently deployed Transantarctic Mountains Northern Network in Antarctica, the current study aims to expand ULVZ investigations in the southern hemisphere. Our dataset samples the CMB in the vicinity of New Zealand, providing coverage between an area to the northeast, where ULVZ structure has been previously identified, and another region to the south, where prior evidence for a ULVZ was inconclusive. This area is of particular interest because the data sample across the boundary of the Pacific Large Low Shear Velocity Province (LLSVP). The Weddell Sea region near Antarctica is also well sampled, providing new information on a region that has not been previously studied. A correlative scheme between a large database of 1-D synthetic seismograms and the observed ScP data demonstrates that ULVZs are required in both study regions. Modeling uncertainties limit our ability to definitively define ULVZ characteristics but also likely indicate more complex 3-D structure. Given that ULVZs are detected within, along the edge of, and far from the Pacific LLSVP, our results support the hypothesis that ULVZs are compositionally distinct from the surrounding mantle and are not solely related to partial melt. ULVZs may be ubiquitous along the CMB; however, they may be thinner in many regions than can be resolved by current methods. Mantle convection currents may sweep the ULVZs into thicker piles in some areas, pushing these anomalies toward the boundaries of LLSVPs. |
author2 |
Ishii, M |
format |
Article in Journal/Newspaper |
author |
Hansen, SE Carson, SE Garnero, EJ Rost, S Yu, S |
spellingShingle |
Hansen, SE Carson, SE Garnero, EJ Rost, S Yu, S Investigating ultra-low velocity zones in the southern hemisphere using an Antarctic dataset |
author_facet |
Hansen, SE Carson, SE Garnero, EJ Rost, S Yu, S |
author_sort |
Hansen, SE |
title |
Investigating ultra-low velocity zones in the southern hemisphere using an Antarctic dataset |
title_short |
Investigating ultra-low velocity zones in the southern hemisphere using an Antarctic dataset |
title_full |
Investigating ultra-low velocity zones in the southern hemisphere using an Antarctic dataset |
title_fullStr |
Investigating ultra-low velocity zones in the southern hemisphere using an Antarctic dataset |
title_full_unstemmed |
Investigating ultra-low velocity zones in the southern hemisphere using an Antarctic dataset |
title_sort |
investigating ultra-low velocity zones in the southern hemisphere using an antarctic dataset |
publisher |
Elsevier |
publishDate |
2020 |
url |
https://eprints.whiterose.ac.uk/157318/ https://eprints.whiterose.ac.uk/157318/7/1-s2.0-S0012821X20300856-main.pdf |
geographic |
Antarctic Weddell Sea Transantarctic Mountains Pacific New Zealand Weddell |
geographic_facet |
Antarctic Weddell Sea Transantarctic Mountains Pacific New Zealand Weddell |
genre |
Antarc* Antarctic Antarctica Weddell Sea |
genre_facet |
Antarc* Antarctic Antarctica Weddell Sea |
op_relation |
https://eprints.whiterose.ac.uk/157318/7/1-s2.0-S0012821X20300856-main.pdf Hansen, SE, Carson, SE, Garnero, EJ et al. (2 more authors) (2020) Investigating ultra-low velocity zones in the southern hemisphere using an Antarctic dataset. Earth and Planetary Science Letters, 536. 116142. p. 116142. ISSN 0012-821X |
op_rights |
cc_by_nc_nd_4 |
op_rightsnorm |
CC-BY-NC-ND |
_version_ |
1766217644370821120 |