Volume 97, Issue 1 pp. 350-357
Special Section

Effects of Spin Transition and Cation Substitution on the Optical Properties and Iron Partitioning in Carbonate Minerals

Jun HU

Jun HU

Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, Hebei, 066004 China

Center for High Pressure Science and Technology Advanced Research, Beijing, 100193 China

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Liangxu XU

Liangxu XU

Center for High Pressure Science and Technology Advanced Research, Beijing, 100193 China

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Jin LIU

Corresponding Author

Jin LIU

Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, Hebei, 066004 China

Center for High Pressure Science and Technology Advanced Research, Beijing, 100193 China

Corresponding author. E-mail: [email protected]; [email protected]Search for more papers by this author
Donghui YUE

Corresponding Author

Donghui YUE

Heilongjiang Province Key Laboratory of Superhard Materials, Department of Physics, Mudanjiang Normal University, Mudanjiang, Heilongjiang, 157012 China

Corresponding author. E-mail: [email protected]; [email protected]Search for more papers by this author
First published: 15 March 2023
Citations: 1

About the first author:

HU Jun, male, born in 1997 in Yancheng, China; graduate student in materials science and engineering at Yanshan University, Qinhuangdao. He is currently interested in the high pressure-temperature synthesis and characterization of carbonate minerals. E-mail: [email protected].

About the corresponding authors:

YUE Donghui, male, born in 1991 in Heilongjiang, China. Ph.D. in physics; lecturer at the Mudanjiang Normal University, Heilongjiang. He has been focused on the physical properties and techniques for thermal transport under extreme conditions since 2014. E-mail: [email protected].

LIU Jin, male, born in 1984 in Jiangsu, China. Ph.D. in mineral physics; staff scientist at the Center for High Pressure Science and Technology Advanced Research (HPSTAR), Beijing. He has been focused on the physics and chemistry of planetary materials under extreme conditions since 2007. E-mail: [email protected].

Abstract

The high-pressure behavior of deep carbonate dictates the state and dynamics of oxidized carbon in the Earth's mantle, playing a vital role in the global carbon cycle and potentially influencing long-term climate change. Optical absorption and Raman spectroscopic measurements were carried out on two natural carbonate samples in diamond-anvil cells up to 60 GPa. Mg-substitution in high-spin siderite FeCO3 increases the crystal field absorption band position by approximately 1000 cm–1 but such an effect is marginal at >40 GPa when entering the low-spin state. The crystal field absorption band of dolomite cannot be recognized upon compression to 45.8 GPa at room temperature but, in contrast, the high-pressure polymorph of dolomite exhibits a strong absorption band at frequencies higher than (Mg,Fe)CO3 in the low-spin state by 2000–2500 cm–1. Additionally, these carbonate minerals show more complicated features for the absorption edge, decreasing with pressure and undergoing a dramatic change through the spin crossover. The optical and vibrational properties of carbonate minerals are highly correlated with iron content and spin transition, indicating that iron is preferentially partitioned into low-spin carbonates. These results shed new light on how carbonate minerals evolve in the mantle, which is crucial to decode the deep carbon cycle.

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