中国古土壤与第四纪环境

PALEOSOLS AND QUATERNARY ENVIRONMENT IN CHINA

中国古土壤现分为埋藏土和残余土两大类。青藏高原高寒区的埋藏土多保存在冰碛物中,具有结构紧密,颜色较为鲜艳,风化程度较深,其微形态呈不同形式铁染基质的特征;西北干旱、半干旱区由于黄土沉积深厚,在早更新统到晚更新统的黄土地层中常见有多层埋藏土,另外该地区尚有残余土的出现;东部季风区的北部埋藏土较发育,而南部琼雷地区可见到不同时代红色风化壳发育的古土壤。这些古土壤在第四纪时期大尺度变化上是可以相互比较的。古土壤是一个较稳定的地理环境因素。其特征和空间分布状况可阐明第四纪环境的变迁,用来推断古气候的演变,新构造运动的强度,地形的改变和植被的演替。为了推动古土壤学研究,适应大系统环境科学研究的需要,必须采用综合研究方法,突出青藏高原、黄土高原和东部季风区古土壤的研究,加强与第四纪有关学科的相互渗透。

Paleosols of China are divided into buried and relict soils. The buried soils in high-cold region of Tibet Plateau, which are characterized by compact structure, gaily colour, intensive weathering and iron-stained matrix as micromorphological feature, are mostly reserved in tills. In the arid and semi-arid regions of northwest China several layers of buried soils are found within aeolian loess sediments from early to late Pleistocene series due to deep deposition of the loess. In addition, relict soils also occur in the region. Buried soils are dominant in north part of east monsoon region, while in the south part (Qionglei region) can be found paleosols on red weathering crust. The greater changes among the paleosols in the three regions during Quaternary can be compared. Because paleosols is a more stable factor for geographical setting, their characteristics and special distribution can explain the environmental change in Quaternary, such as inferring paleoclimatic and vegetative evalution, intensity of neotectonic movement and relief change. In order to promote paleological study and fit the development of systematic environmental science, it is necessary in future to adopt advanced and comprehensive means; to emphasize on the study of paleosols of the Tibet Plateau, Aeolian Loess Plateau and East Monsoon Region; and to pay attention to comprehensive study with paleopedology and the seiences concerning Quatcrnary period.