摘要
对采自贵州合肥地区的绿豆岩（夹于三叠纪沉积地层中的黄绿色玻屑凝灰岩）光片样品，进行了激光质谱４０Ａｒ－３９Ａｒ多阶段升温和全熔融等时年龄研究，得到的一个样品的坪年龄和等时线以及另一样品的全熔融等时年龄分别为２３８．５±４．８Ｍａ、２３８．９±４．８Ｍａ和２３９．６±４．８Ｍａ，三者基本一致。这批年龄数据支持了贵州绿豆岩地层属于中三叠统的观点。首次为该地层提供了可靠的年龄数据，也为火山沉积地层的地质年代学研究开拓了新的前景。
A polished section of 'green pisolites' (glassy tuff)Collected from Zunyi area of Guishou Province has been dated by laser mass-spectrometer 4oAr-39Ar incremental heating technique,which yielded a plateau age and an isochron age of 238. 5±4. 8Ma and 238. 9± 4. 8Ma,respectively.Another polished section of the same rock has been dated by laser mass-spectrometer 4oAr-39Ar total fusion technique, which also yilded a total fusion isochron age of 239.6±4. 8Ma. The data strongly support the viewpoint that the 'green pisolites' was formed in the Middle Triassic. This is the first isotopic date for determined bed. It proves that this technique is a powerful tool for geochronoligical study on volcanic sedimentary beds.
出处
《岩石学报》
SCIE
CAS
CSCD
北大核心
1996年第3期409-415,共7页
Acta Petrologica Sinica
基金
国家自然科学基金
关键词
绿豆岩
激光质谱
氩同位素
年龄
Laer mass spectrometer
￣40Ar-￣39Ar age
Green pisolitesGlassy tuff)
Guizhou
