李希霍芬与黄土的风成学说

第四纪古气候重建在最近半个世纪的时间里取得了前所未有的进展,这在很大程度上与对陆相黄土地层,特别是中国黄土-古土壤序列的研究,以及对深海沉积氧同位素的研究密不可分。现在我们已经可以在黄土-古土壤序列的基础上,建立起260万年来地球轨道尺度的古气候变化。一个不容否认的事实是,这些进展都是在黄土风成成因的基础上,结合土壤地层学、年代学、磁性地层学、古生物学等方面的进展逐渐发展起来的。只有解决了黄土的风成成因,才可能将堆积于各地的黄土,通过搬运粉尘的风力系统与区域、甚至全球的古气候变化联系起来。文章回忆了黄土的早期研究历史,回顾了黄土风成成因的奠基人李希霍芬教授在黄土成因方面的杰出贡献以及其后黄土成因的完善与发展。

RICHTHOFEN AND HIS THEORY OF THE EOLIAN ORIGIN OF LOESS

Loess is widespread in the arid and semiarid regions of world. During the last 150 years, many aspects of loess research including its distribution, origin, provenance, transport, deposition, and post-depositional alternations have been well-studied. Among them, eolian origin of loess, originally proposed by Richthofen, is the basis for the afterwards achievements of climatic studies of loess. Richthofen further argued that loess materials were derived from the arid source areas mainly by near-surface winds, and such eolian dust accumulated as loess (glacial periods) in the downwind regions. After the pioneering works of Richthofen, buried soils (paleosols) were identified from Chinese loess, and the alternations of loess and paleosol well document the cyclic nature of the Quaternary climatic changes. Based on the studies of the most continuous loess sections, we can establish the long-term orbital scale climatic oscillations since ～2.6Ma. Actually, such achievements are closely linked with the foundation of the theory of eolian origin of loess as well as the advances in pedostratigrpahy, chronology, magnetostratigraphy, paleontology etc. Only after the foundation of the eolian origin of loess, can we link the loess deposites, transported by wind systems, to the regional or global scale paleoclimatic changes. In this paper, the early history of loess research and the great contribution of Prof. Richthofen to the eolian origin of loess were reviewed.