摘要
在对玛曲高原东南部具有代表性的黄土-古土壤-风成砂沉积剖面进行常量、微量元素及地球化学风化参数分析的基础上,结合14 C测年结果,探讨了中晚全新世以来玛曲高原的化学风化过程。结果表明：（1）不同地化学元素在剖面中的化学活性表现出明显的差异性,常量元素Ca、Si、Na以强烈迁移淋失为主,Fe、Mg则表现为明显富集;元素活动性及迁移顺序为Ca〉Si〉Na〉Al〉K〉Fe〉Mg;常量元素的迁移特征表明玛曲高原处于脱Ca、Na的初期化学风化阶段;微量元素除Sr迁移淋失显著外,Cu、Mn、Zn均呈现出强富集特征。（2）根据典型地化学元素记录的冷干-凉润-凉干-温湿的气候变化过程,结合化学风化指标将玛曲高原中晚全新世以来的化学风化过程划分为3.8ka BP以前的风化较弱期、3.8~3.5ka BP风化较强期、3.5~1.6ka BP风化减弱期和1.6ka BP以来的风化增强期4个阶段。
Based on the analysis of major elements,trace elements and geochemical weathering parameters about a representative loess-paleosoil-aeolian sediment profile in the southeast of Maqu Plateau,and combined with 14 C dating,we discuss the chemical weathering process since the middle-late Holocene.Research results prove that：（1）Chemical activity of different geochemical elements in section showed obvious variability,the major elements such as Ca,Si and Na were migrated and leached,while the elements Fe and Mg were obviously enriched,the activity and migration of elements were followed by Ca〉Si〉Na〉Al〉K〉Fe〉Mg;the migration features of the major elements indicated that the profile completed the primary process of chemical weathering characterized by leaching of Ca and Na;During the chemical weathering process,trace elements such as Cu,Mn and Zn were obviously accumulated except Sr.（2）Based on the climate change process from cold-dry-cool-humid-cool-dry to warm-humid recorded by the typical geochemical elements and combined with chemical weathering parameters,the chemical weathering process in the Maqu Plateau since the middle-late Holocene can be divided into four stages.Before 3.8 ka BP,the regional chemical weathering was relatively weaker,while it was relatively stronger from 3.8 ka BP to 3.5 ka BP.During 3.5-1.6ka BP,the chemical weathering degree obviously became weaker,since then the chemical weathering tended to be stronger.
出处
《中国沙漠》
CSCD
北大核心
2016年第3期623-635,共13页
Journal of Desert Research
基金
国家自然科学基金项目(41161036
41171018)
甘肃省自然科学基金项目(1010RJZA016)
西北师范大学青年教师科研能力提升计划项目(NWNU-LKON-10-34)
关键词
地化学元素
化学风化
中晚全新世
玛曲高原
geochemical elements
chemical weathering
middle-late Holocene
Maqu Plateau
