CRETACEOUS FLORAS AND BIOSTRATIGRAPHY OF CHINA
CRETACEOUS FLORAS AND BIOSTRATIGRAPHY OF CHINA
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发表时间：
2012
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通讯作者：
Deng Shenghui
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作者：
Deng Shenghui
早白垩世，中国存在华北、华南和藏南三个植物地理区。华北植物地理区属于瓦赫拉梅耶夫西伯利亚加拿大植物地理区，发育热河植物区系、阜新植物区系和达拉子植物区系三个植物区系。热河植物区系分布于义县组和九佛塘组。辽西及其他地区同代地层,以苏铁纲和针叶纲为主,年龄为早白垩世早期。阜新植物区系以丝叶纲、银杏纲、针叶纲为主,苏铁纲、木贼纲丰富,产于辽西沙海组、阜新组等地。植物区系中，Filicopsida以丰富的Dicksoniaceae、Osmundaceae、Schizaeaceae和单孔孢子元素为代表。该植物区系可细分为3个组合，由高到低依次为棘蕨-银杏组合、Ruffordia goepperti-Dryopterites组合和Ctenis lyrata-Chilinia这三个组合分别产于辽西沙海组和阜新组中下、上部。吉林省延吉盆地达子组和松辽盆地泉头组达子植物群以被子植物为主，针叶树丰富，包括鳞片状或锥状叶类植物。华南植物地理区属瓦赫拉梅耶夫欧震旦系植物地理区，以苏铁纲为主，鳞片状或锥状叶针叶树，小而粗的羽片蕨类（主要是代表热带亚热带植物区系，可分为东部亚区、藏北亚区和中部亚区。东部亚区濒临古太平洋，以浙江、福建和山东莱阳盆地植物为代表，鳞片状或鳞片状。锥叶针叶树和 Ptilophyllum of Bennettitales 为主，裂叶蕨类植物 Ruffordia 较多。裂叶蕨类植物 Klukia 和云石蕨类植物 Gleichenites 也有出现，但数量不多。该亚区早白垩世植物区系可分为 3 或 4 个组合，按升序排列， Cupressinocladus-Pagiophyllum 组合、Cladophlebis-Ptilophyllum 组合、Ruffordia-Zamiophyllum 组合和 Suturovagina-Frenelopsis 组合。西藏亚区植物区系与东部亚区具有主要特征，但蕨类植物更为丰富，特别是 Klukia 和 Gleichenites 丰富，并且随着硬蕨属（裂科蕨类植物）和部分木犀科蕨类植物；裸子植物中苏铁纲丰富，针叶纲相对贫乏。藏北亚区的植物区系可进一步细分为两个组合。上述两个亚区之间的中心亚区的特点是干旱环境下植物区系发育不良。植物区系物种多样性低，丰度低。藏南植物地理区属于Vakhrameev（1991）的南方植物地理区，目前在喜马拉雅地区刚刚报道了南洋杉科针叶树和种子蕨类植物化石，目前仅在少数地区发现了晚白垩世植物区系。本文主要以植物化石为基础，结合生物地层和其他地层资料，建立了中国不同植物地理区域白垩纪植物化石地层与相关地层的对比。
In the Early Cretaceous,there existed three phytogeographical regions in China,namely the North China,South China and southern Tibet regions.The North China Phytogeographical Region,which belongs to Vakhrameev'sSiberian Canadian Phytogeographical Region,developed three floras,including the Jehol,Fuxin and Dalazi floras in ascending order.The Jehol flora,which occurs in the Yixian Formation and the Jiufotang Formation of western Liaoning and contemporaneous strata in other areas,is dominated by Cycadopsida and Coniferopsida.It is regared as early Early Cretaceous in age.The Fuxin flora,characterized by the dominanca of the Filicopsida,Ginkgopsida and Coniferopsida,with abundant Cycadopsida and Equisetales,occurs in the Shahai Formation and the Fuxin Formation of western Liaoning and other equivalent strata.The Filicopsida is represented by abundant Dicksoniaceae,Osmundaceae,Schizaeaceae and monolete spore elements in the flora.This flora can be subdivided into three assemblages,which are in ascending order the Acanthopteris-Ginkgo coriacea assemblage,Ruffordia goepperti-Dryopterites assemblage and Ctenis lyrata-Chilinia assemblage.These three assemblages occur,respectively,in the Shahai Formation,and the lower-middle and upper parts of the Fuxin Formation in western Liaoning Province.The Dalazi flora from the Dalazi Formation of the Yanji basin of Jilin Province and the Quantou Formation of the Songliao basin,northeastern China,is characterized by the dominance of angiosperms and abundant scale-like or awl-shaped leaf conifers including Pseudofrenelopsis,Frenelopsis and Suturovagina of the Cheirolepidiacae and the form genera Brachyphyllum and Pagiophyllumm.The South China Phytogeographical Region belongs to Vakhrameev's Euro-Sinian Phytogeographical Region,with the dominance of Cycadopsida,scale-like or awl-shaped leaf conifers,small and thick pinnule ferns(mainly Cladophlebis),and the absence of Ginkgopsida,dicksoniaceous and monolete spore ferns.It represents tropical-subtropical floras,and can be divided into three sub-regions,namely the Eastern sub-region,the North Tibet sub-region and the Center sub-region.The Eastern sub-region,near the ancient Pacific Ocean,is typically represented by plants from Zhejiang and Fujian Provinces and the Laiyang basin of Shandong Province,where the scale-like or awl-shaped leaf conifers and Ptilophyllum of Bennettitales dominated,and schizaeaceous fern Ruffordia commonly occurs.The schizaeaceous fern Klukia and gleicheniaceous fern Gleichenites appear but are not very abundant in the flora.The Early Cretaceous flora of this sub-region can be divided into 3 or 4 assemblages,in ascending order,the Cupressinocladus-Pagiophyllum assemblage,Cladophlebis-Ptilophyllum assemblage,Ruffordia-Zamiophyllum assemblage and Suturovagina-Frenelopsis assemblage.The flora of the Tibet sub-region shares the main characteristics with the Eastern sub-region,but the ferns are more abundant,particularly rich in Klukia and Gleichenites,and with the occurrence of Scleropteris(a schizaeaceous fern) and some matoniaceaous ferns;gymnosperms are rich in Cycadopsida and relatively poor in Coniferopsida.The flora of the North Tibet sub-region could be further subdivided into two assemblages.The Center sub-region between the two sub-regions discussed above is characterized by poorly-developed floras in arid environments.The flora consists of a low diversity of species and low abundance of fossils,and is dominated by scaly or awl-shaped leaf conifers.The southern Tibet phytogeographical region,where fossils,including araucariaceous conifers and the seed fern Pachypteris specifica,have just been reported in the Himalaya area,belongs to the Austral Phytogeographical Region of Vakhrameev(1991).The Late Cretaceous floras hitherto have only been found from a few horizons of some localities scattered in Northeast China,South China and Tibet.It can not be divided into phytogeographical regions or into assemblages due to the lack of sufficient data.Principally based on plant fossils and the intergration of biostratigraphical and other chionostratigraphic data,the correlations of the Cretaceous plant fossil-bearing strata and the relevant strata in different phytogeographical regions of China have been established in the present paper.