【摘要】 <正> 黄土地球化学是研究黄土中元素的分布、分配和迁移、富集的规律。它的研究不仅有助于进一步了解黄土物质成分的特征,而且对探索黄土堆积的地球化学环境,以及黄土形成过程的地球化学实质有重要意义。这些年来,我们继续以黄河中游黄土为重点,结合有关地区,进行了黄土地球化学的研究。现就中国黄土地球化学的若干问题,概述如下:黄土的地质背景中国黄土的分布西起昆仑山,东至渤海中的小岛(例如庙岛群岛),南北大致处于北纬30-40°的范围,面积达44万平方公里。黄土在平面分布上自西北而东南戈壁、沙漠、黄土成带状排列。黄土以黄河中游地区最发育,其最大厚度可达200米。黄土地层自上而下划分为晚更新世马兰黄土,中更新世离石黄土上部和下部,早更新世午城黄土,其间被三个剥蚀面隔开。个别地点发现马兰黄土顶部黑垆土之上覆有全新更多还原

【Abstract】 In many different loess deposits the contents of oxides and trace elements are nearly all the same, so is the REE distribution in the clay fraction of loess, though with regional variations. It shows that the constituents of the loess are uniform. Similarity between the distributional pattern of REE in loess and that in the sands in Northwest China suggests the similar ity of parent materials. In addition, the values of the distributional patterns of REE in loess and its clay fraction approximate that of the earth’s crust, and are also comparable to those of sedimentary rocks (i. e. N. A. S.), but they differ from those of spherulitic meteorites. As determination shows, the values of oxides in the superimposed loess and paleosols from the loess profile are found in rhythmical variations. These chatacteristics might be explained by the hypothesis of repeated climatic fluctuations between aridity (loess) to humid (paleosol) during the Quaternary.更多还原