Baltoscandian conodont diversity (upper Tremadoc and Middle Ordovician) compared to GOBE

GOBE (Great Ordovician Biodiversifi cation Event) is today considered fundamental for development of biodiversity for marine life, especially for shallow-marine shelly benthos. A study of conodont diversifi cation from Baltoscandia is carried out from the upper Tremadoc (Paltodus deltifer Zone) to the Middle Ordovician (Pygodus serra Zone), i.e. the time interval, when Earth’s brachiopod biosphere changed fast from relatively low diverse to high diverse in the early Darriwilian. On Baltica the Tremadocian–Darriwilian sedimentary rocks are composed mainly of cool to temperate limestone and marl with little input of siliciclastic sediments