Ciclicidad de alta frecuencia en la megasecuencia sinrift titónico-berriasiense. Cuenca Ibérica oriental

Abstract

In the Iberian basin, the Tithonian-Berriasian supersequence (ZB-1 2 nd order supercycle) was deposited in a subsident regime during the moderate to intense rifting stages of the Jurassic phase. The repetitive character of the Purbeck facies, which constitute this megasequence has difficulted the basin analysis of this time interval (over 9.5 my), of importance in the evolution of the Mesozoic Iberia n basin. Analysing the high-frequency cyclicity enabled us to deduce the controls on sedimentation for different time scales, correlation throughout the basin and relative sea-level changes. For this, in addition to the sedimentological analysis and the subsidence analysis, data on Fischer plots and fast Fourier transform method of five selected stratigraphic sections are integrated. The results show the cyclicity of the studied megasequence is decomposed into three groups of periods, the two first being identifiable as standard second and third order cycles: i) 4.2-4.7 my, ii) 7,2-7.8 my, and Hi) 200-500 ky.