摘要
按其地层分布自下而上简介如下(图版Ⅰ,表1):Ⅰ.perimneste ancora-Triclypella calcitrapa zone(锚形求偶轮藻-菱形三盾轮藻带)(早白垩世中期):以衡阳盆地东井组为代表,厚0—728米,由棕红色砾岩、含砾砂岩、泥岩组成,夹杂色泥岩透镜体。
Abstract
The charophyte assemblages of the Cretaceous and Paleogene of Hunan Province may be divided into 10 zones(or assemblages)in ascending order.1st zone:- zone(the middle stageof the Early Cretaceous),represented by the Dongjing Formation of Hengyang Basin.2nd zone: zone(the middle-late stages of the Ear-ly Cretaceous),represented by the Qijiahe Formation of Dongting Basin.3rd zone: trivolvis zone(the late stage of the EarlyCretaceous),represented by the Mayang Formation of Yuanma Basin.4th zone: qidongensis zone(the late stage of theEarly Cretaceous),represented represened by the Huitangqiao Formationof Hengyang Basin.5th assemblage:- assemblage(themiddle-late stage of the Late Cretaceous),represented by Daijiaping Forma-tion of Hengyang Basin.6th assemblage:- as- semblage(the late stage of Late Cretaceous),represented by the YanmatouFormation of Dongting Basin.7th assemblage:- as-semblage(the Late Paleocene),represented by the Xinwan Formation of Dongting Basin.8th assemblage:- assemblage(the Early Eocene),represented by the Yuanjiang Formation of Dongting Basin.9th assemblage:- assem-blage(the Middle-Late Eocene),represented by the Hanshou Formation of Dongting Basin.10th assemblage:- assem-blage(the Late Eocene-Early Oligocene),represented by the Xinhekou Forma-tion of Dongting Basin.The boundary between the Cretaceous and Paleogene,according to the evo-lution,distribution and property of charophyte assemblages,should be pro-perly placed between the 6th and 7th assemblages.
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