准层序、岩性变换带在陆相红盆中的应用——以民和盆地1∶5万红古城、新寺乡幅的白垩纪地层为例

Applications of parasequences and lithologic zones to continental red basins:an example from the Cretaceous strata in the Honggucheng and Xinsixiang regions of the Minhe Basin

关键词:  陆相红盆  准层序组  岩性变换带  民和盆地  下白垩统

Key words:  continental red basin  parasequence set  lithologic zone  Minhe Basin  Lower Cretaceous

摘要:

陆相红盆与海相盆地在层序地层的基本单元和沉积作用等方面存在巨大差异。层序地层的基本概念、基本理论具体在陆相盆地中的应用,应紧密结合陆相盆地自身的发育特点,创造出一套真正适合于陆相盆地层序地层学的概念和模式。
陆相地层与海相地层相比规律性不明显,"层板对比"模式不适合陆相盆地地层分布实际。
准层序和岩性变换带的使用,是根据内陆红盆层序地层发育的自身特点,通过民和盆地白垩纪地层工作实践而提出的。它可以揭示陆相红盆层序地层的主控因素,把横向无序变为与成因相关的同期有序地层,使陆相层序、区域地层划分对比的研究不但可能,而且十分有效。

Abstract:

There are gaps in basic units of sequence stratigraphy and sedimentation in both continental red basins and marine basins.The continental strata are always vertically persistent,but inextensive laterally.In this respect,the "strata-plate correlation" model should not be adaptable to continental strata.Caution should be exercised in the application of the fund-mental concepts and theories about sequence stratigraphy of marine strata to continental strata. A parasequence is a relatively conformable succession of genetically related beds or bedsets bounded by marine-flooding surfaces and their correlative surfaces.It represents several stages of initiation,culmination and waning of fluvial event deposition,and therefore may act as a basic element of a parasequence set.A parasequence set is a succession of genetically related parasequences which form a distinctive stacking pattern that is bounded,in many cases,by major marine-flooding surface and their correlative surfaces.Its tectonic settings and sedimentation always remain unchanged throughout an event cycle.The study of the Cretaceous strata in the Honggucheng and Xinsixiang regions of the Minhe Basin was conducted with the aid of parasequences,parasequence sets and lithologic zones,which may make it possible to study the horizontally separated strata in the division and correlation of regional strata in continental basins.