991 resultados para 610.7631
Resumo:
El presente Estudio tiene como fin primordial, la construcción de una Variante de trazado de la carretera CL-612 a su paso por la localidad de San Martín de Valderaduey, evitando así la travesía actual que presenta la CL-612 entre dicho núcleo y el de Villárdiga. Esta nueva variante exige para su realización la disposición de una estructura de tipo puente sobre el cauce del río Valderaduey, por lo que se plantean alternativas que circunvalen de manera global ambas localidades.
Resumo:
A record of carbon and oxygen isotopes in benthic and planktonic foraminifers has been obtained from the interval corresponding to the last 2.4 m.y. of Site 610, Holes 610 and 610A, with a sample resolution of about 30 kyr. The record from the late Quaternary (<0.9 Ma) shows large amplitudes and high frequencies in oxygen isotopic variation. Prior to 0.9 Ma the isotopic variability record is reduced in amplitude (but not in frequency) compared with the late Quaternary, suggesting lower ice-volume and climatic fluctuations, and higher average eustatic sea level. Left-coiling (L, polar) Neogloboquadrinapachyderma were not found in samples between 1.0 and 2.2 Ma, indicating less influence of polar front migrations in the Northeast Atlantic. Both polar planktonic faunas and larger isotope fluctuations reappear in the lowermost samples (2.3 to 2.4 Ma), pointing toward a period of larger climatic variability in the late Pliocene than in the early Quaternary. The variation in benthic d13C and hence in deep-water d13C seems to have been constant through the analyzed section, reflecting a stable variability in the production of North Atlantic Deep Water (NADW) and possibly in Norwegian-Greenland Sea Overflow. Preliminary analyses of amino-acid epimerization in N. pachyderma (L) indicate a constant rate of epimerization to approximately 0.3 Ma. Beneath this level the average epimerization rate is much reduced.
