松辽盆地东缘嫩江组一二段黏土矿物和主量元素地球化学特征及其古气候意义  

Clay Mineral and Major Element Geochemical Features and Their Paleoclimate Significance in Nenjiang Formation 1st and 2nd Members,Eastern Margin of Songliao Basin

作　　者：陈积权 高远[1,2] 秦健铭 覃祚焕 席党鹏[1,2] 钟瀚霆 史忠叶 

机构地区：[1]中国地质大学(北京)地球科学与资源学院,北京100083 [2]中国地质大学(北京)生物地质与环境地质国家重点实验室,北京100083 [3]成都理工大学沉积地质研究院,成都610059

出　　处：《中国煤炭地质》2017年第8期17-24,共8页Coal Geology of China

基　　金：中央高校基本科研业务费优秀教师基金项目(2652015387);中国地质大学(北京)大学生创新创业训练计划项目(2017A11)

摘　　要：松辽盆地嫩江组一二段是一套暗色泥岩沉积,也是重要的烃源岩层位,对其开展古气候-古环境研究有益于理解晚白垩世陆地古气候特征和陆相有机质形成与保存过程。通过对松辽盆地东缘岳王城剖面嫩江组一二段开展矿物学和主量元素地球化学分析,探讨其古气候意义。结果表明,全岩矿物主要含有石英、斜长石、钾长石等,黏土矿物主要为蒙脱石(平均84%),其次为伊利石(平均15%),几乎不含高岭石和绿泥石。黏土矿物呈现片层状且边缘参差不齐的显微形貌,蒙脱石结晶度较差,表明主要由陆源物质风化形成。根据黏土矿物主量元素计算的化学风化指数为71~73,其元素组成相比上地壳和花岗闪长岩的平均组成富铝,指示中等强度化学风化作用。结合已有古气候替代性指标和黏土矿物及其化学成分的新数据,研究认为松辽盆地东缘嫩江组一二段沉积时期物源区主要为温带-亚热带半湿润气候。The Songliao Basin eastern margin Nenjiang Formation 1st and 2nd members as a whole is a set of dark mudstone deposits, also a major source rock horizon. To study its paleoChmate and paleoenvironment is conducive to understand later Cretaceous land pa- leoclimate features and continental organic matter formation and preservation process. The paper has carried out mineralogical and ma- jor element geochemical analyses for Nenjiang Formation 1st and 2nd members strata of the Yuewangcheng section, Songliao Basin east- ern margin, and then discussed their paleoclimate significance. The results have shown that the bulk rock minerals have mainly quartz, plagioclase, K -feldspar etc. , clay minerals have mainly montmorillonite （average 84% ）, illite the second （average 15% ）, almost no kaolinite and chlorite. Clay minerals present lamellar micro - morphology and uneven margin ; montmorillonite has poorer crystallini- ty, indicates its weathered terrigenous deposit origin. Based on clay mineral major element computed chemical weathering index is 71 - 73. In comparison with upper crust and granodiorite average composition, its elemental composition is allitic, indicated moderate chem- ical weathering. Combined with available new data of paleoclimate proxy indices and clay mineral chemical composition, the paper con- sidered that during the deposition of Nenjiang Formation 1 st and 2nd members in Songliao Basin, the climate in the provenance had been mainly temperate -subtropical semihumid climate.

关 键 词：松辽盆地 嫩江组 黏土矿物 主量元素 化学风化 古气候 

分 类 号：P534.53[天文地球—古生物学与地层学] P512.2[天文地球—地质学]