云南金平及其邻区泥盆纪层序地层及其油气意义初探

DEVONIAN SEQUENCE STRATIGRAPHY IN JINPING AND ITS ADJACENT AREAS,YUNNAN

本文通过对云南金平、大理和蒙自地区泥盆纪露头层序地层学的初步研究,识别出该区的泥盆纪层序地层和沉积体系域。金平地区为Ⅱ类层序地层,自下而上为海侵体系域,凝缩段,高水位体系域;大理地区为不完整的Ⅱ类层序地层,自下而上仅见海侵体系域,凝缩段;蒙自-广南地区为Ⅰ类层序地层,自下而上为低水位体系域,海侵体系域,凝缩段,高水位体系域。该区泥盆纪不同时期的海平面变化曲线与全球泥盆纪陆棚沉积环境海平面变化曲线总体趋势基本一致。

The Devonian sequence stratigraphy and system tracts of the Jinping,Dali and Mengzi areas, Yunnan have been recognized through a primary study on the Devonian outcrop sequence stratigraphy in these areas.Devonian strata in Jinping are marked by sequence type Ⅱ,which may be divided in ascending order into the transgressive system tract,condensed section and highstand system tract.Devonian strata in Dali are represented by incomplete sequence type Ⅱ, which is divisible in ascending order into the transgressive system tract and condensed section only. Devonian strata in the Mengzi—Guangnan are marked by sequence type Ⅰ,which consists in ascending order of the lowerstand system tract,transgressive system tract,condensed section, highstand system tract and condensed section.The sea level change curves in varied epochs of the Devonian are given,which are essentially in accord with the global sea level change curves of Devonian shelf sedimentary environments.