岩浆母质对蚀变粘土矿物的约束:以贵州新民剖面P-T界线附近火山灰层为例
发布时间：2019-03-09 11:10
【摘要】：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.
[Abstract]:At present, the stacking structure and the relationship between the content of unit layer and magmatic parent material and environmental conditions in the clay layer are still very little, and the relationship between the content of the unit layer and the magmatic parent material and environmental conditions is still very scarce. The clay mineral assemblage in the volcanic ash layer and the fine structure characteristics of the stacking mode of the Aemon mixed layer in a certain sedimentary environment may record the influence of the sedimentary (including diagenesis) environment on the alteration products of the volcanic material. By means of X-ray diffraction (XRD), scanning electron microscope, (SEM), element geochemical analysis, oxygen isotope analysis, etc. The geochemical characteristics of altered volcanic ash layer and fine structure of clay minerals near the Permian-Triassic boundary of Xinmin deep-sea facies in Guizhou Province are studied in this paper. The results show that the four pozzolanic clay layers all contain two kinds of Aemon mixed layer mineral facies with R3 structure and different mixing layer ratio, and the clay mineral aggregates replace the original pyroclastic particles or grow on the surface of the particles, and the results show that the clay mineral aggregates can replace the original pyroclastic particles or grow on the surface of the particles. Clay minerals are formed in the sedimentary-diagenetic stage, so their argillaceous structure is preserved. The number of Fe~ (3) atoms in XM-5-1 and XM-5-2 were 0.16 and 0.17, respectively, with significant negative Eu anomaly and lower K2O content, while the number of Fe3 atoms in XM-5-3 and XM-5-4 were 0.14, respectively. The results show that compared with the first two clay layers, the latter two magmatic parent materials tend to be more acidic and show stronger alteration degree of diagenetic rocks. The oxygen isotopic composition of clay minerals ranges from 17.3 鈥，
本文编号：2437390
[Abstract]:At present, the stacking structure and the relationship between the content of unit layer and magmatic parent material and environmental conditions in the clay layer are still very little, and the relationship between the content of the unit layer and the magmatic parent material and environmental conditions is still very scarce. The clay mineral assemblage in the volcanic ash layer and the fine structure characteristics of the stacking mode of the Aemon mixed layer in a certain sedimentary environment may record the influence of the sedimentary (including diagenesis) environment on the alteration products of the volcanic material. By means of X-ray diffraction (XRD), scanning electron microscope, (SEM), element geochemical analysis, oxygen isotope analysis, etc. The geochemical characteristics of altered volcanic ash layer and fine structure of clay minerals near the Permian-Triassic boundary of Xinmin deep-sea facies in Guizhou Province are studied in this paper. The results show that the four pozzolanic clay layers all contain two kinds of Aemon mixed layer mineral facies with R3 structure and different mixing layer ratio, and the clay mineral aggregates replace the original pyroclastic particles or grow on the surface of the particles, and the results show that the clay mineral aggregates can replace the original pyroclastic particles or grow on the surface of the particles. Clay minerals are formed in the sedimentary-diagenetic stage, so their argillaceous structure is preserved. The number of Fe~ (3) atoms in XM-5-1 and XM-5-2 were 0.16 and 0.17, respectively, with significant negative Eu anomaly and lower K2O content, while the number of Fe3 atoms in XM-5-3 and XM-5-4 were 0.14, respectively. The results show that compared with the first two clay layers, the latter two magmatic parent materials tend to be more acidic and show stronger alteration degree of diagenetic rocks. The oxygen isotopic composition of clay minerals ranges from 17.3 鈥，
本文编号：2437390
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