摘要:
在对研究区不同相带内典型剖面详细观测、层序界面识别基础上,将区内下、中三叠统划分出六个三级层序,分别命名为S1 ～S6,其中下三叠统印度阶一个 (S1 )、奥伦尼阶两个 (S2 ～S3),中三叠统安尼阶两个 (S4～S5)、拉丁阶一个 (S6),从年代地层考虑早三叠延续时限为 3.9Ma,则S1 、S2 、S3层序延续的时限平均为 1.3Ma。中三叠统延续的时限为 6.1Ma,则S4、S5、S6 层序所延续的时限平均分别为 2.0 3Ma。按层序底面性质可分出 4个Ⅰ型层序 (S2 、S3、S4、S5)和 2个Ⅱ型层序 (S1 、S6),并进行了区域层序对比,进而建立了区内下、中三叠统层序地层格架模型,详细讨论了各层序的次级组成单元 (体系域 )的几何形态和相互关系随时间的迁移所发生的相应变化。
Abstract:
The study area included Sichuan,Yunnan,Guizhou and Guangxi, there, the strata of lower and middle Triassic are widely distributed and well dev eloped, it is one of important areas can be used to study the sequence division, correlation and framework of Triassic system. Therefore, the paper based on th esequence stratigraphy theory, discussed in detail the characteristics of thes equence boundary surface which included uncomformity surface, lithologic-charac ter and facies change surface, karst surface and errosion surface, etc. Among them, the uncomformlty surface, errosion surface and karst surface are type-Ⅰ bo undary surface, and lithologic-character and facies change surface are type-Ⅱ boundany surfaces. Based on the above, the paper divided lower and middle Triassic into six third order seauences, which are namedas S The study area included Sichuan,Yunnan,Guizhou and Guangxi, the re, the strata of lower and middle Triassic are widely distributed and well dev eloped, it is one of important areas can be used to study the sequence division, correlation and framework of Triassic system. Therefore, the paper based on th e sequence stratigraphy theory, discussed in detail the characteristics of the s equence boundary surface which included uncomformity surface, lithologic-charac ter and facies change surface, karst surface and errosion surface, etc. Among th em, the uncomformlty surface, errosion surface and karst surface are type-Ⅰ bo undary surface, and lithologic-character and facies change surface are type-Ⅱ boundany surfaces. Based on the above, the paper divided lower and middle Triassic into six third order seauences, which are namedas S1 to S6, In the view of geologic time, it is known that early Triassic period prolonged 3.9 Ma, S0 S1,S2 and S3 prolonged 1.3 Ma respectively, and middle Tras sic period prolonged 6.1 Ma, S4,S5 and S6 prolonged 2.03 Ma respectively. From the point of sequence boundary surface characteristics, S2,S3,S4 and S5 are type-Ⅰ sequences, and S1 and S6 are type-Ⅱ sequences. The n the paper correlated each sequence from the study area, and built the sequence stratigraphy framework of lower and middle Triassic which showed the evolution of patterns and their relationship of different system tract.1 to S6, In the view of geologic time, it is known that early Triassic period prolonged 3.9 Ma, S0 S1,S2 and S3 prolonged 1.3 Ma respectively, and middle Tras sic period prolonged 6.1 Ma, S4,S5 and S6 prolonged 2.03 Ma respectively. From the point of sequence boundary surface characteristics, S2,S3,S4 a nd S5 are type-Ⅰ sequences, and S1 and S6 are type-Ⅱ sequences. The n the paper correlated each sequence from the study area, and built the sequence stratigraphy framework of lower and middle Triassic which showed the evolution of patterns and their relationship of different system tract.
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