辽宁东部晚古生代本溪组煤系地层鳞木的发现及其意义

Lepidodendrales fossils discovered from the coal bed of the Upper Paleozoic Benxi Formation in eastern Liaoning

最近在辽宁本溪牛毛岭剖面上的上石炭统(宾夕法尼亚亚系)本溪组新洞沟段(本溪组中段)的煤系地层中发现了大量鳞木化石。现有资料证明,在牛毛岭剖面本溪组复洲湾段(本溪组上段)灰岩中发现了属于晚石炭世莫斯科期的牙形石,而在牛毛岭剖面邻近地区本溪组湖田段(本溪组下段)中则发现了属于早石炭世(密西西比亚纪)的亚鳞木、大脉羊齿和贝叶。由此认为,新发现的牛毛岭剖面本溪组新洞沟段(本溪组中段)的鳞木化石,应晚于早石炭世,早于晚石炭世莫斯科期,即应属巴什基尔期。鳞木是辽宁东部第一次成煤期滨海沼泽相成煤植物群中的代表性植物。

A number of Lepidodendrales fossils were recently discovered from the coal bed of the Xindonggou Member in the mid-dle part of the Upper Carboniferous （Pennsylvanian） Benxi Formation, along the Niumaoling section of Benxi, Liaoning Province. Previous researchers have concluded that the age of the conodonts contained in the limestone of the Fuzhouwan Member in the up-per part of Benxi Formation corresponds to the Moscovian （the second age of the Late Carboniferous）, whereas Suplepidodendron, Neuropteris gigantea and Conchophyllum produced in the Hutian Member of the lower part of the Benxi Formation represent the Early Carboniferous taxa. Because the Bashkirian （the first age of the Late Carboniferous） is between the Moscovian and the Early Carboniferous, it is reasonable to infer that the Lepidodendrales fossils found in the Xindonggou Member of the middle part of Benxi Formation represent the Bashkirian taxa, whereas the Lepidodendrales plants were the representative element of the coastal swamp fa-cies in the first coal-forming period in eastern Liaoning.