摘要
中国泥盆纪可识别出 6个珊瑚生物地理区 :南天山区、古特提斯区、华南区、华北北缘区、准噶尔 兴安区和保山区。其中 ,前 4个区均处于当时赤道两侧的低纬度地区 ,属于老世界大区 ;而后 2个区则可能分别位于北温带和南温带区域内 ,不在老世界大区范畴内。中国泥盆纪珊瑚群大多数都是生活在温暖浅海近岸陆棚上富氧透光带中的群落 ,其分异度、丰度和密度各有不同 ,大致属于海洋底栖生物组合BA3—BA4;但也有的生活在远岸大陆斜坡、波基面之下的宁静环境 ,属于底栖组合BA5—BA6 。
Itisnow generallyrecognizedthattherewere threefirst levelmarine,biogeographicdivisionsofthe Devonianworld : 1.TheOldWorldRealm ,whichincludesEura sia,Australia,NorthAfricaandwesternandArctic NorthAmerica. 2 .TheEasternAmericasRealm (orAppalachian Realm) ,whichincludesmostofeasternNorthAmer icaandnorthernSouthAmerica. 3.TheMalvinokaffricRealm ,whichincludes southernSouthAmerica,southernAfricaandAntarc tica. TheOldWorldRealmoccupiedtheancienttrop ics.theMalvinokaffricRealmwaslocatednearthe ancientSouthPoleandtheEasternAmericasRealm wassituatedprobablyinthesoutherntemperature zone . TheOldWorldrealmcoincidedwiththewarm equatorialcurrents.ProvincesoftheOldWorldfauna mayberelatedtovariousbranchesoftheequatorial currents.TheMalvinokaffiricRealmcoincidedwith inundationofthesubpolartopolarpartofGondwana landfromthesmall,cold,clockwisesubpolargyre. TheAppalachian (orEasternAmericas)Realmcoin cidedwithimpingementofthecool,west winddrift ofthesouthernhemisphereuponthetemperatecoast oftheAmericas. Gedinnianprovincialismresultedintheforma tionoftwodiscretefaunalrealms,theOldWorld RealmandtheEasternAmericasRealm .Provincial ismincreasedinlateGedinnianandSiegeniantime andreachedamaximumduringtheearlyEmsianwith theadditionoftheMalvinokaffricRealm .However, theMalvinokaffricRealmdisappearedduringlate Eifeliantime.AttheendofFrasniantimeanumber ofimportantfaunasbecameextinctandFamennian timewascharacterizedbyanewrelativelycosmopoli tanfauna . ThestudyoftheEarlyandearlyMiddle DevoniancoralsofChinapermitsthediscriminationof sixdistinctbiogeographicprovinces:1)theJunggar HingganProvinceischaracterizedbytheabsenceof thetypicalGivetianbrachiopodStringocephalusand the presenceofsmallsolitarynon dissepimentsof corals,e.g .Syringaxon ;2 )theSouthernTianshan Provinceischaracterizedbyextensivedevelopmentof Chalamydophyllum ,AlaiphyllumandDubroviain theEarlyDevonian .Itisprobablyrelatedtothatof theUrals;3)thePalaeotethyanProvinceincluding northernXizang (Tibet)andnorthwesternYunnan , yieldsalotofAustralianelementsofEarlyDevonian age ,suchasEmbolophyllum ,Lyrielasma ,Mar tinophyllum ,LoyolophyllumandCarlinastraea ;4) theSouthChinaProvincewasanareaofhighEarly Devonianendemism ,especiallyintheSiegenianand inthelowerEmsian .However,fromlateEmsianon , thereappearedmanyWestEuropeanandwestern NorthAmerican ,aswellassomeAustraliangenera; 5 )thenorthernmarginoftheNorthChinaProvince appearingasanarrowbeltfromJilintotheBuyan Fault,atthetopoftheGreatBendoftheHuanghe (Yellow)RiverinNeiMonggolAutonomousRegion . Carlinastraea ,StylopeurawerefoundinearlyEarly Devonian (Lochkovian)andSociophyllum ,Utara tuiaappearedintheearlyMiddleDevonian ;6)theBaoshanProvincecoveredasmallareaofChinabut extendedintoBurma,ThailandandMalayPeninsula, i.e.thesocalled“Shan ThaiBlock”or“Sibumasu Block” .ItcontainsalargenumberofAppalachiange nea,forexample,Siphonophrentis,Neoacino phyllum ,MacgeeainthelateMiddleDevonian. Concerningabove mentioned 6provinces,among them ,theSouthernTianshanProvince,the PalaeotethyanProvince,theSouthChinaProvince andthenorthernmarginoftheNorthChinaProvince werelocatedneartheancientequatorandtheresttwo provinces,theJunggar HingganProvinceandthe BaoshanProvincewere probablysituatedinthe northernandthesoutherntemperatezonesrespective ly .Theformer 4provincesmayberelatedtovarious brachesoftheequatorialcurrents.TheJunggar HingganProvincecharacterizedthenorthern partof thewesternboundarycurrantand perhapsinvolved theinfluenceofthenear by,thecool,northernwest winddrift.TheBaoshanProvincecharacterizedthe southern partofthewesternboundarycurrentand perhapsinvolvedtheinfluenceofthecool,southern west winddrift. ThemarineDevonianstrataiswelldevelopedin Chinaandrichinfossilcorals.AccordingtoBoucot’s views,thebenthicassemblagescanbedividedinto six flodclassifications.Inwhich ,BA1andBA2 were intertidalandBA3toBA6weresubtidal.Theyare controlledprimarilybybathymetryandtemperature, andconceptuallyarearrangedinasystematicmanner awayfromtheshoreline .PedderandMcLea
出处
《古生物学报》
CAS
CSCD
北大核心
2000年第1期126-135,共10页
Acta Palaeontologica Sinica
基金
国家自然科学基金!( 495 72 0 79和 49872 0 0 7)资助课题