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《Acta Micropalaeontologica Sinica》 1993-02
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LATE CRETACEOUS PALYNOFLORAS OF CHINA

Zhang Yi-yong Nanjing Institute of Geology and Palaeontology, Academia Sinica, Nanjing 210008  
In contrast with the Tertiary, the Late Cretaceous palynofloras of the China mainlandand its continental shelf are sparsely distributed in space and are discontinuous in time. Alto-gether 35 palynoferous stratigraphic units in 28 areas or basins have been recorded based onthe published data. The Songliao Basin in NE China and the W. Tarim Basin in NW Chinahave displayed a rather complete succession of Late Cretaceous palynofloras. Based on theevolution level of angiospermous pollen observed and correlation with Late Cretaceous paly-nofloras in some other areas of the world, four major evolutionary stages of the Late Creta-ceous palynoflora in China have been recognized as follows: 1)Prebrevaxonate pollen stage——Cenomanian Among angiospermous pollen, tricolpate forms with simple aperture occurring frequent-ly in Albian strata are still present, such as Psilatricolpites, Retitricolpites, Tricolpopollentiesand Cupuliferoidaepollenites. While forms of longaxonate tricolporate types are rarely seen,such as Tricolporopollenites, those brevaxonate tricolporate pollen grains, usually small insize, are occasionally present, such as Gothanipollis, Cupanieidites, Syncolporites, Retitricol-porites oblatus and Nyssapollenites? The cosmopolitan Asteropollis, Clavatipollenites and Lil-iacidites began to decline,sporadically occurring in this stage. Later, a triporate pollen ele-ment, Archaeotriporopollis with triangular outline has been seen in some areas. The Contentof angiospermous pollen is not over 10% in the stage. 2)Brevaxonate pollen stage——Turonian--Santonian As compared with the preceding stage, angiospermous pollen grains of this stage in-crease greatly both in diversity and in abundance. They often have complex aperture and ad-vanced structure with columellate exine. Brevaxonate tricolporate and/or tricolpate pollengrains with a larger body size have substantially increased, including such common elementsas Cranwellia, Borealipollis, Lythraites, Loranthacites, Beaupreaidites, Xinjiangpollis, andNyssapollenites. Together with Cupanieidites, Gothanipollis, Syncolporites, etc., the brevax-onate pollen grains play a more outstanding role in composition than other types of an-giospermous pollen grains, while triporate pollen grains are still not greatly developed sincetheir first occurrence in the preceding stage. Psilatricolpites and Retitricolpites became less important and meagre in this stage as compared with the first stage, while Clavatipollenitesand Asteropollis disappear in this stage. Some forerunners of Triprojectacites andNormapolles appear individually in the upper part, such as Aquilapollenites pyriformis andExtratriporopollenites. Although the angiosperm pollen grains become greatly developed dur-ing this stage, their content is no more than 30% of the total. 3)Advanced angiospermous pollen stage——Campanian This stage is characterized by the high diversity of angiospermous pollen and complexexine with advanced aperture. In addition to the continual presence of brevaxonate tricol-p(or)ate pollen which flourished in the second stage, some genera become relatively rich,such as Proteacidites, Callistopollenites, Cosoliduspollenites, Betpakdalina, Crassimargin-pollenites, Rugupolarpollenites, Jiangsupollis, Aquilapollenites, Jianghanpollis, Parvipro-jectus and Macicorpus. Normapolles pollen grains are still sparsely present, with a contentless than 1% of the total. Those angiospermous genera with a close affinity to the livingplants are the first to occur, although in small amounts. 4)Ulmoideipites stage——Maastrichtian In addition to the continuous flourishment of some characteristic genera, viz.,Aquilapollenites, Callistopollenites, Proteacidites, Betpakdalina, Jianghanpollis and Jiang-supollis in this stage, those pollen grains which are closely related to such families as Ul-maceae, Sapindaceae, Betulaceae, Juglandaceae and Fagaceae, etc., are more or less devel-oped, occurring in association with a few elements of Wodehouseia in some areas. After reviweing the literature published in the past 2 to 3 decades a
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