广南安乐村石炭－二叠系界线层型剖面的磁性地层学研究

A MAGNETIC STRATIGRAPHY STUDY ON THE CANDIDATE STRATOTYPE SECTION OF C-P BOUNDARY AT ANLE, GUANGNAN

本文通过云南广南安乐村剖面的磁性地层学研究，获得了该剖面石炭－二叠系的极性序列。结果表明，在马平组上段底部存在一个具全球意义的短暂正极性亚带，其底界与 类Ｐｓｅｕｄｏｓｃｈｗａｇｅｒｉｎａ带的底界相吻合，笔者赞同以Ｐｓｅｕｄｏｓｃｈｗａｇｅｒｉｎａ的首次出现作为二叠系底界的观点。Ｐｓｅｕｄｏｓｃｈｗａｇｅｒｉｎａ的出现可能具有全球等时性（２８６Ｍａ），并与地磁场的极性转变关系密切。

The Carboniferous-Permian polarity sequence of the Anle Village section, Guangnan, Yunnan is established by the magnetic stratigraphy study of this section. The study result indicates that there is a short duration positive polarity subzone of global significance at the bottom of the upper menber of Maping Formation, whose bottom boundary is consistent with that of the Pseudoschwagerina zone. we agree with the viewpoint that the first occurrence of Pseudoschwagerina can be regarded as the bottom boundary of Permian. The occurrence of Pseudoschwagerina maybe of the global isochronic significance (286 Ma ) and closely connects with the polarity transformation of the geomagnetic field.