Quantifying the chemical composition of weathering products of Hainan basalts with reflectance spectroscopy and its implications for Mars  

作　　者：Xing Wu JiaCheng Liu WeiChao Sun Yang Liu Joseph Michalski Wei Tan XiaoRong Qin YongLiao Zou 

机构地区：[1]State Key Laboratory of Space Weather,National Space Science Center,Chinese Academy of Sciences,Beijing 100190,China [2]Department of Earth Sciences and Laboratory for Space Research,The University of Hong Kong,Hong Kong,China [3]Aerospace Information Research Institute,Chinese Academy of Sciences,Beijing 100094,China [4]Center for Excellence in Comparative Planetology,Chinese Academy of Sciences,Hefei 230026,China [5]University of Chinese Academy of Science,Beijing 100049,China [6]Key Laboratory of Mineralogy and Metallogeny,Guangdong Provincial Key Laboratory of Mineral Physics and Materials,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,China

出　　处：《Earth and Planetary Physics》2024年第6期854-867,共14页地球与行星物理（英文版）

基　　金：National Key Research and Development Project(Grant No.2019YFE0123300);National Natural Science Foundation of China(Grant Nos.42072337,42241111,and 42241129);Pandeng Program of National Space Science Center,Chinese Academy of Sciences.Xing Wu also acknowledges support from the Young Elite Scientists Sponsorship Program by the China Association for Science and Technology(Grant No.2022QNRC001);China Postdoctoral Science Foundation(Grant No.2021M700149).

摘　　要：With the development of the hyperspectral remote sensing technique,extensive chemical weathering profiles have been identified on Mars.These weathering sequences,formed through precipitation-driven leaching processes,can reflect the paleoenvironments and paleoclimates during pedogenic processes.The specific composition and stratigraphic profiles mirror the mineralogical and chemical trends observed in weathered basalts on Hainan Island in south China.In this study,we investigated the laboratory reflectance spectra of a 53-m-long drilling core of a thick basaltic weathering profile collected from Hainan Island.We established a quantitative spectral model by combining the genetic algorithm and partial least squares regression(GA-PLSR)to predict the chemical properties(SiO2,Al2O3,Fe2O3)and index of laterization(IOL).The entire sample set was divided into a calibration set of 25 samples and a validation set of 12 samples.Specifically,the GA was used to select the spectral subsets for each composition,which were then input into the PLSR model to derive the chemical concentration.The coefficient of determination(R2)values on the validation set for SiO2,Al2O3,Fe2O3,and the IOL were greater than 0.9.In addition,the effects of various spectral preprocessing techniques on the model accuracy were evaluated.We found that the spectral derivative treatment boosted the prediction accuracy of the GA-PLSR model.The improvement achieved with the second derivative was more pronounced than when using the first derivative.The quantitative model developed in this work has the potential to estimate the contents of similar weathering basalt products,and thus infer the degree of alteration and provide insights into paleoclimatic conditions.Moreover,the informative bands selected by the GA can serve as a guideline for designing spectral channels for the next generation of spectrometers.

关 键 词：reflectance spectroscopy weathered basalts terrestrial analog quantitative retrieval MARS 

分 类 号：P185.3[天文地球—天文学] V419[航空宇航科学与技术—航空宇航推进理论与工程]