目前对于粘土层中伊蒙混层矿物的堆垛结构、单元层含量与岩浆母质及环境条件关系的了解等,仍然十分匮乏.一定沉积环境下火山灰层中粘土矿物组合、以及伊蒙混层堆垛方式精细结构特征,可能记录了沉积(包括成岩作用)环境对火山物质蚀变产物的影响.采用X射线衍射(XRD)、扫描电子显微镜(SEM)、元素地球化学分析、氧同位素分析方法等方法,对贵州新民深海相二叠系-三叠系(P-T)界线附近蚀变火山灰层的地球化学特征、粘土矿物精细结构特征等进行了深入研究.结果表明,4个火山灰粘土层均含有2种具有R3结构、不同混层比的伊蒙混层矿物相,且均出现粘土矿物集合体取代原先的火山碎屑颗粒或在颗粒表面生长的现象,粘土矿物形成于沉积-成岩阶段因而其泥质结构被保留;样品XM-5-1和XM-5-2的Fe~(3+)原子数分别为0.16和0.17个且具有明显Eu负异常和较低的K2O含量,而XM-5-3和XM-5-4的Fe3+原子数均为0.14个,说明相对于前2个粘土层,后2个的岩浆母质更加偏向酸性而表现为成岩蚀变程度更强.粘土矿物的氧同位素组成为17.3‰~18.1‰,与常温下蒙脱石与海水的平衡数值相近,表明粘土矿物化学组成与海底成岩蚀变环境有关,而不同火山灰层的粘土矿物学特征则主要取决于岩浆岩母质以及成岩蚀变强度. At present, there is still a lack of understanding of the stacking structure of the Yimeng mixed minerals in the clay layer, the understanding of the relationship between the elemental layer content and the parent material of magma and the environmental conditions, etc. Clay mineral assemblages in the volcanic ash layer under a certain sedimentary environment, The fine structural features may record the impact of sedimentary (including diagenesis) environments on alteration products of volcanic material.Using X-ray diffraction (XRD), scanning electron microscopy (SEM), elemental geochemical analysis and oxygen isotope analysis methods, The geochemical characteristics of alterated volcanic ash layer and the fine structural features of clay minerals in the deep sea facies Permian-Triassic (PT) line in Xinmin, Guizhou Province are studied in depth.The results show that all four volcanic clay layers contain two kinds of R3 structure and mixed layers of different layers of Yimeng mixed mineral, and all appear clay mineral assemblages instead of the original volcanic debris or particle growth in the surface of the phenomenon, the formation of clay minerals in the sedimentary - diagenetic stage and its muddy structure is . The number of Fe 3+ atoms in samples XM-5-1 and XM-5-2 were 0.16 and 0.17, respectively, with significant Eu negative anomalies and low K 2 O contents. However, XM- 5-3 and XM-5-4 have 0.14 Fe3 + atoms, indicating that the latter two magmatic parentals are more acidic and show more diagenetic alteration than the first two clay layers. The isotopic composition is 17.3 ‰ ~ 18.1 ‰, which is similar to the equilibrium value of smectite and seawater at room temperature, indicating that the chemical composition of clay minerals is related to the seafloor diagenetic alteration environment. However, the clay mineralogy of different volcanic ash layers is mainly determined by the magmatic rocks Parent material and diagenetic alteration strength.