| 沉积、成岩与铀成矿:中国砂岩型铀矿研究的创新发现与认知挑战 |
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| 引用本文： | 焦养泉,吴立群,荣辉,张帆,乐亮,宋昊,陶振鹏,彭虎,孙钰函,向尧.沉积、成岩与铀成矿:中国砂岩型铀矿研究的创新发现与认知挑战[J].地球科学,2022,47(10):3580-3602. |
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| 作者姓名： | 焦养泉 吴立群 荣辉 张帆 乐亮 宋昊 陶振鹏 彭虎 孙钰函 向尧 |
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| 作者单位： | 1.中国地质大学资源学院, 湖北武汉 430074 |
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| 基金项目： | 国家重点研发计划项目2018YFC0604202国家自然科学基金项目42172128国家自然科学基金项目41502105中央地质勘查基金专题研究项目2008150013国家重点基础研究发展计划2015CB453003中国地质大学(武汉)学科杰出人才基金资助项目102-162301192664 |
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| 摘 要： | 21世纪，中国在砂岩型铀矿勘查领域获得了前所未有的辉煌成就.砂岩型铀矿产出于沉积盆地，铀矿的形成必须经历由沉积埋藏到抬升成矿两个重要的演化阶段.其中，在抬升成矿阶段，大气降水和氧化-还原作用的参与和约束是最显著的成矿特征.显然，这是一种典型的表生成岩作用的产物，是铀储层复杂成岩序列中的重要一环，隶属于“外生成矿”的范畴.虽然，砂岩型铀矿的成矿作用遵循氧化还原与铀变价的普遍机理，但是特殊的沉积背景却导致了铀成矿作用的多样性和地区的专属性.一些由沉积作用、沉积环境和古气候造就的关键控矿要素，能够从“基因”上直接影响表生成岩阶段的铀成矿作用，由沉积、成岩到铀成矿是一个具有成因联系的地质过程，而盆山耦合机制始终是其最根本的原始驱动力.随着对铀成矿作用细节行为研究的深入，一些创新发现不断地冲击着以往固有的认识，诸如碳质碎屑与铀成矿的相互作用、黄铁矿复杂而有序的演化习性、碳酸盐胶结物与铀成矿的共生叠置、敏感矿物的流体示踪、铀储层非均质性制约下的铀成矿机理、双重还原介质制矿模型、铀成矿的复合地球化学障等.还有一些研究对传统地质学理论提出了认知挑战，诸如，铀储层开放成岩环境中碳质碎屑的“碳化作用机理”、黄铁矿溶蚀或者生长界面上的铀沉淀化学动力机制、干旱沉积背景的铀成矿机理等.同时，铀成矿机理和普遍规律的研究，也为砂岩型铀矿的衰变地质效应研究和盆地铀资源的系统探索奠定了良好的地质基础.相信，针对沉积盆地整装的系统的成矿机理与成因联系研究，必将释放巨大的盆地铀资源潜力和矿床产能，在进一步丰富铀成矿理论的同时助力实现“双碳目标”.
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| 关 键 词： | 沉积作用 成岩-成矿作用 成矿机理 砂岩型铀矿 盆地铀资源 沉积学 |
| 收稿时间： | 2022-04-23 |
Sedimentation,Diagenesis and Uranium Mineralization: Innovative Discoveries and Cognitive Challenges in Study of Sandstone-Type Uranium Deposits in China |
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| Abstract: | In the 21th century, China has made brilliant achievements in the exploration of sandstone-type uranium deposits. Sandstone-type uranium deposits are located in sedimentary basins. The formation of uranium deposits must go through two important evolutionary stages from sedimentary burial stage to uplift metallogenic stage. The participation and restriction of atmospheric precipitation and oxidation-reduction are the most significant metallogenic characteristics in the uplift metallogenic stage. Obviously, this is the product of a typical supergene diagenesis, an important link in the complex diagenetic sequence of uranium reservoirs, and belongs to the category of "exogenetic mineralization". Although the mineralization of sandstone-type uranium deposit follows the general mechanism of oxidation-reduction and uranium valence change, the special sedimentary background leads to the diversity and regional specificity of uranium mineralization. Some key ore controlling elements created by sedimentation, sedimentary environment and paleoclimate can directly affect uranium mineralization in epigenetic rock stage from "gene". From sedimentation, diagenesis to uranium mineralization is a geological process with genetic connection, and the basin-mountain coupling mechanism is always the most fundamental original driving force. With the in-depth study of the detailed behavior of uranium mineralization, some innovative discoveries continue to impact the previous inherent understanding, such as the interaction between carbonaceous debris and uranium mineralization, the complex and orderly evolution habit of pyrite, the symbiosis and superposition of carbonate cement and uranium mineralization, the fluid tracing of sensitive minerals, the uranium mineralization mechanism restricted by the heterogeneity of uranium reservoir, the ore making model of double reducing medium, and compound geochemical barrier of uranium mineralization, etc. Other studies have posed cognitive challenges to traditional geological theories, such as the "carbonization mechanism" of carbonaceous debris in the open diagenetic environment of uranium reservoir, the chemical dynamic mechanism of uranium precipitation on the dissolution or growth interfaces of pyrite, the uranium metallogenic mechanism in arid sedimentary background, etc. At the same time, the study of uranium metallogenic mechanism and general law has also laid a good geological foundation for the study of geological effects of sandstone-type uranium deposit decay and the systematic exploration of basin uranium resources. It is believed that the systematic study on the metallogenic mechanism and genetic relationship of the whole sedimentary basin will release the huge basin uranium resource potential and deposit productivity, and help to achieve the "double carbon goal" while further enriching the uranium metallogenic theory. |
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