Characterization of the noble gases and CRE age of the D'Orbigny angrite

Introduction: The D’Orbigny angrite, a 16.55 kg stone, was found 1979 in Argentina [1]. Mineralogy and chemistry of this meteorite were characterized in detail [2-6]. A Pb-U-Th age of 4.559 Ga was obtained for pyroxenes by Jagoutz et al. [7]. Here we report results on the noble gas isotopic composition and, in particular, on the cosmic-ray exposure (CRE) age of D’Orbigny

Glasses in coarse-grained micrometeorites

Micrometeorites (MMs, interplanetary dust particles with 25 - 500 μm diameters) carry the main mass of extraterrestrial matter that is captured by Earth. The coarse-grained MMs mainly consist of olivine aggregates, which - as their counterparts in CC chondrites - also contain pyroxenes and glass. We studied clear glasses in four coarse-grained crystalline MMs (10M12, M92-6b, AM9, and Mc7-10), which were collected from the ice at Cap Prudhomme, Antarctica. Previous studies of glasses (e.g., glass inclusions trapped in olivine and clear mesostasis glass) in carbonaceous and ordinary chondrites showed that these phases could keep memory of the physical-chemical conditions to which extraterrestrial matter was exposed. Here we compare the chemical compositions of MM glasses and glasses from CM chondrites with that in experimentally heated objects from the Allende CV chondrite and with glasses from cometary particles. Our results show that MMs were heated to variable degrees (during entry through the terrestrial atmosphere), which caused a range from very little chemical modification of the glass to total melting of the precursor object. Such modifications include dissolution of minerals in the melted glass precursor and some loss of volatile alkali elements. The chemical composition of all precursor glasses in the MMs investigated is not primitive such as glasses in CM and CR chondrite objects. It shows signs of pre-terrestrial chemical modification, e.g., metasomatic enrichments in Na and Fe2+ presumably in the solar nebula. Glasses of MMs heated to very low degree have a chemical composition indistinguishable from that of glasses in comet Wild 2 particles; giving additional evidence that interplanetary dust (e.g., Antarctic MMs) possibly represents samples from comets. © 2009 Elsevier B.V. All rights reserved.Fil: Varela, Maria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; ArgentinaFil: Kurat, G.. Universidad de Viena; Austri

Scheme for preparation of W state via cavity QED

In this paper, we presented a physical scheme to generate the multi-cavity maximally entangled W state via cavity QED. All the operations needed in this scheme are to modulate the interaction time only once.Comment: 8 pages, 1 figur

Glasses in meteorites and the Primary Liquid Condensation Model

Meteoritic glasses are quenched samples of the silicate liquid that was involved in the formation of chondritic constituents and achondritic rocks. Conventional genetic models see them as residual liquids from which the associated minerals crystallized – as demonstrated by terrestrial igneous rocks – or as locally produced impact melts. These models are all closely related to our experiences with terrestrial geology and petrology and, consequently,make planetary processes, such asmixing andmelting of solid precursors and planetary differentiation primarily responsible for the formation of the large variety of meteoritic rocks. However, different types of glasses (e.g., glass inclusions in minerals, mesostasis glasses, glass pockets, glass veins) in a variety of meteorites (chondrites and achondrites) have particular chemical features that cannot be reconciled with these models: 1)Glasses do not showthe chemical signature of crystallization of theminerals they are associated with – a geochemical impossibility; 2) All types of glasses in all types of meteorites reported here show very similar trace element abundance pattern with the refractory lithophile element abundances at ~ 10–20 x CI chondrite abundances. 3) All refractory element abundance patterns in primitive glasses have unfractionated solar relative abundances (they are flat) and medium refractory and volatile elements are depleted relative to the refractory elements. 4) Medium volatile and volatile elements, when present, display chaotic abundance patterns. The ubiquitous pattern for refractory elements signals vapor fractionation rather than geochemical (“igneous”) fractionation or stochasticmixing of precursorminerals (as in shockmelts). It indicates that the same process must have been involved in the origin of all glasses in chondritic constituents aswell as achondritic rocks and, consequently, in the formation of allmeteorite types investigated. The chaotic abundances of volatile elements signal that chaotic processes were involved during condensation. 279 Herewe present a newmodel - the Primary Liquid Condensation (PLC)model – as an alternative to the currently acceptedmodels for the formation ofmeteoritic rocks. The PLCmodel is capable of accommodating all observational and chemical data accumulated so far on meteorites – with the exception of enstatite and SNC meteorites, which record physico-chemical conditions that were different fromthose of themajority ofmeteoritic rocks (the processes, however, could have been the same). The new model identifies a new role for silicate liquids in cosmochemistry as being an essential phase for the formation of early crystalline condensates from the hot solar nebula. Liquids are identified to have been the first major phase to condense from the solar nebula. In order to be capable to produce early liquid condensates, the nebula must have been either enriched in condensable elements over solar abundances (> 500 times) or was at total pressuresmuch higher than the canonically predicted ones (> 500 times, > 0.5 bar ). Our data require that this liquid – we named it “universal liquid” (UL) - had a refractory composition (Ca-Mg-Al-silicate or CMAS) and facilitated condensation of the major minerals for chondritic constituents as well as for achondritic rocks. The process possibly was a variant of the vapor-liquid-solid (VLS) condensation process, which is utilized in industrial crystal growth. Thereby, the liquid condenses first, then nucleates a crystal of the species that is oversaturated in the vapor – in the case of the solar nebula usually olivine. As this olivine grows from the liquid, it depletes the liquid in Mg and Si. The liquid tries to maintain equilibrium with the solar nebula. Thereby, Mg and Si are replenished by condensation from the gas phase and all incompatible elements are kept at an equilibrium concentration by condensation-evaporation equilibrium. Thus, the contents of incompatible refractory elements are kept at an approximately constant level throughout crystallization of the major minerals olivine and pyroxene. This way not only the abundances of incompatible refractory elements are kept at a constant level but also their relative abundances remain unfractionated solar. The UL also represents the long sought for refractory component of chondritic constituents and appears also to be the source of achondritic “igneous” rocks. Variations in the amount of liquid available, the liquid condensation and crystal nucleation rates, as well as different crystal-liquid mixing proportion will allow the formation of objects of highly variable composition. The final composition (chemical and isotopic) of any chondritic object or achondrite, as well as that of the associated glasses, will be determined by different degrees of post-formational metasomatic elemental exchange processes taking place between solids and the cooling nebular gas. These processes add medium volatile and volatile elements to the products of high temperature condensation. As these processes usually don’t run to completion, an infinite number of chaotic compositional variations are produced – and this is exactly what we observe in meteorites.Fil: Varela, Maria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; ArgentinaFil: Kurat, G.. Vienna University of Technology; Austri

Lunar meteorite Yamato-793274: Mixture of mare and highland components,and barringerite from the Moon

Two small samples of the new lunar meteorite Yamato-793274 have been studied for mineralogical, petrological, and geochemical composition. The meteorite has a coarse grained texture and consists of a dense breccia that contains relatively large and abundant mineral fragments (clinopyroxene, plagioclase, olivine, ilmenite), rare fine-grained granulitic (poikilitic) breccias, and some mostly brownish devitrified glass. The matrix is abundant, dense, and consists of mineral fragments and interstitial mostly recrystallized glass. One large recrystallized melt breccia of anorthositic-noritic-troctolitic (ANT) composition was found. All plagioclase fragments are highly anorthitic, and olivine compositions range from Fo_. The occurrence of these breccias and plagioclases, as well as the chemistry of some matrix glass, is consistent with an origin from the lunar highlands. However, some glasses have a considerably more mafic composition and show admixture of a low mg-component. Pyroxenes are unusually abundant when compared with other lunar meteorites. They usually show exsolution lamellae, are heavily shocked, and their compositions show a bimodal distribution, with low-mg pyroxenes most probably of mare origin. Among opaque phases, kamacite, and a Co-rich taenite were found, and, for the first time in lunar rocks, the rare higher phosphide barringerite, (Fe, Ni)_2 P. The bulk major and trace element composition is unlike the anorthositic lunar highland meteorites (e. g., ALHA81005,Y-791197,Y-86032,MAC88104/5), but somewhat similar to the newly identified mare meteorite EET87521. The mineral compositions as well as the major and trace element compositions of the bulk show a close similarity to certain VLT mare basalts, e. g., the Luna 24 ferrobasalts. This is obvious, for example, in a plot of molar Mg/(Mg+Fe) vs. TiO_2 content. The lithophile trace element abundances in Y-793274 are similar to EET87521 and Apollo 17 and Lunar 24 VLT\u27s. The REE patterns show higher abundances (about 20-10×Cl) than the anorthositic meteorites and a small negative Eu anomaly. They are similar to EET87521 and some Apollo 14 green volcanic glasses. From the mineralogical and chemical data, pairing with any other lunar meteorite is very unlikely. Y-793274 is a shock lithified fragmental breccia containing a minor regolith component and numerous mafic mineral fragments and glasses. It is a mixture of about two thirds mare material and one third highland component, and therefore different from all previously known lunar meteorites

Glasses in meteorites and the Primary Liquid Condensation Model

Meteoritic glasses are quenched samples of the silicate liquid that was involved in the formation of chondritic constituents and achondritic rocks. Conventional genetic models see them as residual liquids from which the associated minerals crystallized – as demonstrated by terrestrial igneous rocks – or as locally produced impact melts. These models are all closely related to our experiences with terrestrial geology and petrology and, consequently,make planetary processes, such asmixing andmelting of solid precursors and planetary differentiation primarily responsible for the formation of the large variety of meteoritic rocks. However, different types of glasses (e.g., glass inclusions in minerals, mesostasis glasses, glass pockets, glass veins) in a variety of meteorites (chondrites and achondrites) have particular chemical features that cannot be reconciled with these models: 1)Glasses do not showthe chemical signature of crystallization of theminerals they are associated with – a geochemical impossibility; 2) All types of glasses in all types of meteorites reported here show very similar trace element abundance pattern with the refractory lithophile element abundances at ~ 10–20 x CI chondrite abundances. 3) All refractory element abundance patterns in primitive glasses have unfractionated solar relative abundances (they are flat) and medium refractory and volatile elements are depleted relative to the refractory elements. 4) Medium volatile and volatile elements, when present, display chaotic abundance patterns. The ubiquitous pattern for refractory elements signals vapor fractionation rather than geochemical (“igneous”) fractionation or stochasticmixing of precursorminerals (as in shockmelts). It indicates that the same process must have been involved in the origin of all glasses in chondritic constituents aswell as achondritic rocks and, consequently, in the formation of allmeteorite types investigated. The chaotic abundances of volatile elements signal that chaotic processes were involved during condensation. 279 Herewe present a newmodel - the Primary Liquid Condensation (PLC)model – as an alternative to the currently acceptedmodels for the formation ofmeteoritic rocks. The PLCmodel is capable of accommodating all observational and chemical data accumulated so far on meteorites – with the exception of enstatite and SNC meteorites, which record physico-chemical conditions that were different fromthose of themajority ofmeteoritic rocks (the processes, however, could have been the same). The new model identifies a new role for silicate liquids in cosmochemistry as being an essential phase for the formation of early crystalline condensates from the hot solar nebula. Liquids are identified to have been the first major phase to condense from the solar nebula. In order to be capable to produce early liquid condensates, the nebula must have been either enriched in condensable elements over solar abundances (> 500 times) or was at total pressuresmuch higher than the canonically predicted ones (> 500 times, > 0.5 bar ). Our data require that this liquid – we named it “universal liquid” (UL) - had a refractory composition (Ca-Mg-Al-silicate or CMAS) and facilitated condensation of the major minerals for chondritic constituents as well as for achondritic rocks. The process possibly was a variant of the vapor-liquid-solid (VLS) condensation process, which is utilized in industrial crystal growth. Thereby, the liquid condenses first, then nucleates a crystal of the species that is oversaturated in the vapor – in the case of the solar nebula usually olivine. As this olivine grows from the liquid, it depletes the liquid in Mg and Si. The liquid tries to maintain equilibrium with the solar nebula. Thereby, Mg and Si are replenished by condensation from the gas phase and all incompatible elements are kept at an equilibrium concentration by condensation-evaporation equilibrium. Thus, the contents of incompatible refractory elements are kept at an approximately constant level throughout crystallization of the major minerals olivine and pyroxene. This way not only the abundances of incompatible refractory elements are kept at a constant level but also their relative abundances remain unfractionated solar. The UL also represents the long sought for refractory component of chondritic constituents and appears also to be the source of achondritic “igneous” rocks. Variations in the amount of liquid available, the liquid condensation and crystal nucleation rates, as well as different crystal-liquid mixing proportion will allow the formation of objects of highly variable composition. The final composition (chemical and isotopic) of any chondritic object or achondrite, as well as that of the associated glasses, will be determined by different degrees of post-formational metasomatic elemental exchange processes taking place between solids and the cooling nebular gas. These processes add medium volatile and volatile elements to the products of high temperature condensation. As these processes usually don’t run to completion, an infinite number of chaotic compositional variations are produced – and this is exactly what we observe in meteorites.Fil: Varela, Maria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; ArgentinaFil: Kurat, G.. Vienna University of Technology; Austri

Lunar meteorite Yamato-86032: Mineralogical, petrological, and geochemical studies

Yamato-86032 is a shock-lithified anorthositic fragmental breccia. It consists mainly of highly feldspathic meta-breccias and meta-meltrocks and possibly contains a small contribution from mare lithologies, but there is no indication of a KREEP component. In many respects Y-86032 is similar to the previously described lunar meteorites Y-82192/3,but there are some notable differences. We have analyzed about 40 major and trace elements in bulk matrix, impact melt, and clast samples from two chips of Y-86032. The abundances of most lithophile and incompatible elements are lower in Y-86032 than in Y-82192 (which contains very low abundances compared to normal lunar highland rocks). The REE abundances are comparable to those of Y-82192. The elements Sc, Cr, Mn, Fe and Co have significantly lower abundances than in Y-82192,and the siderophile element pattern is also different. Since cosmic ray exposure data indicate pairing of Y-86032 with Y-82192/3,the source region for these meteorites on the moon must have been fairly heterogeneous

Gabbroic lunar mare meteorites Asuka-881757(Asuka-31) and Yamato-793169:Geochmical and mineralogical study

Asuka-31 (Asuka-881757) is a new type of gabbroic mare basalt which is similar to VLT mare basalts from Apollo 17 and Luna 24. The small lunar meteorite Yamato-793169 was described to have petrologic characteristics that are similar to those of A-881757; this similarity is confirmed here for trace element compositions. We studied bulk (powder) samples and mineral and rock fragments of A-881757. The mineralogy and mineral chemistry of the separates from A-881757,111 is that of a coarse-grained gabbroic rock of VLT composition; the texture of the mesostases suggests some metamorphic recrystallization with highly unequilibrated mineral compositions. As for mineral phases, we found plagioclase, pyroxene, fayalite, Fe-Ni metal, silica, apatite, and some trace minerals. In addition, we found ulvospinels associated with Na-rich plagioclase, fayalite, apatite, ilmenite, SiO_2,Fe-sulfide, and a rare metal (0.3wt% Ni, 2.0wt% Co) which has a composition unknown so far from any lunar rocks. The trace element contents found in the mineral separates and fragments correspond closely to the mineralogical findings. The chondrite normalized REE patterns for the bulk samples of A-881757 and Y-793169 are relatively flat, with some light REE depletion that is typical of mare basalts. The plagioclasedominated subsamples A31-CL, A31-CL2,and A31-YC show a distinct positive Eu anomaly. The bulk trace element composition of Y-793169 is almost identical to that of A-881757. Solar-wind dervved noble gas and exposure age studies of A-881757 and Y-793169 have indicated marked differences between the two meteorites, indicating that they might have been ejected in different events. These two new gabbroic, VLT-like, mare basalts are therefore valuable new additions to the lunar meteorite collection

The primary liquid condensation model and the origin of Barred Olivine Chondrules.

Barred olivine (BO) chondrules are some of the most striking objects in chondrites. Their ubiquitous presence and peculiar texture caught the attention of researchers and, as a consequence, considerable effort has been expenced on unraveling their origin(s). Here we report on a detailed study of two types of chondrules: the Classic and the Multiple-Plate Type of BO chondrules from the Essebi (CM2) , Bishunpur (LL3.1), Acfer 214 (CH3) and DAG 055 (C3-UNGR) chondrites, and discuss the petrographic and chemical data of their major mineral phases and glasses. Glasses occur as mesostasis or as glass inclusions, the latter either enclosed inside the olivine bars (plates) or still connected to the mesostasis. The chemical composition of all glasses, characterized by being Si-Al-Ca-rich and free of alkali elements, is similar to those of the constituents , such as chondrules, aggregates, inclusions, mineral fragments, etc.) of CR and CV3 chondrites. They all have high trace element contents (~ 10 x CI) with unfractionated CI-normalized abundances of refractory trace elements and depletions in moderately volatile and volatile elements with respect to the refractory trace elements. The presence of alkali elements (Na+K+Rb) is coupled with a low Ca content and is only observed in those glasses that have behaved as open systems. This result supports the previous finding that Ca was replaced by alkalis (e.g., Na-Ca exchange), presumably through a vapor-solid reaction. The glasses apparently are the quenched liquid from which the olivine plates crystallized. However, they do not show any chemical fractionation that could have resulted from the crystallization of the olivines, but rather have a constant chemical compositions throughout the formation of the chondrule. In a previous contribution we were able to demonstrate the role of these liquids in supporting crystal growth directly from the vapor. Here we extend application of the primary liquid condensation model to formulate a new model for the origin of BO chondrules. based on the ability of dust-enriched solar-nebula gas to directly condense into a liquid, provided the gas/dust ratio is sufficiently low. Thus, propose that chondrules can be formed by condensation of a liquid droplet directly from the solar nebula. The extensive variability in chemical composition of BO chondrules, which ranges from alkali-poor to alkali-rich, can be explained by elemental exchange reactions with the cooling nebula. We calculate the chemical composition of the initial liquid droplet from which BO chondrules could have formed and speculate about the physical and chemical conditions that prevail  in the specific regions of the solar nebula that can promote creation of these objects.Fil: Varela, Maria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; ArgentinaFil: Kurat, Gero. Universidad de Viena; AustriaFil: Zinner, Ernst. University of Washington; Estados Unido

A liquid-supported condensation of major minerals in the solar nebula: Evidence from glasses in the Kaba (CV3) chondrite

Glasses, in the Kaba CV3 chondrite, occur as mesostasis in chondrules and aggregates and as inclusions in olivines, both confined or open and connected to the mesostasis. The inclusions in olivine and the glassy mesostasis of aggregates seem to have formed contemporaneously. The confined glass inclusions and open inclusions in olivine were formed during olivine growth and the mesostasis glass during olivine aggregation. All glasses have high trace element contents (10 - 20 × CI) with unfractionated CI-normalized abundances of refractory trace elements. In contrast, V, Mn, Li, and Cr are depleted in all glasses with respect to the refractory trace elements, as is Rb in the glass inclusions in olivine but not in the mesostasis glass. This abundance pattern indicates vapor fractionation and a common condensation origin for both glasses. Glasses of confined glass inclusions in olivine have a Si Al Ca-rich composition with a chondritic Ca/Al ratio. Glasses of open glass inclusions and mesostasis are poor in Ca and enriched in alkalis. However, Ca contents of olivines indicate crystallization from a Ca-rich melt of a composition similar to that of the glass inclusions. In addition, trace element abundances indicate that these glasses (liquids) probably had an original composition similar to that of the inclusion glass. They apparently lost Ca in exchange for alkalis in a metasomatic exchange reaction, presumably with the vapor. There is now growing evidence that liquids can indeed condense from a solar nebula gas, provided the gas/dust ratio is sufficiently low. In these regions with enhanced oxygen fugacity as compared to that of a nebula of solar composition, liquids (the glass precursor) probably played an important role in growing crystals from the vapor by liquid-phase epitaxy. The glasses appear to be the remnants of this thin liquid layer interface that supported the growth of olivine from the vapor following the Vapor-Liquid-Solid process. This liquid will have a refractory composition and will have trace element contents which are in equilibrium with the vapor, and, therefore, will not change much during the time of olivine growth. The composition of the liquid seems to be unconstrained by the phases it is in contact with. Samples of this liquid will be retained as glass inclusions in olivine. The glassy mesostasis could also be a sample of this liquid that got trapped in inter-crystal spaces. The mesostasis glass subsequently behaved as an open system and its Ca was exchanged-presumably with the vapor-for the alkali elements Na, K, and Rb. In contrast, glass inclusions in olivine were protected by the host, could not react, and thus preserved the original composition of this liquid.Fil: Varela, Maria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Geológico del Sur. Universidad Nacional del Sur. Departamento de Geología. Instituto Geológico del Sur; ArgentinaFil: Kurat, Gero. Universidad de Viena; AustriaFil: Zinner, Ernst. Washington University in St. Louis; Estados Unido