甘肃西山坪遗址岩石磁学性质及其研究意义探讨

对甘肃西山坪遗址剖面样品进行磁化率、频率磁化率、热磁分析、非磁滞剩磁和等温剩磁等一系列岩石磁学实验测试,分析环境磁学参数特征变化,试图探讨西山坪遗址研究意义,为今后深入研究该沉积序列蕴含的古环境记录提供了岩石磁学基础.结果表明：西山坪遗址剖面沉积物中磁性矿物主要以低矫顽力的磁铁矿和磁赤铁矿为主,高矫顽力磁性矿物赤铁矿含量极其有限,越向剖面表层,强磁性矿物含量逐渐增加.磁性矿物颗粒表现出黄土的典型特征,以单畴、准单畴为主,含有一定量的超顺磁颗粒,颗粒度越向剖面表层越细.从物源上看,遗址沉积物主要来自近源的黄土风尘堆积,主要是风成堆积,并混合大量人类活动信息,给今后综合研究岩石磁学与人类活动特征的关系有一定借鉴意义.

Rock magnetic properties of the Xishanping Site,Gansu and its research significance

We have made a series of rock magnetic laboratory tests of susceptibility, frequency dependent susceptibility, thermal magnetic analysis, the non-hysteresis remanence and isothermal remanent magnetization on the section samples of Xishanping site, we analyse the environmental magnetic parameters characteristic changes and attempt to explore the significance of the Xishanping site research to serve the study of the sedimentary sequence containing records of the ancient environment, and provide the basis of rock magnetism for future studies. The results show that the magnetic minerals in the Xishanping site sediments are mainly of low-coercivity magnetite and maghemites, high-coercivity hematite is extremely limited, and the closer to the surface, the concentration of strong magnetic minerals more increase. Magnetic mineral grains show the typical characteristics of loess, but contain a certain amount of super-paramagnetic particles (SP), the closer to the surface, the grains size thinner. From the provenance of the material source, the Xishanping site sediments stem mainly from eolian loess accumulation, aeolian accumulation, and are mixed with a lot of human activity information. Comprehensive study on the relationship between rock magnetic characteristics and human activities for the future has a certain referential significance.