Coralline-algal assemblages of a Burdigalian platform slope: implications for carbonate platform reconstruction (northern Sardinia, western Mediterranean Sea)

Abstract

The rhodolithic slope deposits of a Burdigalian carbonate platform in Sardinia near Sedini were analyzed to reconstruct facies and palaeobathymetry. There is a distinct red-algal growth zonation along the platform slope. The clinoform rollover area consists of coralline-algal bindstones, which downslope change into a zone where rhodoliths are locally fused by progressive encrustation. Mid-slope rhodoliths are moderately branched, and downslope rhodoliths have fruticose protuberances, resulting in branching rhodolith growth patterns. There is a sharp change from the rhodolitic rudstones to the basinal, bivalve-dominated rudstones at the clinoform bottomsets. Red-algal genera identiWed include Sporolithon, Lithophyllum, Spongites, Hydrolithon, Mesophyllum, Lithoporella, Neogoniolithon, and other mastophoroids and melobesioids. Genera and subfamilies show a zonation along the clinoforms, allowing palaeobathymetric estimates. The clinoform rollovers formed at a water depth of around 40 m and the bottomsets around 60 m. Results from geometrical reconstruction show that coral reefs in the inner platform formed at water depths of around 20 m. Therefore, the Sedini carbonate platform is an example of a reef-bearing platform in which the edge or the platform-interior reefs do not build up to sea level.

A Diverse Patch Reef From Turbid Habitats in the Middle Miocene (East Kalimantan, Indonesia)

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Thanetian–Ilerdian coralline algae and benthic foraminifera from northeast India: microfacies analysis and new insights into the Tethyan perspective

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Metre-scale cyclicity in Middle Eocene platform carbonates in northern Egypt: Implications for facies development and sequence stratigraphy

“…Coral beds in the lower part of this cycle type represent a moderate energy distal reef flat related facies type Benisek et al (2009), forming a transgressive hemi-cycle. The interval with the highest amount of coral debris, and the high diversity of corals is interpreted as a maximum flooding zone (MFZ).…”