四川东部华蓥山海相二叠/三叠系界线附近的锶同位素组成  

Strontium Isotopic Composition Near Marine Permian/Triassic Boundary of the Huaying Mountain,Eastern Sichuan

作　　者：胡作维[1] 黄思静[1] 刘丽红[1] 佟宏鹏[1] 贺艳祥[1] 

机构地区：[1]成都理工大学油气藏地质及开发工程国家重点实验室沉积地质研究院,四川成都610059

出　　处：《地球学报》2010年第6期853-859,共7页Acta Geoscientica Sinica

基　　金：国家自然科学基金项目(编号:40839908;40672072);教育部博士点基金项目(编号:20050616005)联合资助

摘　　要：二叠/三叠系界线附近的地球化学记录在地球环境重大变革研究中有着重要的意义。根据锶同位素地层学的基本原理,本文对四川东部华蓥山海相二叠/三叠系界线附近碳酸盐岩样品进行显微组构观察、化学成分分析及其对同期海水代表性评估的基础上,测试了这些样品的锶同位素组成。结果表明,这些样品的原始沉积组构保存较好、Sr含量较高,可以认为其只遭受过较低程度的成岩蚀变改造,并保留了较多的海水原始信息,锶同位素比值分布范围在0.707158~0.707334之间,与前人公布的同期海水值吻合较好,体现了全球地质事件对海水锶同位素组成控制的一致性。四川东部华蓥山二叠/三叠系界线附近较为系统的锶同位素演化研究,可望为我国南方海相二叠/三叠系界线附近化学地层学及其对比研究提供一些有价值的基础资料。Geochemical records play an important role in the study of the Permian/Triassic boundary,where geo-logical environment significantly changed.Based on the fundamental principle of strontium isotope stratigraphy,the authors analyzed the rock fabric and chemical composition,made preservative evaluation for coeval seawater of the carbonate rock samples near the Permian/Triassic boundary in the Huaying Mountain,eastern Sichuan,and then measured strontium isotopic composition of the samples.These samples haven’t suffered much from the strong diagenetic alteration and can represent preferably the coeval seawater,as evidenced by their relatively good original sedimentary fabric and high Sr concentrations.The 87Sr/86Sr ratios of six samples vary from 0.707158 to 0.707334,and are consistent with available 87Sr/86Sr ratios of coeval seawater near the Permian/Triassic boundary,suggesting the global control of geological events over the 87Sr/86Sr ratios of seawater.The application of stron-tium isotope stratigraphy to the Permian/Triassic boundary in the Huaying Mountain will provide some useful ba-sic data for the chemo-stratigraphic and global correlative studies of marine Permian/Triassic boundary in South China.

关 键 词：二叠系 三叠系 锶同位素地层学 华蓥山 四川东部 

分 类 号：P534[天文地球—古生物学与地层学] P597.2[天文地球—地质学]