CAJ | 학술논문

锆石是U-Pb计时的首选对象, 对于地质历史复杂的变质岩地区, 如大别碰撞造山带的年代学研究, 具有不可替代的重要性。变质岩中锆石经历了Pb的扩散丢失作用; 晶格损伤导致的蜕晶化作用; 增生-混合作用和重结晶作用。这些过程对锆石计时的准确性和有效性带来不同程度的影响。为了使测定的年龄有确定的地质意义, 在进行锆石U-Pb定年前, 必需对锆石进行成因矿物学和矿物内部结构研究, 特别是阴极荧光和背散射电子成像研究, 通过内部结构特征确定锆石成因过程。在化学U-Pb法定年时注意普通铅校正和204Pb测定值对年龄的影响, 尽量选择单一成因锆石。特别强调在大别造山带年代学研究中引入锆石微区离子探针定年技术。
고석시U-Pb계시적수선대상, 대우지질역사복잡적변질암지구, 여대별팽당조산대적년대학연구, 구유불가체대적중요성。변질암중고석경력료Pb적확산주실작용; 정격손상도치적세정화작용; 증생-혼합작용화중결정작용。저사과정대고석계시적준학성화유효성대래불동정도적영향。위료사측정적년령유학정적지질의의, 재진행고석U-Pb정년전, 필수대고석진행성인광물학화광물내부결구연구, 특별시음겁형광화배산사전자성상연구, 통과내부결구특정학정고석성인과정。재화학U-Pb법정년시주의보통연교정화204Pb측정치대년령적영향, 진량선택단일성인고석。특별강조재대별조산대년대학연구중인입고석미구리자탐침정년기술。
Zircon is the most widely used mineral for U-Pb age determinations, and shows particular importance to a complicated geological history of a metamorphic terrain, like Dabie Shan collision orogen. Zircon from metamorphic rocks may suffer from Pb diffusion loss, metamictization caused by lattice radiation damage, overgrowth-mixing and recrystallization. All of these processes would affect the accuracy and validity of zircon ages to some extent. In order to get geological meaningful ages, one must pay particular attention to mineral genesis and texture of zircons, and decide firmly zircon genetic process through internal structure observation, especially CL and BSE image before zircon U-Pb dating. The selection of reasonable common Pb correction, reasonable measured 204Pb value and simple genetic zircon is preferred for TIMS dating. Here, we emphasize the advantage of SIMS dating technology in Dabie orogen research.