Palaeoecology of Corals and Stromatoporoids in an Upper Silurian Biostrome in Estonia

Abstract

A middle Ludlow biostrome at Katri, western Estonia, the richest accumulation of corals and stromatoporoids in Estonia, is partly exposed in a coastal section. The fully marine biostrome consists of five fossiliferous layers of carbonate skeletons, grouped into Facies 1 (grainstone-packstone, Layers 1, 3, 5) and Facies 2 (wackestone, interbedded Layers 2, 4). Pressure solution degraded original sedimentary relationships and morphologies of stromatoporoids, tabulates and rugosans which constructed the biostrome, but the two facies have major faunal differences. Facies 1 is rich in stromatoporoids “Stromatopora” bekkeri and Plectostroma scaniense (low to high domical up to ca. 30 cm in basal length); and tabulate Favosites forbesi (bulbous to high domical up to ca. 25 cm wide). In Facies 2, all three taxa are less common and much smaller. Instead, the most abundant stromatoporoid is laminar Syringostromella borealis up to 30 cm basal length; the most abundant coral is erect branching Laceripora cribrosa, as...