| 黄土地层中CaCO3含量变化与更新世气候旋迴 |
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| 引用本文： | 卢演俦.黄土地层中CaCO3含量变化与更新世气候旋迴[J].地质科学,1981,0(2):122-131. |
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| 作者姓名： | 卢演俦 |
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| 作者单位： | 国家地震局地质研究所 |
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| 摘 要： | 深海沉积物剖面中CaCO3含量变化与气候变迁密切相关,冰期时的高,间冰期时的低。若大陆上黄土地层中CaCO3含量变化也有类似的性质,就更有利于气候长期变迁的海—陆对比以及探讨气候变迁的原因。本文根据陕西洛川黄土地层剖面中110多块样品的分析资料,用相关分析和方差分析,考察CaCO3含量与黄土、古土壤形成环境的关系,并用频谱分析初步探讨约70万年来气候变迁的周期以及气候变迁的海—陆对比等问题。
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| 关 键 词： | , |
| 收稿时间： | 1979-08-27 |
| 修稿时间： | 1979-08-27; |
PLEISTOCENE CLIMATIC CYCLES AND VARIATION OF CaCO3 CONTENTS IN A LOESS PROFILE |
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| Lu Yanchou.PLEISTOCENE CLIMATIC CYCLES AND VARIATION OF CaCO3 CONTENTS IN A LOESS PROFILE[J].Chinese Journal of Geology,1981,0(2):122-131. |
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| Authors: | Lu Yanchou |
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| Institution: | Institute of Geology, National Bureau of Seismology, Beijing |
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| Abstract: | There are 13 loess units and 14 fossil soil layers in a Middle-late pleistocene profile with thickness of 76 M in Loud man,Shanxi Province.On the basis of weathering-pedogenic degree,the loess units may be divided into the weak pedogenic,medium pedogenic and strong pedogenic loess,whereas the soil layers into the black-loessial soil,earbonate drab soil,drab soil,luvic drab soil and drab-brown earth,respectively (Lu and An,1979).The statistical tests including analyses of variance and regression of the relationship between percentage of CaCO3,and the ratios of microline (Mm)/quartz (Mq) and calcite (Me)/quartz (Mq) in loess and soil layers indicate that: (1) significant difference presents among the three,classes of loess and five types of soil in the profile;(2) a positive linear relation exists between the percentage of CaCO3 and Mm/Mq ratio,and both two factors decrease from the weak pedogenic loess to the drab-brown earth.As a result,by taking CaCO3 contents in the different levels in the profile as an index,it is possible to characterize the bio-climatic environments in which loess units or soil layers were formed.Using two hypothetic age models constructed on the basis of the available data of magneto-stratigraphy,radiocarbonate date and TL date,we have made a spectral analysis of the time series of CaCO3 percentage as a climatic variable.All the spectra calculated for variation in CaCO3 percentage over the past 700,000 years exhibit a dominative spectral peak corresponding to a cycle of 41,700 years (Model I) or 25,000 years (Model Ⅱ).These climatic cycles have also been,recorded by deep-sea sediments in the southern Indian Ocean (Hays,J.D.et al.,1976),and correspond to the cycles of obliquity and precession variation of earth’s axis,respectively.It seems that an important factor to control long-term change of climate is the variation in the earth’s orbital geometry. |
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| Keywords: | , |
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