川西南古红土特性的初步研究

川西南海拔1700—3100米的部分地区,分布有成片的深厚红色土壤,其中一部分具有明显的富铝化特征:粘粒硅铝率2.0以下,硅铝铁率1.5以下;粘粒矿物以高岭和三水铝石为主。它们是第四纪全新世以前低海拔地区湿热气候的产物,以称古红土;由于新构造运动才使其升至现今的高度,古红土上的现代土壤为多元发生土壤,显著区别于母岩上直接风化成土的现代土壤,因而在土壤分类上应予合理区分。

PRELIMINARY STUDY PROPERTIES OF PALEO—RED SOILS IN SOUTH WEST OF SICHUAN

Thick red colour soils are distributed in the mountain areas between 1700 and 3100 metres above sea level in the Southwest of Sichuan. Some of them have strong allitization. Their ratios of sillica-alumina are under 2.0 and ratios of sesquioxides are less than 1.5. The main minerals in the clay are kaolinite and gibbsite. The soils called paleo-red soils, were fonmed in the lower altitude and warm and wet climate areas before the Holocene in the Quaternary period. They were elevated to the present height by means of Neoteclonetics. The soils developed from paleo-red soil have polygenetic properties and are quite different from the recent soils devectly from rock saprolites. So they should be classified rationaly.