近日，中国科学院青海盐湖所Qingyu Hai团队研究了盐湖型硝石矿床氮氧同位素变化及其成因意义。2026年3月11日出版的《地球化学学报》发表了这项成果。

硝酸盐类矿物是工农业生产的关键资源，因此解析大型矿床的成因具有战略意义。根据沉积环境差异，硝酸盐矿床通常分为盐坪型与盐湖型两大类型。前期同位素研究表明，全球最大的阿塔卡马沙漠（智利）硝酸盐矿床以及中国新疆的盐坪型硝酸盐矿床，其硝酸盐主要来源于大气沉降。然而新疆乌宗布拉克和乌勇布拉克硝石矿床（盐湖型）的氮氧同位素特征却与盐坪型存在显著差异，暗示着存在额外的硝酸盐来源。

研究组通过系统分析新疆库米什盆地硝石矿床及相关水样（融雪水、裂隙水、地下水、卤水、泉水）的δ¹⁵N与δ¹⁸O值，精准约束了物质来源。结果表明：盐坪型硝酸盐矿床的硝酸盐完全源自大气沉降；而盐湖型硝石矿床除大气贡献外，还叠加了水体输入的硝酸盐。这种双源混合模型不仅解释了二者迥异的同位素特征，更为区分干旱内流盆地硝石矿床类型提供了理论框架。

附：英文原文

Title: Nitrogen and oxygen isotopic variations in salt lake type niter deposits: Implications for genesis

Author: Ma, Xuehai, Cheng, Huaide, Hai, Qingyu, Han, Wenhua, Ma, Haizhou

Issue&Volume: 2026-03-11

Abstract: Nitrate salts are critical resources for both agriculture and industry, so understanding the genesis of large deposits is of strategic importance. Nitrate deposits are typically classified into two main types based on their depositional environment: salt flat and salt lake. Previous isotopic studies have established that nitrate in the Atacama deposit, Chile, the world’s largest, and in salt flat-type deposits in Xinjiang, China, is of predominantly atmospheric origin. However, the nitrogen and oxygen isotopic signatures of the Wuzongbulake and Wuyongbulake niter deposits (salt lake type) in Xinjiang differ significantly from those of the salt flat type, suggesting an additional nitrate source. This study systematically analyzed the δ15N and δ18O values of nitrate from niter deposits and associated aqueous samples (snowmelt, fracture water, groundwater, brine, and spring water) from the Kumishi Basin, Xinjiang, to constrain these sources. The obtained results reveal that nitrate deposits (salt flat type) derive nitrate solely from atmospheric deposition. In contrast, niter deposits (salt lake type) incorporate nitrate from aqueous pathways in addition to the atmospheric contribution. This dual-source mixing model explains their contrasting isotopic signatures and provides a framework for differentiating niter deposit types in arid endorheic basins.

DOI: 10.1007/s11631-026-00858-2

Source: https://link.springer.com/article/10.1007/s11631-026-00858-2