Diversity patterns and palaeoecology of benthic communities of the Kanosh Formation (Pogonip Group, Utah, western USA)

摘要: The Dapingian to Darriwilian Kanosh Formation is one of the most fossiliferous units Pogonip Group (Great Basin, western US). It records a critical phase so-called Great Ordovician Biodiversification Event (GOBE) during which many marine clades diversified on lower systematic levels. However, comprehensive palaeoecological analysis has not been presented for this unit so far. Based newly collected material from three sections in type area at Ibex, we reconstruct benthic communities, analyse diversity patterns, and discuss its significance GOBE. We find no differences species’ composition across formation with respect brachiopods. Benthic assemblages are dominated by Shoshonorthis michaelis, alongside presence Anomalorthis lonensis utahensis whole unit. Trilobites show more pronounced facies restriction species Kanoshia Pseudomera being observed proximal limestone whereas Bathyurellus Pseudoolenoides occur fine-grained, low-energy deposits. skeletal also abundant bioclasts bryozoans, echinoderms, receptaculitids, suggesting an ecologically diverse tiered community present inner shelf zone. these groups not particularly terms richness. This implies that principle establishment typical members “Palaeozoic Fauna” associated local diversification clades. comparably low habitat Fauna likely reflects environmental constraints such as high rates siliclastic input. Additionally, mainly communities still represent base-line fauna before principal took place.