三门峡会兴沟剖面黄土—古土壤序列的岩石磁学研究

发布时间：2018-03-18 12:20

本文选题：水沟—会兴沟旧石器遗址　切入点：黄土—古土壤序列　出处：《地球科学进展》2017年05期 　论文类型：期刊论文

【摘要】：岩石磁学是古地磁学和环境磁学研究的基础,是鉴定岩石和沉积物中磁性矿物种类、粒度和含量的有效途径。对黄土高原东南部三门峡盆地的水沟—会兴沟旧石器遗址会兴沟剖面黄土—古土壤序列(S_0~S_8)进行系统的岩石磁学研究表明:本剖面沉积物的主要载磁矿物为磁铁矿、磁赤铁矿和赤铁矿,显示准单畴(PSD)磁性颗粒特征。所有磁学参数曲线均表现出基本一致的变化特征,与深海氧同位素曲线能够很好的对应,反映了第四纪以来的冰期—间冰期旋回中,东亚季风影响下的风尘黄土堆积中磁性矿物种类、粒度和含量的周期性变化特征。黄土中高矫顽力磁性矿物的相对含量要高于古土壤中的,而随着成土作用的加强,在古土壤中细粒的低矫顽力磁性矿物显著增加的同时,其中高矫顽力磁性矿物的绝对含量也相应增加。质量磁化率(χ)与非磁滞剩磁磁化率(χ_(ARM))和饱和等温剩磁(SIRM)及磁粒度参数χ_(ARM)/SIRM和χ_(ARM)/χ均呈明显的正相关关系,表明由成土作用产生的单畴(SD)颗粒和较小PSD颗粒对磁化率增强有显著的贡献。
[Abstract]:Petromagnetism is the basis of paleomagnetism and environmental magnetism, and the identification of magnetic minerals in rocks and sediments. An effective way of granularity and content. A systematic petromagnetic study on the loess paleosol sequence of Huexinggou section, Huexinggou Paleolithic site, Huixinggou Paleolithic site in the Sanmenxia Basin, southeast of the Loess Plateau, shows that: the sediment of this section is the sediment of this section. The main magnetite bearing minerals are magnetite, Magneto-hematite and hematite show quasi-single-domain PSD) magnetic particle characteristics. All the magnetic parameter curves are basically consistent with each other, which can correspond well with the deep-sea oxygen isotope curves. It reflects the types of magnetic minerals in the aeolian loess accumulation under the influence of the East Asian monsoon during the glacial to interglacial cycles since the Quaternary. The relative content of high-coercivity magnetic minerals in loess is higher than that in paleosol, but with the enhancement of soil-forming, the low-coercivity magnetic minerals of fine particles in paleosol increase significantly. The absolute content of high coercivity magnetic minerals also increased correspondingly. There was a positive correlation between mass susceptibility (蠂 ~ 2), non-magnetic hysteresis remanence magnetic susceptibility (蠂 _ (+)), saturation isothermal remanence (SIRM), and magnetic particle size parameters 蠂 ~ (+ +) ARM / SIRM and 蠂 ~ (+ +) ARMN / 蠂 ~ (2). It is shown that the single domain SDD particles and the smaller PSD particles produced by the soil-forming process contribute significantly to the enhancement of magnetic susceptibility.
【作者单位】：中国科学院地球环境研究所黄土与第四纪地质国家重点实验室;中国科学院大学;
【基金】：国家自然科学基金项目“中国黄土记录的布容正极性时极性漂移事件研究”(编号:41572164) 黄土与第四纪地质国家重点实验室开放基金课题“汾渭地堑早期人类扩散、迁徙与融合证据”(编号:SKLLQG1502)资助~~
【分类号】：P318.41;P531

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