• 中文核心期刊
  • 中国科技核心期刊
  • CSCD来源期刊
  • DOAJ 收录
  • Scopus 收录

锶同位素在地质学领域的分析技术与应用研究进展

Research Progress on the Application of Strontium Isotope Analysis Techniques in Geology: A Review

  • 摘要: 锶同位素具有时间相关性和环境敏感性等独特的地球化学性质。随着测试技术的不断成熟与理论体系的逐渐完善,锶同位素已成为地学研究的关键技术手段。然而,由于外界复杂环境对锶同位素比值的异常干扰,基于热电离质谱法(TIMS)或多接收电感耦合等离子体质谱仪(MC-ICP-MS)的常规测试结果可能难以准确解释某些地质演化过程。由此,本文基于锶同位素的固有性质和演化特征,总结了锶同位素分析过程中的样品制备和测试方法,并阐明锶同位素在地层学、岩石学、矿床学和水文地质学等方向的最新进展与认识。锶同位素地层学已形成了包含509百万年至今海水锶同位素变迁的时间序列图,但锶同位素组成受岩浆活动和风化作用等多种因素干扰,作为地层学指标时需要结合特定地质背景仔细校正和解释。岩石学领域通常结合锶同位素区分不同类型岩石的成因、沉积岩石的成岩历程、古环境变迁以及地壳构造活动,然而由于风化、变质作用的影响,锶同位素信息可能无法准确解释岩石成因。锶同位素在矿床学领域用于确定矿床成矿物质来源、流体演化过程和矿床成因类型,但铷-锶同位素体系在高温下可能会因扩散作用和矿物重组等因素导致重置,影响矿物年龄的确定。水文地质学领域利用锶同位素分析地下水的来源和水-岩相互作用过程,而复杂的地下水系统可能使得锶同位素的解释较为困难。据此,本文认为未来需要在重建古海洋锶同位素比值的精确历史、揭示不同温度条件下锶同位素分馏机制、开发精细的锶同位素示踪技术等方面开展深入研究,为锶同位素理论发展及应用提供支撑。

     

    Abstract: Strontium (Sr) isotopes have unique geochemical properties such as time dependence and environmental sensitivity. With the development of testing technology and theoretical system, Sr isotope has become a key technique in geoscience research. However, due to the abnormal interference of the Sr isotope ratio in the complex environment, it may be challenging to appropriately interpret some geological evolution processes using conventional test results based on thermoelectric ionization mass spectrometers (TIMS) or multicollector inductively coupled plasma-mass spectrometers (MC-ICP-MS). Based on the inherent properties and evolutionary characteristics of Sr isotope, this paper summarizes the sample preparation and testing methods in the process of Sr isotope analysis, and expounds the latest progress and understanding of Sr isotope in stratigraphy, petrology, ore deposit science and hydrogeology. It is pointed out that Sr isotope stratigraphy has formed a time series map containing the changes of Sr isotope in seawater from 509 million years to the present. When strontium isotope is employed as a stratigraphic index, it must be properly corrected and interpreted in accordance with a particular geological context because it is influenced by a variety of processes, including weathering and magmatic interference. In the field of petrology, the diagenetic processes of sedimentary rocks, the genesis of various rock types, changes in the paleoenvironment, and crustal tectonic activity are all typically distinguished using strontium isotopes. But the information provided by strontium isotopes is insufficient to precisely describe the creation of rocks because of the impact of weathering and metamorphism. Sr isotope is used in the field of ore deposit science to determine the source of ore-forming materials, the process of fluid evolution and the genetic type of ore deposit. However, at high temperatures, diffusion and mineral recombination can cause the rubidium-strontium isotope system to reset, which can interfere with determining the age of the material. The complicated groundwater system may make it challenging to interpret Sr isotope, which is used in hydrogeology to examine the origin of groundwater and the interaction between water and rock. Therefore, this paper makes the following recommendations for future research: to uncover the mechanism of strontium isotope fractionation at varying temperatures, to develop fine strontium isotope tracer technology to get around the limitations of current strontium isotope research, and to reconstruct the accurate history of the paleomarine strontium isotope ratio. It may offer backing for the advancement and utilization of strontium isotope theory.

     

/

返回文章
返回