Recognition of stratigraphic sequences in carbonate platform and slope deposits: empirical models based on microfacies analysis of Palaeogene deposits in southeastern Spain
Abstract The functional morphology and life style of foraminifers can be used to determine their former position on the platform and to detect upwards shallowing and deepening trends in sedimentary sequences. The sequential analysis of the Palaeogene platform deposits of Alicante proved to be greatly enhanced by the use of the palaeoecology of foraminifers. On the basis of this analysis, three different empirical models for platform accommodation cycles could be designed: a ramp model, distinctive for the Lower Eocene, a combined ramp-rimmed model, characteristic for the Middle and Upper Eocene, and a rimmed model representative for Oligocene cycles. The change in platform type through time is thought to be a response to climate-related changes in growth-potential of hermatypic corals. Possible criteria to distinguish systems tracts in slope deposits on their foraminiferal and clast content are put to the test in a slope section, with positive results. From the correlation of the southern Spanish Palaeogene cycles with Eurasian–African plate-boundary events along the Pyrenees, and with Antarctic glaciations, it can be concluded that the majority of the cycles are tectonically controlled with glacio-eustatic contributions since the Middle/Late Eocene boundary.