Late Camrbian (Furongian) to mid.Ordovician euconodont events on Baltica: Invasions and immigrations

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The stratigraphic distributions, taxonomy, diversity, evolutionary lineages and events of late Cambrian to MiddleOrdovician euconodonts of Baltica are briefly reviewed and re-evaluated. The euconodonts of the late Furongian(Stage 10, late Cambrian) to Middle Ordovician successions of Baltica record innovation, immigration and twoinvasions of short duration and one major extinction. The innovation event with an origin on Baltica is the rise oftheProconodontus serratuslineage in the late Furongian (Stage 10). The immigration events comprise theCordylodusimmigration to Baltoscandia in latest Cambrian and this phylogenetic lineage persisted to mid-Tremadocian (Early Ordovician) and vanished at the global mid-Tremadocian extinction event. The late Floian –basal Dapingian transition is a significant event on Baltica. It is characterized by the immigration of the im-portant generaBaltoniodusandMicrozarkodinaand upon their arrival these taxa remained on the Baltica pa-laeocontinent and stayed for a long period forming evolutionary lineages. The basal Darriwilian immigrationevent by the genusLenodusand coeval prominent sea-level lowstand were caused by a short global icehousestage related to the expansion of the polar ice sheets. The extinction event caused the disappearance of thecharacteristicCordylodusfauna. Most events are related to changes in the palaeoclimate resulting from themovement of the Baltica palaecontinent and associated eustatic sea-level changes. However, the cause of theglobal early Tremadocian extinction event is not yet completely clear and remains unsolved. Perhaps abrupt andsignificant palaeoceanographic changes on a global scale (i.e., plate tectonic movements causing sudden changeof ocean currents and climate from warm to cold) were the cause of this significant extinction in the Early Ordovician.
TidsskriftPalaeogeography, Palaeoclimatology and Palaeoecology
Antal sider16
StatusUdgivet - 2020

ID: 231901670