Effects of three oil spill dispersants on marine bacterial populations: I. Preliminary Study. Quantitative Evolution of Aerobes     

Danielle Marty  Armand Bianchi  Claude Gatellier 《Marine pollution bulletin》1979,10(10):285-287

The effects of three hydrocarbon dispersant agents (Corexit 9527, Hydrogamosol LT and OSR LT 126) on the bacterial flora of the marine environment are analysed in 20-square-metre basins filled with lagoon seawater.Four months after the first treatment, oil slicks were no longer visible, whereas the appearance of the untreated reference slick had hardly changed. The treatment of 10-litre crude-oil slicks causes an appreciable and long lasting increase in the bacterial population.  相似文献   

青藏东缘新生代两类高钾岩浆活动的热年代学研究   总被引：22，自引：2，他引：22  

王江海  尹安  周江羽  张玉泉  解广轰  T.M.Harrison  M.Grove 《中国科学D辑》2002,32(7):529-537

⁴⁰Ar/³⁹Ar年龄数据表明, 青藏东缘和印支块体上出露两期新生代具有不同地球化学特征的岩浆活动, 它们的时代分别为40~28和16~0 Ma. 早期高钾岩石沿主走滑断裂如金沙江-红河断裂断续分布, 是在转换压缩过程中产生的. 晚期高钾岩石广泛分布于裂谷盆地中, 它与青藏和东亚地区出现的东-西向伸展有关. 结合地球化学示踪结果可知, 早期岩浆活动是在陆内俯冲过程中形成的, 而晚期岩浆活动则起源于一个新近交代富集的亏损地幔. 岩浆间歇期则代表在印度-亚洲东碰撞带一次重要的地球动力学转变, 即从由地壳变形控制的过程向由地幔构造占主导的过程转变.  相似文献   

Source, genesis, and timing of giant ignimbrite deposits associated with Ethiopian continental flood basalts     

Dereje AyalewPierre Barbey  Bernard Marty  Laurie ReisbergGezahegn Yirgu  Raphael Pik 《Geochimica et cosmochimica acta》2002,66(8):1429-1448

The Ethiopian continental flood basalt (CFB) province (∼30 Ma, > 3 × 10⁵ km³) was formed as the result of the impingement of the Afar mantle plume beneath the Ethiopian lithosphere. This province includes major sequences of rhyolitic ignimbrites generally found on top of the flood basalt sequence. Their volume is estimated to be at least 6 × 10⁴km³, which represents 20% of that of the trap basalts. Their phenocryst assemblage (alkali feldspar, quartz, aegyrine-augite, ilmenite ± Ti-magnetite, richterite, and eckermanite) suggests temperatures in the range of 740 to 900°C. Four units were recognized in the field (Wegel Tena, Jima, Lima Limo, and Debre Birhan areas), each with its own geochemical specificity. Zr/Nb ratios remain constant between basalt and rhyolite in each area, and rhyolites associated with high-Ti or low-Ti basalts are, respectively, enriched or depleted in titanium. Their trace element and isotope (Sr, Nd, O) signatures (high ¹⁴³Nd/¹⁴⁴Nd and low ⁸⁷Sr/⁸⁶Sr ratios, compared to those of rhyolites from other CFB provinces) are clearly different from those of typical crustal melts and indicate that the Ethiopian rhyolites are among the most isotopically primitive rhyolites. Their major and trace element patterns suggest that they are likely to be derived from fractional crystallization of basaltic magmas similar in composition to the exposed flood basalts with only limited crustal contribution. Since Ethiopian high-Ti basalts have been shown to form from melting of a mantle plume, it is likely that Ethiopian ignimbrites, at least those that are Ti-rich, also incorporated material from the deep mantle.Rb-Sr isochrons on whole rocks and mineral separates (30.1 ± 0.4 Ma for Wegel Tena and 30.5 ± 0.4 Ma for Jima ignimbrites) show that most of the silicic volcanism occurred within < 2 Ma during the Oligocene. Ignimbritic eruptions resumed in the Miocene during two episodes dated at 15.4 ± 0.2 Ma and 8.0 ± 0.2 Ma for the Debre Birhan area. The Rb-Sr isochron ages of ignimbrites (both Oligocene and Miocene rhyolites) are indistinguishable within uncertainties from the ⁴⁰Ar/³⁹Ar ages of the underlying flood basalts. The Oligocene ignimbrites and the underlying trap basalts are synchronous with a shift in the oxygen composition of foraminifera recorded in Indian and Atlantic Ocean cores. The temporal coincidence of Ethiopian Oligocene volcanism, which released immense volumes of S (> 1.4 × 10¹⁵ mol) and Cl (6.4 × 10¹⁵ mol) into the atmosphere over a short time span, with the global cooling event at 30.3 Ma suggests that this volcanism might have accelerated the climate change that was already underway.  相似文献   

Oxygen isotopes in single micrometer-sized quartz grains: tracing the source of Saharan dust over long-distance atmospheric transport   总被引：1，自引：0，他引：1  

Jérôme Aléon  Marc ChaussidonBernard Marty  Lothar SchützRuprecht Jaenicke 《Geochimica et cosmochimica acta》2002,66(19):3351-3365

Oxygen isotope compositions were measured by ion microprobe in individual micrometer-sized quartz grains extracted from one aerosol sample collected on the Cape Verde Islands and from four surface samples (three soils and one sediment) representing potential source regions of aerosols in Western and Central Africa (Morocco, Algeria, Niger, and Chad). A large range of δ¹⁸O values, from +6.2‰ to +39.3‰ is present within the aerosol quartz grains. The different size fractions of the quartz grains from the surface samples overlap nearly entirely this range but show significant differences in their δ¹⁸O distributions for the different size fractions of the grains (i.e., different modes, different proportions of grains with low or high δ¹⁸O, ...). These differences in δ¹⁸O distributions can be related to different geological formations (i.e., mantle-derived magmatic rocks, crustal magmatic rocks, or sedimentary rocks) outcropping in each region, thus giving a fingerprint of the source region. Quartz grains with unusually high δ¹⁸O values between +30‰ and +40‰ were attributed to lacustrine cherts formed in evaporitic environments (Chad basin).The existence of distinct δ¹⁸O distributions for the surface samples, which reflect regional geology but indicate some transport of the grains, enables the characterization of mixing processes during dust emission in the atmosphere. Particles are mixed at a regional scale in the dust reservoir, but injection of fine particles into the high troposphere occurs as a discrete and localized event with no mixing during the subsequent long-range transport by the easterlies. The comparison of the δ¹⁸O distribution of the quartz from the aerosol sample with the equivalent size fractions in surface samples shows that the Niger area is the more probable source region for the aerosol although the Moroccan source cannot be excluded. This method gives a valuable tool to trace the source region of dust into the atmosphere or into sediment samples, allowing the reconstruction of air mass circulations.  相似文献   

Dynamic orbit determination and gravity field model improvement from GPS, DORIS and Laser measurements on TOPEX/POSEIDON satellite   总被引：1，自引：1，他引：1  

F. Perosanz  J. C. Marty  G. Balmino 《Journal of Geodesy》1997,71(3):160-170

Summary. In the framework of the GRIM series of gravity field models, the CNES/GRGS GINS precise orbit determination software has been adapted to dynamic GPS data processing. That is simultaneous processing of all available observables (i.e. GPS, DORIS, Laser) and all available satellite orbits (i.e. GPS, TOPEX/POSEIDON) can now be performed. The TOPEX/POSEIDON (T/P) mission satellite is equipped with a GPS receiver, a DORIS receiver and a laser reflector that represents an unprecedented opportunity to compare and combine these three tracking systems to estimate orbital parameters and gravity field coefficients. Different combinations including : GPS + DORIS, DORIS + LASER, GPS + DORIS + LASER, have been tested and have shown small but systematic improvement in T/P orbit accuracy when GPS and DORIS data were processed simultaneously. Five tuned gravity field models have been generated by accumulating different combinations of T/P normal equations associated to the GPS, DORIS and Laser data. GPS data have a greater dynamic impact on gravity field spherical harmonics coefficient determination than DORIS and Laser data. Furthermore, the results obtained with the solutions including and T/P normal equations suggest that indeed these different tracking systems are somehow complementary in a dynamic sense. Received 30 March 1995; Accepted 19 September 1996  相似文献   

Long-wavelength global gravity field models: GRIM4-S4, GRIM4-C4     

P. Schwintzer  C. Reigber  A. Bode  Z. Kang  S. Y. Zhu  F.-H. Massmann  J. C. Raimondo  R. Biancale  G. Balmino  J. M. Lemoine  B. Moynot  J. C. Marty  F. Barlier  Y. Boudon 《Journal of Geodesy》1997,71(4):189-208

Summary.  GFZ Potsdam and GRGS Toulouse/Grasse jointly developed a new pair of global models of the Earth's gravity field to satisfy the requirements of the recent and future geodetic and altimeter satellite missions. A precise gravity model is a prerequisite for precise satellite orbit restitution, tracking station positioning and altimeter data reduction. According to different applications envisaged, the new model exists in two parallel versions: the first one being derived exclusively from satellite tracking data acquired on 34 satellites, the second one further incorporating satellite altimeter data over the oceans and terrestrial gravity data. The most recent “satellite-only” gravity model is labelled GRIM4-S4 and the “combined” gravity model GRIM4-C4. The models are solutions in spherical harmonics and have a resolution up to degree and order 60 plus a few resonance terms in the case of GRIM4-S4, and up to degree/order 72 in the case of GRIM4-C4, corresponding to a spatial resolution of 555 km at the Earth's surface. The gravitational coefficients were estimated in a rigorous least squares adjustment simultaneously with ocean tidal terms and tracking station position parameters, so that each gravity model is associated with a consistent ocean tide model and a terrestrial reference frame built up by over 300 optical, laser and Doppler tracking stations. Comprehensive quality tests with external data and models, and test arc computations over a wide range of satellites have demonstrated the state-of-the-art capabilities of both solutions in long-wavelength geoid representation and in precise orbit computation. Received 1 February 1996; Accepted 17 July 1996  相似文献   

Experimental and major element constraints on the evolution of lavas from Lihir Island,Papua New Guinea   总被引：5，自引：0，他引：5  

A. K. Kennedy  T. L. Grove  R. W. Johnson 《Contributions to Mineralogy and Petrology》1990,104(6):722-734

The major element chemistry of SiO₂-undersaturated arc lavas from Lihir Island, Papua New Guinea, and 1 atmosphere experiments on an alkali basalt from this island show complex polybaric fractionation affected this suite of lavas. Low Ni and MgO are typical of these arc lavas and result from olivine fractionation, probably at high pressure. Fractionation at low pressure (<5 kb) produces two evolutionary trends. Separation of clinopyroxene, plagioclase and minor olivine from the primitive lavas results in increasing normative nepheline contents and major element trends similar to those of the experiments. In contrast, addition of magnetite and amphibole to the fractionating assemblage in the evolved lavas results in decreasing normative nepheline and major element trends which are markedly different from those of the experiments. The composition of experimental glasses and 1 atmosphere liquid lines of descent, derived from anhydrous melting experiments run at the fayalite-magnetite-quartz (FMQ) buffer and at higher oxygen fugacities, are displaced from the lavas on oxide-oxide plots. HighfO₂ produces high Fe³⁺/Fe²⁺ and the early crystallization of abundant magnetite, and high H₂O contents are responsible for crystallization of amphibole. Crystal fractionation of these phases and the high Fe³⁺/Fe²⁺ are responsible for the displacement of the lavas and experimental glasses in mineral projection schemes from the 1 atmosphere olivine-clinopyroxene-plagioclase saturation boundary of Sack et al. (1987).  相似文献   

Primitive basalts and andesites from the Mt. Shasta region,N. California: products of varying melt fraction and water content     

Michael B. Baker  Timothy L. Grove  Richard Price 《Contributions to Mineralogy and Petrology》1994,118(2):111-129

Quaternary volcanism in the Mt. Shasta region has produced primitive magmas [Mg/(Mg+Fe^*)>0.7, MgO>8 wt% and Ni>150 ppm] ranging in composition from high-alumina basalt to andesite and these record variable extents ofmelting in their mantle source. Trace and major element chemical variations, petrologic evidence and the results of phase equilibrium studies are consistent with variations in H₂O content in the mantle source as the primary control on the differences in extent of melting. High-SiO₂, high-MgO (SiO₂=52% and MgO=11 wt%) basaltic andesites resemble hydrous melts (H₂O=3 to 5 wt%) in equilibrium with a depleted harzburgite residue. These magmas represent depletion of the mantle source by 20 to 30 wt% melting. High-SiO₂, high-MgO (SiO₂=58% and MgO=9 wt%) andesites are produced by higher degrees of melting and contain evidence for higher H₂O contents (H₂O=6 wt%). High-alumina basalts (SiO₂=48.5% and Al₂O₃=17 wt%) represent nearly anhydrous low degree partial melts (from 6 to 10% depletion) of a mantle source that has been only slightly enriched by a fluid component derived from the subducted slab. The temperatures and pressures of last equilibration with upper mantle are 1200°C and 1300°C for the basaltic andesite and basaltic magmas, respectively. A model is developed that satisfies the petrologic temperature constraints and involves magma generation whereby a heterogeneous distribution of H₂O in the mantle results in the production of a spectrum of mantle melts ranging from wet (calc-alkaline) to dry (tholeiitic).  相似文献   

Experimental petrology of normal MORB near the Kane Fracture Zone: 22°–25° N,mid-Atlantic ridge     

D. R. Tormey  T. L. Grove  W. B. Bryan 《Contributions to Mineralogy and Petrology》1987,96(2):121-139

Melting experiments carried out at 1-atm and at 2 kbar on mid-ocean ridge basalts dredged from the mid-Atlantic ridge near the Kane Fracture Zone (KFZ, 22° to 25° N. latitude) provide a basis for evaluating the role of crystal fractionation in generating compositional variability observed in normal mid-ocean ridge basalt. The 1-atm olivine-plagioclase-clinopyroxene saturation boundary for KFZ lavas defines a path in mineral projection schemes and in oxide-oxide diagrams that is displaced from the same experimentally determined boundaries in FAMOUS (Grove and Bryan 1983) and Oceanographer Fracture Zone (Walker et al. 1979) basalts. The glass margins of sparsely phyric KFZ lavas record small amounts of near surface, low pressure fractional crystallization, and their glass and bulk rock compositions are similar. An important signature of low pressure differentiation is recorded in the quenched glass margins of moderately phyric KFZ lavas compared to their bulk rock compositions, and the glass has evolved along low-pressure fractionation paths that are similar to those produced in the 1-atm experiments. Many of the lavas have retained phenocrysts in equilibrium proportions, so that their bulk rock compositions represent liquid compositions. When the effects of near-surface differentiation and crystal accumulation are removed from the Kane data set, and only liquid compositions are considered, a suite of basalt magmas can be identified that forms a trend in mineral component projection schemes parallel to the 1-atm oliv-plag-cpx multiple saturation boundary, but displaced from it toward olivine. These basalts have only olivine and plagioclase as phenocrysts, and are well removed from clinopyroxene saturation at low pressure. The compositional variation can not be generated by mixing any primary liquid composition with a low pressure liquid that has evolved along the oliv-plag-cpx multiple saturation boundary. Major and trace element models of this trend using olivine, plagioclase and clinopyroxene as fractionating phases match the compositional variability. This compositional trend is generated by fractionation at pressures greater than 2 kbar, but within the plagioclase stability field. A review of the data for other normal MORB suites from this part of the mid-Atlantic ridge reveals a similar elevated pressure fractionation signature which persists when the effects of low pressure magma mixing are removed from the data set.  相似文献   

Retention of winter flounder larvae within a Rhode Island salt pond     

Richard E. Crawford  Constance Grove Carey 《Estuaries and Coasts》1985,8(2):217-227

Two winter flounder, Pseudopleuronectes americanus, spawning sites in a 630 hectare Rhode Island lagoon were located by collecting eggs with a modified epibenthic sled towed by boat. A two-dimensional vertically-averaged hydrodynamic model predicted that larvae hatched at these spawning sites would be minimally displaced by tidal movement. Ichthyoplankton samples taken hourly during the day at six locations on March 27 and April 27, 1981 reflected the larval distribution predicted by the model. Larval retention within this lagoon appeared to be strongly influenced by the hydrodynamics of this system. It is suggested that the hydrodynamic features of lagoons are exploited in the reproductive strategies of estuarine species and that the relationship between hydrodynamics and the quality of nursery habitat must be considered before making hydraulic modifications to these systems.  相似文献