Impact-induced shock and the formation of natural quasicrystals in the early solar system

• Published in: Nature Communications
• Main Authors: Hollister, Lincoln S., Bindi, Luca, Yao, Nan, Poirier, Gerald R., Andronicos, Christopher L., MacPherson, Glenn J., Lin, Chaney, Distler, Vadim V., Eddy, Michael P., Kostin, Alexander, Kryachko, Valery, Steinhardt, William M., Yudovskaya, Marina, Eiler, John M., Guan, Yunbin, Clarke, Jamil J., Steinhardt, Paul J.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Nature Publishing Group 2014
• Subjects: Khatyrka; Chukotka
• Online Access: https://doi.org/10.1038/ncomms5040

The discovery of a natural quasicrystal, icosahedrite (Al_(63)Cu_(24)Fe_(13)), accompanied by khatyrkite (CuAl_2) and cupalite (CuAl) in the CV3 carbonaceous chondrite Khatyrka has posed a mystery as to what extraterrestrial processes led to the formation and preservation of these metal alloys. Here we present a range of evidence, including the discovery of high-pressure phases never observed before in a CV3 chondrite, indicating that an impact shock generated a heterogeneous distribution of pressures and temperatures in which some portions reached at least 5 GPa and 1,200 °C. The conditions were sufficient to melt Al–Cu-bearing minerals, which then rapidly solidified into icosahedrite and other Al–Cu metal phases. The meteorite also contains heretofore unobserved phases of iron–nickel and iron sulphide with substantial amounts of Al and Cu. The presence of these phases in Khatyrka provides further proof that the Al–Cu alloys are natural products of unusual processes that occurred in the early solar system. © 2014 Macmillan Publishers Limited. Received 26 November 2013; Accepted 06 May 2014; Published 13 June 2014. L.B. thanks M.I.U.R., P.R.I.N. 2009 project 'Structure, microstructure and properties of minerals', the 'MEMA', Centro di Microscopia Elettronica e Microanalisi, Florence, Italy, and 'CRIST', Centro di Cristallografia Strutturale, Sesto Fiorentino, Florence, Italy. This work was supported in part by the National Science Foundation-MRSEC program through New York University (DMR-0820341; P.J.S.), through the Princeton Center for Complex Materials (DMR-0819860; N.Y.) and NASA grant NNX11AD43G (G.J.M.). The expedition to Chukotka was supported by a grant from an anonymous donor to Princeton University (P.J.S., Principal Investigator). The study was conceived and guided by L.S.H., L.B., C.L.A., G.J.M. and P.J.S., who also led the research team. L.S.H., L.B., N.Y., G.R.P., G.J.M. and C.L. performed the SEM studies. L.S.H., L.B., N.Y., C.L., J.J.C. and P.J.S. performed the FIB-TEM studies. ...