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Wang Y, Xu M, Yang L, Yan B, Qin Q, Shao X, Zhang Y, Huang D, Lin X, Lv J, Zhang D, Gou H, Mao HK, Chen C, Ma Y. Pressure-stabilized divalent ozonide CaO 3 and its impact on Earth's oxygen cycles. Nat Commun 2020; 11:4702. [PMID: 32943627 PMCID: PMC7499259 DOI: 10.1038/s41467-020-18541-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 08/25/2020] [Indexed: 11/16/2022] Open
Abstract
High pressure can drastically alter chemical bonding and produce exotic compounds that defy conventional wisdom. Especially significant are compounds pertaining to oxygen cycles inside Earth, which hold key to understanding major geological events that impact the environment essential to life on Earth. Here we report the discovery of pressure-stabilized divalent ozonide CaO3 crystal that exhibits intriguing bonding and oxidation states with profound geological implications. Our computational study identifies a crystalline phase of CaO3 by reaction of CaO and O2 at high pressure and high temperature conditions; ensuing experiments synthesize this rare compound under compression in a diamond anvil cell with laser heating. High-pressure x-ray diffraction data show that CaO3 crystal forms at 35 GPa and persists down to 20 GPa on decompression. Analysis of charge states reveals a formal oxidation state of -2 for ozone anions in CaO3. These findings unravel the ozonide chemistry at high pressure and offer insights for elucidating prominent seismic anomalies and oxygen cycles in Earth's interior. We further predict multiple reactions producing CaO3 by geologically abundant mineral precursors at various depths in Earth's mantle.
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Affiliation(s)
- Yanchao Wang
- State Key Lab of Superhard Materials & International Center for Computational Method and Software, College of Physics, Jilin University, Changchun, 130012, China
| | - Meiling Xu
- School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou, 221116, China
| | - Liuxiang Yang
- Center for High Pressure Science and Technology Advanced Research, Beijing, 100094, China
| | - Bingmin Yan
- Center for High Pressure Science and Technology Advanced Research, Beijing, 100094, China
| | - Qin Qin
- Center for High Pressure Science and Technology Advanced Research, Beijing, 100094, China
| | - Xuecheng Shao
- State Key Lab of Superhard Materials & International Center for Computational Method and Software, College of Physics, Jilin University, Changchun, 130012, China
| | - Yunwei Zhang
- State Key Lab of Superhard Materials & International Center for Computational Method and Software, College of Physics, Jilin University, Changchun, 130012, China
| | - Dajian Huang
- Center for High Pressure Science and Technology Advanced Research, Beijing, 100094, China
| | - Xiaohuan Lin
- Center for High Pressure Science and Technology Advanced Research, Beijing, 100094, China
| | - Jian Lv
- State Key Lab of Superhard Materials & International Center for Computational Method and Software, College of Physics, Jilin University, Changchun, 130012, China
| | - Dongzhou Zhang
- Hawai'i Institute of Geophysics and Planetology, School of Ocean and Earth Science and Technology, University of Hawai'i at Manoa, Honolulu, HI, 96822, USA
| | - Huiyang Gou
- Center for High Pressure Science and Technology Advanced Research, Beijing, 100094, China.
| | - Ho-Kwang Mao
- Center for High Pressure Science and Technology Advanced Research, Beijing, 100094, China
- Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC, 20015, USA
| | - Changfeng Chen
- Department of Physics and Astronomy, University of Nevada, Las Vegas, NV, 89154, USA.
| | - Yanming Ma
- State Key Lab of Superhard Materials & International Center for Computational Method and Software, College of Physics, Jilin University, Changchun, 130012, China.
- International Center of Future Science, Jilin University, Changchun, 130012, China.
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Schmerr N, Garnero EJ. Upper mantle discontinuity topography from thermal and chemical heterogeneity. Science 2007; 318:623-6. [PMID: 17962558 DOI: 10.1126/science.1145962] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Using high-resolution stacks of precursors to the seismic phase SS, we investigated seismic discontinuities associated with mineralogical phase changes approximately 410 and 660 kilometers (km) deep within Earth beneath South America and the surrounding oceans. Detailed maps of phase boundary topography revealed deep 410- and 660-km discontinuities in the down-dip direction of subduction, inconsistent with purely isochemical olivine phase transformation in response to lowered temperatures. Mechanisms invoking chemical heterogeneity within the mantle transition zone were explored to explain this feature. In some regions, multiple reflections from the discontinuities were detected, consistent with partial melt near 410-km depth and/or additional phase changes near 660-km depth. Thus, the origin of upper mantle heterogeneity has both chemical and thermal contributions and is associated with deeply rooted tectonic processes.
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Affiliation(s)
- Nicholas Schmerr
- Arizona State University, School of Earth and Space Exploration, Box 871404, Tempe, AZ 85287-1404, USA.
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Deuss A, Redfern SAT, Chambers K, Woodhouse JH. The Nature of the 660-Kilometer Discontinuity in Earth's Mantle from Global Seismic Observations of
PP
Precursors. Science 2006; 311:198-201. [PMID: 16410518 DOI: 10.1126/science.1120020] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The 660-kilometer discontinuity, which separates Earth's upper and lower mantle, has been detected routinely on a global scale in underside reflections of precursors to SS shear waves. Here, we report observations of this discontinuity in many different regions, using precursors to compressional PP waves. The apparent absence of such precursors in previous studies had posed major problems for models of mantle composition. We find a complicated structure, showing single and double reflections ranging in depth from 640 to 720 kilometers, that requires the existence of multiple phase transitions at the base of the transition zone. The results are consistent with a pyrolite mantle composition.
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Affiliation(s)
- Arwen Deuss
- Department of Earth Sciences, University of Cambridge, Cambridge CB3 0EZ, UK.
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Deuss A, Woodhouse J. Seismic observations of splitting of the mid-transition zone discontinuity in Earth's mantle. Science 2001; 294:354-7. [PMID: 11598296 DOI: 10.1126/science.1063524] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The transition zone of Earth's mantle is delineated by globally observed discontinuities in seismic properties at depths of about 410 and 660 kilometers. Here, we investigate the detailed structure between 410 and 660 kilometers depth, by making use of regional stacks of precursors to the SS phase. The previously observed discontinuity at about 520 kilometers depth is confirmed in many regions, but is found to be absent in others. There are a number of regions in which we find two discontinuities at about 500 and 560 kilometers depth, an effect which can be interpreted as a "splitting" of the 520 kilometer discontinuity. These observations provide seismic constraints on the sharpness and observability of mineralogical phase transitions in the mantle transition zone.
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Affiliation(s)
- A Deuss
- Department of Earth Sciences, University of Oxford, Oxford OX1 3PR, UK.
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