Combined high-pressure and high temperature vibrational studies of dolomite: phase diagram and evidence of a new distorted modification

I. Efthimiopoulos1,*, S. Jahn2, A. Kuras1, U. Schade3, and M. Koch-Müller1

1 Deutsches GeoForschungsZentrum GFZ, Section 4.3, Telegrafenberg, 14473 Potsdam, Germany

2Institut für Geologie und Mineralogie, Universität zu Köln,Zülpicher Str. 49b, 50674 Cologne, Germany

3Helmholtz-Zentrum Berlin, EM-IMM, Albert-Einstein-Str. 15,12489 Berlin, Germany

*Corresponding author:

Supplementary Information

Fig S1 Plot of the determined temperature in one of the high-P & high-T Raman experiments, as measured by a thermocouple (X-axis) and from ruby luminescence (Y-axis, see Experimental Details Section). The dashed red lineis a guide for the eye.

Fig S2Raman spectra of the Dol-II phase with two different pressure transmitting media at T = 300 K, i.e. NaCl (high-PT run, up) and Argon (RT run, down). Notice the overall deterioration of the Raman signal below ~1000 cm-1,whereas the high-frequency mode splitting is resolved in both cases.

Table S1Assignment (White 1974; Valenzano et al. 2007), frequencies, pressure coefficients, and the mode Grüneisen parameters γi of the experimentally observed MIR- and Raman-active modes for the various phases of dolomite, evaluated at a reference pressure PR. The pressure dependence is given by the relation: ν(P) = νR+αP+bP2. The Grüneisen parameters are determined from the relation: γi = (K0/νRi)∙(∂νRi/∂P). We have employed the bulk moduli values K0 = 93 GPa for the Dol-I phase (Zucchini et al. 2014) and K = 152 GPa for the Dol-II phase [estimated from the P-V data of (Merlini et al. 2012)]. The numbers in parenthesis correspond to literature data: MIR fromSantillan and Williams (2004), Raman fromKraft et al.(1991) and Gillet et al.(1993).

Phase / Mode symmetry (IR) / PR (GPa) / νR (cm-1) / ∂ν/∂P
(cm-1/GPa) / ∂2ν/∂P2
(cm-1/GPa2) / γi
Dol-I / Eu / 0.0001 / 730 (740) / 2.4 (1.3) / - / 0.31 (0.17)
Au / 880 (877) / -0.13 (0.27) / - / -0.01 (0.02)
Eu / 1417 (1443) / 4.7 (3.36) / - / 0.31 (0.22)
M / 1485 / 5.2 / -0.03 / 0.33
Dol-II / Au / 17.8 / 773 (763) / 2.4 (1.3) / - / 0.47 (0.26)
Au / 878 (889) / -0.13 (1.34) / -0.02 (0.23)
Au / 1493 (1486) / 1.5 (1.5) / - / 0.15 (0.15)
Au / 1526 (1521) / 2.5 (2.4) / - / 0.25 (0.24)
Au / 1568 (1573) / 5.2 (2.5) / -0.03 / 0.5 (0.24)
Au / 1659 / 5 / -0.04 / 0.46
Mode symmetry (Raman)
Dol-I / Eg / 0.0001 / 176 (177, 178) / 2.5 (1.4, 1.8) / - / 1.32
Eg / 301 (301, 300) / 4.8 (4.4, 4.4) / - / 1.48
Ag / 341 (335) / 5.3 (2.9) / - / 1.45
Eg / 723 (725, 724) / 1.8 (1.1, 1.6) / - / 0.23
Ag / 878 (880) / 0 (N/A) / - / 0
Ag / 1096 (1101, 1097) / 3.3 (3.5, 2.9) / - / 0.28
Dol-Ib / 11 / 170 / 2.7 / -
177 / 2.8 / -
Dol-II / Ag / 16 / 181 / 1.1 / - / 0.92
Ag / 202 / 1.9 / - / 1.43
Ag / 213 / 2.5 / - / 1.78
Ag / 222 / 3.4 / - / 2.33
Ag / 263 / 2.6 / - / 1.5
Ag / 346 / 3.3 / - / 1.45
Ag / 374 / 2.6 / - / 1.06
Ag / 377 / 3.9 / - / 1.57
Ag / 397 / 3.5 / - / 1.34
Ag / 423 / 3.9 / - / 1.4
Ag / 755 / 1.7 / - / 0.34
Ag / 748 / 0.9 / - / 0.18
Ag / 880 / -0.05 / - / -0.01
Ag / 877 / 0.1 / - / 0.02
Ag / 873 / -0.4 / - / -0.07
Ag / 1148 / 2.8 / - / 0.37
Ag / 1155 / 2.6 / - / 0.34

Fig S3 (a) Enthalpies and (b) volumes of the different dolomite phases, as well as the possible dolomite decomposition products (MgCO3, and CaCO3 aragonite and post-aragonite) from DFT-GGA calculations. Lines serve as guides for the eye. The open symbols correspond to single-crystal XRD data from Merliniet al. (2012a).

Table S2Lattice parameters and unit cell volumes of the various dolomite polymorphs from DFT calculations (LDA).

Phase / P (GPa) / a (Å) / b (Å) / c (Å) / α (o) / β (o) / γ (o) / V (Å3) / V per f.u. (Å3)
Dol-I / 0 / 5.8733 / 5.8733 / 10.2757 / 90 / 90 / 120 / 307.17 / 102.39
10 / 5.6093 / 5.6093 / 10.3780 / 90 / 90 / 120 / 282.96 / 94.32
Dol-II / 10 / 4.7418 / 5.5982 / 7.2471 / 103.48 / 89.46 / 91.84 / 187.01 / 93.51
20 / 4.7123 / 5.4182 / 7.0206 / 101.86 / 89.34 / 92.65 / 175.27 / 87.63
30 / 4.6893 / 5.2808 / 6.8500 / 100.44 / 89.32 / 93.33 / 166.56 / 83.28
Dol-III / 30 / 6.3977 / 9.4104 / 11.2122 / 75.15 / 80.30 / 89.99 / 642.97 / 80.37
40 / 6.2977 / 9.3230 / 11.0249 / 74.96 / 81.04 / 89.77 / 617.31 / 77.16
50 / 6.2147 / 9.2437 / 10.8714 / 74.71 / 81.66 / 89.61 / 595.85 / 74.48

Table S3Raman and IR mode frequencies (cm-1) for the Dol-I and Dol-II phases at various pressures (DFT-LDA).

Dol-I
Raman / 1 bar / 10 GPa / IR (LO/TO) / 1 bar / 10 GPa
Eg / 185 / 212 / IR z / 144/194 / 112 / 182
Ag / 223 / 247 / IR Eu x y / 153 / 175 / 145 / 171
Eg / 323 / 374 / IR Eu x y / 287 / 299 / 333 / 343
Ag / 363 / 418 / IR z / 344 / 347 / 381 / 381
Ag / 722 / 744 / IR Eu x y / 386 / 470 / 458 / 528
Ag / 858 / 854 / IR z / 393 / 467 / 463 / 524
Ag / 1109 / 1145 / IR Eu x y / 727/ 730 / 756 / 761
Eg / 1461 / 1511 / IR z / 850 / 874 / 846 / 876
IR z / 1110 / 1110 / 1147 / 1147
IR Eu x y / 1442 / 1592 / 1488 / 1643
Dol-II
Raman / 10 GPa / 20 GPa / 30 GPa / IR / 10 GPa / 20 GPa / 30 GPa
Ag / 87 / 115 / 104 / Au / 106 / 136 / 147
Ag / 151 / 162 / 183 / Au / 144 / 155 / 155
Ag / 162 / 176 / 191 / Au / 166 / 186 / 200
Ag / 180 / 216 / 234 / Au / 179 / 189 / 202
Ag / 200 / 218 / 234 / Au / 209 / 233 / 269
Ag / 202 / 229 / 256 / Au / 243 / 267 / 288
Ag / 221 / 250 / 277 / Au / 313 / 335 / 353
Ag / 247 / 275 / 302 / Au / 321 / 352 / 374
Ag / 264 / 286 / 311 / Au / 344 / 379 / 409
Ag / 321 / 347 / 370 / Au / 363 / 389 / 411
Ag / 341 / 373 / 399 / Au / 375 / 408 / 438
Ag / 372 / 402 / 428 / Au / 391 / 426 / 457
Ag / 378 / 420 / 455 / Au / 445 / 488 / 524
Ag / 401 / 437 / 468 / Au / 450 / 498 / 528
Ag / 416 / 460 / 497 / Au / 466 / 509 / 545
Ag / 458 / 500 / 538 / Au / 722 / 736 / 749
Ag / 470 / 516 / 554 / Au / 747 / 767 / 786
Ag / 480 / 531 / 572 / Au / 750 / 770 / 790
Ag / 731 / 748 / 763 / Au / 759 / 781 / 803
Ag / 739 / 756 / 773 / Au / 844 / 840 / 836
Ag / 745 / 764 / 780 / Au / 850 / 846 / 843
Ag / 757 / 779 / 799 / Au / 1140 / 1168 / 1192
Ag / 851 / 847 / 845 / Au / 1150 / 1179 / 1200
Ag / 856 / 853 / 851 / Au / 1471 / 1499 / 1524
Ag / 1143 / 1172 / 1199 / Au / 1491 / 1526 / 1557
Ag / 1151 / 1179 / 1203 / Au / 1496 / 1534 / 1559
Ag / 1502 / 1537 / 1571 / Au / 1615 / 1656 / 1687
Ag / 1504 / 1559 / 1574
Ag / 1535 / 1573 / 1606
Ag / 1563 / 1607 / 1642

Fig S4 Evolution of the FWHM of the high-frequency 1100 cm-1 dolomite band as a function of pressure, in the vicinity of the DolIb→Dol-II (inset) and Dol-II→Dol-III transitions. The square and star symbols correspond to isothermal compression data at 550 K and 480 K, respectively.

Fig S5 Pressure-induced behavior of the (a) lattice parameters and (b) the distinct O-O bond distances for the Dol-I phase. All of the values have been normalized to facilitate direct comparison. Data from Zucchini et al. (2014).

References

Gillet P, Biellmann C, Reynard B, McMillan P (1993) Raman Spectroscopic Studies of Carbonates Part I: High-Pressure and High-Temperature Behaviour of Calcite, Magnesite, Dolomite and Aragonite. Phys Chem Miner 20:1–18.

Kraft S, Knittle E, Williams Q (1991) Carbonate stability in the Earth’s mantle: A vibrational spectroscopic study of aragonite and dolomite at high pressures and temperatures. J Geophys Res 96:17997–18009.

Merlini M, Crichton WA, Hanfland M, et al (2012) Structures of dolomite at ultrahigh pressure and their influence on the deep carbon cycle. Proc Natl Acad Sci 109:13509–13514.

Santillan J, Williams Q (2004) A high-pressure infrared and X-ray study of FeCO3 and MnCO3: comparison with CaMg(CO3)2-dolomite. Phys Earth Planet Inter 143–144:291–304.

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