At what stratigraphical level is the mid Ludfordian (Ludlow, Silurian) positive carbon isotope excursion in the type Ludlow area, Shropshire, England?

Bulletin of geosciences

Frýda J¹  Loydell DK¹ 

关键词: Silurian;    Ludlow;    carbon isotopes;    conodonts;    chitinozoans;    thelodonts;    stratigraphy;   

DOI  :  

来源: Czech Geological Survey

【 摘 要 】

ThebalanceofevidencesuggeststhatthemidLudfordianpositivecarbonisotopeexcursion(CIE)commencesintheLudlowarea,EnglandintheuppermostUpperWhitcliffeFormation,withtheexcursioncontinuingintoatleastthePlatyschismaShaleMemberoftheoverlyingDowntonCastleSandstoneFormation.TheLudlowBoneBedMember,atthebaseoftheDowntonCastleSandstoneFormationhaspreviouslybeenconsideredtobeofPA™A­dolA­age.Conodontandthelodontevidence,however,areconsistentwiththemidLudfordianageproposedhere.Newdelta;13CorgdataarepresentedfromWeirQuarry,WofLudlow,showingapronouncedpositiveexcursioncommencingintheuppermostUpperWhitcliffeFormation,instratawithapalynologicallyverystrongmarineinfluence.Elsewhereintheworld,themidLudfordianpositiveCIEisassociatedwithmajorfacieschangesindicatedshallowing;thelithofaciesevidencefromtheLudlowareaisconsistentwiththis.ThereappearsnottobeamajorstratigraphicalbreakatthebaseoftheLudlowBoneBedMember.

【 授权许可】

Unknown