基于手持式X荧光光谱仪对乐山大佛赋存砂岩的分析  

Analysis of Sandstone in Leshan Giant Buhhda Based on Hand-Held X-Ray Fluorescence Spectrometer

作　　者：鲁昊 付宛璐[2,3] 柴珺 刘爽 孙作玉 LU Hao;FU Wan-lu;CHAI Jun;LIU Shuang;SUN Zuo-yu(School of History,Beijing Normal University,Beijing 100875,China;School of Earth and Space Sciences,Peking University,Beijing 100871,China;State Key Laboratory of Palaeobiology and Stratigraphy(Nanjing Institute of Geology and Palaeontology,CAS),Nanjing 210008,China;Beijing Museum of Natural History,Beijing 100050,China)

机构地区：[1]北京师范大学历史学院,北京100875 [2]北京大学地球与空间科学学院,北京100871 [3]现代古生物学和地层学国家重点实验室(中国科学院南京地质古生物研究所),江苏南京210008 [4]北京自然博物馆,北京100050

出　　处：《光谱学与光谱分析》2022年第8期2506-2512,共7页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(41572008);现代古生物学和地层学国家重点实验室开放课题基金(213102)资助。

摘　　要：为探索手持式X荧光光谱仪在石窟研究和保护中的应用,结合岩相分析和前期地调数据,使用手持式X荧光光谱仪,对四川乐山大佛从佛脚到胸部位置共42 m厚的砂岩以平均0.5 m间隔进行高密度XRF测试,做出元素含量和比值变化曲线。研究结果显示,手持式XRF测试结果中的Si,Ca,Al和Fe等主量元素可以较好地与岩相分析结果和自然层划分结果吻合,反映石英、方解石、褐铁矿的含量变化以及岩屑绢云母化程度。元素比值能够反映厚层块状岩体内部的抗风化能力差异,Si/(Si+Fe+Al)可以反映砂岩胶结物含量变化和受溶蚀程度,(K_(2)O+CaO)/Al_(2)O_(3)指示抗化学风化强度变化,S元素含量与Fe、Mn元素的去耦合指示了溶孔发育,综合反映了大佛赋存岩体在胶结物成分、孔隙度和层理发育方面的情况。Cl元素的两段高值与乐山大佛胸部带状滞状区及大佛脚部潜水区高度吻合。手持式X荧光光谱仪应用在石质文物分析中具有以下三个优势:(1)对大型、不可移动的石质文物本体来说,手持式X荧光光谱仪提供了高效、无损的岩石化学成分分析手段,主量元素的含量及分布可以较好地与赋存岩体的岩相分析结果和自然层划分结果吻合,能够成为石质文物本体岩性和岩层划分的辅助手段,有利于进行不同区域石质文物的对比研究。(2)对凿造于同一厚层块状岩层中的石质文物来说,手持式X荧光光谱仪能够满足测试间隔不到0.1 m的高分辨XRF扫描,元素比值的波动和元素间耦合关系的变化反应胶结物成分、孔隙度、溶孔发育度等方面反应块状岩体抗风化能力的内部差异。(3)Cl元素含量变化曲线可以精确指示含水量高的岩层,有助于进行滞水、透水情况和水患防治重点的评估,为处于不同气候和水文条件下的石质文物进行病害位置和机制对比提供辅助信息。In order to explore the application of handheld X-ray fluorescence spectrometer in research and protection of grottoes,based on lithofacies analysis and former geological data,we apply handheld X-ray fluorescence spectrometer to carry out high-density XRF tests on sandstone with a total thickness of 42 m from the feet to the chest of Leshan Giant Buddha in Sichuan Province at an average interval of 0.5 m and makes a curve of element content and ratio change.The research results show that the main elements such as Si,Ca,Al and Fe in the handheld XRF test results agree with the lithofacies analysis results and natural layer division results,reflecting the content changes quartz,calcite and limonite and the sericitization of debris.Element ratio can reflect the difference in weathering resistance between thick and massive rock mass.Si/(Si+Fe+Al)reflects the variation of cement content and its dissolution.(K_(2)O+CaO)/Al_(2)O_(3)indicates the change of chemical weathering resistance.The decoupling of S element content with Fe and Mn indicates the development of dissolved pores,which comprehensively reflects the development of cement composition,porosity and bedding of Leshan Giant Buhhda rocks.The two high values of Cl are highly consistent with the banded stagnant water area in the chest and the unconfined water area in the feet of the Leshan Giant Buddha.Therefore,the application of handheld X-ray fluorescence spectrometer in the analysis of stone cultural relics shows the following three advantages.(1)For large and immovable stone cultural relics,handheld X-ray fluorescence spectrometer provides an efficient and non-destructive analysis method of petrochemical composition.The major elements can be in good consistence with the lithofacies analysis results of rock strata on rock mass in grottoes and the natural layer division results,which is helpful for the division of rock strata of stone cultural relics and the comparison of stone cultural relics in different regions.(2)Handheld X-ray fluorescence spectrometer ca

关 键 词：手持式XRF 乐山大佛 砂岩 元素含量 

分 类 号：P585[天文地球—岩石学]