Reply to the comment by Zhang et al. on: “First finding of A-type and adakitic magmatism association in Songpan–Garze fold belt, eastern Tibetan Plateau: Implication for lithospheric delamination”     

Zhang Hong-Fei  Randy Parrish  Li Zhang  Wang-Chuan Xu  Hong-Ling Yuan  Shan Gao  Quentin G. Crowley 《Lithos》2008,103(3-4):565-568

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Oceanic control of multidecadal variability in an idealized coupled GCM     

Quentin Jamet  Thierry Huck  Olivier Arzel  Jean-Michel Campin  Alain Colin de Verdière 《Climate Dynamics》2016,46(9-10):3079-3095

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Large-scale structure of galaxies in the Ophiuchus region     

Takashi Hasegawa  †  Ken-ichi Wakamatsu  ‡  Matthew Malkan  ‡  Kazuhiro Sekiguchi  John W. Menzies  Quentin A. Parker  Jun Jugaku  Hiroshi Karoji  Sadanori Okamura 《Monthly notices of the Royal Astronomical Society》2000,316(2):326-344

The large-scale structure around the Ophiuchus cluster of galaxies in the vicinity of the Galactic Centre ( l =05, b =95, cz =8500 km s⁻¹) is investigated on the basis of a galaxy survey and spectroscopic observations made for a 12°×17° area. The galaxy survey was performed using six ESO/SERC Sky Survey Atlas films, and 4021 galaxies were detected in total. Recession velocities were newly obtained for 179 galaxies to make the total number of galaxies in the survey area with known velocities 219.
In the distribution of bright galaxies, we identified seven new clumps of galaxies. Comparing the surface number density of bright galaxies with the Galactic extinction, which is estimated from the 100‐μm flux density in the IRAS Sky Survey Atlas, we demonstrate that the seven clumps are not spurious as a result of the inhomogeneity of the Galactic extinction. Among the seven clumps, two are found to be clusters and four to be groups on the basis of the histogram of recession velocities and the number of member galaxies. The Ophiuchus cluster, two newly identified clusters, and four groups are all concentrated at 9000 km s⁻¹. Field galaxies are also distributed centred at 8500 km s⁻¹. Hence field galaxies occupy a common three-dimensional region with galaxies in the clusters and groups, and altogether they form a large-scale structure of supercluster size. As opposed to the overdensity in the supercluster region, the mean number density of galaxies in the velocity range 0–5000 km s⁻¹ is only 25 per cent of the mean number density of the Universe, comparable with the density of the well-known Böotes void. Hence this nearby three-dimensional region in Ophiuchus is a void of galaxies also.  相似文献   

A Non-Homogeneous Model for Kriging Dosimetric Data     

Lajaunie  Christian  Renard  Didier  Quentin  Alexis  Le Guen  Vincent  Caffari  Yvan 《Mathematical Geosciences》2020,52(7):847-863

Mathematical Geosciences - This paper deals with kriging-based interpolation of dosimetric data. Such data typically show some inhomogeneities that are difficult to take into account by means of...  相似文献   

Isotopic compositions,nitrogen functional chemistry,and low‐loss electron spectroscopy of complex organic aggregates at the nanometer scale in the carbonaceous chondrite Renazzo     

Christian Vollmer  Jan Leitner  Demie Kepaptsoglou  Quentin M. Ramasse  Henner Busemann  Peter Hoppe 《Meteoritics & planetary science》2020,55(6):1293-1319

Organic matter (OM) was widespread in the early solar nebula and might have played an important role for the delivery of prebiotic molecules to the early Earth. We investigated the textures, isotopic compositions, and functional chemistries of organic grains in the Renazzo carbonaceous chondrite by combined high spatial resolution techniques (electron microscopy–secondary ion mass spectrometry). Morphologies are complex on a submicrometer scale, and some organics exhibit a distinct texture with alternating layers of OM and minerals. These layered organics are also characterized by heterogeneous ¹⁵N isotopic abundances. Functional chemistry investigations of five focused ion beam‐extracted lamellae by electron energy loss spectroscopy reveal a chemical complexity on a nanometer scale. Grains show absorption at the C‐K edge at 285, 286.6, 287, and 288.6 eV due to polyaromatic hydrocarbons, different carbon‐oxygen, and aliphatic bonding environments with varying intensity. The nitrogen K‐edge functional chemistry of three grains is shown to be highly complex, and we see indications of amine (C‐NH_x) or amide (CO‐NR₂) chemistry as well as possible N‐heterocycles and nitro groups. We also performed low‐loss vibrational spectroscopy with high energy resolution and identified possible D‐ and G‐bands known from Raman spectroscopy and/or absorption from C=C and C‐O stretch modes known from infrared spectroscopy at around 0.17 and 0.2 eV energy loss. The observation of multiglobular layered organic aggregates, heterogeneous ¹⁵N‐anomalous compositions, and indication of NH_x‐(amine) functional chemistry lends support to recent ideas that ¹⁵N‐enriched ammonia (NH₃) was a powerful agent to synthesize more complex organics in aqueous asteroidal environments.  相似文献   

HgO at high pressures: the transition to the NaCl structure (HgO-III) and the equation of state of tetragonal HgO-II     

Jinyuan Yan  Bin Chen  Selva Vennila Raju  Budhiram K. Godwal  Alastair A. MacDowell  Jason Knight  Hongwei Ma  Quentin Williams 《Physics and Chemistry of Minerals》2012,39(4):269-275

The high-pressure behavior of HgO-montroydite was investigated up to 36.5 GPa using angle-dispersive X-ray diffraction. The tetragonal phase of this material (HgO-II), a distortion of the NaCl structure, transforms into the cubic NaCl structure (HgO-III) above ~31.5 GPa. The transformation of mercury oxide from the orthorhombic Pnma (HgO-I) structure to a tetragonal I4/mmm structure (HgO-II) is confirmed to occur at 13.5 ± 1.5 GPa. Neither of the high-pressure phases, HgO-II nor HgO-III, is quenchable in pressure. The derived isothermal bulk modulus of HgO-II and its pressure derivative strongly depend on the assumed zero-pressure volume of this phase, but our elasticity results on HgO-II nevertheless lie significantly closer to theoretical calculations than prior experimental results, and the measured pressure of the phase transformation to the NaCl structure is also in agreement with recent theoretical results. The general accord with theory supports the existence of significant relativistic effects on the high-pressure phase transitions of HgO.  相似文献   

The Witputs diamictite in southern Namibia and associated rocks: constraints for a global glaciation?     

Udo Zimmermann  Jennifer Tait  Quentin G. Crowley  Vanessa Pashley  Gijs Straathof 《International Journal of Earth Sciences》2011,100(2-3):511-526

The Witputs section of the Gariep Belt (S Namibia) comprises a sequence of clastic and chemical sediments, which have been interpreted as representative of a Late Neoproterozoic global or near-global ice age event, and recent biostratigraphic work in the upper rocks of the Witputs suggest a Late Ediacaran age. To further characterise this sequence and provide additional age constraints, a detailed sedimentological and detrital zircon study has been carried out. The petrographic, sedimentological and geochemical characteristics of the Witputs diamictite determined in this study are homogenous and indicative of debris flow or palaeo-valley infill sediments, deposited in an oxic environment with no glaciogenic evidence. This homogeneity is also reflected in the detrital zircon age spectra with most ages falling between 1.0 and 1.3?Ga, representing the local geology, with the youngest grain at 1030.2?±?10.9 (2??) (n?=?92?<10% discordance), despite the fact that mid and Late Neoproterozoic volcanic activity is known in the local region. The overlying carbonate rocks, often considered to be ??cap carbonates??, show high Mn (up to 60% MnO), with base metal precipitation (Zn, V, Co), and are recrystallised. Their ??¹³C_VPDB isotope ratios are homogeneous at around-3. Major and trace element ratios reach values which indicate that C?CO isotopes may be disturbed and might not reflect primary global seawater composition, thus questioning their use for global correlation and comparison with composite chemostratigraphic curves. The contact to the overlying Late Ediacaran Sanddrif Member is not exposed, and the rocks dip in a different direction than the underlying carbonate rocks. The c. 40-m-thick section is characterised by rapid lithology changes including shales, calcareous sandstones and wackes, fine-grained conglomerates and rare clean quartz-rich sandstones, all of which have strikingly similar detrital zircon populations, and the youngest zircon is dated at 1082.8?±?10?Ma (2?? errors, from 72 grains with <10% discordance). Acritarchs earlier found in the Sanddrif Member, however, indicate a post-570?Ma depositional age. If the diamictites are glacio-marine deposits, then an interesting conclusion is that the clastic sediments can display a very immature geochemical signature, indicating a localised provenance, with derivation purely from the local basement rocks, which is also reflected in the detrital zircon populations. However, we would hesitate to assign a glacial origin to the deposits as no glacial indicators, other than a diamictitic texture, were observed. Clearly, far more work on the detailed mapping and sedimentology of the Neoproterozoic Gariep Belt deposits is required, particularly as many are currently used for global correlation. Age constraints derived from extensive detrital zircon work can only constrain the deposits as being post 1.03?Ma with the detritus being purely locally derived.  相似文献   

Gravity Modeling of the Au–U Mineralized Crust at the North-Central Cameroon Illustrating Crustal Permeability     

Abate Essi  Jean Marcel  Marcel  Jean  Diab  Diab Ahmad  Yene Atangana  Joseph Quentin  Abossolo Angue  Monique  Mvondo Ondoa  Joseph 《Natural Resources Research》2020,29(1):473-497

Natural Resources Research - The north-central Cameroon is located at the northern edge of Archean Congo–Sao Francisco craton and at the east of the West African craton. This area includes...  相似文献   

The AAO/UKST SuperCOSMOS Hα survey     

Quentin A. Parker  S. Phillipps  M. J. Pierce  M. Hartley  N. C. Hambly  M. A. Read  H. T. MacGillivray  S. B. Tritton  C. P. Cass  R. D. Cannon  M. Cohen  J. E. Drew  D. J. Frew  E. Hopewell  S. Mader  D. F. Malin  M. R. W. Masheder  D. H. Morgan  R. A. H. Morris  D. Russeil  K. S. Russell  R. N. F. Walker 《Monthly notices of the Royal Astronomical Society》2005,362(2):689-710

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A circular planetary nebula around the OH/IR star OH 354.88−0.54 (V1018 Sco)     

Martin Cohen  Quentin A. Parker  Jessica Chapman 《Monthly notices of the Royal Astronomical Society》2005,357(4):1189-1196

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