【作者】 张艳；

【导师】 孙跃武；

【作者基本信息】 吉林大学 ， 古生物学与地层学， 2023， 硕士

【摘要】 本文对红旗凹陷2口连续取芯探井的70块孢粉样品进行了实验分析处理,其中52块孢粉化石丰富,共鉴定、统计101属333种,系统描述了其中的51属77种,附图版20幅。红旗凹陷早白垩世孢粉植物群演化较为迅速,各演化阶段特征明显,依据各属种的纵向分布,借助Tilia软件,首次建立了该凹陷6个连续的孢粉组合带,自下而上为:Biretisporites-Densoisporites-Cycadopites组合带,分布于铜钵庙组下部;Foraminisporis-Undulatisporites-Protoconiferus flavus组合带,分布于铜钵庙组上部;Osmundacidites-Podocarpidites-Protoconiferus flavus组合带,分布于南屯组;Cicatricosisporites-Piceaepollenites-Clavatipollenites组合带,分布于大磨拐河组一段;Appendicisporites-Pinuspollenites-Asteropollis组合带,分布于大磨拐河组二段;Laevigatosporites gracilis-Triporoletes singularis-Tricolpites组合带,分布于伊敏组一段。铜钵庙组底部早白垩世特征属种Cicatricosisporites sp.、Fixisporites sp.等的发现,表明红旗凹陷铜钵庙组的地质时代为早白垩世。通过对各孢粉组合带中已知属种的时代分布,尤其是特征分子的出现,确定了6个孢粉组合带的地质时代:即铜钵庙组下段Biretisporites-Densoisporites-Cycadopites组合带和铜钵庙组上段Foraminisporis-Undulatisporites-Protoconiferus flavus组合带的地质时代为早白垩世Berriasian-Valanginian期,南屯组Osmundacidites-PodocarpiditesProtoconiferus flavus组合带的地质时代为Hauterivian期,大磨拐河组一段Cicatricosisporites-Piceaepollenites-Clavatipollenites组合带的地质时代为Barremian-Aptian早期,大磨拐河组二段Appendicisporites-PinuspollenitesAsteropollis组合的地质时代为Aptian晚期,伊敏组一段Laevigatosporites gracilis-Triporoletes singularis-Tricolpites组合的地质时代为Albian期。上述研究为确定红旗凹陷早白垩世组级地层单元的地质时代提供了可靠的孢粉学依据。前人在海拉尔盆地大磨拐河组曾有过早期被子植物花粉的报道,但一直未见化石图影。本次工作首次在大磨拐河组发现早期被子植物花粉:棒纹粉(Clavatipollenites sp.)和星粉(Asteropollis sp.),在伊敏组一段发现三沟型被子植物花粉:普遍扁三沟粉(Tricolpites vulgaris)和小三沟粉(Tricolpopollenites parvulus),这也是迄今为止在海拉尔盆地首次发现被子植物花粉的棒纹粉演化阶段,据此我们建立红旗凹陷被子植物花粉演化序列,即自下而上为a.棒纹粉演化阶段(大磨拐河组一段沉积时期)、b.棒纹粉-星粉演化阶段(大磨拐河组二段沉积时期)、c.三沟粉演化阶段(伊敏组一段沉积时期)。该凹陷早期被子植物花粉演化阶段的建立,为与全球被子植物花粉演化和时代对比提供了重要的依据。利用孢粉植被分析方法,首次在红旗凹陷开展早白垩世孢粉古植被、古气候重建。红旗凹陷铜钵庙组下部Biretisporites-Densoisporites-Cycadopites孢粉组合植被主要为半干旱～半湿润炎热气候下,由苏铁植物组成的常绿林。铜钵庙组上部Foraminisporis-Undulatisporites-Protoconiferus flavus孢粉组合植被主要为偏湿润的温凉-温湿气候的“古松柏类”针叶林。南屯组OsmundaciditesPodocarpidites-Protoconiferus flavus孢粉组合植被为偏湿润、温凉气候的松科+“古松柏类”针叶林。大磨拐河组一段Cicatricosisporites-PiceaepollenitesClavatipollenites孢粉组合植被为湿润、半湿润的温凉气候的云杉～双束松型针叶林;大磨拐河组二段Appendicisporites-Pinuspollenites-Asteropollis孢粉组合植被为湿润、半湿润的温凉气候的双束松～云杉型针叶林。伊敏组一段Laevigatosporites gracilis-Triporoletes singularis-Tricolpites孢粉组合植被为湿润、半湿润的温暖气候下的双束松针叶林。更多还原

【Abstract】 70 palynological samples from two continuous coring boreholes in Hongqi Sag of Hailar Basin were analyzed by author in this dissertation.Among them,52 samples were productive,and 333 species of 101 genera were counted.Among them,77 species of 51 genera are described,with 20 plates attached.The Early Cretaceous palynofloras in Hongqi Sag of Hailar Basin changed rapidly,and the characteristics of each evolutionary stage were obvious.Based on the vertical distribution of the taxa identified,six palynological assemblage zones were recognized with the cluster analysis(Tilia software)for the first time in the Hongqi sag of Hailar Basin.They are in ascending order: 1)Biretisporites-Densoisporites-Cycadopites assemblage zone(the lower part of Tongbomiao Formation),2)Foraminisporis – Undulatisporites-Protoconiferus flavus assemblage zone(the upper part of Tongbomiao Formation),3)Qsmundacidites-Podocarpidites-Protoconiferus flavus assemblage zone(the Nantun Formation),4)Cicatricosisporites-Piceaepollenites-Clavatipollenites assemblage zone(the first member of Damoguaihe Formation),5)Appendicisporites-Pinuspollenites-Asteropollis assemblage zone(the second member of Damoguaihe Formation),and 6)Laevigatosporites gracilis-Triporoletes singularis-Tricolpites assemblage zone(the first member of Yimin Formation).The occurence of Early Cretaceous characteristic genera such as Cicatricosisporites and Fixisporites in the bottom of the Tongbomiao Formation indicates that the all these assemblages zones are Cretaceous in age.Based on the geological age distribution of known species,especially those characteristic taxa,the geological ages of six palynological assemblage zones are assigned to Berriasian-Valanginian for the Biretisporites-Densoisporites-Cycadopites and Foraminisporis-Undulatisporites-Protoconiferus flavus assemblage zones of Tongbomiao Formation.Hauterivian for the Osmundacidites-Podocarpidites-Protoconiferus flavus assemblage zone in Nantun Formation,to Barremian-early Aptian for Cicatricosisporites-Piceaepollenites-Clavatipollenites assemblage zone in lower Damoguaihe Formation,late Aptian for Appendicisporites-Pinuspollenites-Asteropollis assemblage zone in upper Damoguaihe Formation,and to the early-middle Albian for Laevigatosporites gracilis-Triporoletes singularis-Tricolpites assemblage zone in lower Yimin Formation.This provides basic palynological evidence in age calibration for the lithostratigraphic units in the Hongqi sag of Hailar Basin,and would be benifitial for oil and gas exploration in the basin.As for the early angiosperm pollen record in the Hailar Basin,the present occurence of Clavatipollenites sp.and Asteropollis sp.in the Damoguaihe Formation,Tricolpites vulgaris and Tricolpopollenites parvulus in the first member of Yimin Formation would be the most reliable records in the basin.This enable to see three stages of early angiosperm pollen evolution in the Hongqi Sag,namely a)Clavatipollenites stage(in the first member of Damoguaihe Formation),b)Asteropollis-Clavatipollenites stage(in the second member of Damoguaihe Formation),and c)Tricolpates-Asteropollis-Clavatipollenites stage(in the first member of Yimin Formation).The early angiosperm pollen evolutionary stages in the Hongqi sag are quite consistent with those in North America,Australia and Europe,and provide important tools in correlation of the global Cretaceous terrestrial strata.Furthermore,based on the habits of each taxon,the Cretaceous vegetation and climate are reconstructed for the first time in the Hongqi Sag.The palynofloras of the Biretisporites-Densoisporites-Cycadopites assemblage zone in the lower Tongbomiao Formation,were mainly composed of Cycads evergreen leaved forest in a semi-arid to semi-humid warm climate.Those of Foraminisporis-Undulatisporites-Protoconiferus flavus assemblage zone in the upper Tongbomiao Formation,were mainly composed of “Paleoconifer” coniferous forest in a wet cool and warm humid climate.The vegetation of the Osmundacidites-Podocarpidites-Protoconiferus flavus assemblage zone in the Nantun Formation was represented by “Paleoconifer and Pinaceae” coniferous forest in showing a humid cool climate.The palynofloras of the Cicatricosisporites-Piceaepollenites-Clavatipollenites assemblage zone in the first member of Damoguaihe Formation were Picea and Pinus coniferous forest in a humid or semi-humid cool climate,while the vegetation of Appendicisporites-Pinuspollenites-Asteropollis assemblage zone in the second member of Damoguaihe Formation was mainly composed of Picea and Pinus coniferous forest in a slightly warmer climate.Finally,the palynofloras of Laevigatosporites gracilis-Triporoletes singularis-Tricolpites assemblage zone in the first member of Yimin Formation,were mainly composed of Pinus coniferous forest in a humid or semi-humid warm climate.更多还原