基于模糊层次分析法的赣南离子吸附型中重稀土成矿预测

Metallogenic Prediction of Ion-Adsorption Type Middle and Heavy Rare Earth Deposits in Southern Jiangxi Based on Fuzzy Analytic Hierarchy Process

赣南地区是我国重要的离子吸附型中重稀土资源基地之一。然而,随着赣南稀土资源的不断消耗和境外新的稀土资源不断开发,加之当前对赣南稀土成矿预测主要以传统的定性或半定量预测为主,导致稀土资源优势衰退和潜力不明等问题。为定量预测赣南离子吸附型中重稀土资源潜力,本文采用模糊层次分析法对研究区地质-气候-地貌等多元地质信息进行综合分析处理,并结合已知95个离子吸附型稀土矿床的分布特征,建立综合信息预测模型。基于群决策的层次分析法计算各指标权重,通过模糊数学法构建隶属度函数,利用C-A分形方法确定不同成矿强度对应的阈值,对赣南离子吸附型中重稀土矿进行成矿预测。结果表明:(1)水系沉积物Y/La地球化学比值在不同配分类型稀土矿床中差异较大,轻稀土矿区Y/La比值平均值为0.68,而中重稀土矿区Y/La比值平均值则为1.3。Y/La比值可能是一种重要的评价稀土矿床配分类型的地球化学勘查指标;(2)相比于传统层次分析,通过引入专家权重系数,能有效降低权重判断的主观性,减少模型预测的不确定性;(3)结合研究区地质特征和已知矿床类型、数量和空间分布位置等信息,综合圈定赣南地区离子吸附型中重稀土矿A级远景区5处,B级远景区3处。综合分析认为:赣南离子吸附型稀土矿床成矿强度整体具有“南部强,中部好,东西弱”的分布格局,结合近年来的勘查成果,赣南地区仍有寻找离子吸附型中重稀土矿的巨大潜力。此项研究不仅为赣南地区离子吸附型中重稀土矿的勘探工作提供依据,而且为模糊层次分析法应用于矿产资源潜力评价方面提供了一个有效案例,显示该方法在处理多元地质数据中的应用潜力。

The southern Jiangxi region is a critical source of ion-adsorption type middle and heavy rare earth resources in China.However,continuous resource depletion,coupled with the emergence of new global rare earth sources,has raised concerns about the regional long-term resource viability.Traditional qualitative or semi-quantitative prediction methods have proven inadequate in addressing these challenges,leading to uncertainties in resource potential assessment.This study employs a fuzzy analytic hierarchy process to quantitatively predict the potential of ionadsorption type middle and heavy rare earth resources in southern Jiangxi.The research integrates multidimensional geological data,including geological,climatic,and geomorphological factors,with distribution characteristics of 95 known ion-adsorption type rare earth deposits.A comprehensive predictive model is developed using group decision-based analytic hierarchy process for weight calculation,fuzzy mathematics for membership function construction,and concentration-area(C-A)fractal analysis for threshold determination.Key findings include:(1)The Y/La geochemical ratio in stream sediments varies significantly between different rare earth deposit types,with light rare earth areas showing an average ratio of 0.68,compared to 1.3 in middle and heavy rare earth areas.This ratio emerges as a potential key geochemical indicator for rare earth deposit classification.(2)The incorporation of expert weighting coefficients in the analytical hierarchy process reduces subjectivity and uncertainty in the model predictions compared to traditional methods.(3)The study identifies five Class A and three Class B prospective areas for ion-adsorption type middle and heavy rare earth deposits in southern Jiangxi,based on regional geological characteristics and known deposit information.The research reveals a"strong south,good central,weak east-west"distribution pattern of rare earth mineralization intensity in southern Jiangxi.Recent exploration results suggest significant untapped potential for new ion-adsorption type middle heavy rare earth deposits in the region.This study not only provides a foundation for future rare earth exploration in southern Jiangxi but also demonstrates the effectiveness of the fuzzy analytic hierarchy process in mineral resource potential evaluation.It showcases the method's capability in handling multi-dimensional geological data,offering a valuable case study for similar applications in resource assessment.