Element Geochemical Micro-areas Analysis of Sandstone Reticulated and Its Indicative Significance

Key words: 
• reticular red clay /
• bedrock layer /
• variegated?horizon /
• micro-area analysis /
• reticulated mechanism

Abstract: [Objective]The reticulated laterite in southern China is a good geological carrier for Quaternary environmental changes, but there is currently relatively little microscopic research on bedrock reticulation,Not conducive to a comprehensive understanding of reticulation [Methods]Through micro-area analysis techniques, geostatistical and factor analysis, and other methods to conducted elemental geochemical analysis on the white vein micro-area of the bedrock and variegated?horizon in the Langxi profile. [Results]1) Element content in the white vein micro-area of sandstone: The content of iron group elements such as Fe2O3 (1.14-13.29%) and Mn (87×10-6 -3230×10-6) showed a trend of increasing from the center of the white veins to the periphery. However, the spatial distribution of other major elements and stable elements such as Ti (1294×10-6~ 2454×10-6) and Zr (171 ×10-6~ 197×10-6) showed the opposite trend. The spatial distribution of element content in the bedrock layer is basically consistent with that of the variegated?horizon. 2) Ti/Zr (bedrock layer: 7.23-12.89; reticulated layer: 12.82-21.84) and Ti/Al2O3 (bedrock layer: 0.013-0.018; reticulated layer: 0.044-0.062) were divided into two groups through cluster analysis and scatter plot.They have different provenance 3) The weathering of the bedrock layer (CIA: 86.37%~87.49%; SA: 5.23~5.76) is slightly higher than that of the variegated?horizon (CIA: 85.10%~86.07%; SA: 6.91~8.16;). The leaching intensity of elements such as Al2O3 (17.3%)、 Fe2O3 (73.91%) and MnO (76.68%)in the bedrock white vein micro-area and Al2O3 (15.78%) 、Fe2O3 (70.39%) and MnO (74.84%) in the variegated?horizon white vein micro-area showed a trend of decreasing from the center of the white veins to the periphery. 4) The common feature of factors in the white vein micro-area of the bedrock layer and the reticulated layer is that they are mainly factor 1, which reflects the leaching migration of iron and iron group elements in the white vein, as well as the relative enrichment process of constant elements such asAl2O3、SiO2and K2O and stable elements such as Ti and Zr. [Conclusion] The composition of the white reticulated interior of the bedrock layer and the variegated?horizon are non-spatially homogeneous, and the process of reticulation is a spatial process that extends from the center to the periphery.During reticulation, the leaching of iron and iron group elements dominates, but other elements also have a certain degree of migration, mainly characterized by strong leaching at the center of the reticulation and relatively weak leaching at the periphery. The reticulation process of the two is quite similar.