Xenoliths and microxenoliths in H chondrites: Sampling the zodiacal cloud in the asteroid Main Belt

Meteoritics and Planetary Science

Volumn 47, Issue 5, 2012, Pages 880-902

  Briani, Giacomo ^a,b,d   Gounelle, Matthieu ^b   Bourot Denise, Michèle ^b   Zolensky, Michael E ^c  

^a UNIVERSITY OF FLORENCE   (Italy)

^b MUSÉUM NATIONAL D'HISTOIRE NATURELLE   (France)

^c NASA JOHNSON SPACE CENTER   (United States)

^d CENTRE DE CALCUL DE L INSTITUT NATIONAL DE PHYSIQUE NUCLEAIRE ET DE PHYSIQUE DES PARTICULES   (France)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 84861444013     PISSN: 10869379     EISSN: None     Source Type: Journal    
DOI: 10.1111/j.1945-5100.2012.01367.x     Document Type: Article

References (104)

1. Abreu N. M. and Brearley A. J. 2010. Early solar system processes recorded in the matrices of two highly pristine CR3 carbonaceous chondrites, MET 00426 and QUE 99177. Geochimica et Cosmochimica Acta 74:1146-1171.
2. Bischoff A., Scott E. R. D., Metzler K., and Goodrich C. A. 2006. Nature and origins of meteoritic breccias. In Meteorites and the early solar system II, edited by Lauretta D. S. and McSween H. Y. Tucson, Arizona: The University of Arizona Press. pp. 679-712.
3. Bischoff A., Horstmann M., Pack A., Laubenstein M., and Haberer S. 2010. Asteroid 2008 TC3-Almahata Sitta: A spectacular breccia containing many different ureilitic and chondritic lithologies. Meteoritics & Planetary Science 45:1638-1656.
4. Bland P. A., Smith T. B., Berry F. J., Bevan A. W., Couldt S., and Pillinger C. T. 1996. The flux of meteorites to the Earth over the last 50, 000years. Monthly Notices of the Royal Astronomical Society 233:551-565.
5. Bogard D. D. 1995. Impact ages of meteorites: A review. Meteoritics 30:244-268.
6. Brearley A. J. and Papike J. J. 1993. Carbonaceous chondrite clasts in the Kapoeta howardite (abstract). 24th Lunar and Planetary Science Conference. p. 183.
7. Brearley A. J. and Prinz M. 1992. CI chondrite-like clasts in the Nilpena polymict ureilite-Implications for aqueous alteration processes in CI chondrites. Geochimica et Cosmochimica Acta 56:1373-1386.
8. Briani G., Morbidelli A., Gounelle M., and Nesvorný D. 2011. Evidence for an asteroid-comet continuum from simulations of carbonaceous microxenolith dynamical evolution. Meteoritics & Planetary Science 46:1863-1877.
9. Buchanan P. C. and Zolensky M. E. 2003. Carbonaceous chondrite fragments in the polymict eucrite Yamato 791834 (abstract #1299). 34th Lunar and Planetary Science Conference. CD-ROM.
10. Buchanan P. C., Zolensky M. E., and Reid A. M. 1993. Carbonaceous chondrite clasts in the howardites Bholghati and EET87513. Meteoritics 28:659-669.
11. Bunch T. E., Chang S., Frick U., Neil J. M., and Moreland G. 1979. Carbonaceous chondrites. I-Characterization and significance of carbonaceous chondrite CM xenoliths in the Jodzie howardite. Geochimica et Cosmochimica Acta 43:1727-1729.
12. Campins H. and Swindle T. D. 1998. Expected characteristics of cometary meteorites. Meteoritics & Planetary Science 33:1201-1211.
13. Dodd R. T. and Jarosewich E. 1979. Incipient melting in and shock classification of L-group chondrites. Earth and Planetary Science Letters 44:335-340.
14. Durda D. D., Bottke W. F., Nesvorný D., Enke B. L., Merline W. J., Asphaug E., and Richardson D. C. 2007. Size-frequency distribution of fragments from SPH/N-body simulations of asteroid impacts: Comparison with observed families. Icarus 186:498-516.
15. Flynn G. J., Sutton S. R., and Klöck W. 1993. Compositions and mineralogies of unmelted polar micrometeorites: Similarities and differences with IDPs and meteorites. Proceedings of the NIPR Symposium on Antarctic Meteorites 6:304-324.
16. Fodor R. V. and Keil K. 1976. Carbonaceous and non-carbonaceous lithic fragments in the Plainview, Texas, chondrite-Origin and history. Geochimica et Cosmochimica Acta 40:177-189.
17. Fodor R. V., Keil K., Wilkening L. L., Bogard D. D., and Gibson E. K. 1976. Origin and history of a meteorite parent-body regolith breccia: Carbonaceous and non-carbonaceous lithic fragments in the Abbott, New Mexico, chondrite. In Tectonics and mineral resources of southwestern North America, edited by Woodward L. A. and Northrop S. A. Socorro, New Mexico: New Mexico Geological Society Special Publication, vol. 2. pp. 206-218.
18. Fuchs H. L., Olsen E., and Jensen K. J. 1973. Mineralogy, mineral-chemistry and composition of the Murchison (C2) meteorite. Smithsonian Contribution to the Earth Science 10:1-39.
19. Genge M. J. 2006. Ordinary chondrite micrometeorites from the Koronis asteroids (abstract #1759). 37th Annual Lunar and Planetary Science Conference. CD-ROM.
20. Genge M., Engrand C., Gounelle M., and Taylor S. 2008. The classification of micrometeorites. Meteoritics & Planetary Science 43:497-515.
21. Gordon S. H., Hammond S. J., Howard L. E., and Bland P. A. 2009. Dark inclusions: Clasts of CM-type material within Allende (abstract #1713). 40th Lunar and Planetary Science Conference. CD-ROM.
22. Goswami J. N., Lal D., and Wilkening L. L. 1984. Gas-rich meteorites-Probes for particle environment and dynamical processes in the inner solar system. Space Science Reviews 37:111-159.
23. Gounelle M. 2011. The asteroid-comet continuum: In search of lost primitivity. Elements 7:29-34.
24. Gounelle M., Zolensky M. E., Liou J.-C., Bland P. A., and Alard O. 2003. Mineralogy of carbonaceous chondritic microclasts in howardites: Identification of C2 fossil micrometeorites. Geochimica et Cosmochimica Acta 67:507-527.
25. Gounelle M., Engrand C., Alard O., Bland P. A., Zolensky M. E., Russell S. S., and Duprat J. 2005. Hydrogen isotopic composition of water from fossil micrometeorites in howardites. Geochimica et Cosmochimica Acta 69:3431-3443.
26. Gounelle M., Spurny P., and Bland P. A. 2006. The orbit and atmospheric trajectory of the Orgueil meteorite from historical records. Meteoritics & Planetary Science 41:135-150.
27. Gounelle M., Morbidelli A., Bland P. A., Spurny P., Young E. D., and Sephton M. 2008. Meteorites from the outer solar system? In The solar system beyond Neptune, edited by Barucci M. A., Boehnhardt H., Cruikshank D. P., and Morbidelli A. Tucson, Arizona: The University of Arizona Press. pp. 525-541.
28. Gounelle M., Chaussidon M., Morbidelli A., Barrat J. A., Engrand C., Zolensky M. E., and McKeegan K. D. 2009. A unique basaltic micrometeorite expands the inventory of solar system planetary crusts. Proceedings of the National Academy of Sciences 106:6904-6909.
29. Greshake A., Krot A. N., Meibom A., Weisberg M. K., Zolensky M. E., and Keil K. 2002. Heavily-hydrated lithic clasts in CH chondrites and the related, metal-rich chondrites Queen Alexandra Range 94411 and Hammadah al Hamra 237. Meteoritics & Planetary Science 37:281-293.
30. Grimm R. E. 1985. Penecontemporaneous metamorphism, fragmentation, and reassembly of ordinary chondrite parent bodies. Journal of Geophysical Research 90:2022-2028.
31. Grimm R. E., Bottke W., Durda D. D., Enke B., Scott E. R. D., Asphaug E., and Richardson D. 2005. Joint thermal and collisional modeling of the H-chondrite parent body (abstract #1798). 36th Lunar and Planetary Science Conference. CD-ROM.
32. Grün E., Zook H. A., Fechtig H., and Giese R. H. 1985. Collisional balance of meteoritic complex. Icarus 62:244-272.
33. Grün E., Dikarev V., Frisch P. C., Graps A., Kempf S., Krüger H., Landgraf M., Moragas-Klostermeyer G., and Srama R. 2004. Dust in interplanetary space and in the local galactic environment. Astrophysics of Dust 309:245-263.
34. Gustafson B. A. S. 1994. Physics of zodiacal dust. Annual Review of Earth and Planetary Sciences 22:553-595.
35. Halliday I., Blackwell A. T., and Griffin A. A. 1989. The flux of meteorites on the Earth's surface. Meteoritics 24:173-178.
36. Huss G. R., Keil K., and Taylor G. J. 1981. The matrices of unequilibrated ordinary chondrites: Implications for the origin and history of chondrites. Geochimica et Cosmochimica Acta 45:33-51.
37. Ikeda Y., Kita N. T., Morishita Y., and Weisberg M. K. 2003. Primitive clasts in the Dar al Gani 319 polymict ureilite: Precursors of the ureilites. Antarctic Meteorite Research 16:105-127.
38. Ivanov A. V., Ulyanov A. A., Skripnic A. Y., and Konokona N. N. 1984. The Kaidun polymict carbonaceous breccia: The mixture of incompatible types of meteorites. (abstract). 15th Lunar and Planetary Science Conference. pp. 393-394.
39. Johnson C. A. and Prinz M. 1993. Carbonate compositions in CM and CI chondrites, and implications for aqueous alteration. Geochimica et Cosmochimica Acta 57:2843-2852.
40. Keil K. 1982. Composition and origin of chondritic breccias. In Workshop on Lunar Breccias and Soils and their Meteoritic Analogs, edited by Taylor G. J. and Wilkening L. L. LPI Technical Report 82-02. Houston, Texas: Lunar and Planetary Institute. 65 p.
41. Keil K., Fodor R. V., Starzyk P. M., Schmitt R. A., Bogard D. D., and Husain L. 1980. A 3.6-b.y.-old impact-melt rock fragment in the Plainview chondrite: Implications for the age of the H-group chondrite parent body regolith formation. Earth and Planetary Science Letters 51:235-247.
42. Kleine T., Touboul M., Van Orman J. A., Bourdon B., Maden C., Mezger K., and Halliday A. N. 2008. Hf-W thermochronometry: Closure temperature and constraints on the accretion and cooling history of the H chondrite parent body. Earth and Planetary Science Letters 270:106-118.
43. Krot A. N., Brearley A. J., Ulyanov A. A., Biryukov V. V., Swindle T. D., Keil K., Mittlefehldt D. W., Scott E. R. D., Clayton R. N., and Mayeda T. K. 1999. Mineralogy, petrography and bulk chemical, iodine-xenon, and oxygen-isotopic compositions of dark inclusions in the reduced CV3 chondrite Efremovka. Meteoritics & Planetary Science 34:67-89.
44. Kuehner S. M., Irving A. J., Rumble D., Nicklin I., and Gregory D. A. 2009. Exotic, primitive micrometeorite clasts related to CM chondrites in polymict eucrite breccia Northwest Africa 5232 (abstract #2315). 40th Lunar and Planetary Science Conference. CD-ROM.
45. Lee P., Veverka J., Thomas P. C., and Helfenstein P. 1996. Ejecta blocks on 243 Ida and on other asteroids. Icarus 120:87-105.
46. Leinert C., Roser S., and Buitrago J. 1983. How to maintain the spatial distribution of interplanetary dust. Astronomy & Astrophysics 118:345-357.
47. Leitch C. A. and Grossman L. 1977. Lithic clasts in the Supuhee chondrite. Meteoritics 12:125-139.
48. Levison H. F., Bottke W. F., Gounelle M., Morbidelli A., Nesvorný D., and Tsiganis K. 2009. Contamination of the asteroid belt by primordial trans-Neptunian objects. Nature 460:364-366.
49. Lipschutz M. E., Gaffey M. J., and Pellas P. 1989. Meteoritic parent bodies-Nature, number, size and relation to present-day asteroids. In Asteroids II, edited by Matthews M. S., Binzel R., and Gehrels T. Tucson, Arizona: The University of Arizona Press. pp. 740-777.
50. Lorenz C. A., Ivanova M. A., Kurat G., and Brandstätter F. 2005. FeO-rich xenoliths in the Staroye Pesyanoe aubrite (abstract #1612). 36th Lunar and Planetary Science Conference. CD-ROM.
51. Love S. G. and Brownlee D. E. 1993. A direct measurement of the terrestrial mass accretion rate of cosmic dust. Science 262:550-553.
52. MacPherson G. J., Jarosewich E., and Lowenstein P. 1993. Magombedze-A new H-chondrite with light-dark structure. Meteoritics 28:138-142.
53. Mason B. and Nelen J. 1968. The weatherford meteorite. Geochimica et Cosmochimica Acta 32:661-662.
54. McCall G. J. 1973. Meteorites and their origins. New York: Wiley & Sons.
55. Meibom A. and Clark B. E. 1999. Evidence for the insignificance of ordinary chondritic material in the asteroid belt. Meteoritics & Planetary Science 34:7-24.
56. Meier M. M. M., Schmitz B., Baur H., and Wieler R. 2010. Noble gases in individual L chondritic micrometeorites preserved in an Ordovician limestone. Earth and Planetary Science Letters 290:54-63.
57. Michikami T., Moriguchi K., Hasegawa S., and Fujiwara A. 2007. Ejecta velocity distribution for impact cratering experiments on porous and low strength targets. Planetary and Space Science 55:70-88.
58. Minster J. F. and Allegre C. 1979. Rb-87-Sr-87 chronology of H chondrites-Constraint and speculations on the early evolution of their parent body. Earth and Planetary Science Letters 42:333-347.
59. Mittlefehldt D. W. 1994. The genesis of diogenites and HED parent body petrogenesis. Geochimica et Cosmochimica Acta 58:1537-1552.
60. Miyamoto M., Fujii N., and Takeda H. 1982. Ordinary chondrite parent body: An internal heating model. Proceedings, 12th Lunar and Planetary Science Conference. pp. 1145-1152.
61. Miyamoto H., Yano H., Scheeres D. J., Abe S., Barnouin-Jha O., Cheng A. F., Demura H., Gaskell R. W., Hirata N., Ishiguro M., Michikami T., Nakamura A. M., Nakamura R., Saito J., and Sasaki S. 2007. Regolith migration and sorting on asteroid Itokawa. Science 316:1011-1014.
62. Nakashima D., Nakamura T., and Noguchi T. 2003. Formation history of CI-like phyllosilicate-rich clasts in the Tsukuba meteorite inferred from mineralogy and noble gas signatures. Earth and Planetary Science Letters 212:321-336.
63. Nazarov M. A. and Ariskin A. A. 1993. The Erevan howardite: Petrology of glassy clasts and mineral chemistry (abstract #1049). 24th Lunar and Planetary Science Conference. CD-ROM.
64. Nazarov M. A., Brändstatter F., and Kurat G. 1993. Carbonaceous xenoliths from the Erevan howardite (abstract #1053). 24th Lunar and Planetary Science Conference. CD-ROM.
65. Nazarov M. A., Brandstätter F., Kurat G., Spettel B., and Palme H. 1994. Chemistry of carbonaceous xenoliths from the Erevan howardite (abstract #981). 25th Lunar and Planetary Science Conference. CD-ROM.
66. Nesvorný D., Jedicke R., Whiteley R. J., and Ivezić Ž. 2005. Evidence for asteroid space weathering from the Sloan Digital Sky Survey. Icarus 173:132-152.
67. Nesvorný D., Jenniskens P., Levison H. F., Bottke W. F., Vokrouhlický D., and Gounelle M. 2010. Cometary origin of the zodiacal cloud and carbonaceous micrometeorites. The Astrophysical Journal 713:816-836.
68. Noguchi T., Nakamura T., Nakashima D., Inada A., and Nagao K. 2003. CI-like chondrite clasts in ordinary chondrite regolith breccias and their implication to the investigation of the surface material of asteroids. Geochimica et Cosmochimica Acta Supplement 67:341.
69. Noonan A. F., Nelen J., and Fredriksson K. 1976. Mineralogy and chemistry of xenoliths in the Weston chondrite-Ordinary and carbonaceous. Meteoritics 11:344.
70. Olsen E. J., Davis A. M., Clayton R. N., Mayeda T. K., and Grossman L. 1988. Murchison xenoliths. Geochimica et Cosmochimica Acta 52:1615-1626.
71. Reid A. M., Buchanan P., Zolensky M. E., and Barrett R. A. 1990. The Bholghati howardite-Petrography and mineral chemistry. Geochimica et Cosmochimica Acta 54:2161-2166.
72. Rubin A. E. and Bottke W. F. 2009. On the origin of shocked and unshocked CM clast in H-chondrite regolith breccias. Meteoritics & Planetary Science 44:701-724.
73. Rubin A. E., Scott E. R. D., and Keil K. 1982. Microchondrule-bearing clast in the Piancaldoli LL3 meteorite-A new kind of type 3 chondrite and its relevance to the history of chondrules. Geochimica et Cosmochimica Acta 46:1763-1776.
74. Rubin A. E., Scott E. R. D., Taylor G. J., Keil K., Allen J. S. B., Mayeda T. K., Clayton R. N., and Bogard D. D. 1983. Nature of the H chondrite parent body regolith: Evidence from the Dimmit breccia. Journal of Geophysical Research Supplement 88:A741-A754.
75. Semenenko V. P., Girich A. L., and Nittler L. R. 2004. An exotic kind of cosmic material: Graphite-containing xenoliths from the Krymka (LL3.1) chondrite 1. Geochimica et Cosmochimica Acta 68:455-475.
76. Semenenko V. P., Jessberger E. K., Chaussidon M., Weber I., Stephan T., and Wies C. 2005. Carbonaceous xenoliths in the Krymka LL3.1 chondrite: Mysteries and established facts. Geochimica et Cosmochimica Acta 69:2165-2182.
77. Stöffler D., Keil K., and Scott E. R. D. 1991. Shock metamorphism of ordinary chondrites. Geochimica et Cosmochimica Acta 55:3845-3867.
78. 39Ar ages of H-chondrite impact melt breccias. Meteoritics & Planetary Science 44:747-762.
79. Taylor G. J., Maggiore P., Scott E. R. D., Rubin A. E., and Keil K. 1987. Original structures, and fragmentation and reassembly histories of asteroids: Evidence from meteorites. Icarus 69:1-13.
80. Tomeoka K. and Buseck P. R. 1988. Matrix mineralogy of the Orgueil CI carbonaceous chondrite. Geochimica et Cosmochimica Acta 52:1627-1640.
81. Trieloff M., Jessberger E. K., Herrwerth I., Hopp J., Fiéni C., Ghélis M., Bourot-Denise M., and Pellas P. 2003. Structure and thermal history of the H-chondrite parent asteroid revealed by thermochronometry. Nature 422:502-506.
82. Tsuchiyama A., Uesugi M., Matsushima T., Michikami T., Kadono T., Nakamura T., Uesugi K., Nakano T., Sandford S. A., Noguchi R., Matsumoto T., Matsuno J., Nagano T., Imai Y., Takeuchi A., Suzuki Y., Ogami T., Katagiri J., Ebihara M., Ireland T. R., Kitajima F., Nagao K., Naraoka H., Noguchi T., Okazaki R., Yurimoto H., Zolensky M. E., Mukai T., Abe M., Yada T., Fujimura A., Yoshikawa M., and Kawaguchi J. 2011. Three-dimensional structure of Hayabusa samples: origin and evolution of Itokawa regolith. Science 333:1125-1128.
83. Van Schmus W. R. 1967. Polymict structure of the Mezö-Madaras chondrite. Geochimica et Cosmochimica Acta 31:2027-2028.
84. Wahl W. 1952. The brecciated stony meteorites and meteorites containing foreign fragments. Geochimica et Cosmochimica Acta 2:91-117.
85. Wasson J. T., Boynton W. V., and Chou C.-L. 1975. Compositional evidence regarding the influx of interplanetary materials onto the lunar surface. Moon 13:121-141.
86. Weisberg M. K., Prinz M., Clayton R. N., and Mayeda T. K. 1993. The CR (Renazzo-type) carbonaceous chondrite group and its implications. Geochimica et Cosmochimica Acta 57:1567-1586.
87. Weisberg M. K., Prinz M., Zolensky M. E., and Ivanov A. V. 1994. Carbonates in the Kaidun chondrite. Meteoritics 29:549-550.
88. Weisberg M. K., McCoy T. J., and Krot A. N. 2006. Systematics and evaluation of meteorite classification. In Meteorites and the early solar system II, edited by Lauretta D. S and McSween H. Y. Tucson, Arizona: The University of Arizona Press. pp. 19-52.
89. Wilkening L. L. 1973. Foreign inclusions in stony meteorites-I. Carbonaceous chondritic xenoliths in the Kapoeta howardite. Geochimica et Cosmochimica Acta 37:1985-1986.
90. Wilkening L. L. 1976. Carbonaceous chondritic xenoliths and planetary-type noble gases in gas-rich meteorites. 7th Lunar Science Conference. pp. 3549-3559.
91. Wilkening L. L. 1977. Meteorites in meteorites-Evidence for mixing among the asteroids. In IAU Colloq. 39: comets, asteroids, meteorites: Interrelations, Evolution and origins, edited by Delsemme A. H., Toledo, Ohio: University of Toledo. pp. 389-395.
92. Wilkening L. L. and Clayton R. N. 1974. Foreign inclusions in stony meteorites-III. Rare gases and oxygen isotopes in a carbonaceous chondritic xenolith in the Plainview gas-rich chondrite. Geochimica et Cosmochimica Acta 38:937-938.
93. Willman M. and Jedicke R. 2011. Asteroid age distribution determined by space weathering and collisional evolution models. Icarus 211:504-510.
94. Wlotzka F. 1993. A weathering scale for the ordinary chondrites. Meteoritics 28:460.
95. Zappalà V., Cellino A., Dell'Oro A., and Paolicchi P. 2002. Physical and dynamical properties of asteroid families. In Asteroids III, edited by Bottke W., Paolicchi P., Binzel R. P., and Cellino A. Tucson, Arizona: The University of Arizona Press. pp. 619-631.
96. Zolensky M. E. and Ivanov A. V. 2003. The Kaidun microbreccia meteorite: A harvest from the inner and outer asteroid belt. Chemie der Erde 63:185-246.
97. Zolensky M. E., Barrett R. A., and Gooding J. L. 1989. C11, C12, and CM2 clasts in the Bholghati Howardite and the AI RAIs chondrite (abstract). 20th Lunar and Planetary Science Conference. p. 1247.
98. Zolensky M. E., Hewins R. H., Mittlefehldt D. W., Lindstrom M. M., Xiao X., and Lipschutz M. E. 1992. Mineralogy, petrology and geochemistry of carbonaceous chondritic clasts in the LEW 85300 polymict eucrite. Meteoritics 27:596-604.
99. Zolensky M., Barrett R., and Browning L. 1993. Mineralogy and composition of matrix and chondrule rims in carbonaceous chondrites. Geochimica et Cosmochimica Acta 57:3123-3148.
100. Zolensky M. E., Weisberg M. K., Buchanan P. C., and Mittlefehldt D. W. 1996. Mineralogy of carbonaceous chondrite clasts in HED achondrites and the Moon. Meteoritics & Planetary Science 31:518-537.
101. Zolensky M. E., Nakamura K., Gounelle M., Mikouchi T., Kasama T., Tachikawa O., and Tonui E. 2002. Mineralogy of Tagish Lake: An ungrouped type 2 carbonaceous chondrite. Meteoritics & Planetary Science 37:737-761.
102. Zolensky M. E., Clayton R. N., Mayeda T., Chokai J., and Norton O. R. 2003. Carbonaceous chondrite clasts in the halite-bearing H5 chondrite Zag. Meteoritics & Planetary Science Supplement 38:5216.
103. Zolensky M. E., Briani G., Gounelle M., Mikouchi T., Ohsumi K., Weisberg M. K., Le L., Satake W., and Kurihara T. 2009. Searching for chips of Kuiper Belt objects in meteorites (abstract #2162). 40th Lunar and Planetary Science Conference. CD-ROM.
104. Zolensky M. E., Herrin J., Mikouchi T., Ohsumi K., Friedrich J., Steele A., Rumble D., Fries M., Satake W., Kurihara T., Colbert M., Hanna R., Maisano J., Ketcham R., Goodrich C., Le L., Robinson G., Martinez J., Ross K., Jenniskens P., and Shaddad M. H. 2010. Mineralogy and petrography of the Almahata Sutta ureilite. Meteoritics & Planetary Science 45:1618-1637.