THE COMPREHENSIVE STUDY ON DEPOSITIONAL AGE OF JIOUZHOUTAI LOESS LANZHOU
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摘要: 据上、下粉砂层在剖面上出现的位置、黄土—古土壤地层层序、14C、热释光(TL)和裂变径迹年龄以及古地磁测量结果,兰州九洲台黄土仅仅是距今140—150万年以来才沉积而成的,因而距今220—240万年以来形成的结论不能成立.
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关键词:
- 兰州九洲台黄土 /
- 古土壤序列 /
- 磁性年龄 /
- 绝对年龄(14C、TL和FT) /
- 沉积年代
Abstract: The thickness of Jiouzhoutai loess section of Lanzhou is 318.2m which is the thickest loess section in China and in the world.The upsand loss and low-sand loess marker beds are respectively at 103.5 to 127.0meters and at 45.0 to 52.5 meters high, which shows that the loess section was formed at 1.35 Ma ago and aeolian-loess began to deposit at about 140 Ma ago.The B/M boundary and Jaramiuo normal event are located at 135.0m and at 75.5-92.Om high, which means that the loess scetion should be formed at 1.30 Ma. Also there are thirty-four palaeosols among which the first eight layers of palaeosols are so called the first Wucheng palaeosol.group formed at 1.48 Ma So the profile was formed at 1.40-150 Ma.The fission tract age of gypsum samples collected at profile bottom and at S.Om high are respectively at 1.48Ma and 1.45 Ma. Therefore. the caolianloess of Jiouzhoutai loess profile began to deposit at about 1.30 Ma and Alluvial-loess began to deposit at about 1.40-1.50 Ma. -
[1] 王永众等,1978A,地质科技,第4期,76-84页. [2] 王永众等,1978B,西北大学学报,第2期,1-27页. [3] 王永众等.1982,黄土与第四纪地质,陕西人民出版社. [4] 白凤龙,1987,地质论评,33卷,2期,188-192页. [5] 曹继秀等,1988,兰州大学学报(自然科学版),24卷1期118-122页. [6] 刘东生等,1985,黄土与环魔,科学出版社. [7] 王永众等,1985,中国黄土研究的新进展,陕西人民出版社. [8] 刘顺生等。1984,裂变径迹年龄测定,地质出版社. [9] Burbank, D.W.and Li Jijun1985, Nature, 316 (4) 6026; 41一143. [10] Derbyshire, E.. 1983 Origin and characteristics of some Chinese loess at two locations in china,In' Eolian sediments and processes',Brookfield. M. E. and Ahlbrandt. T, S (eds),Elscvicr, Amsterdam, P.69-90. [11] Derbyshre, E 1984 Granulometry and fabric of loess at Jiuzhoutai, Lanzhou. People':Republic of china,M.Decsi (ed),Geog.Res.Inst., Hungarian. 103-195. [12] Derbyshire. E., Wang Jingtai. john Show and Tim Rolph 1987 Interim results of studies of the sedimentology and remanent magnetion of the loess sucession at Jiuzhoutai, Lanzhou,China, In‘Aspects of loess research’,Liu Tungsheng(ed),China Ocean Press.p.175-191. -

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