投稿时间：2024-07-31
修订日期：2026-03-14
网络发布日期：2026-04-22
中文摘要:桂西沉积型铝土矿广泛分布于各碳酸盐岩台地，各台地含矿岩系层序组合存在明显差异。文章选取桂西靖西台地、东兰-巴马-凤山台地和平果台地沉积型铝土矿为研究对象，通过含矿岩系宏观地质特征、微观岩相学等方法，查明桂西含矿岩系层序组合差异特征，厘定出各层位沉积相并分析了各台地沉积相演化过程及其异同。桂西沉积型铝土矿含矿岩系整体自下而上为“底砾岩-铁铝岩-铝土矿-铝土岩-碳质泥岩”层序建造，其中层序组合差异主要发生在铝土矿层中，靖西台地铝土矿层产出层序由下至上为“豆（鲕）状-土状-致密块状-砂屑状”，东-巴-凤台地为“致密块状-豆（鲕）状-土状-砂屑状”，平果台地则为“豆（鲕）状-致密状-砂屑状-土状”。桂西含矿岩系形成于陆相-海陆过渡相环境，根据岩相可划分为风化壳底砾岩相、深水洼地铁铝岩相、汇水凹地铝土矿相（可分为浅水凹地豆（鲕）状-砂屑状铝土矿相、滨岸高地土状铝土矿相和深水凹地致密块状铝土矿相）、浅水洼地-潮坪铝土岩相、沼泽碳质泥岩相，对应各沉积相演化阶段分为容矿场所准备阶段、铝土矿化早阶段、铝土矿化主阶段、铝土矿化晚阶段、铝土矿化末阶段。铝土矿化主阶段（汇水凹地铝土矿相）各台地内部水体水位在时间上由早到晚存在四次不同程度的升降动态变化，其水体深度不同程度变化均以上一次水体变化后水体深度为参考，导致台地内沉积相演化差异，靖西台地存在“中程度下降-高程度下降-高程度上升-低程度下降”变化，对应“浅水凹地相、滨岸高地相、深水凹地相、浅水凹地相”演化过程，同时期东-巴-凤台地为“高程度上升-中程度下降-高程度下降-中程度上升”变化，对应“深水凹地相、浅水凹地相、滨岸高地相、浅水凹地相”，平果台地存在“中程度下降-高程度上升-低程度下降-高程度下降”变化，对应“浅水凹地相、深水凹地相、浅水凹地相、滨岸高地相”。铝土矿化晚阶段平果台地部分地区发育潮坪环境形成潮坪铝土岩相，平果其他地区和其他台地则发育浅水洼地铝土岩相，铝土矿化末阶段靖西、东-巴-凤台地较为干旱仅局部地区发育潮湿环境形成沼泽碳质泥岩相，而平果台地则受海水影响多发育潮湿环境形成沼泽碳质泥岩相。
Abstract:The sedimentary bauxite deposits are widely distributed in various carbonate platforms in western Guangxi. The stratigraphic sequences assemblage assemblage of ore-bearing formations in each platform showed significant differences. This study focused on the sedimentary bauxite deposits in the Jingxi Platform, the Donglan-Bama-Fengshan Platform and the Pingguo Platform in western Guangxi. Through the analysis of the macroscopic geological characteristics and the microscopic petrography of ore-bearing formations, the differential characteristics of stratigraphic sequence assemblage of ore-bearing formations in these platforms were identified, and the sedimentary facies of each horizon were determined.The evolution process and their similarities and differences of sedimentary facies among the platforms were also analyzed. The sedimentary bauxite ore-bearing formations in western Guangxi are composed of “basal conglomerate, iron-aluminium rock, bauxite, bauxite rock, carbonaceous mudstone” from bottom to top. The main differences of stratigraphic sequence assemblage occurred in the bauxite layer: In Jingxi platform, the sequence of bauxite deposit presented as “pisolitic(oolitic) bauxite, soil-like bauxite, dense massive bauxite, sand-like bauxite” from bottom to top; In Donglan-Bama-Fengshan, the sequence presented as “dense massive bauxite bean, pisolitic(oolitic) bauxite, soil-like bauxite, sand-like bauxite”; in Pingguo platform, and the sequence presented as “pisolitic(oolitic) bauxite, dense massive bauxite, sand-like bauxite, soil-like bauxite”. The ore-bearing formations in western Guangxi were formed in the terrestrial marine-continental transition environment. The sedimentary facies can be divided into weathered crust basal conglomerate facies, deep-water depression iron-aluminium rock facies, catchment depression bauxite facies (which can be further divided into shallow water depression pisolitic(oolitic)-sand like bauxite facies, riparian upland soil-like bauxite facies, and deep water depression dense massive bauxite facies), shallow depression-tidal flat bauxite rock facies, and swamp carbonaceous mudstone facies. The sedimentary facies correspond to the evolution stages: Ore-bearing site preparation stage, early stage of bauxite mineralization, main stage of bauxite mineralization, late stage of bauxite mineralization, and end stage of bauxite mineralization. During the main stage of bauxite mineralization (catchment depression bauxite facies), the water level in the different platforms underwent four cycles of rise and fall to varying degrees over time, leading to differences in the sedimentary evolution among the platforms. There was a “middle degree fall, high degree fall, high degree rise, low degree fall” in the Jingxi Platform, corresponding to the evolution process of “shallow water depression facies, riparian upland facies, deep water depression facies, and shallow water depression facies”. The Dong-Ba-Feng Platform experienced a “high degree rise, middle degree fall, high degree fall, middle degree rise” change during the same period, corresponding to “deep water depression facies, shallow water depression facies, riparian upland facies, and shallow water depression facies”. The Pingguo platform showed a “middle degree fall, high degree rise, low degree fall, high degree fall”, corresponding to “shallow water depression facies, deep water depression facies, shallow water depression facies, and riparian upland facies”. In the late stage of bauxite mineralization, some areas of the Pingguo Platform developed tidal flat environment, forming tidal flat bauxite facies, the other area of Pingguo and other platforms developed shallow depression bauxite facies, Jingxi and Dong-Ba-Feng Platform were relatively arid at end stage of bauxite mineralization, and only local areas developed humid environments to form swamp carbonaceous mudstone facies, while Pingguo Platform was mostly affected by seawater to form swamp carbonaceous mudstone facies.
keywords:metallogenic platform sedimentary evolution sedimentary facies sedimentary bauxite western Guangxi
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基金项目:本文得到国家自然科学基金（编号：41362006）资助
引用文本：
向绍立,庞保成,许箭琪,罗靖伟,陈涛,刘旺,卢光辉,徐海鹏,姚双秋.2026.桂西地区沉积型铝土矿含矿岩系层序组合差异对沉积相演化的指示[J].矿床地质,45(2):352~374XIANG ShaoLi,PANG BaoCheng,XU JianQi,LUO JingWei,CHEN Tao,LIU Wang,LU GuangHui,XU HaiPeng,YAO ShuangQiu.2026.Indication of sedimentary facies evolution due to differences in sequence assemblage of sedimentary bauxite ore-bearing formations in western Guangxi[J].Mineral Deposits45(2):352~374
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