Rock magnetic properties of Nihewan sediments at Xujiayao  

作　　者：王喜生 LφvlieReidar SUPu 苏朴 

出　　处：《Science China Earth Sciences》2002年第10期939-948,共10页中国科学（地球科学英文版）

基　　金：This work was supported by the National Natural Science Foundation of China (Grant No.49474218); The Norwegian MSc-Program financed the stay of Wang Xisheng in Norway for two years. We thank Dr. Harald Walderhaug, Dr. H. Stockhausen, and Dr. F. Hauge

摘　　要：Rock magnetic measurements of Nihewan sediments from Xujiayao section demonstrate that magnetite, hematite and maghemite are dominant remanent magnetization carriers. Monitoring the variations of magnetic susceptibility(MS) and saturating isothermal remanent magnetization(SIRM) at low temperature are the attractive ways of detecting the presence of magnetite, maghemitization and superparamagnetic grain sizes. Low-temperature MS investigations suggest that susceptibility enhancement for Xujiayao samples is mainly due to the remarkable presence of SD/MD magnetite to some degree though some magnetite grains have been partially oxidized at some depths. It is tentatively concluded that both SD/MD magnetite and hematite are of detrital origin and carry a characteristic remanent magnetization(ChRM), whereas maghemite can be attributed to be chemical origin, overprinting a reversed polarity component of Matuyama age.Rock magnetic measurements of Nihewan sediments from Xujiayao section demonstrate that magnetite, hematite and maghemite are dominant remanent magnetization carriers. Monitoring the variations of magnetic susceptibility (MS) and saturating isothermal remanent magnetization (SIRM) at low temperature are the attractive ways of detecting the presence of magnetite, maghemitization and superparamagnetic grain sizes. Low-temperature MS investigations suggest that susceptibility enhancement for Xujiayao samples is mainly due to the remarkable presence of SD/MD magnetite to some degree though some magnetite grains have been partially oxidized at some depths. It is tentatively concluded that both SD/MD magnetite and hematite are of detrital origin and carry a characteristic remanent magnetization (ChRM), whereas maghemite can be attributed to be chemical origin, overprinting a reversed polarity component of Matuyama age.

关 键 词：Nihewan  SIRM  HYSTERESIS loops  DEPOSITIONAL remanent magnetization  CURIE point. 

分 类 号：P318[天文地球—固体地球物理学]