摘要
不整合面作为层序界面,是经典层序地层学派的基本观点,对沉积盆地层序地层格架的建立具有不可替代的作用。但对高频层序分析而言,由于三维空间中沉积作用的连续性、不整合面分布的局限性,以及不整合面并不是一个严格意义上的等时面。因此以不整合面作为层序界面具有明显的局限性。由此在高分辨率层序地层分析中,引入了"转换面"的概念。转换面包含两层意思,一是基准面由上升变为下降或由下降变为上升的转换,一是由于基准面的升降转换所引起的沉积作用的转换。转换面可分为两大类,基准面由下降变为上升的转换面,包括不整合面、顶超面及进积与退积转换面;基准面由上升变为下降的转换面,主要为洪泛面。作者探讨了顶超面、进积与退积作用的转换面和洪泛面的特征及层序意义。"转换面"概念的提出对高频层序(如四级、五级层序)划分具有重要的意义,使层序地层理论与分析方法能更有效地应用于油气勘探与开发实践。以济阳坳陷博兴洼陷沙三段的辫状三角洲-滑塌浊积扇体系为例,通过内部转换面的识别,将沙三段划分为4个长期旋回和8个中期旋回,并以此为基础,建立了研究区较高精度的层序地层格架。
It is the basic view of traditional sequence stratigraphy （Vail sequence） to take unconformity as sequence boundary. For high-frequency sequence analysis, it is obviously limited if only taking unconformity as sequence boundary due to the continuity of sedimentary process, limitations of unconformity distribution and uniformity is not a rigorous isochronous surface. So ＂Turnaround Surface＂ is introduced to high-resolution sequence stratigraphy. ＂Turnaround Surface＂ has two implications： one is turnaround surface of base-level rise and base-level fall, the other is turnaround surface of sedimentation due to base-level rise and base-level fall.Turnaround surfaces are classified into two types., one which are usually presented as unconformity, top-lap is base-level fall to base-level rise turnaround surface, surface and progradation to retrogradation turnaround surface; another is base-level rise to base-level fall turnaround surface, which are usually presented as flooding surface. The implications of all these surfaces are discussed in detail. The presentation of ＂Turnaround Surface＂ is of significance to high-frequency sequence （4th and 5th order sequence） division, which promote the application of sequence stratigraphy in oil and gas exploration and development. A case study is from delta to turbidite depositional system of 3rd member of Shahejie Formation, Boxing sub-depression of Jiyang sag. Through recognition of turnaround surface, four large-scale cycles and eight intermediate-scale cycles are divided in 3rd member of Shahejie Formation. Based on above division and correlation of wells and seismics, the higher resolution sequence framework is formed.
出处
《地学前缘》
EI
CAS
CSCD
北大核心
2008年第2期35-42,共8页
Earth Science Frontiers
基金
国家自然科学基金资助项目(40672078)
关键词
转换面
基准面
不整合面
层序地层
turnaround surface
base-level
unconformity
sequence stratigraphy
