| 川南兴文地区上二叠统龙潭组黏土岩锂的富集特征及赋存状态 |
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| 引用本文： | 郝雪峰,唐屹,潘蒙,贺洋,何洋飘,周颂德,付小方,梁斌.川南兴文地区上二叠统龙潭组黏土岩锂的富集特征及赋存状态[J].地质学报,2024,98(5):1403-1420. |
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| 作者姓名： | 郝雪峰 唐屹 潘蒙 贺洋 何洋飘 周颂德 付小方 梁斌 |
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| 作者单位： | 四川省综合地质调查研究所，四川成都，610081;四川省第七地质大队，四川乐山，614000;西南科技大学环境与资源学院，四川绵阳，621000 |
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| 基金项目： | 本文为四川省自然科学基金项目(编号 23NSFSC0191)和四川省地质调查研究院重大专项(编号SCIGS- CZDXM- 2023002)资助的成果 |
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| 摘 要： | 四川南部位于二叠纪峨眉山大火山岩省中—外带，广泛分布与火成岩风化- 沉积有关的上二叠统龙潭组黏土岩，具有形成锂等关键金属矿产资源的地质背景和成矿条件。本文对川南兴文地区上二叠统龙潭组下部黏土岩进行了较为系统的地质调查，对研究区以及钻孔岩芯样品进行了化学分析，以确定黏土岩中锂等元素的分布特征及富集规律。在此基础上，利用粉晶X- 射线衍射(XRD)分析了富锂黏土岩的矿物组成，采用聚焦离子束飞行时间二次离子质谱仪(FIB- TOF- SIMS)分析了富锂黏土岩微米尺度上的元素分布特征。结果表明，龙潭组下部黏土岩中富集Li以及Ga、Nb等元素，是一个多种关键金属的富集层，具有良好的成矿潜力和找矿前景。本区黏土岩来源于峨眉山大火山岩省火山岩的风化产物，富锂的矿层主要为含黄铁矿高岭石黏土岩，其沉积成岩环境为海陆过渡地区的潟湖还原咸水环境，Li含量与化学风化强度(CIA指数)密切相关，具有风化- 沉积型矿床的特征。富锂黏土岩中锂除少量赋存于锂云母之中外，主要是被吸附于黏土岩的蒙脱石相中，部分进入蒙脱石矿物结构，还有一部分赋存于伊利石中。Li除了来自火山岩的风化释放以外，部分还可能来自滨海浅层地下卤水的直接补给，从而形成含锂云母的高品位的富锂黏土岩。
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| 关 键 词： | 锂 黏土岩 赋存状态 龙潭组 四川南部 |
| 收稿时间： | 2024/1/17 0:00:00 |
| 修稿时间： | 2024/4/7 0:00:00 |
Enrichment characteristics and occurrence state of lithium in claystones of Upper Permian Longtan Formation in Xingwen area, southern Sichuan |
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| HAO Xuefeng,TANG Yi,PAN Meng,HE Yang,HE Yangpiao,ZHOU Songde,FU Xiaofang,LIANG Bin.Enrichment characteristics and occurrence state of lithium in claystones of Upper Permian Longtan Formation in Xingwen area, southern Sichuan[J].Acta Geologica Sinica,2024,98(5):1403-1420. |
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| Authors: | HAO Xuefeng TANG Yi PAN Meng HE Yang HE Yangpiao ZHOU Songde FU Xiaofang LIANG Bin |
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| Institution: | Sichuan Institute of Comprehensive Geological Survey, Chengdu, Sichuan 610081, China;7th Geological Brigade of Sichuan Province, Leshan, Sichuan 614000, China;School of Environment and Resources, Southwest University of Science and Technology, Mianyang, Sichuan 621000, China |
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| Abstract: | Southern Sichuan, located in the middle- outer zone of the Permian Emeishan Large Igneous Province, is extensively distributed with claystones from the Lower Permian Longtan Formation. These claystones, which are related to igneous rock weathering and deposition, have a geological background and metallogenic conditions suitable for forming lithium and other critical metal resources. This paper presents a systematic geological survey of the lower part of the Upper Permian Longtan Formation in the Xingwen area of southern Sichuan.Chemical analysis of samples from the study area and drill cores was conducted to determine the distribution and enrichment of lithium and other elements in the claystones.Additionally, the mineral composition of the lithium- rich claystones was analyzed using powder crystal X- ray diffraction (XRD), and the distribution characteristics of elements at the micrometer scale were analyzed using a focused- ionbeam and time- of- flight secondary ion mass spectrometer (FIB- TOF- SIMS). The results show that the claystones in the lower part of the Longtan Formation are enriched in Li, Ga, Nb, and other elements, making them a valuable source of multiple critical metals with good ore- forming potential and prospecting prospects. These claystones originate from the weathering processes of volcanic rocks within the Emeishan Large Igneous Province.The lithium- rich rocks are mainly pyrite- bearing kaolinitic claystones, witha sedimentary environment in the saline lagoon of the transitional zone between sea and land. The Li content is closely related to the chemical weathering intensity (CIA index), exhibiting the characteristics of weathering- sedimentary deposits. Lithium, apart from being present in lepidolite to a small extent, is mainly adsorbed in the montmorillonite phase of claystones, with some entering the mineral structure of montmorillonite andillite. In addition to weathering release from volcanic rocks, a portion of lithium potentially originates directly from coastal shallow groundwater, contributing to the formation of high- grade lithium- bearing mica within lithium- rich claystones. |
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| Keywords: | lithium claystone occurrence state Longtan Formation southern Sichuan |
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