Origin and evolution of the deep thermochemical structure beneath Eurasia
Abstract
A unique structure in the Earth's lowermost mantle, the Perm Anomaly, was recently identified beneath Eurasia. It seismologically resembles the large low-shear velocity provinces (LLSVPs) under Africa and the Pacific, but is much smaller. This challenges the current understanding of the evolution of the plate–mantle system in which plumes rise from the edges of the two LLSVPs, spatially fixed in time. New models of mantle flow over the last 230 million years reproduce the present-day structure of the lower mantle, and show a Perm-like anomaly. The anomaly formed in isolation within a closed subduction network ∼22,000 km in circumference prior to 150 million years ago before migrating ∼1,500 km westward at an average rate of 1 cm year^(−1), indicating a greater mobility of deep mantle structures than previously recognized. We hypothesize that the mobile Perm Anomaly could be linked to the Emeishan volcanics, in contrast to the previously proposed Siberian Traps.
Additional Information
© 2017 The Author(s). This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ Received: 12 May 2016; Accepted: 05 December 2016; Published online: 18 January 2017. This research was undertaken with the assistance of resources from the National Computational Infrastructure (NCI), which is supported by the Australian Government. N.F. and R.D.M. were supported by ARC IH130200012. S.W. was supported by SIEF RP 04-174. M.G. and D.J.B. were supported by Statoil ASA and by the NSF under grants CMMI-1028978, EAR-1161046 and EAR-1247022. Figures were constructed using the Generic Mapping Tools and matplotlib. We thank T.C.W. Landgrebe for advice in calculating accuracy and sensitivity, D. Steinberg for advice on cluster analysis, J. Ritsema for sharing the seismic filter for S40RTS, and three anonymous reviewers for comments that improved the quality of the manuscript. Author Contributions: N.F. ran and analysed the models, S.W. instigated the study and implemented the cluster analysis, R.D.M. and M.G. developed the concepts of the study and D.J.B., M.G. and N.F. developed the framework to assimilate tectonic reconstructions in CitcomS. All authors contributed to the writing of the manuscript, led by N.F. Data availability: Maps of the geographic distribution of tomography and flow model clusters reported are available at https://www.earthbyte.org/origin-evolution-perm-anomaly/. The computer code that supports the findings of this study is available from the corresponding author upon reasonable request. The authors declare no competing financial interests.Attached Files
Published - ncomms14164.pdf
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Additional details
- PMCID
- PMC5253668
- Eprint ID
- 73607
- Resolver ID
- CaltechAUTHORS:20170123-075227268
- Australian Government
- IH130200012
- Australian Research Council
- RP 04-174
- Science and Industry Endowment Fund (SIEF)
- Statoil ASA
- CMMI-1028978
- NSF
- EAR-1161046
- NSF
- EAR-1247022
- NSF
- Created
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2017-01-23Created from EPrint's datestamp field
- Updated
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2022-04-06Created from EPrint's last_modified field