江西永丰—崇仁盆地上白垩统砾石岩性和磨圆度列联表分析及其对物源的指示  

Contingency Table Analysis of Pebble Lithology and Roundness and Provenance Implications for the Upper Cretaceous of Yongfeng-Chongren Basin,Jiangxi

作　　者：唐超[1,2] 陈留勤[1,2] 郭福生[1,2] 王凤之 习松[2] 张露[2] 余峰[2] 

机构地区：[1]东华理工大学放射性地质与勘探技术国防重点学科实验室,江西南昌330013 [2]东华理工大学地球科学学院,江西南昌330013

出　　处：《现代地质》2014年第5期971-979,共9页Geoscience

基　　金：江西省教育厅科学技术研究项目(GJJ13438);东华理工大学放射性地质与勘探技术国防重点学科实验室开放基金项目(RGET1304);博士后科研启动基金项目(DHBHK1102);江西省博士后科研择优资助项目;中国地质调查局工作项目(1212011120836;1212011220248);东华理工大学大学生创新创业训练计划资助项目(20131005039);东华理工大学研究生创新项目(DHYC2014011)

摘　　要：江西永丰—崇仁盆地上白垩统(包括河口组、塘边组和莲荷组)砾岩地层十分发育,是构成丹霞地貌的物质基础。利用砾石的岩性和磨圆度进行列联表分析,可以为沉积盆地物源判断提供依据。利用列联表分析方法对永丰—崇仁盆地上白垩统砾岩进行研究。砾石成分主要包括石英、酸性岩浆岩、变质岩和砂岩以及少量的泥质岩和灰岩。为了统计方便,将砾石磨圆度分组为棱角状和次棱角状(A+B)、次圆状(C)、圆状和极圆状(D+E)。若棱角状和次棱角状砾石观察值小于期望值,而圆状和极圆状砾石观察值大于期望值则说明砾石经历了较长的搬运距离;反之,则说明砾石搬运距离较短。通过联列表分析,结果显示:河口组砾岩具有多物源的特点,主要来自盆地边缘、鸡笼山、相山和玉华山以及盆地西北的长垅地区;塘边组砾岩主要来自盆地北部的尖顶峰山、玉华山一带以及盆地东南的丰山、新大山地区;莲荷组砾岩主要来自于金华山和嶂岭等盆地边缘地区,盆地北侧的鸡龙岗、松树岭以及东北部的灵谷岭地区。物源分析结果为该地区晚白垩世红盆的形成和演化规律的探讨提供了重要依据。rocks,sandstones and metamorphic rocks,and a small amount of mudstones and limestones.For the conven-ience of counting,the roundness of the gravels are subdivided into three levels including A ＋B （angular and sub-angular）,C （sub-rounded）and D ＋E （rounded and well-rounded）.Normally,when the value of A ＋B is fewer than expected and the value of D ＋E is more than expected,pebbles were considered to be transported for long distance.On the contrary,it shows short distance transport.The following conclusions are drawn：the peb-bles of Hekou Formation came from more than one source,and they would came from the edge of the basin and Jilongshan,Xiangshan and Yuhuashan mountains and the northwestern Changlong area;the pebbles of Tangbian Formation were mainly derived from Jiandingfengshan and Yuhuashan mountains,and some parts from southeast Fengshan and Xindashan mountains;the Lianhe Formation’s pebbles were mainly derived from Jinhuashan and Zhangling mountains,and some might come from Jilonggang,Songshuling and Lingguling mountains in the northeastern part of the basin.The result of the provenance analysis could provide important basis for the forma-tion and evolution of the Cretaceous red basins in south China.

关 键 词：物源 砾石统计 磨圆度 列联表 上白垩统 

分 类 号：P512.2[天文地球—地质学] P534.53