1žĢp`ÂŪŪáââCAN130EDã@ëpÅtßŪáĩ REFERENCES AKAI J. (1988) Incompletely transformed serpentine-type phyllosilicates in the matrix of Antarctic CM chondrites. Geochim. Cosmochim. Acta 52, 1593-1599. ALEXANDER C.M.O.'.D., MAURETTE M., SWAN P., and WALKER R.M. (1992) Studies of Antarctic micrometeorites. Lunar Planet. Sci. 23, 7-8. BARBER D.J. (1985) Phyllosilicates and other layer-structured materials in stony meteorites. Clay Minerals 20, 415-454. BECKERLING W., BISCHOFF A., and KL™CK W. (1992) Mineralogy and chemistry of micrometeorites from Greenland and Antarctica. Meteoritics 27, 200-201. BOSTROEM K. and FREDRIKSSON K. (1966) Surface conditions of the Orgueil meteorite parent body as indicated by mineral associations. Smithson. Misc. Coll. 151/3, 1-39. BRADLEY J.P. (1988) Analysis of chondritic interplanetary dust thin-sections. Geochim. Cosmochim. Acta 52, 889-900. BRADLEY J.P. and BROWNLEE D.E. (1991) An interplanetary dust particle linked directly to type CM meteorites and an asteroidal origin. Science 251, 549-552. BRADLEY J.P., SANDFORD S.A., and WALKER R.M. (1988) Interplanetary dust particles. In Meteorites and the Early Solar System (eds. J.F. Kerridge and M.S. Matthews). Univ. of Arizona Press, Tucson, 861-895. BRANDSTŽTTER F., KURAT G., and GRAHAM A.L. (1987) Primitive carbonates in Y82042 (C2). Meteoritics 22, 336-337. BRANDSTŽTTER F., KURAT G., and MAURETTE M. (1991) Pauschal- und Mineralchemismen antarktischer Mikrometeorite. Beih. Eur. J. Mineral. 3/1, 40. BRANDSTŽTTER F., KURAT G., and IVANOV A.V. (1992) Isolated minerals in Kaidun II (CI). Meteoritics 27, 206. BROWNING L., ZOLENSKY M., and BARRET R. (1991) Serpentine and modal compositions of CM chondrites. Lunar Planet. Sci. 22, 145-146. BROWNLEE D.E. (1981) Interplanetary dust - its physical nature and entry into the atmosphere of terrestrial planets. In Comets and the Origin of Life (ed. C. Ponnamperuma). D. Reidel Publ. Comp., 63-70. BROWNLEE D.E. (1985) Cosmic dust: collection and research. Ann. Rev. Earth Planet. Sci. 13, 147-173. BROWNLEE D.E. (1987) Morphological, chemical and mineralogical studies of cosmic dust. Phil. Trans. Roy. Soc. Lond. A323, 305- 311. BROWNLEE D.E., SCHRAMM L.S., WHEELOCK M.W., and MAURETTE M. (1989) Large mineral grains in interplanetary dust. Lunar Planet. Sci. 20, 121-122. BUNCH T.E. and CHANG S. (1980) Carbonaceous chondrites - II. Carbonaceous chondrite phyllosilicates and light element geochemistry as indicators of parent body processes and surface conditions. Geochim. Cosmochim. Acta 44, 1543-1577. CHRISTOPHE MICHEL-LEVY M. and BOUROT-DENISE M. (1992) Mineral compositions in Antarctic and Greenland micrometeorites. Meteoritics 27, 73-80. DODD R.T. (1981) Meteorites. A Petrologic-Chemical Synthesis. Cambridge Univ. Press, Cambridge. ENGRAND C., MAURETTE M., KURAT G., BRANDSTŽTTER F., and PERREAU M. (1993) A new carbon-rich phase ("COPS") in Antarctic micrometeorites. Lunar Planet. Sci. 24, 441-442. ESSER B.K. and TUREKIAN K.K. (1988) Accretion rate of extraterrestrial particles determined from osmium isotope systematics of Pacific pelagic clay and manganese nodules. Geochim. Cosmochim. Acta 52, 1383-1388. FERGUSON E.E. (1978) Sodium hydroxide ions in the stratosphere. Geophys. Res. Lett. 5, 1035-1038. FLYNN G.J. and SUTTON S.R. (1989) Minor and trace element abundances in eight "chondritic" stratospheric particles: evidence for Ni depletions. Meteoritics 24, 267. FLYNN G.J. and SUTTON S.R. (1990) Synchrotron X-ray fluorescence analyses of stratospheric cosmic dust: new results for chondritic and low-nickel particles. Proc. Lunar Planet. Sci. Conf. 20, 335-342. FLYNN G.J. and SUTTON S.R. (1991) Average minor and trace element contents in seventeen "chondritic" IDPs suggest a volatile enrichment. Meteoritics 26, 334. FLYNN G.J. and SUTTON S.R. (1992a) Element abundances in stratospheric cosmic dust: indications for a new chemical type of chondritic material. Lunar Planet. Sci. 23, 373-374. FLYNN G.J. and SUTTON S.R. (1992b) Trace elements in chondritic stratospheric particles: Zinc depletion as a possible indicator of atmospheric entry heating. Proc. Lunar Planet. Sci. Conf. 22, 171- 184. FLYNN G.J. and SUTTON S.R. (1992c) Trace elements in chondritic cosmic dust: Volatile correlation with Ca abundance. Meteoritics 27, 220-221. FREDRIKSSON K. and KERRIDGE J.F. (1988) Carbonates and sulfates in CI chondrites: formation by aqueous activity on the parent body. Meteoritics 23, 35-44. FREDRIKSSON K., JAROSEWICH E., BEAUCHAMP R., and KERRIDGE J. (1980) Sulphate veins, carbonates, limonite and magnetite: evidence on the late geochemistry of the C-1 regoliths. Meteoritics 15, 291-292. GADSDEN M. (1968) Sodium in the upper atmosphere: meteoric origin. J. Atmosph. Terrestr. Phys. 30, 151-161. GOVINDARAJU K. (1984) 1984 compilation of working values and sample description for 170 international reference samples of mainly silicate rocks and minerals. Geostand. Newsl. 8, Spec. Issue. GRADY M.M., GRAHAM A.L., BARBER D.J., AYLMER D., KURAT G., NTAFLOS T., OTT U., and PALME H. (1986) Yamato 82042: an unusual carbonaceous chondrite with CM affinites. Mem. Nat. Inst. Polar Res. Spec. Iss. 46, 162-178. GRAHAM A.L. and KURAT G. (1991) Phyllosilicates in the Yamato 82042 carbonaceous chondrite - primitive or not?. Lunar Planet. Sci. 22, 475. HOINKES G. and KURAT G. (1975) Preliminary report on the Bali carbonaceous chondrite. Meteoritics 19, 416-417. HUGHES D.W. (1978) Meteors. In Cosmic Dust (ed. J.A.M. McDonnell). J. Wiley, Chichester, 123-185. HUNTEN D.M., TURCO R.P., and TOON O.B. (1980) Smoke and dust particles of meteoric origin in the mesosphere and stratosphere. J. Atmospher. Sci. 37, 1342-1357. HUTCHISON R. (1987) Chromian-manganoan augite in the interchondrule matrix of the Tieschitz (H3) chondritic meteorite. Mineralog. Mag. 51, 311-316. IVANOV A.V. (1989) The Kaidun meteorite: composition and history. Geochem. Internat. 26, 84-91. JAROSEWICH E., CLARKE R.S., JR, and BARROWS J.N. (1987) The Allende Meteorite Reference Sample. Smithson. Contrib. Earth Sci. 27, 49pp. JESSBERGER E.K., BOHSUNG J., CHAKAVEH S., and TRAXEL K. (1992) The volatile element enrichment of chondritic interplanetary dust particles. Earth Planet. Sci. Lett. 112, 91-99. JOHNSON C.A. and PRINZ M. (1993) Carbonates in CM chondrites: Comparison with the CI group and implications for aqueous alteration. Geochim. Cosmochim. Acta 57, xxxxx KALLEMEYN G.W., RUBIN A.E., and WASSON J.T. (1991) The compositional classification of chondrites: V. The Karoonda (CK) group of carbonaceous chondrites. Geochim. Cosmochim. Acta 55, 881- 892. KANE T.J. and GARDNER C.S. (1993) Lidar observations of the meteoric deposition of mesospheric metals. Science 259, 1297- 1300. KELLER L.P., THOMAS K.L., and MCKAY D.S. (1992) An interplanetary dust particle with links to CI chondrites. Geochim. Cosmochim. Acta 56, 1409-1412. KL™CK W., THOMAS K.L., MCKAY D.S., and PALME H. (1989) Unusual olivine and pyroxene composition in interplanetary dust and unequilibrated ordinary chondrites. Nature 339, 126-128. KL™CK W., BECKERLING W., SPETTEL B., FLYNN G., and SUTTON S. (1992a) Bulk composition and mineralogy of Antarctic micrometeorites. Lunar Planet. Sci. 23, 697-698. KL™CK W., FLYNN G.J., SUTTON S.R., and NIER A.O. (1992b) Mineralogy of IDPs with known 4He and trace element contents. Meteoritics 27, 243-244. KOEBERL C. (1993) Instrumental neutron activation analysis of geochemical and cosmochemical samples - a fast and reliable method for small sample analysis. J. Radioanal. Nucl. Chem. Art. 168, 47-60. KOEBERL C., KURAT G., PRESPER T., BRANDSTŽTTER F., and MAURETTE M. (1992) Bulk major and trace element analyses of unmelted micrometeorites from Cap Prudhomme, Antarctica. Lunar Planet. Sci. 23, 709-710. KORNBLUM J.J. (1969) Micrometeoroid interaction with the atmosphere. J. Geophys. Res. 74, 1893-1907. KURAT G. (1975) Der kohlige Chondrit LancŠ: Eine petrologische Analyse der komplexen Genese eines Chondriten. Tschermaks Min. Petr. Mitt. 22, 38-78. KURAT G. (1988) Primitive meteorites: an attempt towards unification. Phil. Trans. R. Soc. Lond. A 325, 459-482. KURAT G., MAYR M., NTAFLOS T., and GRAHAM A.L. (1989a) Isolated olivines in the Yamato 82042 CM2 chondrite: The tracing of major condensation events in the solar nebula. Meteoritics 24, 35-42. KURAT G., PALME H., BRANDSTŽTTER F., and HUTH J. (1989b) Allende xenolith AF: undisturbed record of condensation and aggregation of matter in the solar nebula. Z. Naturforsch. 44a, 988-1004. KURAT G., ZINNER E., and PALME H. (1989c) Primitive olivines with high trace element contents in Allende-AF aggregates. Meteoritics 24, 290. KURAT G., BRANDSTŽTTER F., PALME H., SPETTEL B., and PRINZ M. (1991) Maralinga (CK4): record of highly oxidizing nebular conditions. Meteoritics 26, 360. KURAT G., KOEBERL C., PRESPER T., BRANDSTŽTTER F., and MAURETTE M. (1992a) Bulk compositions of Antarctic micrometeorites: nebular and terrestrial signatures. Meteoritics 27, 246. KURAT G., PRESPER T., BRANDSTŽTTER F., MAURETTE M., and KOEBERL C. (1992b) CI-like micrometeorites from Cap Prudhomme, Antarctica. Lunar Planet. Sci. 23, 747-748. KURAT G., BRANDSTŽTTER F., PRESPER T., KOEBERL C., and MAURETTE M. (1993) Micrometeorites. Geologia i Geofizika 34, 148-164 (in Russian). KYTE F.T. and SMIT J. (1985) Cretaceous-Tertiary spinels: high- temperature relicts from a major accretionary event. Lunar Planet. Sci. 16, 473-474. KYTE F.T. and WASSON J.T. (1986) Accretion rate of extraterrestrial matter: iridium deposited 33 to 67 million years ago. Science 232, 1225-1229. LEE M.S., RUBIN A.E., and WASSON J.T. (1992) Origin of metallic Fe-Ni in Renazzo and related chondrites. Geochim. Cosmochim. Acta 56, 2521-2533. LOVE S.G. and BROWNLEE D.E. (1991) Heating and thermal transformation of micrometeoroids entering the Earth's atmosphere. Icarus 89, 26-43. LOVE S.G. and BROWNLEE D.E. (1993) A direct measurement of the terrestrial mass accretion rate of cosmic dust. Science 262, 550-553. MACKINNON I.D.R. and RIETMEIJER F.J.M. (1984) Bismuth in interplanetary dust. Nature 311, 135-138. MAURETTE M., HAMMER C., BROWNLEE D.E., REEH N., and THOMSEN H.H. (1986) Placers of cosmic dust in the Blue Ice Lakes of Greenland. Science 233, 869-872. MAURETTE M., JEHANNO C., ROBIN E., and HAMMER C. (1987) Characteristics and mass distribution of extraterrestrial dust from the Greenland ice cap. Nature 328, 699-702. MAURETTE M., BROWNLEE D.E., and SCHRAMM L.S. (1989a) Giant micrometeorites from Antarctic blue ice. Lunar Planet. Sci. 20, 636- 637. MAURETTE M., POURCHET M., BONNY P., DEANGELIS M., and SIRY P. (1989b) A new collection of micrometeorites, extracted from 100 tons of artificially melted blue ice, near Cap-Prudhomme in Antarctica. Lunar Planet. Sci. 20, 644-645. MAURETTE M., OLINGER C., WALKER R., and HOHENBERG C. (1989c) Noble gas measurements of extraterrestrial particles from polar sediments. Lunar Planet. Sci. 20, 640-641. MAURETTE M., OLINGER C., CHRISTOPHE MICHEL-LEVY M., KURAT G., POURCHET M., BRANDSTŽTTER F., and BOUROT-DENISE M. (1991) A collection of diverse micrometeorites recovered from 100 tonnes of Antarctic blue ice. Nature 351, 44-47. MAURETTE M., IMMEL G., PERREAU M., POURCHET M., VINCENT C., and KURAT G. (1992a) The 1991 EUROMET collection of micrometeorites at Cap Prudhomme, Antarctica: discussion of possible collection biases. Lunar Planet. Sci. 23, 859-860. MAURETTE M., KURAT G., PRESPER T., BRANDSTŽTTER F., and PERREAU M. (1992b) Possible causes of depletion and enrichment of minor elements in Antarctic micrometeorites. Lunar Planet. Sci. 23, 861- 862. MAURETTE M., BROWNLEE D.E., JOSWIAK D.J., and SUTTON S.R. (1992c) Antarctic micrometeorites smaller than 50 æm. Lunar Planet. Sci. 23, 857-858. MAURETTE M., KURAT G., PERREAU M., and ENGRAND C. (1993) Microanalyses of Cap-Prudhomme Antarctic micrometeorites. Microbeam Anal. 2, 239-251. MšLLER W.F., KURAT G., and KRACHER A. (1979) Chemical and crystallographic study of cronstedtite in the matrix of the Cochabamba (CM2) carbonaceous chondrite. Tschermaks Min. Petr. Mitt. 26, 293-304. NAZAROV M.A., BRANDSTŽTTER F., and KURAT G. (1993) Carbonaceous xenoliths from the Erevan howardite. Lunar Planet. Sci. 24, 1053-1054. NELEN J., KURAT G., and FREDRIKSSON K. (1975) The Renazzo chondrite - a reevaluation. Meteoritics 10, 464-465. PALME H., SUESS H.E., and ZEH H.D. (1981) Abundances of the elements in the solar system. In Landoldt-Boernstein (eds. K.Scheifers and H.H. Voigt). Springer Verlag, Berlin, 2, 257- 273 PALME H., KURAT G., SPETTEL B., and BURGHELE A. (1989) Chemical composition of an unusual xenolith of the Allende meteorite. Z. Naturforsch. 44a, 1005-1014. PERNICKA E., KURAT G., BRANDSTŽTTER F., and HERRWERTH I. (1985) Chainpur (LL-3): fractionated siderophile elements in chondrules, fragments, and chondrite matrix. Meteoritics 20, 729-730. PERNICKA E., BAJT S., TRAXEL K., KURAT G., and BRANDSTŽTTER F. (1989) Composition and interrelationship of chondrules, lithic fragments and fine-grained matrix from Chainpur (LL-3). Meteoritics 24, 316. PERREAU M., MAURETTE M., KURAT G., and ENGRAND C. (1992) Carbon-rich phases in Cap-Prudhomme micrometeorites. Meteoritics 26, 274. PERREAU M., ENGRAND C., MAURETTE M., KURAT G., and PRESPER T. (1993) C/O atomic ratios in micrometer-size crushed grains from Antarctic micrometeorites and two carbonaceous meteorites. Lunar Planet. Sci. 24, 1125-1126. PRESPER T. (1993) Pauschalzusammensetzung und Mineralchemie von arktischen kosmischen Kgelchen und antarktischen Mikrometeoriten. Ph.D.Thesis, Universit„t Mainz, 120 pp. PRESPER T., KURAT G., and MAURETTE M. (1992) Preliminary report on the composition of anhydrous primary phases in micrometeorites from Cap Prudhomme, Antarctica. Meteoritics 26, 278. PRESPER T., KURAT G., KOEBERL C., PALME H., and MAURETTE M. (1993) Elemental depletions in Antarctic micrometeorites and Arctic cosmic spherules: comparison and relationships. Lunar Planet. Sci. 24, 1177-1178. RIETMEIJER F.J.M. (1985) Low-temperature aqueous and hydrothermal activity in a proto-planetary body: goethite, opal-CT, gibbsite, and anatase in chondritic porous aggregate W7029*A. Lunar Planet. Sci. 16, 696-697. RIETMEIJER F.J.M. (1992) Interplanetary dust particle L2005T12 directly linked to type CM chondrite petrogenesis. Lunar Planet. Sci. 23, 1153-1154. RIETMEIJER F.J.M. and MACKINNON I.D.R. (1984a) Layered silicates in chondritic porous aggregate W7029*A: a case of primary growth. Lunar Planet. Sci. 15, 687-688. RIETMEIJER F.J.M. and MACKINNON I.D.R. (1984b) Diagenesis in interplanetary dust: chondritic porous aggregate W7029*A. Meteoritics 19, 301. RIETMEIJER F.J.M. and MACKINNON I.D.R. (1985) Layer silicates in a chondritic porous interplanetary dust particle. J. Geophys. Res. 90, D149-D155. RIETMEIJER F.J.M. and MACKINNON I.D.R. (1990) Titanium oxide Magneli phases in four chondritic porous interplanetary dust particles. Proc. Lunar Planet. Sci. Conf. 20th, 323-333. RIETMEIJER F.J.M. and MCKAY D.S. (1986) Fine-grained silicates in chondritic interplanetary dust particles are evidence for annealing in the early solar system. Lunar Planet. Sci. 17, 710- 711. ROBIN E., BONTE P., FROGET L., JEHANNO C., and ROCCHIA R. (1992) Formation of spinels in cosmic objects during atmospheric entry: a clue to the Cretaceous-Tertiary boundary event. Earth Planet. Sci. Lett. 108, 181-190. SCHRAMM L.S., BROWNLEE D.E., and WHEELOCK M.M. (1989) Major element composition of stratospheric micrometeorites. Meteoritics 24, 99-112. SCOTT E.R.D., BARBER D.J., ALEXANDER C.M., HUTCHISON R., and PECK J.A. (1988) Primitive material surviving in chondrites: matrix. In Meteorites and the Early Solar System (eds. J.F. Kerridge and M.W. Matthews). Univ. Arizona Press, Tucson, 718-745. STEELE I.M. (1986) Compositions and textures of relic forsterite in carbonaceous and unequilibrated ordinary chondrites. Geochim. Cosmochim. Acta 50, 1379-1395. STEELE I.M. (1992) Olivine in Antarctic micrometeorites: Comparison with other extraterrestrial olivine. Geochim. Cosmochim. Acta 56, 2923-2929. STEINWEG A., KRANKOWSKY D., LŽMMERZAHL P., and ANWEILER B. (1992) Metal ion layers in the auroral E-region measured by mass spectrometers. J. Atmos. Terr. Phys. 54, 703-714. SUTTON S.R. and FLYNN G.J. (1988) Stratospheric particles: synchrotron X-ray fluorescence determination of trace element contents. Proc. Lunar Planet. Sci. Conf. 18, 607-614. SUTTON S.R. and FLYNN G.J. (1989) Trace element compositions of interplanetary dust and terrestrial particles collected from the stratosphere. Lunar Planet. Sci. 20, 1091-1092. THOMAS K.L., ZOLENSKY M.E., KL™CK W., and MCKAY D.S. (1990) Mineralogical descriptions of eight hydrated interplanetary dust particles and their relationship to chondrite matrix. Lunar Planet. Sci. 21, 1250-1251. THOMAS K.L., KELLER L.P., FLYNN G.J., SUTTON S.R., TAKATORI K., and MCKAY D.S. (1992) Bulk compositions, mineralogy, and trace element abundances of six interplanetary dust particles. Lunar Planet. Sci. 23, 1427-1428. VAN DER STAP C.C.A.H., VIS R.D., and VERHEUL H. (1986) Interplanetary dust: arguments in favour of a late stage nebular origin of the chondritic aggregates. Lunar Planet. Sci. 17, 1013-1014. WASSON J.T. (1985) Meteorites. Their Record of Early Solar-System History. W.H.Freeman & Comp., New York WASSON J.T. and KALLEMEYN G.W. (1988) Composition of chondrites. Phil. Trans. R. Soc. Lond. A 325, 535-544. WEISBERG M.K., PRINZ M., CLAYTON R.N., and MAYEDA T.K. (1993) The CR (Renazzo-type) carbonaceous chondrite group and its implications. Geochim. Cosmochim. Acta 57, 1567-1586. ZOLENSKY M.E. (1987) Tochilinite in C2 carbonaceous chondrites: a review with suggestions. Lunar Planet. Sci. 18, 1132-1133. ZOLENSKY M. and LINDSTROM D. (1991) Mineralogy of 12 large "chondritic" interplanetary dust particles. Lunar Planet. Sci. 22, 1557-1558. ZOLENSKY M. and MCSWEEN H.Y. (1988) Aqueous Alteration. In Meteorites and the Early Solar System (eds. J.F. Kerridge and M.S. Matthews). Univ. Arizona Press, Tucson, 114-143. ZOLENSKY M., BARRETT R., and BROWNING L. (1993) Mineralogy and composition of matrix and chondrule rims in carbonaceous chondrites. Geochim. Cosmochim. Acta 57, 3123-3148. FIGURE CAPTIONS Figure 1: Backscattered electron (BSE) scanning microphotographs of phyllosilicate-dominated micrometeorites. (a) Particle 4M1, almost totally covered by magnetite and cut by cracks. (b) Polished section of micrometeorite 4M1. Fine- grained (probably dehydrated) phyllosilicates and oxides with a large enstatite (Fs 1.5) in the center and a small one at the surface (left). The particle has several irregular voids, is cut by cracks, and is partly covered by magnetite (light-grey to white). (c) Polished section of micrometeorite 3M8 consisting of densely intergrown fine-grained (probably largely dehydrated) phyllosilicates and a laihunite-like phase (lighter grey) and almost totally covered by a scoriaceous, Fe-rich mantle (light grey) which in turn is covered by magnetite (white). The particle has abundant irregular voids and some open cracks. (d) Polished section of micrometeorite AM5 consisting of fine-grained phyllosilicates including cronstedtite (light grey) and tochilinite (white). The particle has abundant irregular voids, is enveloped by a scoriaceous mantle of variable thickness, and covered by a thin magnetite crust. Figure 2: BSE scanning microphotographs of coarse-grained crystalline micrometeorites. (a) Particle 3M4 consisting of a large enstatite which contains rounded inclusions of tochilinite and magnetite. The surface is slighly dusted by fine-grained magnetite. (b) Polished section of micrometeorite 3M4 consisting of a large enstatite crystal (Fs 3), poikilitically including small round olivines (Fa 2, dark grey) and magnetite (white) and large tochilinite (white). Fa-rich olivine is associated with tochilinite. A few very small magnetites (white) are present at the surface (right side). (c) Porphyritic micrometeorite M1, consisting mainly of orthopyroxene (Fs 20-23), clinopyroxene, chromite, sulfide, and metal (all white), and glass (dark grey). At the right side the porphyritic MM is intergrown with olivine of Fa 2-4 (dark grey). Note the abundant rounded voids. (d) Porphyritic micrometeorite AM9 consisting of olivine (Fa 32-37, light grey), augite (grey), plagioclase (An 12, dark grey), and glass (dark grey). Light phases are sulfide and chromite. The particle has abundant rounded voids and is covered by magnetite only in a few places. Figure 3: BSE scanning images of scoriaceous micrometeorites: (a) Particle 4M12 with rectangular shape, rounded corners, and dense magnetite coating. (b) Polished section of micrometeorite AM10 consisting of two highly versicular club-shaped drops with a discontinous magnetite cover. Note the different shades of grey which indicate variation in Fe contents. (c) Polished section of micrometeorite 4M12 (Fig.3a) displaying a relictic phyllosilicate core (dark grey) enveloped by an Fe-enriched scoriaceous mantle (light grey) and covered by magnetite (white). The light phase at right is Fe-oxide. (d) Polished section of micrometeorite M4, a scoriaceous MM transitional to cosmic spherules. The almost droplet-shaped MM has a dense quench texture (silicate plus magnetite), abundant vesicles (some of rectangular shape), and contains abundant olivine (Fa 1, dark grey) which has partly reacted to form Fe-rich olivine (Fa 28). The particle is incompletely covered by magnetite. Figure 4: Comparison of bulk Fe contents of micrometeorites as determined by EMPA versus those determined by INAA. Bulk data derived from analyzing the total micrometeorite deviate considerably from those derived by EMPA by analyzing the interior which in most cases contains much less Fe than the bulk. Figure 5: Abundances of major and minor elements in micrometeorites (EMPA data, Table 4) normalized to CI abundances (PALME et al., 1981). Elements are separated into lithophile (left) and siderophile (right) elements and arranged in order of increasing cosmochemical volatility from left to right (WASSON, 1985). a) Phyllosillicate MMs b) Crystalline MMs c) Scoriaceous MMs. Figure 6: Abundances of selected lithophile elements in micrometeorites normalized to CI abundances (PALME et al., 1981). Elements are arranged in order of increasing cosmochemical volatility from left to right (WASSON, 1985), with the exception of the rare earth elements, which are arranged according to increasing atomic number. a) Phyllosilicate MMs. b) Crystalline MMs. c) Scoriaceous MMs. Figure 7: Abundances of selected siderophile elements in micrometeorites normalized to CI abundances (PALME et al., 1981). Elements are arranged in order of increasing cosmochemical volatility from left to right (WASSON, 1985). a) Phyllosilicate MMs. b) Crystalline MMs. c) Scoriaceous MMs. Figure 8: Scanning electron microphotographs of magnetite envelopes of micrometeorites. (a) Large platy magnetite covered by smaller octahedral magnetite at the suface of scoriaceous MM M4. SE image. (b) Magnetites lining the walls of an open vesicle at the surface of scoriaceous MM M4. SE image. (c) High magnification of octahedral magnetite with a generation of very small magnetites at the surface of scoriaceous MM M4. SE image. (d) Polished section of scoriaceous MM 4M5, showing a highly vesicular melt with relic olivines and pyroxenes (dark grey). The surface is covered by granular magnetite (white). Note that the magnetite is present everywhere, independent of the substrate. BSE image. Figure 9: Abundances of major and minor elements in matrices of CM chondrite inclusions in the Erevan howardite (NAZAROV et al., 1993), normalized to CI abundances (PALME et al., 1981). Elements are shown in the same order as in Fig. 5 to facilitate comparison. ÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜ܀p`˙˙ÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜ€n(a*a°a˛a+a-aÂanģ>n…?n‡?n‚@n„@nWn@WnrXntXnîYnđYn}[n