四川龙门山中段泥盆纪层序地层

Devonian sequence stratigraphy of central Longmen Mountains, Sichuan

关键词:  龙门山中段  飞来峰  泥盆纪  层序地层  地层格架  沉积环境

Key words:  central Longmen Mountains  klippe  Devonian  sequence stratigraphy  stratigraphic framework  sedimentary environment

摘要:

龙门山中段白石-苟家地区泥盆纪地层十分发育。根据多条剖面的岩石特征、基本层序、生态环境等所反映的相对海平面变化规律,将区内以泥盆纪为主的沉积地层划分为九个层序,并归之于4个层序组。详细分析了每个层序各体系域的特征并建立了层序地层格架。区内泥盆系总体为一套向上变浅的沉积层序,埃姆斯早期存在深水盆地环境,中泥盆世早期盆地呈西深东浅的沉积构造格局。

Abstract:

The Devonian strata are well developed in the Baishi-Goujia region of central Longmen Mountains,Sichuan. Nine sequences which may be assigned to four sequence sets have been distinguished in the light of relative sea-level changes based on lithology, sequence stratigraphy, ecology. The individual systems tracts of each sequence are discussed in detail, and sequence stratigraphic framework of Devonian to Early Carboniferous is constructed for the study area. The Devonian strata in this region generally exhibits a succession of shallowing-upward sedimentary sequence, indicating a deep-water basin environment during the early Emsian(Early Devonian), and still a deep-water sedimentary envi-ronment in the west but a shallower-water sedimentary environment in the east during the early Middle Devonian.