H and Cl isotope systematics of apatite in brecciated lunar meteorites Northwest Africa 4472, Northwest Africa 773, Sayh al Uhaymir 169, and Kalahari 009     

Romain Tartèse  Mahesh Anand  Katherine H. Joy  Ian A. Franchi 《Meteoritics & planetary science》2014,49(12):2266-2289

We have investigated the H and Cl systematics in apatite from four brecciated lunar meteorites. In Northwest Africa (NWA) 4472, most of the apatites contain ～2000–6000 ppm H₂O with δD between ?200 and 0‰, except for one grain isolated in the matrix, which contains ～6000 ppm H₂O with δD of ～500–900‰. This low‐δD apatite contains ～2500–7500 ppm Cl associated with δ³⁷Cl of ～15–20‰, while the high‐δD grain contains ～2500 ppm Cl with δ³⁷Cl of ～7–15‰. In NWA 773, apatites in a first group contain ～700–2500 ppm H₂O with δD values averaging around ～0 ± 100‰, while apatites in a second group contain ～5500–16500 ppm H₂O with δD ～250 ± 50‰. In Sayh al Uhaymir (SaU) 169 and Kalahari (Kal) 009, apatites are similar in terms of their H₂O contents (～600–3000 ppm) and δD values (?100 to 200‰). In SaU 169, apatites contain ～6000–10,000 ppm Cl, characterized by δ³⁷Cl of ～5–12‰. Overall, most of the analyzed apatite grains have δD within the range reported for carbonaceous chondrites, similar to apatite analyzed in ancient (>3.9 Ga) lunar magmatic. One grain in NWA 4472 has H and Cl isotope compositions similar to apatite from mare basalts. With an age of 4.35 Ga, this grain could be a representative of the oldest known lunar volcanic activity. Finally, since numerous evolved clasts in NWA 773 formed through silicate liquid immiscibility, the apatite grains with extremely high H₂O contents, reaching pure hydroxylapatite composition, could provide insights into the effects of such process on the evolution of volatiles in lunar magmas.  相似文献   

Washington photometry of open cluster giants: two moderately metal-poor anticentre clusters     

M. Celeste Parisi  Juan J. Clariá  rés E. Piatti  Douglas Geisler 《Monthly notices of the Royal Astronomical Society》2005,363(4):1247-1256

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Effect of Pinus radiata plantations on water balance in Chile     

Anton Huber  Andrés Iroumé  James Bathurst 《水文研究》2008,22(1):142-148

The effect of Pinus radiata (D. Don) plantations on water resources at different Chilean sites located between 33 and 40 south was determined. Incoming precipitation, canopy interception loss, evapotranspiration, net evapotranspiration (transpiration and evaporation from the soil), percolation and soil water content were measured in each site, where Pinus radiata plantations were 12 to 17 years old and between 700 and 830 trees ha^?1 dense. The results were compared with those obtained from areas covered with perennial grasses and shrubs at the same sites. The pine canopies intercepted on average 36–40% of the annual rainfall at all sites where rainfall was less then 1200 mm, while only 15% of the mean rainfall was intercepted in the southernmost and rainy (2081 mm year^?1) site. Annual net evapotranspiration increased from south to north from 32% of the incoming precipitation for the southernmost site to 55% for the one located at the lower latitude. In this northernmost site almost the entire incoming precipitation was evapotranspired. Annual percolation registered its minimum value in the northern site (5% of incoming precipitation) and its maxima in the southern one (53%). The values of net evapotranspiration and percolation were regulated by the pluviometric regime and the soil moisture retention capacity in each site. Compared with the shrub or grass covers, sites under Pinus radiata plantations registered higher water consumption by evapotranspiration and reduced percolation. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Ages and metallicities of eight star clusters and their surrounding fields in the inner disc of the Large Magellanic Cloud     

Doug Geisler  rés E. Piatti  Eduardo Bica  Juan J. Clariá 《Monthly notices of the Royal Astronomical Society》2003,341(3):771-784

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New OSL dating of UK loess: indications of two phases of Late Glacial dust accretion in SE England and climate implications     

Michèle L. Clarke  Antoni E. Milodowski  Jon E. Bouch  Melanie J. Leng  Kevin J. Northmore 《第四纪科学杂志》2007,22(4):361-371

Windblown dust deposits or loess, locally known in the UK as brickearth, blanket many parts of southern England outside the limits of the British and Irish Ice Sheet. The best‐studied loess exposures occur in Kent, southeast England, where the deposits are believed to be Late Glacial in age. New sedimentological evidence is presented for phases of accretion with two distinct units, a calcareous brickearth exhibiting periglacial cryoturbation and a non‐calcareous, massive brickearth. Optically stimulated luminescence (OSL) dating has been applied to chemically isolated modal quartz silts to derive a chronology for sediment accretion and to better understand the palaeoclimatic significance of these deposits. © British Geological Survey/Natural Environment Research Council copyright 2007. Reproduced with the permission of BGS/NERC. Published by John Wiley & Sons, Ltd.  相似文献   

Modelling the Dust Envelope in Symbiotic Systems: The Case of CH CYGNI     

R.D.D. Costa  D. Mékarnia  J. Lefèvre 《Astrophysics and Space Science》1997,251(1-2):185-188

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FIRST RESULTS FROM VIRGO,THE EXPERIMENT FOR HELIOSEISMOLOGY AND SOLAR IRRADIANCE MONITORING ON SOHO   总被引：1，自引：0，他引：1  

Fröhlich  Claus  Andersen  Bo N.  Appourchaux  Thierry  Berthomieu  Gabrielle  Crommelynck  Dominique A.  Domingo  Vicente  Fichot  Alain  Finsterle  Wolfgang  Gómez  Maria F.  Gough  Douglas  Jiménez  Antonio  Leifsen  Torben  Lombaerts  Marc  Pap  Judit M.  Provost  Janine  Roca Cortés  Teodoro  Romero  José  Roth  Hansjörg  Sekii  Takashi  Telljohann  Udo  Toutain  Thierry  Wehrli  Christoph 《Solar physics》1997,170(1):1-25

First results from the VIRGO experiment (Variability of solar IRradiance and Gravity Oscillations) on the ESA/NASA Mission SOHO (Solar and Heliospheric Observatory) are reported. The observations started mid-January 1996 for the radiometers and sunphotometers and near the end of March for the luminosity oscillation imager. The performance of all the instruments is very good, and the time series of the first 4–6 months are evaluated in terms of solar irradiance variability, solar background noise characteristics and p-mode oscillations. The solar irradiance is modulated by the passage of active regions across the disk, but not all of the modulation is straightforwardly explained in terms of sunspot flux blocking and facular enhancement. Helioseismic inversions of the observed p-mode frequencies are more-or-less in agreement with the latest standard solar models. The comparison of VIRGO results with earlier ones shows evidence that magnetic activity plays a significant role in the dynamics of the oscillations beyond its modulation of the resonant frequencies. Moreover, by comparing the amplitudes of different components ofp -mode multiplets, each of which are influenced differently by spatial inhomogeneity, we have found that activity enhances excitation.  相似文献   

The influence of Crowding on DENIS point source detection rates     

András Holl  Erik Deul 《Astrophysics and Space Science》1994,217(1-2):19-22

In this paper we estimate the effects of crowding (resulting in failure to detect sources due to unresolvable blends) on DENIS point source extraction. Crowding, together with confusion (flux contribution from sources below the detection limit), is expected to be a major quality-degrading factor close to the galactic plane. Correcting for the incompleteness of the DENIS data could produce accurate starcounts very close to the galactic plane.  相似文献   

DENIS: A deep near-infrared survey of the southern sky     

N. Epchtein  B. De Batz  E. Copet  P. Fouqué  F. Lacombe  T. Le Bertre  G. Mamon  D. Rouan  D. Tiphène  W. B. Burton  E. Deul  H. Habing  J. Borsenberger  M. Dennefeld  A. Omont  J. C. Renault  B. Rocca Volmerange  S. Kimeswenger  I. Appenzeller  R. Bender  T. Forveille  F. Garzon  J. Hron  P. Persi  M. Ferrari-Toniolo  I. Vauglin 《Astrophysics and Space Science》1994,217(1-2):3-9

The DENIS project is the first attempt to carry out a complete digitized survey of the southern sky in the range 1–2.5µm. The main objectives of the programme and the main specifications of the camera and of the data processing stream are briefly outlined  相似文献   

First Results on it p Modes from GOLF Experiment     

M. Lazrek  F. Baudin  L. Bertello  P. Boumier  J. Charra  D. Fierry-Fraillon  E. Fossat  A. H. Gabriel  R. A. García  B. Gelly  C. Gouiffes  G. Grec  P. L. Pallé  F. Pérez Hernández  C. Régulo  C. Renaud  J.-M. Robillot  T. Roca Cortés  S. Turck-Chièze  R. K. Ulrich 《Solar physics》1997,175(2):227-246

The GOLF experiment on the SOHO mission aims to study the internal structure of the Sun by measuring the spectrum of global oscillations in the frequency range 10^-7 to 10^-2 Hz. Here we present the results of the analysis of the first 8 months of data. Special emphasis is put into the frequency determination of the p modes, as well as the splitting in the multiplets due to rotation. For both, we show that the improvement in S/N level with respect to the ground-based networks and other experiments is essential in achieving a very low-degree frequency table with small errors ∼ 2 parts in 10^-5). On the other hand, the splitting found seems to favour a solar core which does not rotate slower than its surface. The line widths do agree with theoretical expectations and other observations.  相似文献