Abstract
The structures of Ti-bearing anhydrous phase B and superhydrous phase B synthesized at 12 GPa/1600 °C and 21 GPa/1600 °C, respectively, have been determined by single-crystal X-ray diffraction. Anhydrous phase B has space group Pmcb. The structure of superhydrous phase B was refined in space groups Pnnm and Pnn2; crystallographic arguments unambiguously indicated that the centrosymmetric space group Pnnm is the correct choice for the crystal studied here. Ti orders at the octahedrally coordinated Si(1) site in both phases. The refined site occupancies at the Si(1) sites of anhydrous phase B and superhydrous phase B are 0.848(3) Si + 0.152 Ti and 0.92(1) + 0.08 Ti, respectively. These Ti occupancy levels correlate with a 4% expansion of the Si(1)O6 octahedron relative to values typically observed for end-member anhydrous phase B, Fe2+-bearing anhydrous phase B, and end-member superhydrous phase B. Ordering of Ti at the Si(1) is explained in terms of a homovalent substitution VISi → VITi4+, being the only option for these structures. There is no evidence for a deprotonation substitution of the kind Mg + 2OH− → Ti4+ + 2O2−, as occurs in humites. Synthesis of Ti-bearing superhydrous phase B indicates that it is stable at typical P–T conditions of the mantle transition zone and the lower mantle. Hence, water can be transported by Ti-bearing superhydrous B into the lower mantle even at temperatures of the normal mantle geotherm.
Similar content being viewed by others
References
Akimoto S, Akaogi M (1980) The system Mg2SiO4–MgO–H2O at high pressures and temperatures—possible hydrous magnesian silicates in the mantle transition zone. Phys Earth Planet Inter 23:268–275
Bindi L, Sirotkina EA, Bobrov AV, Irifune T (2014a) Chromium solubility in perovskite at high pressure: The structure of (Mg1–xCrx)(Si1–xCrx)O3 (with x = 0.07) synthesized at 23 GPa and 1600 °C. Am Mineral 99(4):866–869
Bindi L, Sirotkina EA, Bobrov AV, Irifune T (2014b) Chromium solubility in MgSiO3 ilmenite at high pressure. Phys Chem Minerals 41(7):519–526
Bindi L, Sirotkina EA, Bobrov AV, Nestola F, Irifune T (2016) Chromium solubility in anhydrous Phase B. Phys Chem Minerals 43(2):103–110
Bindi L, Sirotkina EA, Bobrov AV, Walter MJ, Pushcharovsky D, Irifune T (2017) Bridgmanite-like crystal structure in the novel Ti-rich phase synthesized at transition zone condition. Am Mineral 102(1):227–231
Brown ID, Shannon RD (1973) Empirical bond-strength–bond-length curves for oxides. Acta Cryst A29:266–282
Finger LW, Hazen RM, Prewitt CT (1991) Crystal structures of Mg12Si4O19(OH)2 (phase B) and Mg14Si5O24 (phase AnhB). Am Mineral 76(1–2):1–7
Frost DJ (1999) The stability of dense hydrous magnesium silicates in Earth’s transition zone and lower mantle. Mantle petrology: field observations and high pressure experimentations. The Geochemical Society Spec Publ 6. The Geochemical Society, Houston, pp 283–296
Fujino K, Takéuchi Y (1978) Crystal chemistry of titanian chondrodite and titanian clinohumite of high-pressure origin. Am Mineral 63(5–6):535–543
Ganguly J, Frost DJ (2006) Stability of anhydrous phase B: experimental studies and implications for phase relations in subducting slab and the X discontinuity in the mantle. J Geophys Res Solid Earth. https://doi.org/10.1029/2005JB003910
Gasparik T (1993) The role of volatiles in the transition zone. J Geophys Res 98:4287–4300
Hayman PC, Kopylova MG, Kaminsky FV (2005) Lower mantle diamonds from Rio Soriso (Juina area, Mato Grosso, Brazil). Contr Min Petr 149(4):430–445
Hazen RM, Finger LW, Ko J (1992) Crystal chemistry of Fe-bearing anhydrous phase B: implications for transition zone mineralogy. Am Mineral 77(1–2):217–220
Herzberg CT, Gasparik T (1989) Melting experiments on chondrite at high pressures: stability of anhydrous phase B. Eos Trans AGU 70(15):484
Irifune T, Fujino K, Ohtani E (1991) A new high-pressure form of MgAl2O4. Nature 349(6308):409
Irifune T, Kubo N, Isshiki M, Yamasaki Y (1998) Phase transformation in serpentine and transportation of water into the lower mantle. Geophys Res Lett 25:203–206
Irifune T, Kurio A, Sakamoto S, Inoue T, Sumiya H, Funakoshi KI (2004) Formation of pure polycrystalline diamond by direct conversion of graphite at high pressure and high temperature. Phys Earth Planet Int 143:593–600
Kakizawa S, Inoue T, Nakano H, Kuroda M, Sakamoto N, Yurimoto H (2018) Stability of Al-bearing superhydrous phase B at the mantle transition zone and the uppermost lower mantle. Am Mineral 103:1221–1227
Kaminsky F, Zakharchenko O, Davies R, Griffin W, Khachatryan-Blinova G, Shiryaev A (2001) Superdeep diamonds from the Juina area, Mato Grosso State, Brazil. Contr Min Petr 140(6):734–753
Katsura T, Ito E (1989) The system Mg2SiO4–Fe2SiO4 at high pressure and temperatures: precise determination of stabilities of olivine, modified spinel and spinel. J Geophys Res 94:15663–15670
Koch-Müller M, Dera P, Fei Y, Hellwig H, Liu Z, Van Orman J, Wirth R (2005) Polymorphic phase transition in superhydrous phase B. Phys Chem Miner 32:349–361
McDonough WF, Sun SS (1995) The composition of the Earth. Chem Geol 120(3–4):223–253
Ohtani E, Litasov K, Suzuki A, Kondo T (2001) Stability field of new hydrous phase, δ-AlOOH, with implications for water transport into the deep mantle. Geophys Res Lett 28(20):3991–3993
Ohtani E, Toma M, Kubo T, Kondo T, Kikegawa T (2003) In situ X‐ray observation of decomposition of superhydrous phase B at high pressure and temperature. Geophys Res Lett. https://doi.org/10.1029/2002GL015549
Pacalo RE, Parise JB (1992) Crystal structure of superhydrous B, a hydrous magnesium silicate synthesized at 1400 °C and 20 GPa. Am Mineral 77(5–6):681–684
Robinson K, Gibbs GV, Ribbe PH (1971) Quadratic elongation: a quantitative measure of distortion in coordination polyhedra. Science 172(3983):567–570
Shannon RD (1976) Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides. Acta Cryst A32:751–767
Sheldrick GM (2008) A short history of SHELX. Acta Crystallogr A 64(1):112–122
Sirotkina EA, Bobrov AV, Bindi L, Irifune T (2015) Phase relations and formation of chromium-rich phases in the system Mg4Si4O12–Mg3Cr2Si3O12 at 10–24 GPa and 1600 °C. Contrib Mineral Petrol 169(1):2
Sirotkina EA, Bindi L, Bobrov AV, Aksenov SM, Irifune T (2018a) Synthesis and crystal structure of chromium-bearing anhydrous wadsleyite. Phys Chem Minerals 45:1–6
Sirotkina EA, Bobrov AV, Bindi L, Irifune T (2018b) Chromium-bearing phases in the Earth’s mantle: evidence from experiments in the Mg2SiO4–MgCr2O4 system at 10–24 GPa and 1600 °C. Am Mineral 103(1):151–160
Thomas SM, Koch-Müller M, Kahlenberg V, Thomas R, Rhede D, Wirth R, Wunder B (2008) Protonation in germanium equivalents of ringwoodite, anhydrous phase B, and superhydrous phase B. Am Mineral 93(8–9):1282–1294
Thomson AR, Walter MJ, Kohn SC, Brooker RA (2016) Slab melting as a barrier to deep carbon subduction. Nature 529(7584):76
Wilson AJC (1992a) International tables for crystallography, vol C. Kluwer Academic Publishers, Dordrecht
Wilson DS (1992b) Focused mantle upwelling beneath mid-ocean ridges: evidence from seamount formation and isostatic compensation of topography. Earth Planet Sci Lett 113(1–2):41–55
Yamada A, Inoue T, Irifune T (2004) Melting of enstatite from 13 to 18 GPa under hydrous conditions. Phys Earth Planet Inter 147:45–56
Yuan L, Ohtani E, Shibazaki Y, Ozawa S, Jin Z, Suzuki A, Frost DJ (2018) The stability of anhydrous phase B, Mg14Si5O24, at mantle transition zone conditions. Phys Chem Minerals 45:523–531
Zou Y, Irifune T (2012) Phase relations in Mg3Cr2Si3O12 and formation of majoritic knorringite garnet at high pressure and high temperature. J Mineral Petrol Sci 107:197–205
Acknowledgements
The constructive reviews of anonymous referees were very helpful for improving the quality of the manuscript. This study was supported by the Russian Science Foundation (Project No. 17-17-01169 to AB, EM). The experimental and structural studies were supported by the Russian Foundation for Basic Research (Project No. 18-05-00332 to DP). In this study, we used the author’s database of high-pressure phase associations, created with the support of Program 8P No. 0137-2018-0043.
Author information
Authors and Affiliations
Corresponding author
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Electronic supplementary material
Below is the link to the electronic supplementary material.
Rights and permissions
About this article
Cite this article
Matrosova, E.A., Welch, M.D., Bobrov, A.V. et al. Incorporation of Ti into the crystal structures of the high-pressure dense silicates anhydrous phase B and superhydrous phase B. Phys Chem Minerals 46, 909–920 (2019). https://doi.org/10.1007/s00269-019-01050-0
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00269-019-01050-0