从常规体系域到非常规体系域——河流相层序地层学研究的一个重要进展

From Conventional Systems Tracts to Unconventional Systems Tracts:An Important Progress of Fluvial Sequence Stratigraphy Research

在与海平面变化存在联系的近滨线河流相地层中,源于海岸碎屑沉积体系的层序地层学概念得到了较好的应用,从而在河流相地层中产生了低水位体系域(LST)、与海侵体系域类似的水进体系域(TST)及高水位体系域(HST)等常规体系域下的河流相层序地层划分方案。由于源于海岸沉积体系的早期体系域划分存在着概念体系的不协调,故常规体系域划分在河流相层序中的使用也就存在着概念体系的不协调。非常规体系域(低可容纳空间体系域,LAST;高可容纳空间体系域,HAST)的提出可避免这种概念体系的不协调,并为研究复杂的河流沉积过程和提取地层记录规律提供重要的线索和思路。

The sequence stratigraphy which originates from the shoreline siliciclastic sedimentary environment has been used in the fluvial strata which have a link with the sea level changes. It results in forming the conventional systems tracts models of fluvial sequence which include lowstand systems tract（LST） and transgressive systems tract（TST） and high- stand systems tract（HST）. With deep research in the inland sedimentary environments which have not correlated with the sea level changes, the early division of fluvial sequence that is used in the shoreline sedimentary systems tracts is incon- sistent, so the concept of low- and high-accommodation systems tracts （LAST and HAST）（unconventional systems tracts） is raised, which represents the latest research progress in fluvial sequence stratigraphy. The concept convert from conventional systems tracts to unconventional systems tracts will provide important clues and ideas for studying complex fluvial deposition process and extracting stratigraphic record rules.