Microcodium en calizas del Eoceno Medio (Luteciense) de la Sierra de la Pila (Prebético Interno, Murcia)

Resumen

Microcodium is a calcitic microfeature, mainly interpreted as root calcification products of terrestrial plants on carbonate-rich substrates, that is abundant in Paleogene successions of the peri-Tethyan realm. In the Betic Cordillera most of Microcodium appears as reworked in calcarenites interbedded in pelagic sedimentary rocks. In this study we analyse outcrops with in situ Microcodium aggregates located in Sierra de la Pila (Internal Prebetic, Murcia province). Microcodium appears on top of Lutetian (Middle Eocene) platform limestones and shows: 1) cylindrical morphologies showing «corncob» colonies longitudinally, and «rosette» structures in transverse section, and 2) individual or plural globular morphologies, similar to «rosettes» in section. Microcodium is interpreted as developed in calcic paleosols, related with a seasonal semiarid climate, before the boundary Middle-Upper Eocene and the important climatic change marked with the beginning of the transition from the extreme global warmth of the early Eocene «greenhouse « climate to the present glaciated state.