Abstract
Shock-produced akimotoite was identified in the Suizhou chondritic meteorite, which occurs in two kinds of occurrence. The first is the irregular layers of akimotoite up to 4 μm in thickness occurring in fractures and cracks of low-Ca pyroxene enclosed in the shock veins. The second is the zonal polycrystalline aggregates of akimotoite in shocked pyroxene grains close to the shock vein, where akimotoite occurs in a zonal area in between pyroxene and MgSiO3-glass as irregular small clumps up to 5 μm in size. This investigation suggests a solid-state transformation mechanism of pyroxene to akimotoite, and that akimotoite should have nucleated and grew in the area with abundant defects caused by shock deformation because the defect significantly enhances the solid-state reactivity and the kinetics of nucleation of high-pressure phase. The spatial relationship among the composed grains of pyroxene, akimotoite and MgSiO3-glass (possibly vitrified perovskite) demonstrates a temperature gradient from the vein wall to the unmelted chondritic meteorite.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Agee C B, Li J, Shannon M C, et al. 1995. Pressure-temperature phase diagram for Allende meteorite. J Geophys Res, 100: 17725–17740
Chen M, Sharp T G, El Goresy A, et al. 1996. The majorite-pyrope+magnesiowustite assemblage: Constrains on the history of shock veins in chondrites. Science, 271: 1570–1573
Chen M, Shu J F, Xie X D, et al. 2003a. Natural CaTi2O4-structured FeCr2O4 polymorph in the Suizhou meteorite and its significance in mantle mineralogy. Geochim Cosmochim Acta, 67: 3937–3942
Chen M, Shu J F, Mao H K, et al. 2003b. Natural occurrence and synthesis of two new postspinel polymorphs of chromite. Proc Nat Acad Sci USA, 100: 14651–14654
Chen M, Xie X D, El Goresy A. 2004. A shock-produced (Mg, Fe) SiO3 glass in the Suizhou meteorite. Meteorol Planet Sci, 39: 1797–1808
Chen M, Li H, El Goresy A, et al. 2006. Fracture-related intracrystalline transformation of olivine to ringwoodite in the shocked Sixiangkou meteorite. Meteorit Planet Sci, 41: 731–737
Chen M, Chen J, Xie X et al. 2007. A microstructural investigation of natural lamellar ringwoodite in olivine of the shocked Sixiangkou chondrite. Earth Planet Sci Lett, 264: 277–283
Chen M, Shu J F, Mao H K. 2008. Xieite, a new mineral of high-pressure FeCr2O4 polymorph. Chin Sci Bull, 53: 3341–3345
Durben D J, Wolf G, 1992. High-temperature behavior of metastable MgSiO3 perovskite: A Raman spectroscopic study. Am Mineral, 77: 890–893
Ferroir T, Beck P, Van de Moortèle B, et al. 2008. Akimotoite in the Tenham meteorite: Crystal chemistry and high-pressure transformation mechanisms. Earth Planet Sci Lett, 275: 26–31
Gasparik P. 1993. The role of volatiles in the transition zone. J Geophys Res, 98: 4287–4299
Hogrefe A, Rubie D C, Sharp T G, et al. 1994. Metastability of enstatite in deep subducting lithosphere. Nature, 372: 351–353
Liu L G. 1976. The high-pressure phases of MgSiO3. Earth Planet Sci Lett, 31: 200–208
McMillan P. 1984a. Structure studies of silicate glasses and melts-Applications and limitations of Raman spectroscopy. Am Mineral, 69: 622–644
McMillan P. 1984b. A Raman spectroscopic study of glasses in the system CaO-MgO-SiO2. Am Mineral, 69: 649–659
Nagy Sz, Bérczi Sz, Józsa S, et al. 2010. Olivine and pyroxene high- pressure polymorphs in melt veins of the strongly shocked NWA 5011 meteorite sample. In: 41st Lunar Planetary Science Conference, Houston, No.1228
Ohtani E, Kimura Y, Kimura M, et al. 2004. Formation of high-pressure minerals in shocked L6 chondrite Yamato 791384: Constraints on shock conditions and parent body size. Earth Planet Sci Lett, 227: 505–515
Presnell D C. 1995. Phase diagrams of earth-forming minerals. In: Ahrens T J, ed. Mineral Physics and Crystallography: A Handbook of Physical Constants. Amer Geophys Union. 248–268
Thadhani N N. 1994. Shock induced and shock-assisted solid-state chemical reactions in powder mixtures. J Appl Phys, 76: 2129–2138
Tomioka N, Fujino K. 1997. Natural (Mg, Fe) SiO3-ilmenite and — perovskite in the Tenham meteorite. Science, 277: 1084–1086
Tomioka N, Fujino K. 1999. Akimotoite, (Mg, Fe) SiO3, a new silicate mineral of the ilmenite group in the Tenham chondrite. Am Mineral, 84: 267–271
Sharp T G, Lingemann C M, Dupas C, et al. 1997. Natural occurrence of MgSiO3-ilmenite and evidence for MgSiO3-perovskite in a shocked L chondrite. Science, 277: 352–255
Stöffler D, Keil K, Scott E R D. 1991. Shock metamorphism of ordinary chondrites. Geochim Cosmochim Acta, 55: 3845–3867
Xie X D, Chen M, Wang D Q. 2001. Shock-related mineralogical features and P-T history of the Suizhou L6 chondrite. Eur J Mineral, 13: 1177–1190
Xie X D, Minitti M E, Chen M, et al. 2003. Tuite, γ-Ca3(PO4)2, a new phosphate mineral from the Suizhou L6 chondrite. Eur J Mineral, 15: 1001–1005
Xie X D, Chen M, Wang D Q. 2005. Two types of silicate melts in naturally shocked meteorites. In: Papers and abstracts of the 5th Annual Meeting of IPACES, Guangzhou. 12–14
Xie X D, Sun Z Y, Chen M. 2011. The distinct morphological and petrological features of shock melt veins in the Suizhou L6 chondrite. Meteorit Planet Sci, 46: 459–469
Xie Z D, Sharp T G. 2004. High-pressure phases in shock-induced melt veins of the Umbarger L6 chondrite: Constraints of pressure. Meteor Planet Sci, 39: 2043–2054
Zhang A C. 2006. Pyroxene polymorphs in melt veins of the heavily shocked Sixiangkou L6 chondrite. Eur J Mineral, 18: 719–726
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Chen, M., Xie, X. Shock-produced akimotoite in the Suizhou L6 chondrite. Sci. China Earth Sci. 58, 876–880 (2015). https://doi.org/10.1007/s11430-014-5039-5
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11430-014-5039-5