Hostname: page-component-cd9895bd7-dzt6s Total loading time: 0 Render date: 2024-12-27T22:20:14.424Z Has data issue: false hasContentIssue false
  • English
  • Français

Igneous graphite in enstatite chondrites

Published online by Cambridge University Press:  05 July 2018

Alan E. Rubin
Alan E. Rubin*
Affiliation:
Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA 90095-1567, USA
Get access Rights & Permissions [Opens in a new window]

Abstract

Igneous graphite, a rare constituent in terrestrial mafic and ultramafic rocks, occurs in three EH and one EL enstatite chondrite impact-melt breccias as 2–150 µm long euhedral laths, some with pyramidal terminations. In contrast, graphite in most enstatite chondrites exsolved from metallic Fe-Ni as polygonal, rounded or irregular aggregates. Literature data for five EH chondrites on C combusting at high temperatures show that Abee contains the most homogeneous C isotopes (i.e. δ13C = −8.1 ± 2.1‰); in addition, Abee's mean δ13C value is the same as the average high-temperature C value for the set of five EH chondrites. This suggests that Abee scavenged C from a plurality of sources on its parent body and homogenized the C during a large-scale melting event. Whereas igneous graphite in terrestrial rocks typically forms at relatively high pressure and only moderately low oxygen fugacity (e.g., ∼ 5 kbar, logfO2 ∼ −10 at 1200°C), igneous graphite in asteroidal meteorites formed at much lower pressures and oxygen fugacities.

Keywords

igneous graphiteenstatite chondriteimpact-melt brecciaoxygen fugacity
Type
Research Article
Information
Mineralogical Magazine , Volume 61 , Issue 408 , October 1997 , pp. 699 - 703
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1997

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Balhaus, C. and Stumpfl, E.F. (1985) Occurrence and petrological significance of graphite in the Upper Critical Zone, Western Bushveld Complex, South Africa. Earth Planet. Sci. Lett., 74, 58–68.CrossRefGoogle Scholar
Belsky, T. and Kaplan, I.R. (1970) Light hydrocarbon gases, C13, and the origin of organic matter in carbonaceous chondrites. Geochim. Cosmochim. Acta, 34, 257-78.CrossRefGoogle Scholar
Berkley, J.L. and Jones, J.H. (1982) Primary igneous carbon in ureilites: petrological implications. Proc. Lunar Planet. Sci. Conf., 13th, A353-A364.CrossRefGoogle Scholar
Brett, R. and Sato, M. (1984) Intrinsic oxygen fugacity measurements of seven chondrites, a pallasite, and a tektite and the redox state of meteorite parent bodies. Geochim. Cosmochim. Acta, 48, 111—20.CrossRefGoogle Scholar
Field, S.W. and Haggerty, S.E. (1990) Graphitic xenoliths from the Jagersfontein kimberlite, South Africa: Evidence for dominantly anhydrous melting and carbon deposition (abstract). EOS, 71, 658.Google Scholar
Fogel, R.A., Hess, P.C. and Rutherford, M.J. (1989) Intensive parameters of enstatite chondrite meta-morphism. Geochim. Cosmochim. Acta, 53, 2735-46.CrossRefGoogle Scholar
Grady, M.M., Wright, I.P., Carr, L.P. and Pillinger, C.T. (1986) Compositional differences in enstatite chondrites based on carbon and nitrogen stable isotope measurements. Geochim. Cosmochim. Acta, 50, 2799-813.CrossRefGoogle Scholar
Hatton, C.J. and Gurney, J.J. (1979) A diamond-graphite eclogite from the Roberts Victor Mine. In The Mantle Sample: Inclusions from Kimberlites and Other Volcanics (F.R. Boyd and H.O.A. Meyer, eds.), pp. 29—36. American Geophysical Union.CrossRefGoogle Scholar
Herndon, J.M. and Rudee, M.L. (1978) Thermal history of the Abee enstatite chondrite. Earth Planet. Sci. Len., 41, 101-6.CrossRefGoogle Scholar
Hollister, V.F. (1980) Origin of graphite in the Duluth Complex. Econ. Geology, 75, 764—6.CrossRefGoogle Scholar
Hughes, D.W. (1982) Asteroidal size distribution. Mon. Not. R. astron. Soc., 199, 1149–57.CrossRefGoogle Scholar
Huss, G.R. and Lewis, R.S. (1995) Presolar diamond, SiC, and graphite in primitive chondrites: Abundances as a function of meteorite class and petrologic type. Geochim. Cosmochim. Acta, 59, 115-60.CrossRefGoogle Scholar
Keil, K. (1968) Mineralogical and chemical relation-ships among enstatite chondrites. J. Geophys. Res., 73, 6945-76.CrossRefGoogle Scholar
Kornprobst, J., Pineau, F., Degiovanni, R. and Dautria, J.M. (1987) Primary igneous graphite in ultramafic xenoliths: I. Petrology of the cumulate suite in alkali basalt near Tissemt (Eggere, Algerian Sahara). J. Petrol., 28, 293–311.CrossRefGoogle Scholar
Larimer, J.W. and Buseck, P.R. (1974) Equilibration temperatures in enstatite chondrites. Geochim. Cosmochim. Acta, 38, 471—7.CrossRefGoogle Scholar
Mason, B. (1966) The enstatite chondrites. Geochim. Cosmochim. Acta, 30, 23–39.CrossRefGoogle Scholar
Pearson, D.G., Boyd, F.R. and Nixon, P.H. (1990) Graphite-bearing mantle xenoliths from the Kaapvaal Craton: Implications for graphite and diamond genesis. Ann. Rpt. Geophys. Lab., Carnegie Inst. Wash. 1989-1990, 11-19.Google Scholar
Ramdohr, P. (1973) The Opaque Minerals in Stony Meteorites, Elsevier Pub. Co., Amsterdam, 245 pp.Google Scholar
Robinson, D.N. (1979) Diamond and graphite in eclogite xenoliths from kimberlite. In The Mantle Sample: Inclusions in Kimberlites and Other Volcanics (Boyd, F.R. and Meyer, H.O.A., eds.), pp. 50—8. American Geophysical Union.CrossRefGoogle Scholar
Rubin, A.E. (1983) The Adhi Kot breccia and implications for the origin of chondrules and silica-rich clasts in enstatite chondrites. Earth Planet. Sci. Lett., 64, 201-12.CrossRefGoogle Scholar
Rubin, A.E. (1997) Sinoite (Si2N2O): Crystallization from EL chondrite impact melts. Amer. Mineral., 82, in press.CrossRefGoogle Scholar
Rubin, A.E. and Keil, K. (1983) Mineralogy and petrology of the Abee enstatite chondrite breccia and its dark inclusions. Earth Planet. Sci. Lett., 62, 118-31.CrossRefGoogle Scholar
Rubin, A.E. and Scott, E.R.D. (1997) Abee and related EH chondrite impact-melt breccias. Geochim. Cosmochim. Acta, 61, 425—35.CrossRefGoogle Scholar
Rudee, M.L. and Herndon, J.M. (1980) The thermal history of Abee (abstract). Meteoritics, 15, 361.Google Scholar
Russell, S.S., Pillinger, C.T., Arden, J.W., Lee, M.R. and Ott, U. (1992) A new type of meteoritic diamond in the enstatite chondrite Abee. Science, 256, 206—9.CrossRefGoogle ScholarPubMed
Scott, E.R.D. (1971) Studies of the structure and composition of iron meteorites. Ph.D. dissertation, University of Cambridge.Google Scholar
Semenenko, V.P. (1996) New data on a carbonaceous clast in the Krymka chondrite (abstract). Met. Planet. Sci., 31, A126-A127.Google Scholar
Semenenko, V.P. and Girich, A.L. (1995) Mineralogy of a unique graphite-containing fragment in the Krymka chondrite (LL3). Mineral. Mag., 59, 443-54.CrossRefGoogle Scholar
Semenenko, V.P., Kolesov, G.M., Samoilovich, L.G., Golovko, N.V. and Ljul, A.Yu. (1991) Carbonaceous inclusions in the Krymka (LL3) chondrite (abstract). Lunar Planet. Sci., 22, 1213-4.Google Scholar
Skinner, B.J. and Luce, F.D. (1971) Solid solutions of the type (Ca,Mg,Mn,Fe)S and their use as geotherm- ometers for the enstatite chondrites. Amer. Mineral., 56, 1269-96.Google Scholar
Spry, A. (1969) Metamorphic Textures, Pergamon Press, Oxford, 350 pp.Google Scholar
Treiman, A.H. and Berkley, J.L. (1994) Igneous petrology of the new ureilites Nova 001 and Nullarbor 010. Meteoritics, 29, 843–8.CrossRefGoogle Scholar
Turcotte, D.L. and Schubert, G. (1982) Geodynamics: Applications of Continuum Physics to Geological Problems, Wiley, 450 pp.Google Scholar
Walker, D. and Grove, T. (1993) Ureilite smelting. Meteoritics, 28, 629-36.CrossRefGoogle Scholar
Warren, P.H. and Kallemeyn, G.W. (1992) Explosive volcanism and the graphite-oxygen fugacity buffer on the parent asteroid(s) of the ureilite meteorites. Icarus, 100, 110-26.CrossRefGoogle Scholar