摘要
本文报道由蓝田、陕县、洛川、西峰、平凉、兰州及靖远等剖面获得的古地磁研究结果．主要结论为：１．中国黄土剖面记录了Ｂｒｕｎｈｅｓ正极性带与Ｍａｔｕｙａｍａ负极性带，Ｂｒｕｎｈｅｓ／Ｍａｔｕｙａｍａ极性转换过程位于第８层黄土（Ｌ８）．在段家坡黄土剖面该转换过程对应的地层厚度为０．３７５ｍ，持续时间约６０００ａ．转换过程由３次极性变化构成，每次经历的时间约为４００ａ．２．Ｊａｒａｍｉｌｌｏ正极性亚带（Ｊ）位于标志层Ｌ９至Ｌ１５之间，大约Ｓ１０－Ｓ１３位置．３．Ｏｌｄｕｖａｉ正极性亚带（Ｏ）对应的地层为Ｓ２７－Ｓ３３４．Ｒｅｕｎｉｏｎ正极性亚带（Ｒ）由两部分组成，在蓝田段家坡黄土剖面分别位于Ｌ３６和Ｓ３８５．Ｍａｔｕｙａｍａ负极性带与Ｇａｕｓｓ正极性带界限（Ｍ／Ｇａ）位于黄土和红色粘土交界处，中国黄土的底界年龄为２．４８Ｍａ左右．黄土与红色粘土为整合接触关系．６．黄土下伏的红色粘土记录了Ｇａｕｓｓ正极性带，Ｇｉｌｂｅｒｔ负极性带和古地磁年表编号５（Ｅｐｏｃｈ５）．
This paper presents the results of palaeomagnetism polarity boundary of loesssection in Lantian,Shaanxian,Luochuan.Xifeng,Pingliang,Lanzhou and Jingyuan.The results show:1) Brunhes normal polarity zone and Matuyama reversal polarityzone were recorded in Chinese loess section.The Matuyama-Brunhes transition islocated in the loess layer L8.The thickness of transition is 0.375m,and time is estimated to be about 6000a.The M-B transition field is made up of three reversal,and every reversal is less than 400a.2) Jaramillo normal polarity subzone Is Iocatedbetween marker beds L9 and L15,about in S10-S13. 3) Olduvai normal polaritysubzone is located in S27-S33.4) Reunion normal polarity subzone was found atDuanjiapo loess section of Lantian.The R subzone composed of two parts of R1and R2. The R1 is located L36,and R2 is located S38. 5) Gauss-matuyama boundarycorresponds to loess/red clay boundary.Chinese loess began to form at 2.48 MaB.P.The red clay is underlying formation of loess.6)Gauss normal polarity chron.Gilbert reversal polarity chron and Epoch 5 were recorded in the redclay underthe loess.
出处
《地球物理学报》
SCIE
EI
CSCD
北大核心
1995年第3期310-320,共11页
Chinese Journal of Geophysics
基金
国家自然科学基金
关键词
古地磁
极性界限
黄土
古土壤
红色粘土
Palaeomagnetism,Polarity boundary,Loess-paleosoil sequence,Red clay.
