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471.
正The Laguna Mar Chiquita,located northeast of the province of Córdoba in Argentina,is the only non-Andean place where three flamingo species regularly coexist in the southern part of South America.Two of these species, 相似文献
472.
Sergio E. Ruiz-Hernandez Ricardo Grau-Crespo A. Rabdel Ruiz-Salvador Nora H. De Leeuw 《Geochimica et cosmochimica acta》2010,74(4):1320-13861
We have investigated the thermodynamics of mixing between aragonite (orthorhombic CaCO3) and strontianite (SrCO3). In agreement with experiment, our simulations predict that there is a miscibility gap between the two solids at ambient conditions. All SrxCa1−xCO3 solids with compositions 0.12 < x < 0.87 are metastable with respect to separation into a Ca-rich and a Sr-rich phase. The concentration of Sr in coral aragonites (x ∼ 0.01) lies in the miscibility region of the phase diagram, and therefore formation of separated Sr-rich phases in coral aragonites is not thermodynamically favorable. The miscibility gap disappears at around 380 K. The enthalpy of mixing, which is positive and nearly symmetric with respect to x = 0.5, is the dominant contribution to the excess free energy, while the vibrational and configurational entropic contributions are small and of opposite sign. We provide a detailed comparison of our simulation results with available experimental data. 相似文献
473.
Ricardo Arevalo Jr Jeremy Bellucci William F. McDonough 《Geostandards and Geoanalytical Research》2010,34(4):327-341
Recent developments from 2008 to 2009 in ICP-MS engineering, methods and applications are reviewed here. Of particular emphasis are advances in: (a) maximising sensitivity and reducing elemental/isotopic fractionation during laser ablation processing; (b) developing new analytical techniques to measure major, minor and trace element abundances without depending on matrix-matched calibrating materials, pre-determined internal standard concentrations and/or multiple analytical methods; (c) applying in situ and solution-based ICP-MS techniques to the analysis of forensic materials for criminal and/or nuclear investigations; and (d) improving precision and limits of detection of laser ablation multi-collector ICP-MS measurements of (ultra) trace elemental and isotopic abundances. 相似文献
474.
Natalia Hauser Massimo Matteini Ricardo H. Omarini Márcio M. Pimentel 《Mineralogy and Petrology》2010,100(3-4):153-184
In the Río Grande Valley, NW Argentina, several porphyritic panidiomorphic, ocelli-bearing dykes and sills intrude the Neoproterozoic to lower Paleozoic basement of the Eastern Cordillera. New petrographical and geochemical data permit us to classify these rocks as ocellar-analcime monchiquites, a feldspar-free variety of alkaline lamprophyre composed of Ti-rich-diopside/augite, Ti-rich biotite/phlogopite, forsteritic olivine, titanian-pargasite and analcime, with abundant ocelli filled with analcime/carbonate. In terms of geochemical compositions they are characterized by LILE and LREE enrichment and lack of Nb-Ta and Eu anomalies. The 87Sr/86Sr and 143Nd/144Nd initial ratios range between 0.70377 to 0.70781 and 0.512506 and 0.512716 respectively, and TDM model ages vary between 0.25–0.64 Ga. A K-Ar age of 163?±?9 Ma suggests that these rocks are related to the pre-rifting stage of the Mesozoic-Cenozoic continental Salta Rift in NW Argentina. Partial melting of a heterogeneous enriched metasomatized lithospheric mantle, magma mixing and fractionation are envisaged to explain the petrographic, geochemical and isotope characteristics of these magmas. 相似文献
475.
Ricardo P. Schiavon 《Astrophysics and Space Science》1999,265(1-4):289-290
476.
477.
Marangoni Gazineu Marinho Pinto Paula Martins Campos Ricardo Gallo Marcos Nicolas Parente Ribeiro Carlos Eduardo 《Ocean Dynamics》2023,73(6):303-315
Ocean Dynamics - Accurate simulations of significant wave height (Hs) are extremely important for the safety of navigation, port operations, and oil and gas exploration. Thus, accurate forecasts of... 相似文献
478.
479.
Campos Ricardo Martins Alves Jose-Henrique G.M. Penny Stephen G. Krasnopolsky Vladimir 《Ocean Dynamics》2020,70(3):405-419
Ocean Dynamics - Forecasts of 10-m wind (U10) and significant wave height (Hs) from the National Centers for Environmental Prediction (NCEP) Ensemble Forecast System are evaluated using altimeter... 相似文献
480.
Elda Miramontes Gwenael Jouet Estelle Thereau Miguel Bruno Pierrick Penven Charline Guerin Pascal Le Roy Laurence Droz Stephan J. Jorry F. Javier Hernández-Molina Antoine Thiéblemont Ricardo Silva Jacinto Antonio Cattaneo 《地球表面变化过程与地形》2020,45(6):1469-1482
Evidences of sedimentation affected by oceanic circulation, such as nepheloid layers and contourites are often observed along continental slopes. However, the oceanographic processes controlling sedimentation along continental margins remain poorly understood. Multibeam bathymetry and high-resolution seismic reflection data revealed a contourite depositional system in the Mozambican upper continental slope composed of a contourite terrace (a surface with a gentle seaward slope dominated by erosion) and a plastered drift (a convex-shape sedimentary deposit). A continuous alongslope channel and a field of sand dunes (mainly migrating upslope), formed during Holocene, were identified in the contourite terrace at the present seafloor. Seismic reflection data of the water column show internal waves and boluses propagating in the pycnocline near the upper slope. The channel and the dunes are probably the result of the interaction of the observed internal waves with the seafloor under two different conditions. The alongslope channel is located in a zone where intense barotropic tidal currents may arrest internal solitary waves, generating a hydraulic jump and focused erosion. However, upslope migrating dunes may be formed by bottom currents induced by internal solitary waves of elevation propagating landwards in the pycnocline. These small-scale sedimentary features generated by internal waves are superimposed on large-scale contouritic deposits, such as plastered drifts and contourite terraces, which are related to geostrophic currents. These findings provide new insights into the oceanographic processes that control sedimentation along continental margins that will help interpretation of palaeoceanographic conditions from the sedimentary record. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd 相似文献