强制性水退与不整合的关系--以松辽盆地长垣以西地区姚一段地层为例

Forced regression of Talaha in the north of Sonliao basin

在分析松辽盆地长垣以西地区姚一段三级层序(SQ1)、体系域及准层序组特征的基础上,分析了强制性水退沉积模式下姚一段内部地层及其与下伏青山口地层的接触关系.结果表明:长垣以西地区姚一段地层在强制性水退背景下形成,低位域内3个准层序组逐渐向盆地进积,滨岸线向盆地中心迁移;在强制性水退机制作用下形成的侵蚀不整合面穿时性强,姚一段地层与青山口地层之间在滨线坡折带之上为侵蚀不整合,在滨线坡折带之下为整合接触;在滨线坡折带之下姚一段地层内部水进域与低位域之间存在局部侵蚀不整合.

Based on the systematic research of characteristics of K1y1 Ⅲ SQ1, system domain and meta SQ in the west of placanticline of Songliao Basin, contact relationship of inner formation of K1y1, which deposited under the forced regression, and K1q is analyzed. It’s considered that the formation of K1y1 is formed at the background of forced regression, three meta SQ of low order domain gradually pregraded to basin while shoreline migrated to the center of basin; the erosion unconformity which formed under the forced regression has strong diachroneity, formation of K1y1 and K1q is erosion unconformity above shoreline break zone and conformity contact below shoreline break zone, and local erosion unconformity exist between water ingressed domain and low order domain in inner formation of K1y1 below shoreline break zone.