Multikilometer-sized reefs built by foraminifera (Solenomeris) from the early Eocene of the Pyrenean domain (S. France, N. Spain): Palaeoecologic relations with coral reefs

Abstract : Solenomeris (Foraminifera) reefs of the early Ypresian Pyrenean Gulf were previously mistaken for red algal or incertae sedis algal reefs. Solenomeris has recently been referred to the acervulinid Foraminifera. These Foraminifera buildups are described in detail and their palaeoecology is discussed. The distribution of these reefs within the Languedoc Basin demonstrates their preference for bathymetric highs of external platforms, in common with coral reefs to which they locally succeed during the early Ypresian transgression. All Solenomeris reefs examined are located either at the outer periphery of a lagoon with small Operculina or on the external margin of a carbonate platform characterized by various Miliolida. They extend into deeper waters than the associated coral reefs, even in turbid environments unfavourable for encrusting coralline algae. The reconstruction of the palaeoecology of Solenomeris shows many similarities with corals. However, corals probably require higher light and oxygen levels, especially when present near their northern limit. The global distribution of Solenomeris reefs can not be established until their correct identifications have been made instead of “algal reefs”.