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    对江西晚白垩世赣州群茅店组的重新厘定

    Revision of the Late Cretaceous Maodian Formation of the Ganzhou Group in Jiangxi Province

    • 摘要: 提要:根据1∶5万区调最新成果资料,对《江西省岩石地层》中的赣州群茅店组进行了重新厘定,在原茅店组正层型剖面上,识别出了5种不同性质的沉积界面,即沉积不整合界面、超覆不整合界面、平行不整合界面、相转变面、同相叠复面,从而将原茅店组划分为两个不同的组级岩石地层单位。按照岩石地层单位的命名原则,超覆不整合面之下的原茅店组中下部层位划归赣州群茅店组,其中发育的一套玄武岩-火山碎屑沉积岩组合单独划出,新建为陈坑火山岩段;超覆不整合面之上的原茅店组上部层位的粗碎屑沉积岩,则划归晚白垩世灌溪群宏冈组1。重新厘定的茅店组仅相当于原正层型茅店组的中、下部层位,且可细分为下段、陈坑火山岩段和上段。

       

      Abstract: Abstract: On the basis of the latest data of 1:50000 regional geological mapping, the authors revise the Maodian Formation of the Ganzhou Group in the Lithostratigraphic units of Jiangxi Province. Five types of sedimentary interfaces of different natures are identified in the orthostratotype of the original Maodian Formation; they are the sedimentary unconformity, overlapping unconformity, disconformity, facies change surface, and synthetic stacked surface, and thus the original Maodian Formation is divided into two different formation-rank lithostratigraphic units. According to the naming principle of lithostratigraphic units, the middle and lower horizons of the original Maodian Formation below the overlapping unconformity are assigned to the Maodian Formation of the Ganzhou Group, and the association of basalt-pyroclastic-sedimentary rocks developed in the horizons is separated from the horizons and the Chenkeng Volcanic Member is established separately. The coarse clastic sedimentary rocks in the upper part of the original Maodian Formation above the overlapping unconformity are assigned to the Honggang Formation of the Late Cretaceous Guanxi Group. The revised Maodian Formation only corresponds to the middle and lower horizons of the original orthostratotype Maodian Formation, and it is subdivided into three members, i. e. the Lower Member, Chenkeng Volcanic Member, and Upper Member.

       

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