巖漿母質對蝕變粘土礦物的約束:以貴州新民剖面P-T界線附近火山灰層為例
發(fā)布時間：2019-03-09 11:10
【摘要】：目前對于粘土層中伊蒙混層礦物的堆垛結構、單元層含量與巖漿母質及環(huán)境條件關系的了解等,仍然十分匱乏.一定沉積環(huán)境下火山灰層中粘土礦物組合、以及伊蒙混層堆垛方式精細結構特征,可能記錄了沉積(包括成巖作用)環(huán)境對火山物質蝕變產物的影響.采用X射線衍射(XRD)、掃描電子顯微鏡(SEM)、元素地球化學分析、氧同位素分析方法等方法,對貴州新民深海相二疊系-三疊系(P-T)界線附近蝕變火山灰層的地球化學特征、粘土礦物精細結構特征等進行了深入研究.結果表明,4個火山灰粘土層均含有2種具有R3結構、不同混層比的伊蒙混層礦物相,且均出現粘土礦物集合體取代原先的火山碎屑顆�；蛟陬w粒表面生長的現象,粘土礦物形成于沉積-成巖階段因而其泥質結構被保留;樣品XM-5-1和XM-5-2的Fe~(3+)原子數分別為0.16和0.17個且具有明顯Eu負異常和較低的K2O含量,而XM-5-3和XM-5-4的Fe3+原子數均為0.14個,說明相對于前2個粘土層,后2個的巖漿母質更加偏向酸性而表現為成巖蝕變程度更強.粘土礦物的氧同位素組成為17.3‰~18.1‰,與常溫下蒙脫石與海水的平衡數值相近,表明粘土礦物化學組成與海底成巖蝕變環(huán)境有關,而不同火山灰層的粘土礦物學特征則主要取決于巖漿巖母質以及成巖蝕變強度.
[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，
本文編號：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，
本文編號：2437390
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