碳酸盐岩钙同位素化学分离方法改进及其在青藏高原地质样品中的应用前景

本文报导了在前人基础上改进的碳酸盐岩(白云石－方解石)地质样品钙同位素化学分离方案。通过对比云南永善桧溪剖面白云岩－灰岩过渡岩性在不同浓度盐酸下淋洗结果,确定了4N浓度盐酸能有效富集白云石－方解石体系中的钙元素,且热电离质谱(TIMS)测试结果显示4N盐酸与1.6N盐酸淋洗方案处理后钙同位素测试结果一致,表明在相同测试精度的情况下,针对白云石－方解石体系下碳酸盐岩地质样品化学分离方案能提高化学分离效率。本文进一步结合青藏高原研究热点问题,对钙同位素在青藏高原地质样品的应用前景进行了分析,分析表明,钙同位素在青藏高原隆升前古海洋环境重建、隆升期构造活动恢复及隆升后火成岩来源示踪上具有广泛应用前景。

Improvement of chemical separation method of calcium isotopes in carbonate rocks and its application prospect in geological samples of the Qinghai-Tibet plateau

This paper reports an improved scheme for chemical separation of calcium isotopes from carbonate rock (dolomite-calcite) geological samples. By comparing the leaching results of dolomite limestone transition lithology in Huixi Section, Yongshan, Yunnan, under different concentrations of hydrochloric acid, it is determined that 4N concentration hydrochloric acid can effectively enrich calcium in dolomite calcite system, and the thermal ionization mass spectrometry (TIMS) test results show that the calcium isotope test results after treatment of 4N hydrochloric acid and 1.6N hydrochloric acid leaching scheme are consistent, indicating that under the same test accuracy, The chemical separation scheme for carbonate geological samples in dolomite calcite system can improve the chemical separation efficiency. This paper further analyzes the application prospects of calcium isotopes in the geological samples of the Qinghai Tibet Plateau in combination with the hot issues in the study of the Qinghai Tibet Plateau. The analysis shows that calcium isotopes have broad application prospects in the reconstruction of the paleomarine environment before the uplift of the Qinghai Tibet Plateau, the restoration of tectonic activity during the uplift, and the tracing of the source of igneous rocks after the uplift.