关中东部TSG全新世剖面粒度分形特征及古气候意义

利用分形理论计算可知,关中东部TSG全新世剖面的土壤粒度分布具有分形特征,剖面分形维数值在2.5443~2.7123之间,其中古土壤S0的分形维数均值最大。粒度分形维数的高值指示暖湿的气候,低值指示干冷的气候。分形特征所揭示的关中东部地区的环境演变过程为:全新世早期,粒度分形维数值相对偏低,风尘堆积占优势,为干旱寒冷的环境,成壤作用较弱;全新世中期,粒度分形维数值偏大,其平均值为2.6713,指示温暖湿润的气候,成壤作用较强;全新世晚期以来,粒度分形维数值降低,土壤颗粒粒径增大,气候变得相对干旱,成壤作用也减弱,但是全新世晚期的分形维数值高于末次冰期。

Grain-size Fractal Characteristics of TSG Holocene Profile and Its Significance in Eastern Guanzhong

On the basis of fractal theory and grain-size data,this paper analyzed the fractal dimensions of particle in TSG Holocene profile.The results showed that there was a fractal feature of TSG Holocene profile in Eastern Guanzhong Basin.The whole profile fractal dimension value was between 2.5443 and 2.7123,with the highest average value in the paleosol(S0).The higher values of grain-size fractal dimension reflected warm and humid climate,the lower values reflected arid and cold.The fractal characteristics indicated the change of environment during Holocene in Eastern Guanzhong.It showed that granularity fractal dimensions were relative lower in the Early Holocene,with an arid and cold environment.In the Mid-Holocene fractal dimensions were much higher,with an average of 2.6713,so climate was warm and humid,and pedogenesis was stronger.In the stage of Late Holocene,fractal dimension values were slight dropped,and soil particle size was increased,with a low degree of self-organization,so climate became relatively arid,and a weak pedogenesis,but the fractal dimension was much higher than that in the last glacier.