Registro del evento anóxivo oceánico OAE1a (Aptiense inferior) en un contexto de plataforma. Prebético (provincia de Alicante)

Resumen

The Early Aptian was a time of major global events, being probably the most notable the Oceanic Anoxic Event 1a. In this paper, we present the study of the record of the OAE1a in a platform setting, the Prebetic Zone of the Betic Cordillera, which represents the shallow platform environments of the Southern Iberian Palaeomargin during the Mesozoic. In this context, several events of global and regional character are recorded, whose timing and relationships are extremely interesting to be clarified. The correlation between the studied sections has permitted the establishment of the timing of the main sedimentary events. The transgressive general context recorded in the studied units, linked to the tectonic subsidence, resulted in several retrogradational pulses, leading finally to the drowning of the shallow platform, which was postdated by the OAE1a event. The record of the OAE1a in a platform setting is explained as related to a local combination of factors, as a transgressive general context, strong local subsidence rate, and important input of terrestrial organic matter in the platform, as has been supported by the data provided from the analysis of the organic matter contained in the sediments.