三峡库区秭归盆地岩性构造对坡地紫色土某些特性影响

Influence of Rock Feather and Structure on some Properties of Purple Soil of Slope Land in Zigui Basin

秭归盆地是侏罗纪紫红色砂页岩组成的红色盆地 ,为一开阔的向斜构造 ,断裂构造为北北东向。通过大量野外调查和室内对各时代地层岩土性质分析与研究 ,结果表明 :侏罗纪地层具有粗—细—粗的沉积旋迥 ,其发育的土壤颗粒亦呈现粗—细—粗的变化趋势 ;紫色岩含钾较高、低磷、缺氮 ,由其发育的土壤也具有这一性质 ;盆地内部滑坡与岩性和地质构造密切相关 ,松散堆积体滑坡比重较大 ;与断层有关的滑坡 ,呈北北东向展布 ;与向斜有关的滑坡 ,东坡的滑坡发生向斜的西翼 ,西坡的滑坡发生向斜的东翼 。

Zigui Basin is covered by purplish red sandy shale of Jurassic Period. It is also called red basin with an open syncline structure and NNE direction of fault. The vast field investigation and analysis of each era's stratum rock and soil properties were conducted. The result showed as follows: Particle size distribution of purple soil (Inceptisoils) inherited from composition of rock, which are coarse—fine—coarse. Purple rock is rich in potassium, poor in phosphorus and deficient in nitrogen, and the soil derived from purple rock also has the same trend. Landslide is closely related to rock properties and geologic structure, which controlled by the direction of fault and the syncline. Landslide is spread out in NNE, and always occurred at sites where the slope has the same direction as the dip of rock, which takes place in the eastern slope if the hill located at western side of syncline and in western slope if the hill at eastern side of syncline.\;