Carbonate shelf environments and faunal communities in the Upper Bringewood Beds of the British Silurian

Abstract

The Upper Bringewood Beds of the type Ludlow Series preserve a lateral suite of carbonate shelf facies. From west to east, the shelf edge is represented by three parallel belts of sediments: thin-bedded biocalcarenites (downslope deposits), biosparrudites (bank deposits), and thin-bedded biocalcarenites (overwash deposits). Further east, the inner shelf is represented by highly bioturbated calcisiltites, calcilutites, and mud-supported biocalcarenites. The shelf edge was a high-energy environment with high species diversity and dense populations of crinoids and the pentamerid brachiopod Kirkidium. Low-energy mud environments of the inner shelf contained a low-diversity community of tetracorals, ostracords, Bryozoa, and the brachiopod Atrypa. The composition and distribution of benthic communities across the shelf was determined by substrate, palaeogeographic relations, and the historical factor of previous communities in the area.