Integrating taphonomy and facies analysis to assess the palaeoecology of Oligocene Kuphus-beds (Prebetic, Southeastern Spain)

Abstract

Kuphus is a genus of teredinid bivalves whose modern counterpart, K. polythalamius, colonises oxygen-poor and restricted marine environments enriched in plant remains. In the Oligocene, Kuphus colonies are quite abundant worldwide, but their depositional setting has never been studied in detail. We describe the first report of Oligocene Kuphus beds from the Iberian Peninsula, cropping out in platform deposits of the Prebetic (Southeastern Spain). By means of anterior endings and taphonomic characters as orientation of Kuphus tubes, fragmentation, packing and mixing with other fauna, four skeletal concentrations were distinguished: SkC A represents in situ colonies with anterior endings well preserved and with local dolomitisation around the tubes and was recorded in the inner lagoon; SkC B, with parallel and horizontally reoriented tubes, was formed by tidal currents; SkC C records high-energy events breaking down the tubes and resedimenting them close to the source area; SkC D is characterised by fragmented tubes mixed with other bioclasts, deposited by storms in the outer platform. The recorded skeletal concentrations are consistent with the environmental setting of K. polythalamius, but the morphological differences and the absence of data on the presence of plant remains could possibly reflect adaptations to higher variety of palaeoenvironments.