Silurian Bivalvia from Chichagof Island, Southeast Alaska (Alexander terrane)

Bulletin of geosciences

Blodgett RB¹  Kříž J¹  Rohr DM¹ 

关键词: Bivalvia;    Silurian;    late Wenlock to early Ludlow;    new taxa;    Alexander terrane;    Southeast Alaska;    U.S.A.;    palaeoecology;    slope facies;    palaeogeography;    Perunica;    Baltica;   

DOI  :  

来源: Czech Geological Survey

【 摘 要 】

ThenewSilurianBivalviaGoniophorathula-MytilarcaboucotiCommunityfromanewlocalityeastoftheHoonahAirportonChichagofIsland,SoutheastAlaska,U.S.A.iscomposedof9species[?Colpomyaaff.huginiLiljedahl,1994and?Colpomyaaff.audaeLiljedahl,1994(Colpomyidae);Modiolopsisaff.modiolarisConrad,1838(Modiolopsidae);Mytilarcaboucotisp.nov.(Ambonychiidae);?Schizodussp.Aand?Schizodussp.B(Schizodidae);Sanguinolitessp.(Sanguinolitidae);?Modiomorphasp.andGoniophorathulasp.nov.(Modiomorphinae)].Inthispapertwonewspeciesaredescribed.TheGoniophorathula-MytilarcaboucotiCommunitymostprobablyoccupiedagentlyinclinedupperslopeenvironmentlyingseawardofacyanobacterialreeffrontwhichmarkedtheouteredgeofalateSiluriancarbonateplatform(representedbytheKennelCreekLimestone).Thefaunaofthislocalityconsistsofarichbenthos,especiallyrichinbrachiopods,butsecondarilydominatedbybivalvesandgastropods.Cephalopodsarerare,favositidtabulatecoralsarealsopresent,butformonlyaveryminorcomponent.ThenewcommunityismostcloselyrelatedtothehomologousandanalogouslateWenlockBivalviacommunitydescribedfromGotland,Sweden,Baltica.SimilarbiotictiesarewiththeshallowwaterearlyLudlowJaniculapotensCommunityfromthePragueBasin,Bohemia,Perunica.CosmopolitanismischaracteristicfortheSilurianBivalviagenera,whichweredispersedinmostregionsoftheworldduetotheirrelativelylongpelagiclarvallifeandrelativelysmalldistancesbetweenthebasins,islandsandcontinentsintheSilurian.ForthedistributionofBivalviaduringtheSilurianweremorelimitingphysicalfactorsliketemperature,salinity,substrate,food,oxygencontent,light,anddepth.ThefaunadescribedhereisfromtheAlexanderterrane,anaccretedterranewhichappearstorepresentariftedblockoftheeasternSiberianpalaeocontinent.Thelatterinterpretationisbasedonfaunalaffinities,notablybrachiopods,butsuggestedbyothergroupssuchasgastropodsandsponges,aswellasonthebasisofsimilaritiesinsedimentarysuccession.

【 授权许可】

Unknown