High-pressure compressibility and vibrational properties of (Ca,Mn)CO3 |
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Knowledge of potential carbon carriers such as carbonates is critical for our understanding of the deep-carbon cycle and related geological processes within the planet. Here we investigated the high-pressure behavior of (Ca,Mn)CO3 up to 75 GPa by synchrotron single-crystal X-ray diffraction, laser Raman spectroscopy, and theoretical calculations. MnCO3-rich carbonate underwent a structural phase transition from the CaCO3-I structure into the CaCO3-VI structure at 45-48 GPa, while CaCO3-rich carbonate transformed into CaCO3-III and CaCO3-VI at approximately 2 and 15 GPa, respectively. The equation of state and vibrational properties of MnCO3-rich and CaCO3-rich carbonates changed dramatically across the phase transition. The CaCO3-VI-structured CaCO3-rich and MnCO3-rich carbonates were stable at room temperature up to at least 53 and 75 GPa, respectively. The addition of smaller cations (e.g., Mn2+, Mg2+, and Fe2+) can enlarge the stability field of the CaCO3-I phase as well as increase the pressure of the structural transition into the CaCO3-VI phase. Publication name | AMERICAN MINERALOGIST, 101 (12):2723-2730; 10.2138/am-2016-5742 DEC 2016 | Author(s) | Liu, Jin; Caracas, Razvan; Fan, Dawei; Bobocioiu, Ema; Zhang, Dongzhou; Mao, Wendy L. | Corresponding author(s) | LIU Jin jinliu1@stanford.edu Stanford Univ, Dept Geol Sci, Stanford, CA 94305 USA. | Author(s) from IGCAS | FAN Dawei | View here for the details
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