摘要
通过粘粒矿物的定量分析,研究了我国东部花岗岩发育的红壤和黄壤的粘粒矿物组成。赤红壤、红壤和黄红壤的粘粒(<2μm)中高岭石含量分别为54%、42%和35%,这与该土壤的年均气温之间有明显的正相关(r=0.998,n=3),然而这三个土壤粘粒的风化淋溶系数与年均气温呈良好的负相关(r=1.000,n=3)。黄壤与红壤的粘粒矿物组成有明显的差异,黄壤中含有较多的三水铝石和2:1型粘土矿物,而高岭石较少;红壤中三水铝石很少,在安徽的黄红壤中虽有不少非晶质氧化铝,但未见有三水铝石存在。
In this paper the clay mineral composition of red earths and yellow earths derived from granites in Guangdong,Jiangxi and Anhui Provinces were studied by using a quantitative analysis approach.It will be helpful for explaining mineralogical properties of red earths and yellow earths in different zones of the eastern China are also given in it.(1)The clay mineral composition of red earthsLateritic red earths,red earths and yellow-red earths vary significantly in the clay mineral composition of clay fraction(<2μm).Lateritie red earth taken from Guangdong contained about 54%kaolinites and a few hydromicas and 1.4nm intergradient minerals,in addition to 3%gibbsites and 17%amorphous materials.Red earth taken from Jiangxi contained about 42%kaolinites,13—17%hydromicas and a small amount of 1.4nm intergradient minerals and chlorites,still with 2%gibbsite.Yellow-red earth taken from Anhui contained about 35%kaolinites,35%amorphous materials and some smectites,but crystallized gibbsites were not found.Results indicated that there was a significantly positive correlation(r=0.998,n=3)between the content of kaolinites in the clay fraction(<2μm)of lateritic red earths,red earths and yellow-red earths and the mean annual temperature.However,there existed a good negatire correlation(r=—1.000,n=3)between the leaching coefficient of the clay fraction of the three soils and the mean annual temperature.(2)The difference of clay minerals composition between red earths and yellow earths.The composition of clay mineral of the yellow earths differed from that of red earth by 2:1 type clay minerals and gibbsites but less kaolinite.The content of gibbsites in the clay frac tion of three yellow earths taken from Guangdong,Jiangxi and Anhui were 20—24%,9—17%and 6—7%respectively.However,the red earths contained a considerable amount of amorphous AlO.In addition,yellow earths and red earths taken from Jiangxi and Anhui still contained a small amount of chlorites,but chlorites were not found in the yellow earth and lateritic red earth taken from Guangdong.(3)Discussion about the calculation of silica-alumina ratio of the clay fraction in the yellow earths.When we calculate the tested results by following the old routine,the silica-alumina ratio of the yellow earths,which contained more gibbsites,is usually less than that of red earths,sometime even less than that latosol.For the soils in mountainous region,however,only the silica-alumina ratio that the sum of AlOof gibbsite in the Clay fraction(<2μm)is deducted can better reflect the weathering intensity of the soil.
作者
杨德湧
蒋梅茵
Yang Deyong;Jiang Meiyin(Institute of Soil Science,Academia Sinica,Nanjing,210008)
出处
《土壤学报》
CAS
CSCD
北大核心
1991年第3期276-283,共8页
Acta Pedologica Sinica
基金
国家自然科学基金资助项目850828号研究成果之一。
