Study On The Petrological Characteristics Of N₂ Red Clay In Northern Shanxi

The theory and method of sedimentology,petrology and engineering geology and other disciplines was applied in this paper as a guide.According to observation and study of 4 section,such as Gaojiagou section and six drilling cores,such as SK2,this paper has does a research about The Petrological characteristics,the sedimentary environment,the characteristics of petrology and the influence of the engineering geological characteristics.The results of previous studies on the typical red clay profile based on the combination of the sporopollen assemblage classification and correlation,the regional comparison of Pliocene Baode group in the study area and the Pliocene Jingle group,the two boundaries 5.2Ma B.P..The red clay dominated by quartz,feldspar and containing a small amount of time debris and heavy minerals,fillings are mainly clay minerals,cement with clay minerals,a secondary carbonate cement and iron manganese cutans;with the particle size of less than 0.005 mm of the wind into basic grain group;clay rock is mainly mudstone and mud types thin siltstone and argillaceous siltstone thick conglomerate in Baode group,clamps the coarse lithic quartz sandstone and limestone,summarizes the features of different types of rock.The study area of red clay experienced compaction,cementation,metasomatism and alteration diagenetic transformation in early diagenesis stage B.Based on the distinguish of sedimentary environment sign,two types of sedimentary environments,alluvial fan and forest steppe,were identified in the study area.The sedimentary environment of the study area is affected by tectonic activities,and it has experienced a series of sedimentary evolution from alluvial fan to warm and wet forest,and the establishment the type of Yingshan distribution,and the type of distribution of mountain and tectonic stability type three sedimentary model.The facters of high mineral content,good grain size gradation,and strong calcareous cementation play a constructive influence in laterit strength.The facters of developmented Micro crack,water absorption of clay minerals play a Negative effect,and increased the permeability.