Upper Eocene larger foraminiferal–coralline algal facies from the Klokova Mountain (southern continental Greece)

Abstract

Within the Gavrovo–Tripolitza area (southern continental Greece), marine carbonate platforms existed from the Late Triassic to the Late Eocene. The Middle–Upper Eocene marine shallow-water carbonates of the Klokova Mountain represent remnants of the large volumes of sediment that were produced on a middle ramp sedimentary system which culminated in the Lower Oligocene terrigenous deposits. Facies analysis of Bartonian–Priabonian shallow-water carbonate successions and the integration with palaeoecological analysis are used to produce a detailed palaeoenvironmental model. In the proximal middle ramp, porcelaneous foraminiferal packstone facies is characterised by larger foraminifera such as Praturlonella and Spirolina. These forms thrived in a shallow-water setting with low turbidity, high-light intensity and low-substrate stability. The foraminiferal packstone facies, the thin coralline wacke–packstone facies and the rhodolith packstone facies deposited approximately in the same depth range adjacent to one another in the middle-ramp. Nummulitids (Nummulites, Assilina, Pellatispira, Heterostegina and Spiroclypeus) increase in abundance in the middle to distal mid-ramp together with the orthophragminids. Coralline algae, represented by six genera, are present in all facies. Rhodoliths occur in all facies but they show different shapes and growth forms. They develop laminar sub-ellipsoidal shapes in higher turbulence conditions on mobile sand substrates (foraminiferal packstones and rhodolith rudstones), whilst sub-discoidal shapes often bound by thin encrusting coralline plants in lower hydrodynamic settings. The distinctive characteristics of the palaeoecological middle-ramp gradient are an increase in dominance of melobesioids, a thinning of the encrusting coralline plants and a flattening of the larger benthic foraminiferal shells.