塔里木盆地艾克提克群中放射虫化石及其意义

New Dis-covery of Radiolarian Fossils from Aiktik Group at in Tarim Basin and Its Significance

中国南天山西端的艾克提克群是卷入南天山造山带的一个重要的岩石地层单元,其与相邻地层单元均以断层接触。以往根据在其灰岩和砂质灰岩中发现的Pseudostaffellasp.,Profusulinellasp.和Fusulinellasp.将其归属于上石炭统。我们的放射虫化石发现于托什罕河上游的哈拉道克剖面,主要包括AlbaillellaundulataDeflandre,Al-baillellaparadoxaDeflandre,Albaillellasp.aff.A.paradoxaDeflandre,Albaillellasp.cf.A.deflandreiGourmelon,Albaillellasp.,AlbaillellaexcelsaIshiga,KitoandImoto(?),Beloweavariabilis(OrmistonetLane),Callellacf.C.parvispinosaWon,Entactiniacf.E.tortispinaOrmistonetLane,Entactiniaaff.E.tortispinaOrmistonetLane,En-tactiniavariospinaWon,Entactiniasp.,Eostylodictyarota(Won),Latentifistulaimpella(OrmistoneetLane)(?),La-tentifistulaturgidaOmistonetLane,Latentifistulidaegen.et.sp.indet.和Polyentactiniacf.araneaGourmelon。其中,AlbaillellaexcelsaIshiga,KitoandImoto(?)的时代为晚二叠世(存疑),其余可以划分出早石炭世早期和晚期两个放射虫化石组合:前者以AlbaillellaundulataDeflandre,AlbaillellaparadoxaDeflandre和Albaillellasp.cf.A.

Aiktik group,distributed at the western end of South Tianshan Mountains in China,is an important lithostratigraphic unit involved in south Tianshan orogen.It is separated from the adjacent rocks with faults.Generally,the geologists classified it into Upper Carboniferous according to Pseudostaffella sp.,Profusulinella sp.and Fusu-linella sp.found from the limestone and sandy limestone of Aiktik.Our radio larian fossils were obtained from the chert sam ples collected from Haladaok section located at the upper stream of Tuoshihan river.The fossils include mainly Al -baillella undu lata Deflandre,Al bail lella paradoxa Deflandre,Albaillella sp.aff.A.paradoxa Deflandre,Albail-lella sp.cf.A.deflandrei Gourmelon,Al baillella sp.,Albaillella excelsa Ishiga,Kito and Imoto(?),Belowea variabilis(Ormiston et Lane),Callella cf.C.parvispinosa Won,Entactinia cf.E.tortispina Ormiston et Lane,Entactinia aff.E.tortispina Ormiston et Lane,Entac tinia variospina Won,Entactinia sp.,Eostylodictya rota(Won),Latentifistula im pella(Ormis tone et Lane)(?),Latentifistula turgida Omiston et Lane,Latentifistulidae gen.et.sp.indet.和Polyen tactinia cf.aranea Gourmelon.In which,Al baillella excelsa Ishiga,Kito and Imoto(?)is a Late Permian species with some element of unsure as there is only one unwell-preserved individual fossil of this species found so far.And two ra diolarian assem blages can be identi fied out from the other fossils.One is the early Early Carboniferous assem blage repre sented with Albail lella undulata Deflandre,Albaillella paradoxa Deflandre and Al -baillella sp.cf.A.deflan drei Gourmelon.And the other is the late Early Carboniferous assemblage represented with Eostylodictya rota(Won).This is the first discovery of radiolarian fossils in Aik tik group,also the first discovery of Late Permian radiolarian fossil in Chinese South Tianshan.Meanwhile,this is the current most-west sampling place of radio-larian fossil in Chinese South Tianshan.