Geometría de las unidades superiores del relleno holoceno del canal estuarino del Odiel (Huelva, SO de España)

Resum

Since the 90s decade, the authority of Huelva harbor located on the estuary of the Odiel River, has made numerous vibracores in the port channel. These data are available in their files. In this study 258 of these vibracores were analyzed, along with other 72 vibracores carried out by the research team of authors since 1992. In addition, 15 drilling cores were obtained and analyzed from a sedimentological point of view. The record of each core was represented under standards criteria and introduced in a GIS, to synthesize and facilitate the analysis of geological data. On the other hand, 38 seismic profiles were obtained during September 2013 in order to make a three-dimensional model of the sedimentary units constituting the most recent filling of the system. All these stratigraphic and sedimentological information was used to develop 33 geological profiles and to obtain three-dimensional facies models of central and marine domains of the Odiel river estuary. This model used the combination of information on the sedimentary units and their facies offered by cores and the geometry of the lithosismics units observed in seismic profiles. The study of the sedimentary records allowed distinguishing 9 Holocene lithological units deposited on upper Pleistocene basal bodies which in turn are erosively overlaying Upper Miocene blue marls. The total thickness of the entire Holocene succession reaches more than 30 m in the deepest part of the estuary. The 3 lower units represent a transgressive sequence deposited under conditions of sea-level rise, while the upper 3 units constitute a regressive (prograding) sequence deposited under a more or less stable sea level. The disposal of reflective surfaces allowed characterizing the geometry of different sedimentary units, which are separated by erosive discordances.