南方红土中的磁极倒转以及磁化率变动记录  

GEOMAGNETIC POLARITY REVERSAL RECORDS AND SUSCEPTIBILITY VARIATIONS OF THE LATERITE IN SOUTH CHINA

作　　者：刘育燕[1] 林文姣[1] 朱宗敏[1] 袁爱华[1] 

机构地区：[1]中国地质大学地球科学学院,湖北武汉430074

出　　处：《地质科技情报》2003年第3期33-36,共4页Geological Science and Technology Information

基　　金：中国地质调查局项目"中国南方红土型第四系的划分与对比"(200113900072);湖北省地球表层系统开放实验室2001年开放基金资助项目

摘　　要：江西省修水县杨梅山剖面244个定向样品的岩石磁学研究表明,杨梅山剖面的磁极倒转自上而下分别为布莱克(Blake)反向极性偏移、安比拉(Emperor)反向极性偏移、布容—松山(Brunhes-Matuyama)极性带界线以及上部贾拉米洛(UpperJaramillo)正向亚带;杨梅山剖面样品的磁性矿物为磁赤铁矿;杨梅山剖面浓度(数量)归一化的磁化率变动和深海氧同位素变化具备较好的一致性,该剖面的磁化率变动对应着深海氧同位素自第5阶至第23阶的变化;杨梅山剖面跨越了布容—松山极性带界线以及深海氧同位素的第19阶,中国南方红土的底界年龄可能大于78Ma,即早于中国北方黄土的L8黄土层。This paper presents the results of rock magnetism studies of 244 directed samples collected from Yangmeishan section in Xiushui County,Jiangxi Province.Several geomagnetic polarity reversals can be identified in Yangmeishan section, which, in their topdown order, are Blake reverse polarity excursion, Emperor reverse polarity excursion, the boundary of BrunhesMatuyama polarity zone and the Upper Jaramillo normal subzone.The magnetic mineral in this section is Maghemite, and the susceptibility variations (normalized by consistency) are in remarkable consistency with the variations of the deepsea oxygen isotope, corresponding to the stages from the 5th to the 23rd.Yangmeishan section spans the boundary of BrunhesMatuyama polarity zone and the 19th stage of the deepsea oxygen isotope variations. Therefore, the bottom age of the laterite in South China might be older than 78 Ma, viz. older than the L8 loess in North China.

关 键 词：磁极倒转 磁化率 磁赤铁矿 归一化 江西 修水县 岩石磁学 南方红土 

分 类 号：P539.3[天文地球—古生物学与地层学] P318.4[天文地球—地质学]