摘要： 本文从层序地层学和沉积动力学角度, 对西昌复合盆地进行了初步的研究。西昌复合盆地在不同地质演化阶段具有不同的大地构造属性, 在区域上表现为不同区块具有不同的层序成因格架, 显示典型的纵向叠加、横向复合的复式特点。盆地层序充填序列包括2个超层序、5个巨层序、8个一级层序、14个二级层序、76个三级层序以及若干个次一级层序,分别代表2个、5个、8个、14个、76个和若干个相应周期的海(湖)平面变化产物。盆地形成和发展受特提斯洋张力和不同块体边缘聚力的复合控制, 其演化经历了褶皱基底固结、被动边缘海盆发展、陆内盆地改造三大阶段,具体包括造山裂谷(Z₁)、初始被动边缘(Z₂)、稳定被动边缘(∈—P₂)、边缘热隆—拉裂 (P₃)、残余海盆(T₁—T₂)、周缘前陆(T₃—J₁)、陆内坳陷(-J₂—K₁)、挤压改造(K₂—E₁) 8个不同时期。

关键词: 西昌复合盆地, 层序充填序列, 沉积动力演化

Abstract: This paper, in terms of sequence stratigraphy and sedimentary dynamics, deals with sequence filling succession and sedimentary dynamic evolution of Xichang Compound Basin. The authors suggest that this basin possesses different tectonic nature during different geological evolution, and different genetic framework within different areas, revealing a typical composite characteristic of superposition in vertical and complex in horizontal. The sequence filling succession includes 2 supper-sequences, 5 mega sequences, 8 1st order sequences, 14 2nd order sequences, 76 3nd order sequences and lots of next hierarchy sequences, suggesting corresponding sea (lake) level changes with the same amount and cycles, respectively. Its formation and evolution are controlled by both tensile forces deduced from Tethyan plate and converging force from assembling among various plates. Its evolution underwent 3 stages, i e. fold base formation, passive marginal development and intracontinental reworking, includes orogenic rifting(Z₁), passive continental margin(∈—P₂), mantle budge and tension (P₃), residual sea basin (T₁—2), foreland basin(T₃—J₁), intracontinental depression, (J₂—K₁) and extrusion reworking (K₂—E₁) stages.

Key words: Xichang Compound Basin, sequence filling succession, sedimentary dynamic evolution

中图分类号: 

• F582