江西玉山Etagraptus approximatus笔石带疑源类化石的发现及其意义

Discovery of Early Ordovican Acritarchs from the Ningguo Formation in Yushan Area, Jiangxi Province, and Its Geological Significance

首次报道发现于江西玉山 Ｅｔａｇｒａｐｔｕｓａｐｐｒｏｘｉｍａｔｕｓ笔石带的疑源类化石，计 １２属 ２３种，其中包括 ３个未定种．含量最高的 ３属是 Ｓｔｅｌｌｉｆｅｒｄｉｕｍ、Ｐｏｌｙｇｏｎｉｕｍ、Ｍｉｃｒｈｙｔｒｉｄｉｕｍ，占总含量的７７．４％，此外，Ｍｕｌｔｉｐｌｉ－ｃｉｓｐｈａｅｒｉｄｉｕｍ、Ｃａｌｄａｒｉｏｌａ、Ｂａｌｔｉｓｐｈａｒｉｄｕｍ、Ｐｔｅｉｏｓｐａｅｒｉｄｉｕｍ也较常见，一定程度上反映了阿仑尼格期早期疑源类组合面貌.

A well-preserved acritarchs assemblage was discovered in the Etagraptus approximatus zone of the Ningguo Formation in Yushan County, Jiangxi Province, and 23 species belonging to 12 genera were recognized for the first time. Three representative genera, Stelliferidium, Polygonium, Micrhystridium, Amounting to 77.4%, with the frequently occurrence of Multiplicisphaeridium, Caldariola, Baltispharidium, Pteinosphaeridium and Tetraniveum arenigum, seem to indicate the studied assemblage belongs to the Arenig age, which is basically in ac- cordance with the age indicated by graptolites.