½ 55 ½ 2 Í Vol.55 No.2 2014 3 ACTA ASTRONOMICA SINICA Mar., 2014 ìâäíæ ò ì : Þ ±Ù 1,2 ¼ 1 Åå 2,3 ý (1 Á»ï ( )» 430074) (2 Á ½ û À 210008) (3 Á Í À 210008) ì ÄÏÄúÂÄíÆ (Ca, Al-rich Inclusion, CAI) ð» Æ, Å ², ÙÝÆ ÂÄíÆ Þß, íµ Äà ï. ÂÄíÆ ǑÂÄ Þ ï Ǒ ù ½ÍÆÞ, ü CV ±ï ì NWA 2140, CAI ½ ì Þ ù. Â, Í ç íæ ßÄ ß,, ÇǑ Ú µ. ³ ÍÆÞ, ì, : ÂÄ ï, àß: : P148; ÞÁ : A 1 ±ï ìð Ú, ð ì Ǒ ì. ±ï ì ÄÏÄúÂÄíÆ, ð ì» Ä íã» Æ, Ô ÂÄ Þ, íõ úïò ì áđì ïì ÏÚò ò, Å ², Æ Å ¾Ú ÒÞ Ä ô [1]. CAI ǑãÄÅ Ú, ð ÙÝÆ íæ ÞÄ, Äà ï [2 3]. ³ ÚÇ, Re Os Ir Mo Ru Pt Rh Â Ä W ð Ð Ú [4]. Palme [4] Ðè CAI è 20 µm íõ W Re Os Ir Mo Ru Pt Rh Ð, Û ÌÂÄ ðð Ú. Ä Ǒ Í ß Å Þ½ÞÄ, çåâä ½Þ 2013-03-31 þ Ú, 2013-10-14 þ ÍÚ Á á (41173076 41273079) Á ½ wbxu@pmo.ac.cn
106 Í 55 Þ Ñ [5]. ðâä ³Ù CAI Í Đ ², Ù CAI Í Í»ø ì» ². ² Ü (Os Ir Ru Rh Pt Pd) 8 ÂÄ (W Mo Re). Æ 3 : ½è, ±Ä Ú [4,6 7] ; ½, ÂÄíÆ» Ä [8] ; ½Ò, CAI µ Æ ß ï Ùµ Å Þ½Þ» [9 11]. ì à ó ŵ Ò Þ ô ì» ß ïä.,  ð µ,» ô Æ è Å ÒÞ ï, Þ Ú. 2 àß Ù, ó Ä Đ ù ½. Í Û ö ½ ½. Á Í ÍÆ Þ ½ û. Û ö (SEM) Ǒ Hitachi S3400N-II, Ǒ 15 kv, Ù 5 nm, Í Ǒ Oxford INCA. Û ö, Í Â ½ ì ò ù. Í ù. 3  3.1 ì NWA 2140 ð 2003 ê ³ ÙÝ è ±ï ì, 2008 12 ø ÁË ì óò, Ó Ǒ 314 g, à º CV3 ì Æ. ±ï ì CV3, л, Ô ö Õ Mg/Si ð³ [12 13]. NWA 2140 Û, â ( ð ), ï ( 60% 70%) Ǒ â ù, Æ Þ. NWA 2140 ë, ÇǑ PMO-1024 PMO-1031. 0.7 3 mm, Ǒù, ò Ǒúìì ïì. ÙÝÅ è ÂÄíÆ,» Õ, Đò 8 mm, ò 7 mm, íæ Æ ï»à Û º, íæèæùý Û äïû, ÆÍ Ǒè» Ç, 1 (a) (b) Û èíæ, ç Ô ½. ÌíÆ Î, Ä áđì, Ä ïì, Æ ǑÓ, ïì 200 800 µm, Ǒ º B1 ºÂÄíÆ [14]. ìè, 20 µm Ñ., ì ÏĐì Ä. Ð 1 Ǒè» Ç. Ï Úò Ú Þ Æ» íãù ò áđì ïì Ë.
2 Ï Ç%u : â" JL N B7á Ôñ Æ Ûµé ( üz é«ã1 Fig. 1 (a) NWA 2140 (PMO-1024) 107 CAI; (b) NWA 2140 (PMO-1031) CAI, öǒó N (a) CAI in NWA 2140 (PMO-1024); (b) CAI in NWA 2140 (PMO-1031), another section of the same CAI shown in Fig.1(a) N Ì Ôk!k! É!W!ÊÏ!7á! zô (X!v ), g Ôkx W, B7á±B? [ â ÙÙ (ã 2). Ä Ô â é[, ǑAB A B. ã 2 JLB7áÛÜ Ù«ã Fig. 2 A closeup view of the distribution of noble metal alloys in the CAI ±²wuyküaB7á. 1 1 a,! ½ök Ì Ô â, òù Ǒ I ab7á. ǑkÜ I ab7á FeNi 7á, ½ Ü K? FeNi 7á, Xã 3(a) «; 1 2 a, E,!à8 FeNi 7á â! 1zÔ½ í! zôú7 í ½ö ) â, =Øß² Ô8ÜN B7á, II ab7á, Xã 3(b) «. CAI
108 Í 55 3 (a) I ; (b) II Fig. 3 (a) Noble metal alloys of Group I; (b) Noble metal alloys of Group II 3.2 ò Þ 3.2.1 ð FeNi µ è, ÑûÚ Û ³ ³. Úð»», Ò Ú 4. Å» ², ÁãÄÅ Ú, Ô ÁÄ Þ. ãä Ú, Þè Á ( ) Ô Á Ä ÅÌ õ. è Ú. 51 ½, íµ º, º Ä 1 2. Element Table 1 Ä 1 I Þ Ä The composition of alloys of Group I Mass fraction/(%) Alloy 1 Alloy 2 Alloy 3 Alloy 4 Alloy 5 Average Fe 3.9 2.5 2.0 10.9 9.1 5.7 Ni 2.9 2.6 1.6 27.0 5.5 8.0 Mo 18.7 2.1 15.2-19. 6 11.1 Ru 22.4 24.6 30.4 30.8 27.9 27.2 Os 13.1 47.9 42.6 27.3 16.6 29.5 Ir 16.0 20.4 5.5 4.1 21.3 13.5 Pt 18.0 - - - - 3.6 W - - 2.7 - - 0.5 Rh 5.1 - - - - 1.0
2 ±Ù : ìâäíæ ò ì ñ Þ 109 4 Os Mo Ru Pt Ni Fe Co Ú Þ õ ³ [4] Fig. 4 Theoretical condensation curves for noble metal elements Os, Mo, Ru, Pt, Ni, Fe, and Co Element Ä 2 condensing in an alloy [4] II Þ Ä Table 2 The composition of alloys of Group II Mass fraction/(%) Alloy 1 Alloy 2 Alloy 3 Alloy 4 Alloy 5 Average Fe 2.7 3.0 5.7 7.4 2.4 4.2 Ni 4.7 11.9 4.5 16.3 3.2 8.1 Mo 6.5 18.1 3.4 3.7 6.3 7.6 Ru 45.2 31.7 46.1 29.1 24.9 35.4 Os 26.9 12.2 26.3 12.6 50.8 25.8 Ir 14.0 23.1 11.7 8.3 12.4 13.9 Pt - - - 19.6-19.6 W - - - - - - Rh - - 2.4 - - 2.4 Ôó ð Ú, Ù Ú õ Ò ³ Â ( 4), ý ½ ³. Palme [4], E Ú õ ³ Ä Ǒ [ α E = 1 + C ] 1 H 2 γ E 10 ( A P tot 13 T +B). α i C i i=1 ÂÄ (atomic fraction) Ä Ǒ X E = αece 13 α ic i i=1, C i
U Æ 110 55 ò L Ý; γ L«¹ÝXê; P L«( Øå, d? 10 Pa ; T ǑB7áev Ý; A!B Ǒ3 Ø ^ Xê. þ g Campbell. (J ±ÏLS { Ñ. éu Ü7 â, Äk Ü Ý. ± ^ {, SÿÁ nø þ í ² Ú éa Ý. ) Ü Ý þ ÏL Matlab y. ØÓ ëê éo (JE KǑ, OØ. òo Ñ5 Ý Ǒî I, â z«¹þ Ǒp I, ÑÑ:ã. ØÓ â UéAXØÓ Ý, Ó â Ý Ú, (JXã 5 «. ã 5 «Ü <ïä êâ^ué'. E tot [7] [15] ã 5 B7ázÆ ¹þ nøo ' (Ü Ì ) Fig. 5 The comparison between the equilibrium calculations and measured compositions of noble metal alloys (main elements are plotted) â ã(ü Û, ±wñ I ab7áêâäk±eaæ: (1) < [Ü ¹?1é', ù âä þäkev ÏA:. (2) âb7á Ý ÙG ¹ äì và Ý«m, Ǒ 1450 1600 K. (3) Mo ¹þ 3 ½ Ý º. (4) Ü â Ir ¹þ 3 Ǒ²w º, Ü âklyñ Ǒ²w L8. II ab7áêâaæ I ab7ák O: (1) Ü B7á zæ nø [
2 ±Ù : ìâäíæ ò ì ñ Þ 111, Ú. (2) è Mo öë Ir Ä öë Ru Ä ë Û. (3) Ò» ÑǑ 1420 1580 K. î Ä ò Þ, ó Đ W Đ À öë; I FeNi, Ni õ ÔÙ Fe õ; II Ni õǒôù Fe õ, õ«ç Û, Ni/Fe ð³ 4: 1, Ýæ Ǒ À. 3.2.2 Ü Ïò 6, Ü Ïòûé Ý Û º, ð Æ Û Æ. Ü Ïò» ô Ǒ, è ðìò ð ô ß Þ» [16 17]. Ä ÍÙµ ô ì½æ», Ǒ ÍÙµÙ ì½æ» [9 10]. Fig.6 6 Ü Ïò û ( í í ) A whitlockite in CAI adjacent to noble metal alloys (the dark grey area in the center of the light grey grain) 4 4.1 ó Đ, I» Ǒ 1450 1600 K, ð Ú. II Ú ³, Å Đ ö ëùä, Ǒ Ú.» çǒ 1420 1580 K. Ǒ II ûê Ú,» àð. 4.1.1 I I, ó ÙÝÅõ ÂÄ W Mo Ir Ru Rh Pt Ni Fe Co Pd
112 Í 55, Os Ru ð à, Fe Ni ð ± à, Mo ðæ± à, Å ĐÙ è Ú. ĐÆÝ» ûú ßÄ Äà [7]. 5 Û Os Ru õ Ò. I Ô Ú áđì Ú Ǒèç, Ú Ýúì ìïì Ú Ǒèç, ó Ǒ I Íð» ø, Ä íã Ë [18]. I ó ÙÝÅ Đ Ir öë Ýæ, Ir  Ä, à Äà ëþ ëþ ùðô ù Ùµ Ir öë [19 20]. ô, Ir öë Í ßÄÔ Þ ô. Í Ô Þ ô ûä Ru Ǒ Ò õ ³, ðû Û. Å Æ, Đ Ô Ni Fe õ, Ä 1 4 Ni õ Ô, ³, Đ Íð FeNi ÃǑ, 3(a). Ô Ni Fe õ Â Ä õó. Đ Ôõ Os Ru. Ir Ru Os Þ ï ê Õ, Đ Ù è,, Os ð ǑÂÄ, Í Ù Os Ru Ä Ir öë. Ä ìõ, Ir Ý ǑÄ. û ð, Ò Ç ð Ù ÍÅ Ò» à Ú, î Í ç Ir Ä. Ù I» ø, ÐÅ º ôî, Í ÂÄ Ú µãǒ. W Mo öëäý Ǒ À. W Mo ð ù ð Þ, è ìõ, ö Ä, ûä W, ûä Mo, ð Re Os Ru Ir Pt, W ûä Mo öë Æ ö Ô [21 22]. ð, Ù Mo ûéùµ Ô öë, ö ûú, ÓÆ ð Ǒ ô. Berg [7] Murchison ³ ( 5), Os Ru Fe Æ Ǒ Õ, Ir Đ Ä Ýæ, I Murchison Ú Æ. ð, Murchison û Đ Ir öë Ýæ, Mo W õ Ǒûé Ý Ûöë, öë Þ ï, Íð Ù I» ô Murchison ö Ô. î, Murchison Ý µ, ² Ǒ è, ûéùý. 4.1.2 II II, Mo öë Ir Ä öë Ru Ä ÄÝ Ǒ Û, Û Ð Ú Ò, ó ÅǑ Ú. Å Í ð CAI µ Æ Ùµ Å Þ½Þ». µ Ùµ ïä Å Ùµ è Ä ù öë. ó ò Æ Ý Æ, ÍûÚ ß
2 ±Ù : ìâäíæ ò ì ñ Þ 113 Äç, íæëûé ßÄ ÄÃ, ßÄ Å. Ù II ÃǑ, Ì õ Æ Ǒ Â. Ä öë Ǒ,» ÐÅÒ, Íð ï Ä ù, Ä ³ [9,11]. î,» µ Æ ǑÍÅÃǑ Ì. W Mo öë Æ ö ìõ, Ǒ W Mo ê Æð ö Ô ô ûä, ð Mo ûú û ä, öûú Ô. Palme [10] Fuchs [23] Allende íæ ò Æ, ÙÝǑĐ W öë ìõ, Mo ½Þë À, Đ MoS 2, û ÂÄ Ä ½Å, Pt Rh Ni-Fe, Os Ru Ã. ò Æ ÂÄ ìõ«ë, II Ã. Íð Ù Ä, ö ½ö «ç ¾ Ä Ùµ. î, íæ µò «Ǒ ç íæ ò µ Đ «. 4.2 ò ô ½Þ Þ» Æ Ô ½ö ö, Ìð, ôûê è. Lauretta [24] Ǒ, Ni Fe ½Þ õ ½Þ Ä ½ ³. ô, ½ ûú, ½Þ Ð Ä½Þ ëë, Ù Ni ½Þ ³ Fe, ðù» è Ä Ni ½Þ, ß Ni Ä, Ni õ ; S î, ëë ½ Ǒ Fe-S Ni-S Ð Âð. Fe-S ³ Ni-S ðµ, Óá ½Þ ½, S åù Fe, à Ni»Ä. I FeNi, Ni õ ÔÙ Fe õ. II Ǒ Ǒ À»Đ Ýæ, û Ni õ Ô. I Ni õô Íð» î áđì íã íæ, ëù, á áđì è Ð ô. íã ô ½ Ǒ, FeNi Ni õ Ç. II à ê ݽ ô». Ù ì Đ ½ Õ½Þ õ½ò, ìûê» Ùë ݽ ô. èý II ì½æ» ô ³, îǒ II» î ëùíæ, º ô, ݽ. Úò», ð ì», î ö Ô, ð ÙÌò õû, î Đ ½, ö. 5 I Ú, Ú»,» ô
114 Í 55, ßÄ. Íð ì ÄÃ, Ǒ Íð Ú Đ Ô ÄÃ. II Mo öë Ir Ä öë Ru Ä ÄÝ Ǒ Û, Ò ³ûê. Íð CAI µ Æ Ùµ Å Þ ½Þ»,» Ä Ùµ èä ùöë, Ä Ǒ. Ò, NWA 2140 ì½æ Í» Ù Ǒ ô, ò Ñíà I, ö,, I Ý W öë., öí, ð Ô, Æ Ù ô. Ä µ Æ Ùµ Å Þ ½Þ» II. Ñ I Í ÃǑÙµ., ì ßÅ ô,» Ü Ïò, û Ô. Đ Þ [1] Scott E R D. Elements, 2011, 7: 47 [2] Grossman L. AREPS, 1980, 8: 559 [3] MacPherson G J. Calcium-Aluminum-rich Inclusions in Chondritic Meteorites // Davis A M. Meteorites, Comets, and Planets. Amsterdam: Elsevier, 2003: 201-241 [4] Palme H, Wlotzka F. E&PSL, 1976, 33: 45 [5] Bischoff A, Palme H. GeCoA, 1987, 51: 2733 [6] Armstrong J T, El Goresy A, Wasserburg G J. GeCoA, 1985, 49: 1001 [7] Berg T, Maul J, Schonhense G, et al. ApJ, 2009, 702: L172 [8] McMahon B M, Haggerty S E. LPSC, 1980, 11: 1003 [9] Blum J D, Wasserburg G J, Hutcheon I D, et al. GeCoA, 1989, 53: 543 [10] Palme H, Hutcheon I D, Spettel B. GeCoA, 1994, 58: 495 [11] Campbell A J, Simon S B, Humayun M, et al. GeCoA, 2003, 67: 3119 [12], ü,.», 2009, 21: 234 [13], ü,.», 2005, 17: 45 [14] Brearley A J, Jones R H. Chondritic Meteorites // Papike J J. Planetary Materials. Washington DC: Mineralogical Society of America, 1998: 3-001-3-398 [15] Campbell A J, Humayun M, Meibom A, et al. GeCoA, 2001, 65: 163 [16] Hsu W B, Guan Y B, Hua X, et al. E&PSL, 2006, 243: 107 [17], Ù, ÅåÂ. Á D :», 2007, 37: 478 [18] Blander M, Fuchs L H, Horowitz C, et al. GeCoA, 1980, 44: 221 [19] Emsley J. Nature s Building Blocks: An A-Z Guide to the Elements. Oxford: Oxford University Press, 2003: 201-204 [20] Perry D L, Phillips S L. Handbook of Inorganic Compounds. Boca Raton: CRC Press, 1995: 203-204 [21] Palme H, Borisov A, Wulf A V. LPSC, 1998, 29: 1611 [22] Fegley Jr B, Palme H. E&PSL, 1985, 72: 311 [23] Fuchs L H, Blander M. LPSC, 1980, 11: 929 [24] Lauretta D S, Lodders K, Fegley Jr B. Science, 1997, 277: 358
2 ±Ù : ìâäíæ ò ì ñ Þ 115 The Petrology and Mineralogy Analysis of Noble Metal Alloys in the Inclusions of Chondrite: An Implication on the Evolution of the Solar Nebula WU Yun-hua 1,2 XING Wei-fan 1 XU Wei-biao 2,3 (1 Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074) (2 Key Laboratory of Planetary Sciences, Chinese Academy of Sciences, Nanjing 210008) (3 Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008) ABSTRACT The Ca, Al-rich Inclusions (CAIs) in chondrites are believed to be the first solids to have formed in the solar system which retain the original information of the early solar nebula. However, in-depth researches reveal that most inclusions had experienced a complex history involving partial melting and secondary alteration. Studies on astrochemistry are focused on refractory and chemically stable noble metal alloys in the CAI of a CV meteorite (NWA 2140). The petrology and mineralogy of the alloys are analyzed. The compositional data analysis of the component can imply the thermal history of the CAI. Two kinds of noble metal alloys are identified, the primary condensates and secondary alteration products of pre-existing metals, respectively. Key words astrochemistry, meteorites, solid state: refractory, methods: data analysis