Climacograptus longxianensis在甘肃平凉的发现及地质意义  

The Discovery of Climacograptus longxianensis in Pingliang,Gansu Province and Its Geological Significance

作　　者：谢从瑞[1] 付力浦 朱小辉[1] 王洪亮[1] 周志强[1] 

机构地区：[1]国土资源部岩浆作用成矿与找矿重点实验室,中国地质调查局西安地质调查中心,陕西西安710054

出　　处：《西北地质》2017年第1期1-3,共3页Northwestern Geology

基　　金：中国地质调查局“祁连山地区区域地质调查片区总结与服务产品开发”项目(DD20160345-16)

摘　　要：鄂尔多斯地台西南缘上奥陶统的龙门洞组,自从建立以来就一直存在着争论。它和平凉组的主要区别在于前者的时代包括了后者而且延伸的更新。前者含有5个笔石带,既Glyptograptus teretiusculus带,Nemagraptus gracilis带,Climacograptus peltifer带,C.longxianensis带和C.spiniferus带,后者仅含前2个笔石带。既前者所跨的时代比后者长3个笔石带。近年来,通过笔者在该地区的进一步工作,在平凉组中发现了Climacograptus bicornis和C.longxianensis 2个新的笔石带,这样两者的时代近乎一致。再者二者位于同一地层小区,岩性岩相一致,属于同一构造环境下的产物,属于同物异名。因此建议停用龙门洞组,沿用平凉组一名。The Upper Ordovician Longmendong Formation on the southwestern margin of Ordos platform is disputed since its nomination. Its main difference from Pingliang Formation is the for-mation age. The former consists of five graptolite zones, which are Glyptogra ptus teretiusculus zone, Nemagraptus gracilis zone , Climacograptus peltifer zone, C. longxianensis zone and C. spiniferus zone, but the latter one only comprises the first two graptolite zones. Recently, through the study on this area, two more graptolite zones have been discovered in Pingliang For-mation ,including Climacograptus bicornis zone and C. longxianensis zone. As a result , the age range of Pingliang Formation is nearly same as the one of Longmendong Formation. In addition, they have the same lithological characters and are formed in the same tectonic environment, so they are synonym. According to the stratum nomination rule, the Longmendong Formation is suggested to be abandoned, while the Pingliang Formation is suggested to be used.

关 键 词：Climacograptus longxianensis 笔石 平凉组 龙门洞组 奥陶系 

分 类 号：P52[天文地球—古生物学与地层学]