黄土与风成红黏土土壤微形态对比研究——以西安和董湾为例  

Comparative Study on Soil Micromorphology of Loess and Aeolian Red Clay:A Case Study of Xi an and Dongwan

作　　者：王练 毛学刚[1,2,3] 刘秀铭[1,2,3,4] WANG Lian;MAO Xuegang;LIU Xiuming(School of Geographical Sciences,School of Carbon Neutrallity Future Technology of Fujian Normal University,Fuzhou 350117,China;Institute of Geography of Fujian Normal University,Fuzhou 350117,China;Cultivation Base of State Key Laboratory of Humid Subtropical Mountain Ecology of Fujian Normal University,Fuzhou 350117,China;Department of Earth and Environmental Sciences,Macquarie University,Sydney,NSW 2109,Australia)

机构地区：[1]福建师范大学地理科学学院、碳中和未来技术学院,福州350117 [2]福建师范大学地理研究所,福州350117 [3]福建师范大学湿润亚热带山地生态国家重点实验室培育基地,福州350117 [4]Department of Earth and Environmental Sciences,Macquarie University,Sydney,NSW 2109,Australia

出　　处：《亚热带资源与环境学报》2025年第1期99-108,共10页Journal of Subtropical Resources and Environment

基　　金：国家自然科学基金项目(42130507);福建省自然科学基金项目(2022J0114)。

摘　　要：黄土高原新近纪风成红黏土和第四纪黄土是重建古气候的良好载体,黄土和红黏土中土壤发育特征是理解古气候的基础。长期以来,对红黏土土壤发育强弱及其代表的古环境还存在争论,而微形态是认识土壤发育特征的直观途径。黄土高原不同地区第四纪黄土中土壤的发育特征已得到统一认识,选取西安任家坡黄土剖面上部五层古土壤和五层黄土层典型样品进行微形态分析,揭示不同土壤发育程度的微形态特征。同时选取了甘肃董湾红黏土剖面中不同发育特征的红黏土层、钙积层、红黏土上覆黄土层等典型样品,与西安黄土-古土壤微形态对比研究,进而加深对红黏土形成环境的认识。本研究认为:(1)风成沉积微形态中碳酸钙的淀积形式和黏土的光向定性是判断黄土和红黏土土壤发育的基础;黄土层中碳酸钙以针状或棒状、网状和结核状为主,黏土光性定向不显著,而在古土壤层碳酸钙少,以条带状和泉华状黏土胶膜为主,成壤程度明显高于黄土层。(2)红黏土中碳酸钙淀积显著且形式多样,微形态显示经历了沿裂隙的快速淀积和较长时间的水分饱和状态,成壤程度相对较弱。(3)红黏土中大部分黏土颗粒不具有光性定向,表明红黏土的颜色不是沉积后成壤形成,部分红黏土层中少量的黏土胶膜说明成壤稍强,但远不及西安第四纪古土壤。(4)红黏土自身的滞水性和胀缩性影响其发育,以此可更好地理解红黏土土壤发育弱、钙积层多种成因和地层空间对比难等关键问题。本研究提出,基于微形态判断风成沉积土壤发育特征的依据,为更加准确理解红黏土的成壤特征和古环境提供直接参考。The Neogene eolian red clay and Quaternary loess of the Loess Plateau serve as valuable archives for paleoclimate reconstruction,with soil development characteristics providing critical insights into past climates.However,debates remain regarding the development intensity of red clay soils and their paleoenvironmental implications.Micromorphology offers a direct and effective approach to characterizing soil development.While the soil development characteristics of Quaternary loess across different regions of the Loess Plateau are well understood,red clay remains less comprehensively studied.This study analyzes the micromorphological features in five paleosol layers and five loess layers from the upper part of the Renjiapo loess section in Xi an to assess varying degrees of soil development.Additionally,samples from the Dongwan red clay profile in Gansu Province-including red clay layers,calcareous layers,and loess layers overlying red clay were compared with the Xi an loess-paleosol samples to deepen our understanding of red clay formation environments.The findings are as follows,1)the depositional forms of calcium carbonate and the optical orientation of clay particles are key indicators of soil development in loess and red clay.In the loess layers,calcium carbonate predominantly appears in needle-like,rod-like,reticulate,and nodular forms,with weak optical orientation of clay particles.In paleosol layers,calcium carbonate is scarce and occurs mainly as strip-like or sinter-like clay films,indicating significantly stronger soil development.2)Red clay exhibits remarkable and diverse calcium carbonate deposition.Micromorphological evidence suggests both rapid deposition along fractures and prolonged water saturation,reflecting relatively weak soil development.3)Most clay particles in red clay lack optical orientation,indicating that its reddish color is not a result of post-depositional soil formation.While minor clay films in some red clay layers suggest slightly stronger soil development,it remains far less deve

关 键 词：黄土-古土壤 红黏土 微形态 黏土胶膜 钙积层 

分 类 号：P534.622[天文地球—古生物学与地层学] P588.2[天文地球—地质学]