Bulletin of geosciences | |
Lower to Middle Ordovician trilobite faunas along the Ural border of Baltica | |
Pärnaste H1  Bergström J1  | |
关键词: Ordovician; trilobites; Urals; Baltica; palaeogeography; | |
DOI : | |
来源: Czech Geological Survey | |
【 摘 要 】
RecentrevisionoftheOuml;landiantrilobitefaunasinBaltoscandiaandtheUralMountainsthrowsnewlightonthedevelopmentofthetrilobitefaunasinBalticaandpossiblemigrationlinkstosurroundingterranes.Thetrilobiteassemblagesof104generaontheUraliansideofBalticashowdifferentdevelopmentpatternsforthesouthandnorththroughtheTremadociantotheDarriwilian.TheoldestUraliantrilobites-disputablyoflatestCambrianorearliestOrdovicianage-arrivedprobablyfromtheSiberianandKazakhterranesbeingrepresentedbymostlyendemicgenerasuchasKujandaspisandJdyia,butalsowithpandemicAkoldinioidiaandMicragnostus.ThefollowingKidryasian,KolnabukianandKuagachianfaunaschangegraduallytoshowincreasingdifferencebetweenthesectionsintheSouthUralsandthoseinthenorthernPolarUralsorPay-Khoy.InKidryasiantheolenidsdominateintheSouthUralsastheydoinmanyotherregionsduringtheearlyTremadocian.TheKolnabukiantrilobitesrepresentthemostdiversetrilobiteassociationintheregion,andarecomparabletotheCeratopygefauna.TheKuagachianfaunacontainsafewadditionalelements,increasingthedifferencebetweensouthandnorthbutwithreducedgenericdiversity.Theroutesoffaunalexchangearemodifiedtoo.ThusduringtheEarlyOrdovicianmigrationbetweentheUraliansideofBalticaandtheBaltoscandia,KazakhandAltai-SayanterranesbecomesmoreimportantthanthatbetweentheUraliansideofBalticaandtheSiberia,NorthandSouthChinaplates.TheDarriwilianKarakoľ-MikhailovskianfaunalassociationshowsaclearseparationbetweennorthandsouthUralswiththeformerregion,asinBaltoscandia,dominatedbyasaphids,whileinsouthareefalillaenid-cheiruridassociationofLaurentiangeneraoccurs.ThisisratherintriguinggiventhewidelyacceptedpalaeogeographicaldisparatepositionandlatitudeofLaurentiaatthetime.
【 授权许可】
Unknown
【 预 览 】
Files | Size | Format | View |
---|---|---|---|
RO201912090783203ZK.pdf | 2891KB | download |