摘要
选择了关注较少,第四纪红土分布最西界——四川成都平原中的一个第四纪红土剖面作为研究对象,通过系统的环境磁学分析,结合色度和常量地球化学元素指标,探讨磁学参数的环境指示意义,探寻适用的气候代用指标.结果表明:(1)成都地区第四纪红土剖面经历了细粒亚铁磁性矿物转化分解、剖面整体呈低磁性、磁性矿物主要为反铁磁性矿物、磁性颗粒以假单畴(PSD)和多畴(MD)的粗颗粒为主.(2)剖面弱网纹层成土强度较弱、亚铁磁性矿物含量较高、磁性较强、磁性矿物粒径较细;典型网纹层成土强度较高、磁性较弱、磁性颗粒较粗.(3)剖面土壤发育序列的CIA、磁学特征的变化指示了当地气候趋于冷干,且不及同时期的长江中下游地区暖湿.(4)反映剖面反铁磁性矿物的赤铁矿、针铁矿信息的色度参数与CIA对应良好,可以作为南方地区古气候变化研究的代用指标.
This paper selects a Quaternary red earth profile in Chengdu Plain as the research object, which is located in the westernmost boundary of Quaternary red earth distribution and receives less attention. Through systematic environmental magnetic analysis, combined with chromaticity and constant geochemical element indicators, the environmental indication significance of magnetic parameters is discussed, and the applicable climate proxy indicators are explored. The results show that:(1) The Quaternary red earth profile in Chengdu area has undergone the transformation and decomposition of fine-grained ferrimagnetic minerals, the overall profile is low magnetic, the magnetic minerals are mainly antiferromagnetic minerals, and the magnetic particles are mainly coarse particles of pseudo-single domain(PSD) and multi-domain(MD).(2) The weak reticulated layer in the profile has weaker pedogenesis strength, higher content of ferrimagnetic minerals, stronger magnetisms, and finer particle size of magnetic minerals;typical reticulated layers have higher pedogenesis strength, weaker magnetism, and coarser magnetic particles.(3) The changes in CIA and magnetic characteristics of the soil development sequence in the profile indicate that the local climate tends to be cold and dry, and not as warm and humid as the middle and lower reaches of the Yangtze River during the same period.(4) The chromaticity parameters of hematite and goethite that reflect the information of antiferromagnetic minerals in the profile correspond well with CIA, and can be used as a proxy index for the study of paleoclimate change in the southern region.
作者
杜佳昊
吕镔
DU Jiahao;LU Bin(Key laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education,Fiyjian Normal Universily,Fuzhou 350007,China;School of Geographical Sciences,Fujian Normal University,Fuzhou 350007,China;Institute of Geography,Fujian Normal University,Fuzhou 350007,China)
出处
《福建师范大学学报(自然科学版)》
CAS
2022年第3期82-93,共12页
Journal of Fujian Normal University:Natural Science Edition
基金
国家自然科学基金资助项目(41402149、41877435)。
关键词
第四纪红土
环境磁学
磁性矿物
古气候变化
成都地区
Quaternary red earth
environmental magnetism
magnetic minerals
paleoclimate change
Chengdu area