Sedimentación lacustre y ciclicidad: las sucesiones fluvio-lacustres del Oligoceno superior del sector SE de la cuenca del Ebro

Abstract

A cyclostratigraphic study of Late Oligocene fluvio-lacustrine and lacustrine sequences was carried out in the Ebro basin. Fourier spectral analysis was used to analyze four stratigraphic and sedimentological parameters (thickness, colour, lithology and an estimative depth index) and was proved the appearance of periodicities of 39 and 16 to 18 ky which approximately fit the 41 ky (obliquity cycle) and 19 ky (short precession cycle). In all spectra, the obliquity cycle is a strong signal in the lacustrine intervals, but in fluvial intervals the ciclycity was concealed, likely as a consequence of overprinting of tectonic influence