摘要
我国是一个黄土分布极为辽阔的国家。我国北部广大地区的黄土,吸引着许多科学工作者的注意。自上世纪下半叶始,近百年来,国内外的许多地质和地理工作人员,围绕着我们北部的黄土问题,进行了大量的研究,并对我国黄土的成因提出了各种解释,但迄今为止,这一问题却仍需进一步探讨。 近年来,笔者有机会接触到华北和东北某些地区的黄土问题,汇集了一些实际观察资料。本文从这些资料出发,对黄土的分布、地貌学、岩石学、地层学,特别是对黄土的成因问题进行讨论。
Geomorphologic,petrologic and stratigraphic field surveying in North and North-East. China show that loess has a very complex origination, Genetically loess may be classified into glaciofluvial, diluvial, alluvial, drifting residual and aeolian loess. And the glacio-fluvial loess has the most extensive distribution.The glacio-fluvial loess is characterized by it s distribution either in mountains, at piedmonts or on plains. From their topographic and petrologic character, their intercalated crust of weathering and fossil soil ,and the contact relationships of the composing layers, the glacio-fluvial loess may be classified in an upward succession as yellow,brown,red and purple earth. The later three are deg enerated ylllow earethThe other kinds of loess have also the characteristics as revealed in corresponding diluvial, alluvial,drifing residual and aeolian sediments, and can beclassified into yellow, brown, red and purple earth, too.The places where loess occurred in North and North-East China are all districts that had been prevailed by pleistocene glaciation.The sediments composing loess were derived through processes of weathering, abrasion, and erosion related to glaciation. But loess was not the products purly of diflerent transporting agencies but was products of loessification-aspecial physic-chemical alteration of the deposited material in semiarid region. Loessification might be carried out either through courses of production, transportation and sedimentation or after sedimentation of the detrital material.Loess was produced in glacial epoch, and the intercalated crust of weathering and fossil soilwere peoduced in interglacial epochs. The degenerated brown, red and purple earth were also products in interglacial epochs.The ages of the purple, red,brown and yellow earth were subjected to Po-yang, Tagu, Lushan and Tali glacial epoch respectively. And the superposed crust of weathering and fossil soil were subjected to the interglacial epochs respectively.
出处
《吉林大学学报（地球科学版）》
EI
CAS
1982年第2期1-10,共10页
Journal of Jilin University：Earth Science Edition
