A komatiite component in Apollo 16 highland breccias: implications for the nickel-cobalt systematics and bulk composition of the moon     

A.E. Ringwood  Stefan Seifert  Heinrich Wnke 《Earth and Planetary Science Letters》1987,81(2-3)

The lunar crust at the Apollo 16 landing site contains substantial amounts of a “primitive component” in which the ferromagnesian group of elements is concentrated. The composition of this component can be retrieved via an analysis of mixing relationships displayed by lunar breccias. It is found to be a komatiite which is compositionally similar to terrestrial komatiites both in major and minor elements. The komatiite component of the lunar crust is believed to have formed by extensive degrees of melting of the lunar interior at depths greater than were involved in the formation of the lunar magma ocean which was parental to the crust. After formation of the anorthositic crust, it was invaded by extensive flows and intrusions of komatiite magma from these deeper source regions. The komatiites became intimately mixed with the anorthosite by intensive meteoroid impacts about 4.5 b.y. ago, thereby accounting for the observed mixing relationships displayed by the crust. The compositional similarity between lunar and terrestrial komatiites strongly implies a corresponding similarity between the compositions of their source regions in the lunar interior and the Earth's upper mantle. The composition of the lunar interior can be modelled more specifically by combining the komatiite composition with its liquidus olivine composition (as determined experimentally) in proportions chosen so as to produce a cosmochemically acceptable range of Mg/Si ratios for the bulk Moon. Except for higher FeO and lower Na₂O, the range of compositions thereby obtained for the bulk moon is very similar to the composition of the Earth's upper mantle.The effects of meteoritic contamination on the abundances of cobalt and nickel in lunar highland breccias were subtracted on the assumption that the contaminating projectiles were chondritic. The cobalt and nickel residuals thereby obtained were found to correlate strongly with the (Mg + Fe) content of the breccias, demonstrating that the Co and Ni are associated with the ferromagnesian component of the breccias and are genuinely indigenous to the Moon. The lunar highland Co and Ni residuals also display striking Ni/Co versus Ni correlations which follow a similar trend to those displayed by terrestrial basalts, picrites and komatiites. The lunar trends provide further decisive evidence of the indigenous nature of the Co and Ni residuals and suggest the operation of extensive fractionation controlled by olivine-liquid equilibria in producing the primitive component of the lunar breccias. Indigenous nickel abundances at the Apollo 14, 15 and 17 sites are much lower than at the Apollo 16 site, although rocks from all sites follow the same Ni/Co versus Ni trends. It is suggested that the primitive component at the Apollo 14, 15 and 17 sites was generally of basaltic composition, in contrast to the komatiitic nature of the Apollo 16 primitive component.  相似文献   

Transmission electron microscopic study of antiphase domains in CaAl2Ge2O8-Feldspar     

Wolfgang Friedrich Müller  Yusof Vojdan-Shemshadi  Horst Pentinghaus 《Physics and Chemistry of Minerals》1987,14(3):235-237

Transmission electron microscopic study of synthetic CaAl₂Ge₂O₈-feldspar revealed two types of antiphase domains: type “b”-antiphase domains with the displacement vector 1/2 [110] and type “c”-antiphase domains with the displacement vector 1/2 [111]. The “b”-domains were on the order of 0.1 μm in size, while the “c”-domains displayed wall to wall distances mostly between 0.1 and 1 μm. The formation of the two types of antiphase domains is due to reductions in translational symmetry associated with the phase transitions \(C\bar 1 \to I\bar 1 \to P\bar 1\) . The antiphase domain textures of CaAl₂Ge₂O₈-feldspar are very similar to the textures found in natural and synthetic anorthite, CaAl₂Si₂O₈.  相似文献   

Announcements     

G. Friedrich 《Mineralium Deposita》1983,18(1):133-133

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Oxygen deficient perovskites in the system CaSiO3–CaAlO2.5 and implications for the Earth’s interior     

U. W. Bläß  F. Langenhorst  D. J. Frost  F. Seifert 《Physics and Chemistry of Minerals》2007,34(6):363-376

Oxygen deficient perovskites of the system CaSiO₃–CaAlO_2.5 have been synthesised at high-pressure and -temperature conditions relevant to the Earth’s transition zone in order to investigate their stabilities in the Earth’s mantle and determine structural properties associated with vacancy incorporation. Two polysomes of thermodynamically stable defect perovskites with Ca(Al_0.4Si_0.6)O_2.8 and Ca(Al_0.5Si_0.5)O_2.75 stoichiometry have been identified. The ordering of oxygen defects into pseudo-cubic (111) layers results in well-ordered ten- or eightfold superstructures, respectively. At all other compositions examined, a metastable formation of perovskites has been observed instead, which are assumed to grow initially disordered. These are now characterised by tiny domains, formed due to subsequent ordering of vacancies along various pseudo-cubic {111} layers. Both ordered defect perovskites show a large P–T stability field ranging from about 9–18 GPa and 4–12 GPa, respectively. Microstructural TEM analyses revealed the presence of growth and ferroelastic twins, which indicate a phase transition from rhombohedral to monoclinic symmetry during quenching. Electron energy loss spectroscopy of Si and Al K edges point at the presence of tetrahedral, octahedral and maybe some pentacoordinated silicon, whereas aluminium is predominantly octahedrally coordinated with minor fractions in lower coordination. Observed properties are interpreted in terms of a new structural model, explaining the observed phase transition and formation of different twin laws as well as giving reasons for the development of such large superstructures. With respect to phase relations of the transition zone, the potential occurrence of such defect perovskites in the Earth’s interior is discussed.  相似文献   

Ophiolites of the Eastern Peninsulas zone (Eastern Kamchatka): Age, composition, and geodynamic diversity     

Nikolay V.  Tsukanov  Wolfgang  Kramer  Sergey G.  Skolotnev  Marina V.  Luchitskaya  Wolfgang  Seifert 《Island Arc》2007,16(3):431-456

Abstract   The geological, geochemical and mineralogical data of dismembered ophiolites of various ages and genesis occurring in accretionary piles of the Eastern Peninsulas of Kamchatka enables us to discriminate three ophiolite complexes: (i) Aptian–Cenomanian complex: a fragment of ancient oceanic crust, composed of tholeiite basalts, pelagic sediments, and gabbroic rocks, presently occurring in a single tectonic slices (Afrika complex) and in olistoplaques in Pikezh complex of the Kamchatsky Mys Peninsula and probably in the mélange of the Kronotsky Peninsula; (ii) Upper Cretaceous complex, composed of highly depleted peridotite, gabbro and plagiogranite, associated with island arc tholeiite, boninite, and high-alumina tholeiitic basalt of supra-subduction origin; and (iii) Paleocene–Early Eocene complex of intra-island arc or back-arc origin, composed of gabbros, dolerites (sheeted dykes) and basalts produced from oceanic tholeiite melts, and back-arc basin-like dolerites. Formation of the various ophiolite complexes is related to the Kronotskaya intra-oceanic volcanic arc evolution. The first ophiolite complex is a fragment of ancient Aptian–Cenomanian oceanic crust on which the Kronotskaya arc originated. Ophiolites of the supra-subduction zone affinity were formed as a result of repeated partial melting of peridotites in the mantle wedge up to the subduction zone. This is accompanied by production of tholeiite basalts and boninites in the Kamchatsky Mys segment and plagioclase-bearing tholeiites in the Kronotsky segment of the Kronotskaya paleoarc. The ophiolite complex with intra-arc and mid-oceanic ridge basalt geochemical characteristics was formed in an extension regime during the last stage of Kronotskaya volcanic arc evolution.  相似文献   

Bestimmung der Phytoplanktonvolumina — Methodik und Ergebnisse am Beispiel Niederrhein     

Marlies Pohlmann  Günther Friedrich 《Limnologica》2001,31(3)

For data treatment of phytoplankton countings in the Lower Rhine the specific biovolume was calculated. The used computer-aided method is described, and the correlation between phytoplankton biomass, cell number and chlorophyll a is presented.  相似文献   

Zwei neue Harpacticoidenformen aus dem Grundwasser     

Friedrich Kiefer 《Aquatic Sciences - Research Across Boundaries》1963,25(1):49-55

Ohne Zusammenfassung  相似文献   

Die Westwärts-Intensivierung des Polarfront-Jetstream in den Winkel zwischen Polarfront und Tropopause an der Ostseite eines polaren Kälteausbruchs,eine Erweiterung des klassischen Grenzflächenproblems von Margules     

Friedrich Defant 《Meteorology and Atmospheric Physics》1959,11(2):197-217

Zusammenfassung Es wird eine auf rein dynamischen Grundlagen beruhende Erklärung für die starke Westwärts-Intensivierung des Polar-front-Jetstream in den Winkel zwischen der geneigten Polarfrontfläche und der gegengeneigten Tropopause an der Ostflanke eines polaren Kälteausbruches gegeben.Eine gewisse Ähnlichkeit des Atmosphärenaufbaues mit dem Aufbau des Ozeans im Stromstrich des Golfstromes führt dazu, die Trägheitsgrenzschichten-Theorie vonJ. Charney [1] auf ein solches atmosphärisches System anzuwenden. Ein dreigeschichtetes Atmosphärenmodell wird entwickelt, und für dieses werden Bewegungsgleichungen abgeleitet, die es erlauben, das Problem entsprechend dem LösungsgangCharneys zu behandeln.Der Vergleich mit den aus den Beobachtungen abgeleiteten Neigungen der Polarfront und der Tropopause und der beobachteten Westwärts-Intensivierung des Stromes fällt sehr befriedigend aus. Diese Theorie erfaßt selbstverständlich nur die rein dynamische Seite der Erscheinung und berücksichtigt den sicher wichtigen Beitrag der thermodynamischen Prozesse durch die Verwendung des rohen Modells nur näherungsweise.

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Summary Based on purely dynamical reasoning an explanation for the strong westward-intensification of the polarfront jetstream into the angle between the inclined polarfront surface and the opposite inclined tropopause on the eastern side of an outbreak of cold polar air is presented.Certain similarity of the structure of the atmosphere with that of the ocean in the main core of the gulf stream has guided me to apply the inertial boundary layer theory ofJ. Charney [1] to such an atmospheric system. A three-layered model of the atmosphere has been developed and corresponding equations of motion were derived, which allow to handle the problem according to the solution ofCharney.The comparison with the slopes of polarfront and tropopause according to the observations and with the observed westward intensification of the flow is rather satisfactory. However, we must understand that this theory only considers the dynamical side of the phenomenon and does only approximately account for the important contribution of thermodynamic processes by the use of the rather simple model.

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Résumé L'auteur tente d'expliquer du point de vue purement dynamique l'intensification vers l'Ouest du jet situé dans l'angle compris entre le front polaire et la tropopause d'inclinaison contraire, sur le flanc oriental d'un afflux d'air polaire.Une certaine analogie entre la structure de l'atmosphère et celle de l'océan à l'endroit du Gulf-stream incite à appliquer au cas évoqué ici la théorie de la couche limite d'inertie deJ. Charney [1]. On imagine un type d'atmosphère à trois couches pour lequel on établit les équations du mouvement permettant de traiter le problème en cause à l'aide du procédé deJ. Charney.Les observations concernant l'inclinaison du front polaire et de la tropopause ainsi que celles de l'intensification du jet vers l'Ouest confirment la théorie de façon très satisfaisante. Cette dernière, purement dynamique, ne tient compte que d'une manière approchée des processus thermodynamiques sans doute importants.

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Mit 7 Textabbildungen  相似文献   

Beitrag zur Kenntnis der planktisch lebenden Ruderfusskrebse (Crustacea Copepoda) des Engstlensees (Berner Oberland)     

Prof. Dr. Friedrich Kiefer Friedrich Kiefer 《Aquatic Sciences - Research Across Boundaries》1970,32(2):418-428

Zusammenfassung Eine am 22. September 1969 im 1850 m hoch gelegenen Engstlensee gesammelte Planktonprobe enthielt zwei verschiedene Copepodenarten. Der Diaptomide ist ein Gield der GattungArctodiaptomus. Bereits 1885 ist er aus diesem Gew?sser als neue Artalpinus erw?hnt worden. Sp?tere Forscher haben ihn dann aber—wie alle ?hnlichen Populationen hochgelegener Alpenseen—mit der Speziesbacillifer Koelbel identifiziert. Nach den Ergebnissen vergleichender Untersuchungen des Verfassers istalpinus indessen doch als selbst?ndige Art zu bewerten, die hier zum erstenmal ausführlich beschrieben wird. DerCyclops des Engstlensees wird alsCyclops abyssorum tatricus (Kozminski, 1927) gekennzeichnet.

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Résumé Le 22 septembre 1969, l’auteur a effectué une récolte de faune pélagique dans l’Engstlensee. L’étude de cette récolte a permis de déterminer les deux Copépodes suivants:Arctodiaptomus alpinus (Imhof) etCyclops abyssorum tatricus (Kozminski). Tous les deux sont des Crustacés caractéristiques pour la faune pélagique de beaucoup de lacs élevés des Alpes. Jusqu’à présent, l’Arctodiaptomus alpinus a été nommébacillifer. Mais au cours d’une revision du ?groupebacillifer? du genreArctodiaptomus, l’auteur a constaté que ?bacillifer Koelbel? et ?alpinus Imhof? sont en réalité deux espèces différentes. Les résultats complets de cette revision seront publiés par un autre journal d’hydrobiologie.

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Herrn Prof. OttJaag zum 70. Geburtstag  相似文献   

Zur Frage der Altersstellung und Genese der Blei-Zink-Vorkommen der Sierra de Cartagena in Spanien     

Stefan Graeser  Günther Friedrich 《Mineralium Deposita》1970,5(4):365-374

Zusammenfassung Bleiglanzproben aus verschiedenen Lagerstätten der Sierra de Cartagena wurden auf ihre Blei-Isotopen-Verhältnisse untersucht. Auffallend ist deren völlig identische Pb-Isotopen-Zusammensetzung, aus der sich nach dem Houtermans-Modell ein Modell-Alter von 30 Millionen Jahren errechnen läßt. Die Blei-Mineralisation im Erzdistrikt von Cartagena steht daher in einem sicheren Zusammenhang mit der Tätigkeit jungtertiärer subvulkanischer Magmenherde. Das Alter der Andesite wurde mittels Rb/Sr-Methode an einem Biotit des Atalaya-Andesites mit 44±27 m.y. bestimmt. Dieser Wert stimmt sehr gut mit einer Altersbestimmung an einem leukogranitischen Gang aus der Sierra Cabrera überein (50±3 m.y.). Die Ergebnisse der Spurenelement-bestimmung an Bleiglanzproben werden im Zusammenhang mit schon früher mitgeteilten Schwefel-Isotopen-Daten diskutiert.

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Lead isotope ratios have been determined in galena samples from the Sierra de Cartagena (Spain). The range of the Pb-isotopes is extremely narrow within the ore district, which contains different types of ore deposits. The age of the galena bearing ore deposits has been determined by using the Houtermansmodel: 30 million years. The lead minertalisation in the district therefore may be linked to the subvolcanic activity of Tertiary age. Ascribing the mineralisation to three volcanic episodes of Palaeozoic, Miocene and Pliocene ages and two periodes of supergene processes is not possible. Rb/Sr ratios have been determined in a biotite sample from the Atalaya andesite. The mica age is 44±27 m.y. which is in closest agreement with the age given for rocks in the Sierra Cabrera (50±3 m.y.). The results of trace element analyses are discussed in connection with previously studied sulphur isotope composition.

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