Jurassic and Cretaceous radiolarian assemblages from the Bornova mélange in northern Karaburun Peninsula (western Turkey) and its connection to the İzmir–Ankara mélanges     

Patrice Moix  Špela Goričan 《Geodinamica Acta》2013,26(1-2):56-67

Two large blocks of red bedded chert identified within the Late Cretaceous–Paleocene Bornova mélange in northern Karaburun Peninsula yielded Jurassic (late Bathonian–early Oxfordian) and Cretaceous (middle–late Albian) radiolarian assemblages. These new data confirm the correlation of the Bornova mélange with the Bornova Flysch Zone (BFZ) and the ?zmir–Ankara mélanges. A review of all previously obtained ages in chert blocks of the BFZ and the ?zmir–Ankara mélanges is provided in order to strengthen this correlation.  相似文献   

Reconstruction of the upper ocean 3D dynamics from high-resolution sea surface height     

Aurelien L. Ponte  Patrice Klein 《Ocean Dynamics》2013,63(7):777-791

The present study investigates the reconstruction of the 3D dynamics of a turbulent mesoscale eddy field driven at a depth by a baroclinic instability of the Phillips type. It uses a high-resolution primitive equation simulation as a testbed. The method of reconstruction is based on potential vorticity principles and extends an earlier approach (Lapeyre and Klein, J Phys Oceanogr 36:165–176, 2006) to a regime where the signature of surface density anomalies on the dynamics is weak. The crux and the originality of the reconstruction lie in the estimation from sea surface height and surface density anomalies of the interior quasigeostrophic potential vorticity (PV) anomalies and its subsequent inversion. The estimation of PV anomalies relies on the vertical correlation between PV anomalies and on the knowledge on stratification and horizontal gradients of background PV. PV anomalies are accurately estimated over the first 500 m of the water column and over a wide range of wavenumbers. Density anomalies play a minor role in the PV estimation, though their omission leads to an overestimation of PV by a factor of less than 2 at scales of order 20 km and less. Inversion of the estimated PV leads to a geostrophic streamfunction which in turn provides reliable reconstructions of the relative vorticity and vertical velocity (via the omega equation).  相似文献   

Polarization in the young cluster NGC 6611: circumstellar, interstellar, or ... both?     

Pierre Bastien  François Ménard  Patrice Corporon  Nadine Manset  Frédérick Poidevin  Gaspard Duchêne  Jean-Louis Monin 《Astrophysics and Space Science》2004,292(1-4):427-433

We obtained linear polarization observations of 82 A/B-type stars in the young cluster NGC 6611, in order to probe the circumstellar material and to search for any evidence of intracluster or interstellar material that could also contribute to the polarization. We found linear polarization values that reach up to 14%. We consider the distribution of the polarization, its position angle, correlations with extinction and membership probability, polarization variability and wavelength distribution to identify the origin of the polarization toward NGC 6611. The polarization is found to be dominated by interstellar polarization, although some stars also have some circumstellar polarization. There is no evidence for intracluster dust. Rather, the dust must be located in a low density cloud toward the general line of sight to NGC 6611 and in front of it. The depth of that cloud along the line of sight increases slowly from the south–east to the north–west. The cloud is threaded by a very uniform magnetic field.  相似文献   

Geometric Effect of Asperities on Shear Mechanism of Rock Joints     

Ali Fathi  Zabihallah Moradian  Patrice Rivard  Gérard Ballivy  Andrew J. Boyd 《Rock Mechanics and Rock Engineering》2016,49(3):801-820

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Climate change and warm‐water species at the north‐western boundary of the Mediterranean Sea          下载免费PDF全文

Valeriano Parravicini  Luisa Mangialajo  Laure Mousseau  Andrea Peirano  Carla Morri  Monica Montefalcone  Patrice Francour  Michel Kulbicki  Carlo Nike Bianchi 《Marine Ecology》2015,36(4):897-909

The effects of global change are particularly serious in areas where range shifts of species are physically constrained such as the Ligurian Sea, which is one of the coldest sectors of the Mediterranean. In this basin, historical information on water temperature (from the sea surface down to 75 m depth) dates back to the 1950s. Early studies also recorded warm‐water species occurrence. Thanks to these data we provide the first detailed characterization of water temperature variation from 1958 up to 2010 in the layer 0–75 m depth. We coupled this analysis with the available information on rocky reef epibenthic communities (literature review from 1955 to 1964 and field data from 1980 to 2010). The analysis of water temperature revealed several patterns of variation: a cooling phase from 1958 to 1980, a phase of rapid warming from 1980 to 1990 and a phase of slower warming from 1990 to 2010. Inter‐annual variation in temperature increased over the entire period for the water layer down to 20 m. Warm‐water native and alien species richness increased during the warming phases. Literature estimates suggest a decrease in warm‐water native species richness during the cooling phase. The analysis of quantitative data collected in the early 1990s and late 2000s indicated a decrease in the cover of warm‐water native species on shallow rocky reefs and an increase in deeper waters. We argue that increased inter‐annual variation in water temperature may disadvantage native warm‐water species in shallow waters. Our results indicate that the effect of temperature rises in cold, constrained basins may be more complex than the simple prediction of species changing their geographical range according to their thermal limits.  相似文献   

Les ensembles fluviatiles néogènes du bassin subandin d'Équateur et implications dynamiquesThe Neogene fluvial systems of the Ecuadorian foreland basin and dynamic inferences     

Frédéric Christophoul  Patrice Baby  Jean-Claude Soula  Michel Rosero  José Burgos 《Comptes Rendus Geoscience》2002,334(14):1029-1037

A sedimentological study of the Neogene continental infill of the Subandean foreland basin of Ecuador led us to define an evolution of the fluvial system from an alluvial plain to an alluvial fan with an increasing slope in the same time as the drainage changed from mostly longitudinal to transverse. Combined with the data presently available on palaeotopography, exhumation, tectonic evolution and geomorphology, these results enable us to infer that, in contrast with the other Subandean foreland basins of Bolivia and Peru, the progradation of the Neogene alluvial fans proceeded by an overall expansion, associated with a relatively small tectonic shortening and not as a result of the development of successive thrust-related depocentres. This also indicates that the surrection of the Cordillera progressed in Ecuador throughout the Neogene. To cite this article: F. Christophoul et al., C. R. Geoscience 334 (2002) 1029–1037.  相似文献   

Tidal frequency dynamics of a Southern Brazil coastal lagoon: Choking and short period forced oscillations     

Osmar O. Möller  Patrice Castaing  Elisa Helena Leão Fernandes  Pascal Lazure 《Estuaries and Coasts》2007,30(2):311-320

The Patos Lagoon is a choked, microtidal coastal laggon situated in southern Brazil between 30°S and 32°S. The response of the lagoon to tidal oscillations is studied through data analysis and numerical modeling experiments. Two types of high frequency oscillations are observed in the tidal frequency band: mixed tides, predominantly diurnal; and forced oscillations having a period of 24 h occurring in the inner lagoon. In the southern portion of the lagoon, tides are selectively filtered by the entrance channel. The main diurnal constituent O₁ is linearly attenuated as it progresses landwards. In the inner parts of the lagoon, 24-h oscillations are mainly forced by the combined effect of diurnal tides and sea breeze action. They are tied with a natural period of oscillation of 24 h. Results also indicate that these are not inertial frequency oscillations, despite the lagoon being placed in a critical 30°S area. The interaction between astronomical tides and meteorological effects produces a complicated picture for tidal forecasting derived from data collected inside the lagoon.  相似文献   

The Bolcana Cu–Au ore deposit (Metaliferi Mountains,Romania): first data on the alteration and related mineralisation     

Viorica Milu  Jacques L Leroy  Patrice Piantone 《Comptes Rendus Geoscience》2003,335(8):671-680

The Bolcana ore deposit (Metaliferi Mountains, western Romania) is a porphyry ore deposit with associated epithermal veins. On the basis of different parageneses, four alteration types were distinguished: potassic, phyllic, argillic and propylitic. The mineralogical and geochemical data and estimated crystallisation temperatures of alteration minerals indicate an evolution of the system from an early period of porphyry type mineralisation (Cu+Au) to a late period of low-sulphidation epithermal mineralisation (Au+base metal). To cite this article: V. Milu et al., C. R. Geoscience 335 (2003).  相似文献   

A detailed fluid inclusion study in silicified breccias from the Kombolgie sandstones (Northern Territory, Australia): inferences for the genesis of middle-Proterozoic unconformity-type uranium deposits     

Donatienne Derome  Michel Cuney  Michel Cathelineau  Ccile Fabre  Jean Dubessy  Patrice Bruneton  Amlie Hubert 《Journal of Geochemical Exploration》2003,80(2-3):259-275

The relative chronology and detailed chemistry of paleofluids circulating at the base of the Kombolgie Sub-basin were investigated in the East Alligator River district (Northern Territory, Australia), where world-class unconformity-type uranium deposits are located. The chemistry of fluid inclusions was determined using in-situ analysis (Raman microprobe and laser-induced breakdown spectroscopy [LIBS]) and by observing the melting sequences by microthermometry. This study revealed the occurrence of three distinct fluids: (i) a sodium-rich brine that corresponds to a diagenetic fluid percolating at the bottom of the Kombolgie sandstones at a temperature close to 150±15 °C; (ii) a calcium-rich brine, probably corresponding to a residual brine in evaporitic environment that has evolved by fluid–rock interactions with the basement lithologies; and (iii) a low salinity fluid, heated in the basement, injected into the base of the sandstone cover. H₂ and O₂ and/or traces of CH₄ were detected in the vapor phase of some fluid inclusions, especially in the low salinity ones in quartz breccia samples taken above mineralized areas. Hydraulic brecciation of the sandstone was associated with a pressure decrease favoring fluid mixing and the subsequent cementation of breccias. According to the fluid inclusion study and other geologic constrains, the minimum thickness of the Sub-Kombolgie Basin is estimated at 4 km. Drusy quartz breccias with evidence of fluid mixing are quite common at the base of the Kombolgie Basin, but not necessarily linked to U-mineralization. However, it is proposed that the presence of gases such as H₂ and O₂ in fluid inclusions, which results from water radiolysis, constitutes an indicator of gas linked to significant U concentrations deeper in the basement rocks.  相似文献   

Investigation on Planetary Atmospheres Using Laboratory Simulation Experiments The Example of Saturn's Moon (Titan)     

Coll  Patrice  Raulin  François 《Earth, Moon, and Planets》1998,80(1-3):113-133

The main goals of experimental simulation in the laboratory of a planetary atmosphere are to feed the theoretical models, and to help the treatment of observations. This type of simulation permits the direct study of objects that space missions can't study or have not studied yet, through the production of laboratory analogues of gaseous or solid phases. But the representativity of these laboratory analogues is of crucial importance. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献