赣东北构造带中的“放射虫硅质岩”不是“茅口组硅质岩”

赣东北构造带中的“放射虫硅质岩”主要分布于樟树墩—茅桥一带的赣东北蛇绿杂岩带之张村群中,与周边岩石地层呈断层接触关系,矿物成分和化学成分一致显示为泥质硅质岩,岩石遭受低级绿片岩相区域变质作用的改造,与泥质千枚岩、变质火山岩、蛇绿岩密切共生,含有“可疑的”晚古生代放射虫化石;茅口(孤峰)组硅质岩遍布于赣东北—皖南广大地区,整合于乐平组煤系地层之下、小江边组灰岩之上,具稳定的层位压盖关系,矿物成分和化学成分反映为纯硅质岩,岩石无变质重结晶现象,与碳质泥岩、灰岩互层,含大量的、珊瑚及腕足类化石,地层时代为二叠纪。因此,两者应分属不同的地层单位。

The "Radiolarian Cherts" in the Structural-Ophiolitic Melange Belt, Northeastern Jiangxi,Is Not the "Siliceous Rock" of Maokou Formation

The "radiolarian cherts"within the Northeastern Jiangxi tectonic belt are mainly distributed in(Zhangshudun)-Maoqiao area,belonging to structural-ophiolitic melange belt in Zhangcun Group,flanked by fault to the around lithostratigraphy.They are argillaceous siliceous rocks revealed by their mineral and chemical components.These rocks,associated with argillaceous phyllite,metavolcanite and ophiolite,contain "doubtful" Late Paleozoic radiolarian and are reconstructed by low greenschist-facies metamorphism.While the(siliceous) rock of Maokou(and/or Gufeng) Formation are widely developed in the Northeastern Jiangxi and South Anhui,they accord with the law of superposition(Smith Stratigraphy) and conformbly located under the coal measure strata of Leping Formation and on the limestone of Xiaojiangbian Formation.These rocks are "pure" siliceous rocks,belonging to the Permian Period.They contain aboundant fossils like the Brachiopod,Fusulinidea faunas and corals,without metamorphism and re-crystallization,associated with carbon-mudstone and limestone.Thus,the "radiolarian cherts" and the siliceous rock of Maokou Formation are diferent lithostratigraphic units.