Since 1990s, with the discoveries of abundant rare fossils such as Confuciusornis sanctus, Sinosauropteryx prima, Eomaia scansoria and Archaefructus liaoningensis, western Liaoning has become the most famous area for the study of Mesozoic strata, the origin and evolution of primitive birds, primitive mammals and early angiosperms in China and even all over the world.
Avaliable data show that the primitive angiospermous pollen grains of the genus Stellatopollis are major elements of early angiospermous microflora and useful in precisely dating and correlating Early Cretaceous sediments.
The association of Eosestheria wit . Yan jiestheria and of Lycoptera and Kuntulunia with Eosestheria and Yanjiestheria, and the occurrence of early angiosperms and spore-pollen in the Fuxin Formation and its equivalents also demonstrate that the Lycopten-bearing bed should be assigned to the Cretaceous.
After analysing the palynoglora in the basin,angiospermous pollen of 12 genus had been discoved. These angiospermus pollen are important data when research the development trend of angiospermous plant in early period and the divide of evolutional stage. It is also an important factor that defines the age of wangshi formation.
Mesozoic paleogeography and early angiosperm history
Changes in Mesozoic paleogeography also appear to clarify several other puzzling aspects of early angiosperm history and distribution, including their early appearance at middle latitudes.
brasiliensis are discussed in a wider context, compared with data from otherMagnoliidae, and related to aspects of early Angiosperm evolution.
The Baisha Basin situated in the middle of the Hainan Island is a continental sedimentary basin of the Mesozoic in the southernmost part of China.The Cretaceous of the Baisha Basin is composed of the"red-bed arkose", and can be divided into two groups: the Lumuwan Group of Early Cretaceous and the Baowan Group of Late Cretaceous.The sporo-pollen fossils presented in this paper were encountered in the middle part of the Lumuwan Group. This assemblage is composed of 50 genera and 75 species, and characterized...
The Baisha Basin situated in the middle of the Hainan Island is a continental sedimentary basin of the Mesozoic in the southernmost part of China.The Cretaceous of the Baisha Basin is composed of the"red-bed arkose", and can be divided into two groups: the Lumuwan Group of Early Cretaceous and the Baowan Group of Late Cretaceous.The sporo-pollen fossils presented in this paper were encountered in the middle part of the Lumuwan Group. This assemblage is composed of 50 genera and 75 species, and characterized by the predominance of gymnospermous pollen (accounting for 83％ of the total number in the assemblage), including 28 genera and 47 species. Spores of Pteridophyta comprise 20 genera and 25 species (accounting for 14.2％ of the total number in the assemblage). In addition, there are also angiospermous pollen grains, such as Clavatipollenites hughesii,Asteropollis asteroides and Asteropollis microreticulatus (accounting for 2.8％ of the total number in assemblage).This sporo-pollen assemblage probably belongs to the Aptian of Early Cretaceous, very likely indicating tropic-subtropical paleoclimate. At that time,the region was largely located in the transitional area between the arid zone and the equatorial damp zone established by Vachramcyev (1978).
Stellatopollis magifica sp. nov. was discovered from the Early Cretaceous Hadatu Formation of Nei Monggol,China. Avaliable data show that the primitive angiospermous pollen grains of the genus Stellatopollis are major elements of early angiospermous microflora and useful in precisely dating and correlating Early Cretaceous sediments.A new simple method was developed to undertake combined light and scanning eletron microscopy of the same pollen grain.
The Lycoptera-bearing bed lies over the upper part of the Upper Jurassic, which has been verified by the fossil evidence such as the Nestoria-Keratestheria fauna and the Ostracod Eoparacypris-Luanpingella-Darwinula assemblage from the Debei gou Formation (in a narrow sense) and by the age 145.2 Ma as determined with the Rb-Sr isochron method of the Beiqi Formation, and the complete stratigraphical sequence in the Yanliao region. The Jehol fauna includes primitive Trigonioidids, Eosestheria and Lycoptera etc....
The Lycoptera-bearing bed lies over the upper part of the Upper Jurassic, which has been verified by the fossil evidence such as the Nestoria-Keratestheria fauna and the Ostracod Eoparacypris-Luanpingella-Darwinula assemblage from the Debei gou Formation (in a narrow sense) and by the age 145.2 Ma as determined with the Rb-Sr isochron method of the Beiqi Formation, and the complete stratigraphical sequence in the Yanliao region. The Jehol fauna includes primitive Trigonioidids, Eosestheria and Lycoptera etc. and their own laws of evolution expound that they belong to the Cretaceous faunas. The association of Eosestheria wit . Yan jiestheria and of Lycoptera and Kuntulunia with Eosestheria and Yanjiestheria, and the occurrence of early angiosperms and spore-pollen in the Fuxin Formation and its equivalents also demonstrate that the Lycopten-bearing bed should be assigned to the Cretaceous.The confirmation of the existence of Aucellina in the Jixi Group and the correlation of Trigonioidids and Cyprididae with those in the equivalent strata of Japan and W. Europe have also verified the existence of the corresponding Cretaceous marine strata. The palaeomagnetic stratigraphical data from Zhejiang and the Song-liao area have ascertained that in China the Cretaceous Mo between the lower mixed polarity zone and the middle normal polarity zone is located in the upper member of the Huangjian Formation of the Jiande Group and the top member of the Deng-louku Formation. Moreover, the isotopic age data obtained from the Jehol and Jiande Groups show that the approximate geological age of the Lycoptera bed is 135-122 Ma. All this has proved that the Lycoptera bed should be attributed to the Cretaceous.
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