摘要
选择岷江上游干旱河谷区汶川段不同基岩类型的岩石—土壤垂向剖面,开展地球化学测试分析工作,据此研究不同类型风化壳剖面元素垂向分布特征,探究基岩对土壤化学元素含量的影响,并从地质角度出发为该区域农业生产种植和生态环境修复提供建议.风化壳剖面自上而下可划分为腐殖层(A)、淀积层(B)、母质层(C)和基岩层(R),腐殖层中Al、Ca、K、Mg、Fe、Se、Zn、Cu、Cd、Pb均值高于其在全国土壤中的平均值,Si、Na、Mn、Cr、As、Cd、Hg均值低于全国土壤中的平均值.不同基岩风化壳剖面中,除去在基岩中含量较高的元素在所对应的土壤层中含量较高外,相同元素在其余土壤层中含量大致相同.风化剖面由基岩层至腐殖层,化学风化强度逐渐增强,土壤的风化程度普遍高于基岩风化程度.元素含量除继承母岩特征外,还发生了分异,Al、K、Se在腐殖层富集,Na、Fe、Si、Pb、Cu、Zn、Mn、As、Cd、Cr、Hg在淀积层富集,Mg、Ca在母质层富集.
Abstract
This study conducted geochemical tests and analyses for vertical rock-soil profiles with different bedrock types in the Wen-chuan section in the upper arid valley of the Minjiang River.Based on the above,this study explored the vertical distributions of ele-ments in these weathering crust profiles to investigate the influence of bedrocks on the contents of chemical elements in soils.From a geological perspective,this study provided proposals for planting in agricultural production and eco-environmental restoration for the study area.The results of this study are as follows:(1)From top to bottom,weathering crust profiles can be divided into four layers:the humus layer(A),the illuvial layer(B),the soil parent material layer(C),and the bedrock layer(R).The humus layers exhib-it higher average values of Al,Ca,K,Mg,Fe,Se,Zn,Cu,Cd,and Pb and lower average values of Si,Na,Mn,Cr,As,Cd,and Hg,compared to corresponding national average values in soils;(2)In weathering crust profiles with different bedrock types,except for elements with higher contents in both bedrocks and corresponding soil layers,the same elements manifest similar contents in other soil layers;(3)The chemical weathering intensity increased from the bedrock to the humus layers,with soil weathering degrees gener-ally higher than bedrock weathering degrees;(4)In addition to characteristics inherited from soil parent materials,elements in weathe-ring crust profiles show content differentiation,characterized by enriched Al,K,and Se in humus layers,enriched Na,Fe,Si,Pb,Cu,Zn,Mn,As,Cd,Cr,and Hg in illuvial layers,and enriched Mg and Ca in soil parent material layers.
基金项目
中国地调局军民融合地质调查中心项目(DD20220955)
国家科技期刊平台
NSTL
万方数据