中国陆相上新统麻则沟阶

年代地层单位麻则沟阶是中国上新统的两个阶之一,代表陆相上上新统,1999年由第二届全国地层委员会正式命名,对应于麻则沟期。"麻则沟"一名源自同名岩石地层单位麻则沟组,典型剖面位于山西省榆社县云簇镇赵庄—大马岚。麻则沟阶对应于"国际地层表"中的皮亚琴察阶,其共同的底界定义为古地磁Chron C2An.3n的底,即高斯正极性带的底,绝对年龄为3.6 Ma,这条界线在榆社赵庄剖面位于第6层麻则沟组下部的紫红色黏土层的中部,以张洼沟姬鼠(Apodemus zhangwagouensis)的首现为标志。麻则沟期与欧洲陆生哺乳动物分期的Villa-nyian早期或Villafranchian早期相当,包含1个哺乳动物群单位,即NMU13,可与欧洲的MN16对比。在榆社盆地发现的麻则沟动物群就相当于NMU13。在中国的上新世哺乳动物群中,甘肃灵台的任家沟动物群和雷家河V带动物群、河北阳原泥河湾的稻地动物群、陕西渭南的游河动物群、山西静乐的贺丰动物群、四川德格的汪布顶动物群也相当于NMU13。河北泥河湾的花豹沟剖面是麻则沟阶的辅助层型剖面。

THE MAZEGOUAN STAGE OF THE CONTINENTAL PLIOCENE SERIES IN CHINA

The chronostratigraphic unit,Mazegouan Stage,is one of the two stages of the Chinese Pliocene Series,representing the continental Upper Pliocene.It was formally nominated by the Second China National Commission on Stratigraphy in 1999,corresponding to the Mazegouan Age.The name "Mazegou" is derived from the lithostratigraphic unit Mazegou Formation,and its typical section is located at Zhaozhuang-Damalan in Yuncu Town,Yushe County,Shanxi Province.The Mazegouan Stage is correlated to the marine Piacenzian Stage in the International Stratigraphical Chart,and they share the same definition of the lower boundary at the base of the paleomagnetic Chron C2An.3n,i.e.,the base of the Gauss epoch,with an age of 3.6 Ma.At the Zhaozhuang section in the Yushe Basin,this boundary is situated in the middle part of the purple clays of the Mazegouan Formation at Bed 6 of this section,marked by the first appearance of the rodent Apodemus zhangwagouensis.The Mazegouan Age is correlated to the early Villanyian age or the early Villafranchian age of the European land mammal ages,and it includes a Neogene mammal faunal unit,i.e.,NMU 13,corresponding to the European MN 16.The Mazegouan fauna from the Yushe Basin belongs to NMU 13.Among the Pliocene mammalian faunas in China,the Renjiagou fauna and Leijiahe fauna V from the Lingtai,Gansu,the Daodi fauna from Yangyuan,Hebei,the Youhe fauna from Weinan,Shaanxi,the Hefeng fauna from Jingle,Shanxi,and the Wangbuding fauna from Dege,Sichuan also belong to NMU 13.The Huabaogou section of the Nihewan Basin in Hebei is a supplementary candidate stratotype of the Mazegouan Stage.