1 Introduction Stratigraphy,placing the sequence of events in Earth history into order,is a fundamental part of the geosciences.Traditionally the starting point is a regional stratigraphy,based on lithological,mappabl...1 Introduction Stratigraphy,placing the sequence of events in Earth history into order,is a fundamental part of the geosciences.Traditionally the starting point is a regional stratigraphy,based on lithological,mappable units,correlated by fossils with local,regional and global chronostratigraphical schemes.Chronostratigraphic units were traditionally defined on their fossil content,as essentially unit stratotypes.But,commonly there were no clear boundaries.展开更多
Late Ordovician shelly faunas occur at several localities in the(O|¨)stersund area of J(a|¨)mtland,central Sweden,an area that today is included in the Lower Allochton of the Swedish Caledonides.The Late Ord...Late Ordovician shelly faunas occur at several localities in the(O|¨)stersund area of J(a|¨)mtland,central Sweden,an area that today is included in the Lower Allochton of the Swedish Caledonides.The Late Ordovician faunas of J(a|¨)mtland have developed against a background of intense and rapid global climate change.The faunas are present approximately in the middle of the Kyrk(?)s Quartzite in the east and occur in the uppermost Kogsta Siltstone in the west. Changes in faunas and depositional environments provide regional evidence of these global cooling and regressive events.The faunas occur in shale and siltstone facies and are used to effect展开更多
基金the Leverhulme Trust for financial support.This is a contribution to IGCP 653 project’The onset of the Great Ordovician Biodiversification Event’.
文摘1 Introduction Stratigraphy,placing the sequence of events in Earth history into order,is a fundamental part of the geosciences.Traditionally the starting point is a regional stratigraphy,based on lithological,mappable units,correlated by fossils with local,regional and global chronostratigraphical schemes.Chronostratigraphic units were traditionally defined on their fossil content,as essentially unit stratotypes.But,commonly there were no clear boundaries.
文摘Late Ordovician shelly faunas occur at several localities in the(O|¨)stersund area of J(a|¨)mtland,central Sweden,an area that today is included in the Lower Allochton of the Swedish Caledonides.The Late Ordovician faunas of J(a|¨)mtland have developed against a background of intense and rapid global climate change.The faunas are present approximately in the middle of the Kyrk(?)s Quartzite in the east and occur in the uppermost Kogsta Siltstone in the west. Changes in faunas and depositional environments provide regional evidence of these global cooling and regressive events.The faunas occur in shale and siltstone facies and are used to effect
