三叠系的阶与牙形刺生物地层

Triassic stages and conodont biostratigraphy

三叠纪的3统7阶时限相差极大,晚三叠世的时限最长。牙形刺是三叠纪生物地层的主导化石门类,在生物地层划分中的作用越来越重要。中国三叠纪牙形刺生物地层的牙形刺带已达50带,还会增加,特别是在晚三叠世。阶是全球的地质年代单位,应全球统一,使用共同的名称和定义。不要按国别建阶,更不能按岩相或生物群建阶。陆相地层不适宜建阶,陆相地层的阶名也不宜再使用。

The time interval of three series and seven stages of Triassic are quite different,of which the Late Triassic is the longest. As a leading fossil group,conodont becomes more and more important in the divisions of biostratigraphy. The Triassic conodont biozones in China have reached 50 biozones,and could be increased more in the future,especially in the Upper Triassic. Stage is a global chronological unit,it should be used globally,with uniform name and definition. It should not be established based on country,lithological facies or biogroup.Terrestrial strata are not suitable for establishing stage,the terrestrial chronostratigraphic stage names should be abandoned.