From Subduction to LLSVP: The Core-Mantle Boundary Heterogeneities Across North Atlantic
The distribution of Ultra-low Velocity Zones (ULVZs) is generally associated with the Large Low Shear Velocity Zones (LLSVPs). However, subducted slabs may be important for the characteristics of the ULVZs as well. Here we use ScS precursor (SdS) and postcursor (ScscS) phases, as well as Scd phases...
Published in: | Geochemistry, Geophysics, Geosystems |
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Online Access: | http://ir.gig.ac.cn/handle/344008/66367 https://doi.org/10.1029/2021GC009879 |
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ftchacadscgigcas:oai:ir.gig.ac.cn:344008/66367 2023-05-15T17:30:51+02:00 From Subduction to LLSVP: The Core-Mantle Boundary Heterogeneities Across North Atlantic Fan, An Sun, Xinlei Zhang, Zhou Zhang, Peng Zong, Jianye 2022 http://ir.gig.ac.cn/handle/344008/66367 https://doi.org/10.1029/2021GC009879 英语 eng AMER GEOPHYSICAL UNION GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS http://ir.gig.ac.cn/handle/344008/66367 doi:10.1029/2021GC009879 Geochemistry & Geophysics POST-PEROVSKITE PHASE COMPLETE SYNTHETIC SEISMOGRAMS ULTRALOW-VELOCITY ZONES LOWERMOST MANTLE SEISMIC EVIDENCE SEISMOLOGICAL CONSTRAINTS PACIFIC LLSVP PARTIAL MELT BENEATH TRANSITION 期刊论文 2022 ftchacadscgigcas https://doi.org/10.1029/2021GC009879 2022-12-19T19:16:55Z The distribution of Ultra-low Velocity Zones (ULVZs) is generally associated with the Large Low Shear Velocity Zones (LLSVPs). However, subducted slabs may be important for the characteristics of the ULVZs as well. Here we use ScS precursor (SdS) and postcursor (ScscS) phases, as well as Scd phases recorded by USArray to investigate the lowermost mantle structure across the north Atlantic, which spans the African LLSVP and the subducted Farallon slab. Our results show a ULVZ located near the edge of the African LLSVP, with thicknesses ranging from 11-16 km and S wave velocity reductions of 12%-24%. At the same time, a thin high-velocity layer (HVL) with thicknesses of 20-30 km, Vs increases of 3%-4%, is also detected outside the LLSVP in the northwest region. Further west there is a clear D" layer at 250 km above the core mantle boundary (CMB), overlaid by a low velocity layer with Vs reduction of 3%. This transition profile from D" to HVL to ULVZ provides an excellent opportunity for us to understand the heterogeneities near the CMB region. We propose that interactions between the subducted Farallon slab with ambient mantle and LLSVP material, together with thermal effects, may result in this transition between different seismic structures along the CMB. Report North Atlantic Guangzhou Institute of Geochemistry: GIG OpenIR (Chinese Academy of Sciences) Pacific Geochemistry, Geophysics, Geosystems 23 1 |
institution |
Open Polar |
collection |
Guangzhou Institute of Geochemistry: GIG OpenIR (Chinese Academy of Sciences) |
op_collection_id |
ftchacadscgigcas |
language |
English |
topic |
Geochemistry & Geophysics POST-PEROVSKITE PHASE COMPLETE SYNTHETIC SEISMOGRAMS ULTRALOW-VELOCITY ZONES LOWERMOST MANTLE SEISMIC EVIDENCE SEISMOLOGICAL CONSTRAINTS PACIFIC LLSVP PARTIAL MELT BENEATH TRANSITION |
spellingShingle |
Geochemistry & Geophysics POST-PEROVSKITE PHASE COMPLETE SYNTHETIC SEISMOGRAMS ULTRALOW-VELOCITY ZONES LOWERMOST MANTLE SEISMIC EVIDENCE SEISMOLOGICAL CONSTRAINTS PACIFIC LLSVP PARTIAL MELT BENEATH TRANSITION Fan, An Sun, Xinlei Zhang, Zhou Zhang, Peng Zong, Jianye From Subduction to LLSVP: The Core-Mantle Boundary Heterogeneities Across North Atlantic |
topic_facet |
Geochemistry & Geophysics POST-PEROVSKITE PHASE COMPLETE SYNTHETIC SEISMOGRAMS ULTRALOW-VELOCITY ZONES LOWERMOST MANTLE SEISMIC EVIDENCE SEISMOLOGICAL CONSTRAINTS PACIFIC LLSVP PARTIAL MELT BENEATH TRANSITION |
description |
The distribution of Ultra-low Velocity Zones (ULVZs) is generally associated with the Large Low Shear Velocity Zones (LLSVPs). However, subducted slabs may be important for the characteristics of the ULVZs as well. Here we use ScS precursor (SdS) and postcursor (ScscS) phases, as well as Scd phases recorded by USArray to investigate the lowermost mantle structure across the north Atlantic, which spans the African LLSVP and the subducted Farallon slab. Our results show a ULVZ located near the edge of the African LLSVP, with thicknesses ranging from 11-16 km and S wave velocity reductions of 12%-24%. At the same time, a thin high-velocity layer (HVL) with thicknesses of 20-30 km, Vs increases of 3%-4%, is also detected outside the LLSVP in the northwest region. Further west there is a clear D" layer at 250 km above the core mantle boundary (CMB), overlaid by a low velocity layer with Vs reduction of 3%. This transition profile from D" to HVL to ULVZ provides an excellent opportunity for us to understand the heterogeneities near the CMB region. We propose that interactions between the subducted Farallon slab with ambient mantle and LLSVP material, together with thermal effects, may result in this transition between different seismic structures along the CMB. |
format |
Report |
author |
Fan, An Sun, Xinlei Zhang, Zhou Zhang, Peng Zong, Jianye |
author_facet |
Fan, An Sun, Xinlei Zhang, Zhou Zhang, Peng Zong, Jianye |
author_sort |
Fan, An |
title |
From Subduction to LLSVP: The Core-Mantle Boundary Heterogeneities Across North Atlantic |
title_short |
From Subduction to LLSVP: The Core-Mantle Boundary Heterogeneities Across North Atlantic |
title_full |
From Subduction to LLSVP: The Core-Mantle Boundary Heterogeneities Across North Atlantic |
title_fullStr |
From Subduction to LLSVP: The Core-Mantle Boundary Heterogeneities Across North Atlantic |
title_full_unstemmed |
From Subduction to LLSVP: The Core-Mantle Boundary Heterogeneities Across North Atlantic |
title_sort |
from subduction to llsvp: the core-mantle boundary heterogeneities across north atlantic |
publisher |
AMER GEOPHYSICAL UNION |
publishDate |
2022 |
url |
http://ir.gig.ac.cn/handle/344008/66367 https://doi.org/10.1029/2021GC009879 |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS http://ir.gig.ac.cn/handle/344008/66367 doi:10.1029/2021GC009879 |
op_doi |
https://doi.org/10.1029/2021GC009879 |
container_title |
Geochemistry, Geophysics, Geosystems |
container_volume |
23 |
container_issue |
1 |
_version_ |
1766127959580606464 |