【作者】 王丽岩；

【导师】 张梅生；

【作者基本信息】 吉林大学 ， 古生物学与地层学， 2008， 硕士

【摘要】 本文描述了塔木察格盆地井下白垩纪岩石地层序列,对井下样品分析获得的孢粉化石资料进行了分类学研究,描述孢粉化石62属80种,其中新种3个:Biretisporites punctatus sp.nov.,Chasmatosporites reticulates sp.nov.,Concentrisporites contractus sp.nov.。是塔木察格盆地井下地层划分和对比的重要孢粉化石之一。在分类学研究的基础上,依据井下孢粉化石属种在纵横向上的变化规律,自下而上划分出4个孢粉化石组合:Bayanhuasporites sp.～Hailarspora sp.～Concentrisporites sp.组合(铜钵庙组)、Foraminisporisasymmetricus～Classopollis sp.～Pseudopicea sp.组合(南屯组)、Cicatricosisporites australiensis～Matonisporites equiexinus～Protopicea sp.组合(大磨拐河组)、Appendicisporites macrorhyzus～Pinuspollenites sp.～Retitricolpites geogensis组合(伊敏组),和2个藻类组合:Vesperopsisgranulata～Dinogymniopsis sp.组合(大磨拐河组)、Tetraedron sp.～Vesperosisfragilis组合(伊敏组)。上述孢粉和藻类组合既是塔木察格盆地井下白垩系划分对比的生物标准,也是确定各个岩石地层单元时代的重要依据。孢粉地层学研究证明,铜钵庙组地质时代为Berriasian-Valanginian期。南屯组为Valanginian-Hauterivian期,大磨拐河组为Hauterivian-Barremian期,伊敏组为Barremian-Albian期。文中附化石图版33幅,图2幅,表6张。更多还原

【Abstract】 Based on the investigation of the Cretaceous stratigraphic sections in Tamtsag basin, Mongolia and the research history of the Cretaceous in this area and nearby,the Cretaceous petrological stratigraphic sequences in Tamtsag basin are established following the international stratigraphy criterion.Taxonomic research of the pollen and spores in the drillings is undergone systematically,totally 80 species of 62 genera(including 3 new species)are described in the Tamtsag basin.Moreover,4 pollen and spores assemblages and 2 algae assemblages are recognized by their vertical distribution of different palynological taxa in descending order for the Cretaceous of the Tamtsag basin.In order to study the geological time of the pollen and spores assemblages,the biostratigraphic significance of 7 genera of pollen and spores are summarized in detail.The geological ages of every petrological stratigraphic unites are discussed based on the palynological data.The sedimentary strata of the Tamtsag basin can be divided into three groups in ascending order.The Xinganling Group:Middle Jurassic-Lower Cretaceous Tamulangou Formation, Lower Cretaceous Tunbomiao Formation,Lower Cretaceous Nantun Formation(the Tunbomiao and Nantun formations equal horizentally to the Shangkuli Formation at the margin of the basin).The Zhalainor Group:Damoguaihe Formation and Yimin Formation.The Bairhu Group:Upper Cretaceous Qinyuangang Formation,Pliocene Hucashan Formation and Quanternary.Totally 80 species(including 3 new species)of 62 genera are described from the Cretaceous of Tamtsag basin.The new species are Biretisporites punctatus sp.nov., Concentrisporites reticulates sp.nov.and Chasmatosporites contractus sp.nov..There are some pollen and spores in the Cretaceous of the Tamtsag basin,such as Cicatricosisporites,Paleoconifers(Paleoconiferus,Protoconiferus,Paleopinus,Paleopicea, Pseudopicea,Piceites,Protoabies,Pseudopinus,Protopicea,Pseudopodocarpus,Walchites, Pseudowalchia,Protopinus,Protocedrus,Pinites,Protopodocarpus,etc.),Pilosisporites, Triporoletes,Aequitriradites,Appendicisporites,Clavatipollenites etc.which are very important for the division and correlation of the Cretaceous,and are usually taken as index fossils in determining the geological age of the strata.The biostratigraphic significance of these index fossils is particularly summarized.4 pollen and spores assemblages are recognized from the Cretaceous in the Tamtsag basin. They are:1)Bayanhuasporites sp.-Hailarspora sp.- Concentrisporites sp.Ass.,distributed in the Tunbomiao Formation;2)Foraminisporis asymmetricus - Classopollis sp.- Pseudopicea sp.Ass.,distributed in the Nantun Formation;3)Cicatricosisporites australiensis -Matonisporites equiexinus - Protopicea sp.Ass.,distributed in the Damoguaihe Formation;4) Appendicisporites macrohyzus - Pinuspollenites sp.-Retitrcolpites geogensis Ass.,distributed in the Yimin Formation.These 4 pollen and spores assemblages are not only the biostratigraphic criteria for the division and correlation of Cretaceous in the wells of Tamtsag basin,but also the main evidence to ascertain the geological age of every petrological stratigraphic unite.2 algae assemblages are recognized from the Cretaceous in the Tarntsag basin.They are:1) Vesperopsis granulata -Dinogvmniopsis sp.Ass.,distributed in the Damoguaihe Formation of the Tartan depression in Tamtsag basin;2)Tetraedron sp.- Vesperosis fragilis Ass., distributed in the Yimin Formation of the Tanan and the Bayangebi depressions in Tamtsag basin.These 2 algae assemblages are not only the biostratigraphic criteria for the division and correlation of Cretaceous in the wells of Tamtsag basin,but also the main evidence to ascertain the geological age of every petrological stratigraphic unite.Of all kinds of fossils,palynological fossil records of the Tamtsag basin are most abundant and continuous,playing an important role in confirming the geological age of the strata.The results of palynological chronology analysis show that the geological age of the Tunbomiao Formation might be Berriasian-Valanginian,the Nantun Formation might be Valanginian-Hauterivian in age,the geological age of the Damoguaihe Formation might be Hauterivian-Barremian of the Early Cretaceous and the Yimin Formation might be Barremian-Albian.Totally33 plates,2 pictures,6 tables are included in the present thesis.更多还原