古地理学报 ›› 2025, Vol. 27 ›› Issue (2): 307-320. doi: 10.7605/gdlxb.2025.045

• 沉积矿产资源专题 • 上一篇    下一篇

中国含铝岩系中稀土元素的赋存形式: 主量元素数据驱动的集成机器学习分析*

周锦涛1,2(), 余文超1,2(), 杜远生1,2, 邓旭升2,3, 翁申富2,4, 雷志远2,5   

  1. 1 中国地质大学(武汉)地球科学学院,湖北武汉,430074
    2 自然资源部基岩区矿产资源勘查工程技术创新中心,贵州贵阳 550081
    3 贵州省地质调查院,贵州贵阳 550081
    4 贵州省地质矿产勘查开发局106地质大队,贵州遵义 563003
    5 贵州省地质矿产勘查开发局,贵州贵阳 520300
  • 收稿日期:2024-08-24 修回日期:2024-11-19 出版日期:2025-04-01 发布日期:2025-04-01
  • 作者简介:
    周锦涛,男,1998年生,博士研究生,主要从事铝土矿沉积地质学研究。E-mail:
  • 基金资助:
    *国家重点研发计划项目“植物登陆的环境资源效应”(编号:2022YFF0800200)和湖北省创新群体项目“地球生物学大数据与计算模拟”(编号:2023AFA006)联合资助

Occurrence forms of rare earth elements in aluminum-bearing rock series in China: ensemble machine learning analysis driven by major element data

ZHOU Jintao1,2(), YU Wenchao1,2(), DU Yuansheng1,2, DENG Xusheng2,3, WENG Shenfu2,4, LEI Zhiyuan2,5   

  1. 1 School of Earth Sciences,China University of Geosciences(Wuhan),Wuhan 430074,China
    2 Innovation Center of Ore Resources Exploration Technology in the Region of Bedrock,Ministry of Natural Resources of People’s Republic of China,Guiyang 550081,China
    3 Guizhou Geological Survey,Guiyang 550081,China
    4 Geological Brigade 106,Bureau of Geology and Mineral Exploration and Development of Guizhou Province, Guizhou Zunyi 563003,China
    5 Bureau of Geology and Mineral Exploration and Development of Guizhou Province,Guiyang 520300,China
  • Received:2024-08-24 Revised:2024-11-19 Online:2025-04-01 Published:2025-04-01
  • About author:
    ZHOU Jintao,born in 1998,is a Ph.D. candidate in the School of Earth Sciences at China University of Geosciences(Wuhan). His primary research focus is on sedimentary geology of bauxite. E-mail: .
  • Supported by:
    Co-funded by the National Key R & D Program of China(No. 2022YFF0800200)and the Innovation Group of Hubei(No. 2023AFA006)

摘要:

铝土矿及含铝岩系中的稀土元素是重要的潜在供应源,随着技术进步和市场需求增长,其勘探、开发和利用变得日益重要。目前,对含铝岩系中稀土元素的主要赋存形式和富集机制仍有争议,尤其是重稀土(HREE)。本研究汇编了中国含铝岩系的地球化学数据,利用机器学习方法预测轻稀土(LREE)和重稀土(HREE)含量,探讨其赋存形式。研究构建了随机森林(RF)、极限梯度提升(XGBoost)、支持向量机(SVM)和多层感知器(MLP)4种模型,并结合最优的2种模型构建集成模型,以提高预测性能。结果表明,集成模型在预测HREE和LREE含量方面表现更佳,能较好预测剖面尺度的稀土变化规律,并对高稀土含量剖面更敏感。特征重要性评估显示,P2O5和TFe2O3是预测HREE含量的关键变量,表明铁相矿物和磷酸盐矿物是HREE的主要载体。HREE可能通过类质同象替代和内环络合形式在磷酸盐矿物和铁相矿物中富集。含铝岩系中铁相矿物的存在是赋存HREE的基础,而磷酸盐矿物则是富集HREE的关键。对于LREE,P2O5的重要性显示含磷矿物是其重要赋存载体,即含磷稀土矿物为代表的独立稀土矿物是中国含铝岩系LREE的重要赋存形式。黏土矿物和铝矿物的离子吸附形式作为一种背景现象同样存在,但对稀土异常富集影响较小。研究建议,在找矿勘查中,针对LREE应关注P2O5含量较高的层位,含铝岩系的岩性应关注贫铁铝土矿和黏土质铝土矿。对于HREE,应首先关注TFe2O3含量较高的层位,若同时有较高的P2O5含量,则HREE富集可能性更大,建议关注的岩性包括富铁铝土矿和铝土质黏土岩。本研究建立的稀土含量预测模型在中国含铝岩系伴生稀土预测方面展现出潜力,需进一步验证、优化与应用。

关键词: 集成模型, 铁相矿物, 磷酸盐矿物, 稀土矿物

Abstract:

Bauxite and associated aluminum-bearing rock series,which host rare earth elements(REE),are considered significant potential sources of REE. With the advancement of new technologies and the increasing global market demand,the exploration,development,and utilization of REE associated with aluminum-bearing rock series have become increasingly critical. However,the dominant occurrence forms of REE in these rock series remain controversial. Moreover,most studies have primarily focused on Light Rare Earth Elements(LREE),while the occurrence forms and enrichment mechanisms of Heavy Rare Earth Elements(HREE)remain poorly understood. To address these issues,this study compiled geochemical data from Chinese aluminum-bearing rock series and attempted to utilize machine learning methods based on major elemental compositions to predict LREE and HREE contents,as well as to explore the occurrence forms of REE in these rock series. Four models were constructed for this purpose: Random Forest(RF),Extreme Gradient Boosting(XGBoost),Support Vector Machine(SVM),and Multi-Layer Perceptron(MLP). Additionally,two ensemble models were developed by combining the two best-performing models among the four. The results demonstrated that the ensemble models exhibited superior predictive performance for both HREE and LREE contents. The two ensemble models successfully predicted the variation of REE at the profile scale and delineated the REE enrichment horizons. These models demonstrated enhanced sensitivity to profiles with higher overall REE content,leading to improved predictive performance. Feature importance analysis revealed that P2O5 and TFe2O3 are critical variables for predicting HREE content,indicating that iron-bearing and phosphate minerals are primary carriers of HREE. The enrichment of HREE in phosphate minerals likely occurs via a substitution mechanism,while iron-bearing minerals enrich HREE through inner-sphere complexation. The presence of iron-bearing minerals in aluminum-bearing rock series is fundamental to HREE occurrence,and their absence may result in lower HREE content. Phosphate minerals play a crucial role in HREE enrichment,complementing iron-bearing minerals to facilitate high HREE content in aluminum-bearing rock series. The high importance of P2O5 in predicting LREE content suggests that phosphorus-bearing minerals are significant carriers of LREE. Independent REE minerals,particularly phosphorus-bearing REE minerals,represent an important form of LREE occurrence in Chinese aluminum-bearing rock series. While clay and aluminum minerals contribute to ion adsorption as a background phenomenon,they have minimal impact on abnormal REE enrichment. This study recommends focusing on strata with higher P2O5 content for potential LREE enrichment in practical mineral exploration. For aluminum-bearing rock series,attention should be given to low-iron bauxite and clayey bauxite. For HREE,strata with higher TFe2O3 content should be prioritized,especially when accompanied by elevated P2O5 levels. Lithologies suggested for attention include iron-rich bauxite and bauxitic claystone. In addition,the prediction model developed in this study shows potential in predicting REE associated with aluminum-bearing rock series in China,and is in urgent need of further optimization for validation and application.

Key words: ensemble model, iron-bearing mineral, phosphate mineral, REE mineral