Aubrites and diogenites: Trace element clues to their origin     

Rainer Wolf  Mitsuru Ebihara  Gerhard R. Richter  Edward Anders 《Geochimica et cosmochimica acta》1983,47(12):2257-2270

We have analyzed by RNAA 25 aubrite and 9 diogenite samples for 13 to 29 siderophile, volatile, and lithophile trace elements. Both meteorite classes show a typically igneous siderophile element pattern, with Ir, Os, Re, Ge more depleted than Au, Ni, Pd, Sb. But aubrites tend to have about 10 × higher abundances (10^?3 ? 10 ^{? 4} × Cl for the first 4 and 10^?2?10^?3 × Cl for the last 4 siderophiles), apparently reflecting smaller metal/silicate distribution coefficients at lowerf(O₂), or less complete segregation of metal. Se is surprisingly abundant in aubrites (up to 0.4 × Cl), but Te is less so ($\text{Se}\text{Te}\text{? 5 × Cl}$), apparently due to its stronger siderophile character. Other volatiles (Ag, Zn, In, Cd, Bi, T1) show depletions intermediate between lunar dunite and the Earth's mantle.Of 7 aubrites analyzed for REE (Ce, Nd, Eu, Tb, Yb, Lu), 6 are depleted in REE (0.08?0.5 × Cl) and 5 show negative Eu anomalies (the exceptions are Bishopville and Mt. Egerton silicate). This supports an igneous origin, as already noted by Boynton and Schmitt (1972). No samples of the complementary, basaltic and feldspathic rocks have been found thus far, but one of our samples of Khor Temiki dark is a candidate for the basalt. It is 5?7 × enriched in REE and only slightly less so in Rb, Cs, and U. Though shocked and enriched in siderophiles to ~0.05 × Cl, it apparently represents a new meteorite class.Three diogenites analyzed for REE show very diverse patterns, from strongly depleted in light REE for Tatahouine (Ce = 0.01 × Cl) to flat for Garland (~2.5 × Cl). The data confirm the trends found by Fukuokaet al. (1977) as well as their interpretations.Factor analysis shows several parallel groupings for aubrites and diogenites: siderophiles (Re, Ir, Os, Pd, Ge), chalcophiles (Se, Te), volatiles (Ag, In, Tl) and incompatibles (U, REE, and Cs or Rb). But there are some differences for elements such as Ni, Sb, Cd, Bi, Au, and Zn, most of which behave more sensibly in aubrites than in diogenites.Several element pairs that differ greatly in volatility (Cs-U, Ge-Ir) correlate closely in aubrites, in approximately Cl-chondrite proportions. These correlations, and other lines of evidence, suggest strongly that aubrites originated by igneous processes in their parent body, not by direct nebular condensation. The source material may have resembled EL chondrites in oxidation state and depletion of refractories, metal, and volatiles.  相似文献   

Continental drift and the origin of certain mineral deposits     

Dr. Erich Blissenbach  Dr. Rainer Fellerer 《International Journal of Earth Sciences》1973,62(3):812-840

In the course of continental drift, the following subsequent phases are recognized: early arid advanced graben stages, and, after continental breakup, early and advanced drift stages; possibly concluded by a later drift stage.Several mineral potentials of the sea bed or its subsurface do not originate in connection with continental drift (e.g. placers), others are only conditionally related (e. g. hydrocarbons, phosphorites, oozes with U and other metals). Only the metalliferous muds of the Red Sea type and the manganese nodules of the deep sea can be attributed to specific stages.Metalliferous muds form preferably during the early drift stage. An economic evaluation of the Red Sea occurrences is under way. It is assumed that fossil deposits of this type origin are relatively common; prospective areas are tentatively indicated.Manganese nodules with interesting values of Ni, Cu, Co are generated on abyssal plains formed during the advanced drift stage, in particular in areas of extremely low sedimentation. The nodules may represent a major economic potential; sizable fossil deposits of this type can, however, not be expected.

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Zusammenfassung Im Ablauf der Kontinentaldrift werden, aufeinanderfolgend, das frühe und das fortgeschrittene Grabenstadium und, nach Auseinanderbrechen der kontinentalen Kruste, das frühe und das fortgeschrittene Driftstadium unterschieden; die Entwicklung mag durch das späte Driftstadium abgeschlossen werden.Verschiedene Mineralpotentiale des Meeresbodens und seines Untergrundes haben keinen ersichtlichen Zusammenhang mit Kontinentaldrift (z. B. Seifen), andere nur bedingte (z. B. Kohlenwasserstoffe, Phosphorite, organische Schlämme mit Uran und anderen Metallen). Lediglich die Erzschlämme vom Rotmeertyp und die Manganknollen der Tiefsee sind bestimmten Stadien zuzuordnen.Erzschlämme entstehen bevorzugt im frühen Driftstadium. Eine wirtschaftliche Bewertung der bisher aus dem Roten Meer bekannten Vorkommen ist eingeleitet. Eine mäßig häufige Verbreitung fossiler Lagerstätten dieser Genese ist abzuleiten; Hinweise für prospektive Areale deuten sich bereits an. Manganknollen mit interessanten Gehalten an Ni, Cu, Co bilden sich in den Ebenen der Tiefsee, die im Zuge des fortgeschrittenen Driftstadiums entstehen, und zwar in den Gegenden geringster Sedimentation. Die Manganknollen mögen ein großes wirtschaftliches Potential vorstellen; nennenswerte fossile Lagerstätten sind jedoch nicht zu erwarten.

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Résumé Au cours de la dérive continentale on distingue, successivement, un stade premier et un stade avancé de formation du Graben et, après la dislocation de l'écorce continentale, un stade premier et le stade avancé de la dérive; ce développement peut être terminé par un stade tardif ou final de dérive.Plusieurs potentialités minérales du fond de la mer et de son soubassement ne sont pas visiblement liées à la dérive continentale (par exemple placers); d'autres ne montrent que certaines relations avec ce dernier processus (par exemple hydrocarbures, phosphorites, boues organiques contenant de l'uranium et d'autres métaux). Seules les boues métallifères du type «Mer Rouge »et les nodules de manganèse de la mer abyssale sont à attribuer à certains stades.Des boues métallifères sont formées surtout au cours du premier stade de dérivol. Une évaluation économique des gisements de la Mer Rouge connus jusqu'à présent est abordée. On peut en déduire la répartition assez fréquente de gisements fossilifères de cette genèse. Des indications concernant les surfaces à prospecter en resorrtent désà. Des nodules de manganèse avec des teneurs intéressantes en nickel, cuivre, et cobalt se forment dans les plaines abyssales, qui naissent au cours du stade avancé de la dérive, et, à la vérités, dans les zones de très faible sédimentation. Les nodules de manganèse représentent peut-être un grand potentiel économique; toutefois, il ne faut pas s'attendre à l'existence de gisements fossiles notables.

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Organic compounds in the early atmosphere formed abiotically from atomic carbon     

Prof. Dr. Friedemann Freund  Dipl. Min. Rolf Knobel  Dr. Heinz Wengeler  Dipl. Min. Hendrik Kathrein  Dipl. Min. Gert Oberheuser  Dr. Rainer G. Schaefer 《International Journal of Earth Sciences》1982,71(1):1-21

The recent discovery that atomic carbon occurs plentiful in olivines from mantle-derived rocks opens new aspects for the chemical evolution of the early atmosphere and the origin of life. It has been shown conclusively that atomic carbon which is dissolved in the model oxide MgO is capable of reacting in an O₂-free atmosphere with the lattice oxygen to give CO₂ and with the lattice hydrogen, derived from OH^–, to give a profuse variety of hydrocarbons.The diffusional processes and low temperature gas/solid interface reactions involved in these processes are expected to introduce, purely abiotically, isotope fractionation resulting in a¹³C enrichment of the CO₂ fraction and in a¹³C depletion of the hydrocarbon fraction which may be confused with the¹²C/¹³C isotope fractionation along biological pathways.Atomic carbon dissolved in olivines and in basalts shows a similar behaviour and yields similar quantities as C in MgO: 1–2 mg/g CO₂ and 25–100g/g hydrocarbons degassing between 400 and 1000 °C. On a geological scale this means that each cubic kilometer of basaltic magma degassing in an O₂-free atmosphere has the capacity of sending off about 3–6·10⁹ kg (2·10⁹ m³) of CO₂ and about 1–3·10⁸ kg (2·10⁸ m³) of hydrocarbons. The presence of water modifies the composition to give, among others, alcohols and organic acids.On the basis of these results we are led to the conclusion that the early atmosphere of the earth may have contained a very high concentration of abiotically formed organic compounds of great chemical complexity.

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Zusammenfassung Die Entdeckung des atomar gelösten Kohlenstoffs in Olivinen aus Mantelgesteinen führt zu neuen Vorstellungen über die Zusammensetzung der Uratmosphäre und Entwicklungsbedingungen des Lebens. Atomarer Kohlenstoff im MgO ist in der Lage, in einer O₂-freien Atmosphäre mit dem Gittersauerstoff zu CO₂ zu reagieren und mit dem aus OH^– stammenden Gitterwasserstoff eine große Vielfalt von organischen Verbindungen zu bilden.Diffusionsprozesse und Gas-Festkörper-Austauschreaktionen, die an diesen Reaktionen beteiligt sind, führen nach ersten Untersuchungen zu einer¹³C-Anreicherung im CO₂ und einer¹³C-Abreicherung bei den Kohlenwasserstoffen. Diese¹²C/¹³C-Fraktionierung ist gleichsinnig mit der biologischen¹²C/¹³C-Fraktionierung.Atomarer Kohlenstoff in Olivinen und Basalten zeigt ein sehr ähnliches Reaktionsverhalten wie im MgO und führt zu ähnlichen Reaktionsprodukten: 1–2 mg/g CO₂ und 25–100g/g Kohlenwasserstoffe zwischen 400–1000 °C. Übertragen auf geologische Verhältnisse bedeutet dies, daß jeder km³ eines entgasenden basaltischen Magmas 3–6·10⁹ kg (2·10⁹ m³) CO₂ und 1–3·10⁸ kg (2·10⁸ m³) abwüschen Kohlenwasserstoff abgeben kann. Die Anwesenheit von Wasser führt zur Bildung von Alkoholen und organischen Säuren. Diese Ergebnisse deuten darauf hin, daß die Uratmosphäre und die Ursuppe viel reicher waren als bisher angenommen an komplexen organischen Verbindungen, die rein thermisch entstanden sind.

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Résumé La découverte du carbone atomique dans les olivines du manteau entraîne de nouvelles idées sur la composition de l'atmosphère originelle et sur les conditions du développement de la vie. Comme l'est le cas pour le MgO, le carbone atomique dans les olivines est capable de réagir, dans une atmosphère exempte de O₂, avec l'oxygène du réseau cristallin en formant du CO₂, et avec l'hydrogène provenant des groupements OH^– du réseau, pour former une grande variété de composés organiques.Les processus de diffusion et d'échange gas-solide liés à ces réactions provoquent, d'après les premiers résultats, un enrichissement en¹³C dans le CO₂ et un appauvrissement en¹³C dans les hydrocarbures formés. Ceci ressemble au fractionnement dû à des réactions biologiques.Le comportement du carbone atomique et sa réactivité se retrouvent dans les basaltes et les olivines. La gamme des produits de réaction et leur quantité ressemble à celle du MgO: 1–2 mg/g CO₂ et 25–100g/g composés organiques. A l'échelle géologique ceci implique que chaque km³ de magma basaltique dégazé en contact avec une atmosphère exempte d'oxygène pouvait émettre 3–6·10⁹ kg, soit 2·10⁹ m³ de CO₂ et 1–3·10⁸ kg, soit 2·10⁸ m³ d'hydrocarbures abiotiques. La présence d'eau entraîne la formation d'alcools et d'acides organiques.La conclusion tirée de ce travail indique que l'atmosphère originelle et la»soupe primordiale» étaient plus riches qu'on ne l'a admis jusqu'à présent en composés organiques dûs à des processus purement thermiques, et donc abiotiques.

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. MgO , COg, -, , . , , — — ¹³ ₂ . ¹²/¹³ , . , , - : 1–2 / O₂ 25–100 / , 400–1000 . , 3–6·109 (2·10^{9 3}) ₂ 1– 3·10⁸ (2·10^{8 3}) . . , , , , .

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Presented in part at the meeting Precambrian Problems, Copenhagen, March 1981.  相似文献   

Identification of the projectile at the Brent crater,and further considerations of projectile types at terrestrial craters     

Herbert Palme  Richard A.F Grieve  Rainer Wolf 《Geochimica et cosmochimica acta》1981,45(12):2417-2424

Impact melt samples from drill hole B1-59 at the 3.8 km diameter Brent crater (Ontario) have been analysed for siderophile trace elements indicative of meteoritic contamination. Samples from the basal melt zone at 823–857 m depth are enriched in Ir, Os, Pd, Ni, Co, Cr and Se over basement, with the abundance pattern suggesting a chondritic projectile for Brent. From a Ni-Cr correlation of 10 melt samples an L or LL chondrite is inferred. The contribution of an ultramafic country rock (alnoite) in the melt is too small to significantly influence its $\text{Ni}\text{Cr}$ ratio. Glass-rich breccias from the allochthonous breccias filling the crater also contain a meteoritic component. Interelement ratios (e.g. $\text{Ni}\text{Cr}$) are, however, fractionated relative to the melt zone samples. This, as well as the low Au content of all Brent samples, is probably a product of alteration.Additional data on impact melts from the 65 km diameter crater Manicouagan still did not reveal a meteoritic component, as also for the Mistastin crater (28 km diameter) where Cr analyses set an upper limit of 1% of an achondritic projectile component in the melt. Irghizites (tektite like glasses) from the Zhamanshin impact structure have been found to contain high Ni and Co concentrations, and our data show that Ir is also enriched. It is however not possible to define the projectile-type. Enrichment of an Ivory Coast tektite in Ir is confirmed. There are large differences in siderophile element concentrations among tektites, with otherwise similar chemical composition.There are now four known craters formed by chondrites (Clearwater East, Lapparjärvi, Wanapitei, and Brent), with Brent being the smallest of these. For smaller craters the projectiles appear to be limited to iron or stony-iron meteorites, because of atmospheric destruction of relatively small stony meteorites. It appears, however, that all major classes of meteorites are represented among the projectiles at terrestrial impact craters.  相似文献   

Hingganite-(Y) from a small aplite vein in granodiorite from Oppach,Lusatian Mts., E-Germany     

Thomas  Rainer  Davidson  Paul 《Mineralogy and Petrology》2017,111(6):821-826

Mineralogy and Petrology - Crystals of hingganite-(Y) occur co-trapped in quartz crystals from miarolitic cavities in an aplite vein in the Cadomian granodiorite from Oppach/Lusatian, Germany. We...  相似文献   

Effects of aqueous alteration on primordial noble gases and presolar SiC in the carbonaceous chondrite Tagish Lake     

M. E. I. Riebe  H. Busemann  C. M. O'D. Alexander  L. R. Nittler  C. D. K. Herd  C. Maden  J. Wang  R. Wieler 《Meteoritics & planetary science》2020,55(6):1257-1280

Effects of aqueous alteration on primordial noble gas carriers were investigated by analyzing noble gases and determining presolar SiC abundances in insoluble organic matter (IOM) from four Tagish Lake meteorite (C2‐ung.) samples that experienced different degrees of aqueous alteration. The samples contained a mixture of primordial noble gases from phase Q and presolar nanodiamonds (HL, P3), SiC (Ne‐E[H]), and graphite (Ne‐E[L]). The second most altered sample (11i) had a ~2–3 times higher Ne‐E concentration than the other samples. The presolar SiC abundances in the samples were determined from NanoSIMS ion images and 11i had a SiC abundance twice that of the other samples. The heterogeneous distribution of SiC grains could be inherited from heterogeneous accretion or parent body alteration could have redistributed SiC grains. Closed system step etching (CSSE) was used to study noble gases in HNO₃‐susceptible phases in the most and least altered samples. All Ne‐E carried by presolar SiC grains in the most altered sample was released during CSSE, while only a fraction of the Ne‐E was released from the least altered sample. This increased susceptibility to HNO₃ likely represents a step toward degassing. Presolar graphite appears to have been partially degassed during aqueous alteration. Differences in the ⁴He/³⁶Ar and ²⁰Ne/³⁶Ar ratios in gases released during CSSE could be due to gas release from presolar nanodiamonds, with more He and Ne being released in the more aqueously altered sample. Aqueous alteration changes the properties of presolar grains so that they react similar to phase Q in the laboratory, thereby altering the perceived composition of Q.  相似文献   

Dynamics of dimensions in factor-space cosmology     

U. Bleyer  M. Rainer  M. Mohazzab 《Astronomische Nachrichten》1996,317(1):3-13

For multi-dimensional cosmological models we investigate the dynamics of both, scales and dimensions. The classical equation of motions and the corresponding Wheeler-de Witt equation are set up generally and the qualitative behaviour of the system is discussed for some specific model with 2 factor spaces: A space M₁ with dynamical dimension, and a compact internal space M₂ of constant dimension. With a natural choice of some contraint, there exist a solution where M₁ expands as usual space while M₂ is shrinking down to unobservable scales.  相似文献