碳酸盐矿物激光原位U-Pb定年基本原理、分析方法与地学应用

碳酸盐矿物作为地壳中沉积作用与流体活动的直接产物，记录了沉积、热事件的全过程，是进行同位素年代学研究的理想矿物。碳酸盐矿物传统的U系列定年法、同位素稀释法定年体系成功率低，耗时长，导致定年难度大，限制了碳酸盐矿物地质年代学的发展。近年来，碳酸盐矿物激光原位U-Pb定年技术取得重要进展，使低U碳酸盐矿物地质年代的精确测定成为了可能。碳酸盐矿物LA-ICP-MS U-Pb年代学具有空间分辨率高、耗时短等显著优势，被广泛应用于地学研究中。文章归纳总结了碳酸盐矿物同位素定年体系的基本原理及分析方法，回顾了近5年碳酸盐矿物LA-ICP-MS U-Pb年代学应用的研究进展，重点论述该方法在确定脆性变形时代、岩石破裂以及盆地流体流动时限、碳酸盐地层的成岩时代和成矿热液活动时限4个方面的应用，并梳理了该方法尝试解决的科学问题和取得的新认识。碳酸盐矿物定年方法的发展和应用，增强了人们对地壳变形和演化的理解，解决了部分迄今为止难以确定的地质体历史演化问题，为未来地质年代学的研究提供了新思路，在地球科学研究中具有重要潜力。

Principle, methods, and geological applications of carbonates LA-ICP-MS U-Pb geochronology

Carbonates are ubiquitous, forming in a wide range of settings including caves, soils, the oceans, during burial from hydrothermal fluids, and along faults, with recording the processes of fluid occurrence. Thus, accurate ages of the minerals are necessary to understand the lifespan of fluid events. However, low uranium carbonates are difficult to date using traditional U series dating and isotope dilution due to ultra-low concentrations, the lack of ideal standards and the time-consuming process. With the recent advent of in-situ high precision analysis techniques, LA-ICP-MS has made significant progress in obtaining more accurate dating results with the advantages of high spatial resolution and rapid data acquisition and has been widely used in different geological fields. Herein, this paper investigates the research progress for carbonate U-Pb dating and introduces and discusses the related fundamentals and methodologies of the U-Pb dating system. The new technique with untapped potential for solving numerous geochronological problems from the timing of faulting and the age of sedimentation, ore deposits and diagenesis are furthermore reviewed in the present study. The applications mentioned have enriched the understanding of the formation and evolution of the crust and resolved some complicated evolution history in geosciences. In the future, it is promising that applying the U-Pb dating of carbonates and rare earth element analysis will be a significant development direction and provide new insights into carbonate geochronology studies. It is worth noting that the widespread use of U-Pb geochronology is the premise of application success.