秦岭北麓黄土沉积环境

秦岭北麓黄土最早形成于2.45Ma.区内各地质时代的黄土层中几乎都发现了大量哺乳动物化石和人类化石.黄土颜色深,颗粒细,粘化重;古土壤色鲜艳,层数多,底部钙质结核常联结成钙板;黄土中的原生碳酸钙几乎全部被淋溶,光性方位粘土较显著.这些说明本区黄土物质沉积后经受了比较强烈的淋滤作用和成土作用,反映出第四纪期间秦岭北麓黄土沉积环境要比黄土高原西北部温暖而湿润。

Environment of Loess Deposits in the Northern Piedmont of Qinling

The earlest loess in the northern piedmont of Qinling was formed at 2450 000 years ago.In this region,vast typical mammalian and human fossils were found in the loess stra- ta of various geological times.The loess appears reddish in colour,fairly fine-grained, and hight viscosity.The paleosols intercalated in loess deposits are very clear.The original calcium carbonate has been almostly leached.The optical clay illuviates in the pores or on the surface of grains.From the above-mentioned it may be secn that the loess in the north- ern piedmont of Qinling has experienced powerly leaching and pedogenesis,which reflects that the environment of loess deposits in this region is more warm-humid than that in northwestern parts of the loess Plateau during Quaternary Period.