A novel mechanism of uranium mineralization: The role of zircon adsorption at the Qigequan deposit, Qaidam Basin, NW China

IF 3.3 2区地球科学 Q1 GEOLOGY

Sedimentary Geology Pub Date : 2026-03-01 Epub Date: 2026-01-07 DOI:10.1016/j.sedgeo.2026.107027

Yi-Han Lin , Ming-Sen Fan , Pei Ni , Jun-Yi Pan , Zhe Chi , Zhi-Lin Cheng , Wen-Yi Wu , Chen Zhang , Bing-De Qi , Xue-Bin Wei

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Abstract

Uranium mineralization in sandstone-hosted deposits is influenced by the adsorption capacity of minerals, especially in basin fluids with sub-saturation uranium concentrations. This study investigates the Qigequan sandstone-type uranium deposit in the Qaidam Basin, focusing on uranium distribution and adsorption behavior in zircon. Samples were analyzed using TIMA, BSE, CL imaging, EDS, and EPMA. Results show zircon is abundant in both matrix and clastic components, with uranium occurring in three forms: U1 (in growth zones or inclusions), U2 (in fractures), and U3 (on grain rims). U1 is a magmatic or early hydrothermal product with low U/Th, while U2 and U3 are associated with surface adsorption by mineralizing fluids and have high U/Th. By contrast, uranium minerals unrelated to zircon (i.e., Other-U) have different Th and U characteristics. EPMA mapping reveals that absorbed uranium around rims correlates with elements like Th, Y, Mg, and Ti. Zircon demonstrates a stronger and more selective uranium adsorption capacity than other accessory minerals, despite their higher abundance. We suggest that uranium is absorbed by zircon through a physical-chemical adsorption mechanism, primarily controlled by pH changes caused by the mixing of mildly alkaline oil-gas-related fluids and supergene oxidized fluids. These findings highlight the significant role of zircon as a uranium adsorbent in sandstone-hosted uranium deposits and suggest that surface adsorption, in addition to classical precipitation due to fluid supersaturation, is an important pathway for uranium enrichment. This mechanism offers new insights into uranium mineralization and may refine genetic models of sandstone-type uranium deposits.

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柴达木盆地奇格泉铀矿化新机制：锆石吸附作用

砂岩矿床中的铀矿化受矿物吸附能力的影响，特别是在含铀亚饱和的盆地流体中。本文对柴达木盆地奇格泉砂岩型铀矿床进行了研究，重点研究了铀在锆石中的分布和吸附行为。采用TIMA、BSE、CL成像、EDS和EPMA对样品进行分析。结果表明：锆石在基质和碎屑组分中均富集，铀以3种形式赋存：U1（生长带或包裹体）、U2（裂缝）和U3（颗粒边缘）。U1为岩浆或早期热液产物，U/Th较低，U2和U3与矿化流体表面吸附有关，U/Th较高。而与锆石无关的铀矿物（Other-U）则具有不同的Th和U特征。EPMA图显示，在轮辋周围吸收的铀与Th、Y、Mg和Ti等元素相关。尽管锆石的丰度较高，但其对铀的选择性吸附能力较其他副矿物强。认为铀被锆石吸附是一种物理-化学吸附机制，主要受温和碱性油气流体与表生氧化流体混合引起的pH变化控制。这些发现强调了锆石在砂岩型铀矿床中作为铀吸附剂的重要作用，并表明除了流体过饱和引起的经典沉淀外，表面吸附是铀富集的重要途径。这一机制为铀矿化提供了新的认识，并可能完善砂岩型铀矿床的成因模式。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Sedimentary Geology 地学-地质学

CiteScore

5.10

自引率

7.10%

发文量

133

审稿时长

32 days

期刊介绍： Sedimentary Geology is a journal that rapidly publishes high quality, original research and review papers that cover all aspects of sediments and sedimentary rocks at all spatial and temporal scales. Submitted papers must make a significant contribution to the field of study and must place the research in a broad context, so that it is of interest to the diverse, international readership of the journal. Papers that are largely descriptive in nature, of limited scope or local geographical significance, or based on limited data will not be considered for publication.