Soils dominated by 2:1 clays(montmorillonite, vermiculite, illite), more frequently found in temperate zones, but also present in tropical and subtropical areas;

• 我们常在温带地区发现的2:1型粘土矿物（蒙脱石、蛭石、伊利石）为主的土壤，也出现在热带和亚热带地区。